Item 1. Business.

Overview

At Erasca, our name is our mission: to erase cancer.

We are a clinical-stage precision oncology company singularly focused on discovering, developing, and commercializing therapies for patients with RAS/MAPK pathway-driven cancers. Molecular alterations in RAS, the most frequently mutated oncogene, and the MAPK pathway, one of the most frequently altered signaling pathways in cancer, account for approximately 5.5 million new patients diagnosed with cancer globally each year. Our company was co-founded by leading pioneers in precision oncology and RAS targeting to create novel therapies and combination regimens designed to comprehensively shut down the RAS/MAPK pathway for the treatment of cancer. We have assembled what we believe to be the deepest, wholly-owned or controlled RAS/MAPK pathway-focused pipeline in the industry, comprising 11 modality-agnostic programs aligned with our three therapeutic strategies of: (1) targeting key upstream and downstream signaling nodes in the RAS/MAPK pathway; (2) targeting RAS directly; and (3) targeting escape routes that emerge in response to treatment. The target breadth and molecular diversity represented in our pipeline enable us to pursue a systematic, data-driven clinical development effort to identify single agent and combination approaches with the goal of prolonging survival in numerous patient populations with high unmet medical needs.

Our modality-agnostic approach aims to allow us to selectively and potently inhibit or degrade critical signaling nodes with small molecule therapeutics, large molecule therapeutics, and protein degraders. Our purpose-built pipeline includes three clinical-stage programs (ERK and SHP2 inhibitors, which together comprise our first, innovative MAPKlamp, and an EGFR inhibitor), one preclinical-stage program (CNS-penetrant KRAS G12C inhibitor), and seven discovery-stage programs targeting other key oncogenic drivers. In 2023, we expect to have four product candidates in the clinic. In addition, we expect to file an additional investigational new drug application (IND) every 12-18 months through 2026. We believe our world-class team’s capabilities and experience, further guided by our scientific advisory board (SAB), which includes the world’s leading experts in the RAS/MAPK pathway, uniquely position us to achieve our bold mission of erasing cancer.

Of the approximately 5.5 million new patients diagnosed globally per year with cancers driven by RAS/MAPK pathway molecular alterations, over 90% have limited or no treatment options. While the RAS/MAPK pathway has been well characterized and validated based on multiple compounds approved or in development targeting discrete signaling nodes in the cascade, most of these compounds face resistance and tolerability challenges, highlighting the need for new approaches to target this pathway. We believe that to effectively shut down a pathway that signals as promiscuously as RAS/MAPK, a holistic approach must be taken to target not just individual nodes, but multiple nodes and cooperative mechanisms in parallel. As depicted in the following figure and described below, we are pursuing three therapeutic strategies that may be used in combination with the goal of comprehensively, and perhaps synergistically, shutting down the RAS/MAPK pathway.

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To pursue these therapeutic strategies, we have assembled and are developing what we believe is the deepest pipeline targeting multiple signaling nodes to shut down the RAS/MAPK pathway. We intend to study these agents either alone or in rational combinations across multiple relevant tumor types. The following table summarizes our current, wholly-owned or controlled, modality-agnostic pipeline to eradicate RAS/MAPK pathway-driven cancers, and programs that arise from an investment made by Erasca Ventures, LLC (Erasca Ventures) in a third party.

Our lead product candidates are ERAS-007 (our oral ERK1/2 inhibitor) and ERAS-601 (our oral SHP2 inhibitor), which together comprise our first MAPKlamp. The extracellular signal-regulated kinases (ERK), ERK1 and ERK2, belong to a family of serine-threonine kinases that regulate cellular signaling, and comprise the terminal node of the RAS/MAPK pathway. ERK proteins propagate signaling for multiple cellular functions involved in cell growth and differentiation, which are often overactivated in RAS/MAPK pathway-driven cancers. We in-licensed ERAS-007 from Asana BioSciences (Asana) based in part on preclinical studies that demonstrated the highest potency and longest target residence time of ERK inhibitors of which we are aware. ERAS-007 has been evaluated as a single agent in a Phase 1 clinical trial in patients with advanced solid tumors completed by Asana. Forty-nine patients were enrolled and administered ERAS-007 once a day (QD) or once weekly (QW). Objective responses have been observed at doses from 120 mg to 250 mg QW in multiple tumor types (melanoma, salivary gland tumor, non-small cell lung cancer [NSCLC], and thyroid cancer) that all harbor alterations (BRAF, HRAS, and NRAS) in the RAS/MAPK pathway, supporting the development of ERAS-007 QW as a monotherapy or combination therapy in diverse, biomarker-selected tumor types. In this trial, ERAS-007 demonstrated a reversible and manageable adverse event profile.

We are pursuing a broad clinical development plan across multiple tumor types for ERAS-007, which we refer to as our HERKULES series of clinical trials, that will include both monotherapy and combinations with approved and investigational agents, such as RTK, SHP2, RAS, and/or RAF inhibitors. The first four HERKULES Phase 1b/2 proof-of-concept (POC) clinical trials are exploring both tissue agnostic and tissue specific indications in patients with solid tumors and hematologic malignancies, including NSCLC, colorectal cancer (CRC), and acute myeloid leukemia (AML). In May 2021, we dosed the first patient in HERKULES-1, a Phase 1b/2 clinical trial evaluating ERAS-007 as a single agent and in combination with ERAS-601 (our first MAPKlamp) in advanced solid tumors. In September 2021, we dosed the first patient in HERKULES-2, a Phase 1b/2 master protocol clinical trial for ERAS-007 and/or ERAS-601 in combination with various agents in patients with NSCLC. In September 2021, we dosed the first patient in HERKULES-3, a Phase 1b/2

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master protocol clinical trial for ERAS-007 in combination with various agents in patients with GI cancers, with an initial focus on advanced CRC. In September 2021, we announced a clinical trial collaboration and supply agreement with Pfizer Inc. (Pfizer) in connection with the HERKULES-3 trial. Under the terms of the collaboration, we are sponsoring and funding the clinical trial and Pfizer is providing its BRAF inhibitor, encorafenib (BRAFTOVI), at no cost. Additionally, in March 2022, we announced a clinical trial collaboration and supply agreement with Eli Lilly and Co. (Lilly) in connection with the HERKULES-3 trial. Under the terms of the collaboration, we are sponsoring and funding the clinical trial and Lilly is providing its EGFR antibody, cetuximab (ERBITUX), at no cost. Finally, we anticipate dosing the first patient in HERKULES-4, a Phase 1b/2 master protocol clinical trial for ERAS-007 and/or ERAS-601 in combination with various agents in patients with hematologic malignancies. The master protocols for each of the HERKULES-2, -3 and -4 Phase 1b/2 clinical trials provide the flexibility to explore additional combinations and expand into other NSCLC, GI cancer and hematological malignancy indications, respectively. While providing POC data, these trials may be expanded to enable potential accelerated approvals in their respective indications.

The second prong of our first MAPKlamp approach, ERAS-601, is designed to be a potent and selective oral inhibitor of SHP2, a convergent node for upstream RTK signaling and a critical “on/off switch” that activates RAS-GTP signaling. SHP2 also drives tumor cell proliferation and development of resistance. ERAS-601 is designed to block oncogenic signal transduction and delay the onset of therapeutic resistance, and thereby serve as a backbone of combination therapy. In the fourth quarter of 2020, we dosed the first patient in FLAGSHP-1, a Phase 1 clinical trial for ERAS-601 in patients with advanced solid tumors.

In February 2022, we dosed the first patient in our THUNDERBBOLT-1 Phase 1 clinical trial for ERAS-801, our CNS-penetrant EGFR inhibitor, in patients with recurrent glioblastoma multiforme (GBM). In the second half of 2022, we expect to file an IND with the US Food and Drug Administration (FDA) for ERAS-3490, the development candidate (DevCan) we nominated from our CNS-penetrant KRAS G12C inhibitor program. We are also advancing seven other programs targeting key oncogenic drivers in the RAS/MAPK pathway, which we will need to successfully progress through discovery and IND-enabling activities prior to advancing these programs into clinical development, if at all.

Our core values, team, and social mission

We are a team of experienced drug discoverers, developers, and company builders who are united by our mission to erase cancer and passionate about creating potentially life-saving precision oncology medicines singularly focused on targeting the RAS/MAPK pathway. Our leadership team has broad and deep experience in oncology, including advancing therapeutic candidates from discovery research to clinical development, regulatory approval, and commercialization. Our core values are embodied by our quest for the CURE:

Dr. Jonathan Lim, our Chairman, CEO, and Co-Founder, has pioneered transformative advancements in precision oncology and drug delivery, including leading Ignyta’s trailblazing pursuit of a global tissue agnostic label for ROZLYTREK, which became the first drug in biopharmaceutical history to achieve the unprecedented triple crown of breakthrough designations with BTD (FDA), PRIME (EMA) and Sakigake (PMDA). He has served as Chairman and/or CEO and founding investor of six biotechnology companies that have collectively achieved global regulatory approval and launch of seven therapeutic products in oncology, immunology, and drug delivery, benefitting thousands of patients worldwide.

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Dr. Michael Varney, our Chair of R&D, SAB member, and a member of our board of directors, is a pioneer drug discoverer and biotech leader. His leadership at Agouron resulted in the discovery of multiple currently marketed anti-cancer agents, including XALKORI and INLYTA. As Executive Vice President and Head of Genentech’s Research and Early Development (gRED) and a member of the Roche Corporate Executive Committee, he was responsible for all aspects of gRED innovation, drug discovery and development, and built a team-based organization that today contributes to more than 40% of Genentech’s development portfolio, including the marketed anti-cancer agents ERIVEDGE and COTELLIC. Under his leadership, gRED teams discovered and developed successful medicines that include VENCLEXTA with AbbVie, the first BCL-2 inhibitor, and POLIVY, an antibody drug conjugate for the treatment of diffuse large B-cell lymphoma (DLBCL).

Dr. Wei Lin, our Chief Medical Officer, was responsible for all development functions and the clinical development of Nektar’s pipeline, including advancing bempegaldesleukin into multiple registrational trials and achieving FDA breakthrough therapy designation in metastatic melanoma. Prior to Nektar, Dr. Lin was the global development lead in cancer immunotherapy for lung cancer and head and neck cancer at Roche/Genentech. Under his leadership, his team oversaw 10 registrational studies, completed five positive Phase 3 trials, and achieved three US and EU regulatory approvals for TECENTRIQ, including the first advancement in first-line small cell lung cancer in three decades. He was also the site head for oncology product development for Roche China, where his team achieved multiple additional regulatory approvals for AVASTIN, ZELBORAF, and TARCEVA.

Dr. David Chacko, our Chief Financial Officer, joined us initially as Chief Business Officer from Versant Ventures, where he was a Principal with both investing and operating responsibilities. He helped lead investment opportunities across multiple therapeutic areas and advanced several Versant portfolio companies operationally through company formation, fundraising, corporate and business development, and clinical and regulatory activities. His prior roles at Alcon/Novartis, McKinsey, SR One, and Morgan Stanley bring to Erasca deep experience in strategy, finance, fundraising, business development, and operations.

Many members of our leadership team have worked together previously at Ignyta or Roche/Genentech, or have joined us from other leading companies in the biopharmaceutical and life science tools sectors such as Aragon, Illumina, Lilly, Medivation, Merck, Myovant, Neurocrine, Pfizer, Seragon, Synthorx, and Turning Point, and have worked on numerous oncology drugs that have been approved and launched for the benefit of patients.

Dr. Lim founded Erasca with Dr. Kevan Shokat (Professor and Chair of the Department of Cellular and Molecular Pharmacology at UCSF; Professor of Chemistry at the University of California, Berkeley; and an investigator at the Howard Hughes Medical Institute), who sits on our SAB with other RAS/MAPK pathway experts:

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At Erasca, while our mission to erase cancer inspires us, we know we can do more to make an even broader contribution to society. To that end, we are pursuing environmental, social, and governance (ESG) initiatives that are aligned with our core mission.

Our corporate strategies to erase cancer

Our mission is to erase cancer by eradicating RAS/MAPK pathway-driven cancers. Our corporate strategies to achieve our mission include:

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Our singular focus on the RAS/MAPK pathway

Background

The RAS/MAPK pathway is one of the most frequently altered signaling pathways in cancer. Molecular alterations in key signaling nodes within the RAS/MAPK pathway have been shown to drive cell proliferation across a wide range of tumor types. As described further below, our wholly-owned or controlled pipeline targets all of the key signaling nodes colored in purple, either directly or indirectly as single agents and in combination in order to prolong survival in a wide range of patient populations.

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EGFR/FLT3

EGFR and FLT3 are RTKs, which are proteins that are embedded in the cell membrane and relay growth signals from the outside environment to the cell’s internal machinery. At rest, these proteins reside on the cell membrane as inactive monomers. Growth factors secreted by nearby cells bind to specific RTKs, such as growth factor EGF binding to EGFR and FL binding to FLT3, and cause these RTKs to dimerize. Dimerized RTKs activate one another through transphosphorylation of their intracellular regions. Intracellular proteins, such as adapter proteins, bind to these phosphorylated regions and propagate the pro-growth signals within the cell via one or more signaling pathways. Cells express a variety of RTKs so that environmental cues can be relayed to specific cell populations in specific contexts. EGFR mediates pro-growth signaling in skin and in the ducts and outer surfaces of many organs. FLT3 predominantly mediates pro-growth signaling in immature blood cells.

Overactive RTK signaling can result in uncontrolled cell growth and survival that transforms normal cells into cancer cells.

SHP2

SHP2 is a protein tyrosine phosphatase and a key positive regulator of the growth signals from the RTK growth factor receptors to the intracellular signaling pathways (including RAS/MAPK and PI3K) that promote growth and survival of normal cells and cancer cells. As such, SHP2 is a convergent node for upstream RTK signaling: activated SHP2 upregulates (“turns up”) the positive signals and downregulates (“turns down”) the negative signals in the signaling cascades. SHP2 also serves as a central node in relaying the growth and survival signals from RTKs such as EGFR and FLT3 to RAS/MAPK and other intracellular pathways. SHP2 is an attractive target because SHP2 inhibition ubiquitously blocks the growth signals from multiple RTKs, preventing cancer cells from bypassing the blockade on a specific RTK (e.g., EGFR inhibitor) through activation of other RTK growth factor receptors (e.g., MET).

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SOS1

SOS1, or Son of Sevenless-1, is a protein that is recruited to RTK complexes and, in turn, recruits and activates members of the RAS protein family. SOS1 activates RAS proteins by acting as a guanine nucleotide exchange factor (GEF), which facilitates the exchange of the RAS-bound nucleotide from guanine diphosphate (GDP) to guanine triphosphate (GTP). When GDP is exchanged for GTP, RAS adopts an active conformation that enables it to bind and activate downstream effector proteins, such as the RAF family, which ultimately results in RAS/MAPK pathway activation.

NF1

NF1, or neurofibromin, is a protein that accelerates the transition of RAS proteins from the active RAS-GTP state to the inactive RAS-GDP state. NF1 is classified as a GTPase activating protein (GAP) because it boosts the ability of RAS to hydrolyze bound GTP to GDP. Although RAS can autonomously hydrolyze GTP, it is dependent on GAPs such as NF1 to rapidly cycle it from the active state to the inactive state and thereby prevent overactive signaling. If NF1 is inactivated due to a mutation (NF1 loss-of-function mutation), RAS proteins may spend more time in the active RAS-GTP state. This can result in hyperactive RAS/MAPK pathway activation that drives aberrant cell growth and ultimately tumorigenesis. This is observed in patients affected by a genetic disorder caused by somatic mutations in the NF1 gene called neurofibromatosis type 1. NF1 loss-of-function mutations are observed in a variety of cancers, including melanoma and CRC, where they activate RAS/MAPK signaling alone or in conjunction with other RAS/MAPK pathway activating mutations.

RAS

RAS proteins are ubiquitously expressed GTPase proteins. The RAS protein family consists of KRAS, NRAS, and HRAS proteins and acts as the entry node in the MAPK signaling pathway. KRAS is the most abundantly expressed RAS protein followed by NRAS and then HRAS. RAS proteins act as signaling transducers since they are recruited to activated RTK complexes where they are converted into an active conformation (RAS-GTP) that enables them to activate downstream effector proteins, such as RAF proteins. The activation state of a RAS protein is dictated by the phosphorylation state of the bound guanosine: RAS adopts an inactive RAS-GDP conformation when bound to GDP and an active RAS-GTP conformation when bound to GTP. Conversion of RAS into an active conformation is mediated by binding to co-factor proteins, e.g., SOS1, and these co-factor proteins enable the exchange of the RAS-bound nucleotide from GDP to GTP. In the active state, RAS-GTP proteins interact with multiple effector proteins to propagate cell signaling through multiple pathways. For example, activated RAS-GTP proteins interact with RAF proteins to activate MAPK signaling, and PI3K proteins to activate PI3K pathway signaling. RAS can transition from the active state into the inactive state by hydrolyzing its bound nucleotide from GTP to GDP either intrinsically or catalyzed through interactions with co-factor proteins, such as NF1. RAS proteins are the most frequently mutated oncoproteins in cancer. These mutations occur at hotspots, such as amino acid residues 12, 13, and 61, and these hotspot mutations impair RAS’s ability to hydrolyze GTP to GDP. As a result, mutant RAS-GTP remains in the active state for prolonged periods of time resulting in hyperactive stimulation of the RAS/MAPK and other pathways.

RAF

RAF proteins are ubiquitously expressed serine-threonine kinases that are a part of the RAS/MAPK pathway and whose activity is regulated by RAS proteins. The RAF protein family consists of ARAF, BRAF, and CRAF (RAF1). In the absence of activated RAS-GTP, RAF proteins assume an autoinhibited conformation in complex with downstream effector proteins, MEK1 and MEK2. RAF proteins can homodimerize (e.g., BRAF-BRAF dimers) or heterodimerize (e.g., CRAF-BRAF dimers). When RAF proteins bind to activated RAS-GTP, they adopt an active conformation that results in activation of their kinase domains. The activated kinase domains then phosphorylate complexed MEK proteins, activating those proteins and releasing them from the RAF-MEK complex. Activated MEK then signals further down the RAS/MAPK pathway. Mutations in RAF proteins, especially in BRAF, have been observed in many cancers, such as melanoma, CRC, NSCLC, and thyroid cancer. For example, the BRAF V600E mutation (a class I BRAF mutation) is frequently observed in melanoma and this mutation enables BRAF to constitutively activate MEK as a monomer. Approved BRAF inhibitors for class I mutations include vemurafenib, dabrafenib, and encorafenib. Class II BRAF mutations enable BRAF to constitutively dimerize and activate MEK. Class III BRAF mutations impair the ability of the mutant BRAF protein to phosphorylate MEK, but class III mutant BRAF proteins can aberrantly dimerize with wildtype RAF proteins and enable their dimerized wildtype RAF partners to activate MEK. To our knowledge, there are no approved inhibitors of BRAF Class II or Class III mutations. A number of inhibitors targeting BRAF Class II and Class III mutations, as well as pan-RAF inhibitors designed to disrupt wildtype RAF signaling, are in development; however, to our knowledge, none have received regulatory approval.

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MEK

MEK1 and MEK2 proteins are ubiquitously expressed serine-threonine kinases that are activated by RAF-mediated phosphorylation and signal downstream by activating ERK proteins. MEK1 and MEK2 proteins form complexes with RAF proteins in the inactive state and are recruited as a unit to activated RAS-GTP. RAS-GTP then activates the RAF-MEK complex by binding to RAF, which then activates MEK via phosphorylation and releases from the RAF-MEK complex. Activated MEK then selectively phosphorylates ERK1 and ERK2 proteins, which are the terminal nodes of the RAS/MAPK pathway. Currently approved MEK inhibitors, such as trametinib, binimetinib, cobimetinib, and selumetinib, allosterically bind MEK proteins and inhibit MEK activation, either as free proteins alone or in complex with RAF. The inhibition of RAS/MAPK signaling by MEK inhibitors can result in an upregulation of signaling upstream of MEK due to negative feedback loops within the RAS/MAPK pathway. This increased signaling pressure can overwhelm MEK inhibitors and result in reactivation of MAPK signaling. Most MEK inhibitors are approved in combination with a BRAF inhibitor partially due to their vulnerability of being overwhelmed by the reactivation of MAPK signaling. In this combination, BRAF inhibitors attenuate upstream signaling pressure on MEK inhibitors, and MEK inhibitors further limit downstream MAPK signaling not inhibited by the BRAF inhibitor.

ERK

The extracellular signal-regulated kinases (ERK), ERK1 and ERK2, are ubiquitous serine-threonine kinases that regulate cellular signaling in both physiological and pathological states and comprise the terminal node of the RAS/MAPK pathway. Once activated by MEK, ERK proteins phosphorylate thousands of downstream proteins, propagating RAS/MAPK signaling across multiple cellular functions. In contrast to currently approved allosteric MEK inhibitors, ERK inhibitors in development are ATP-competitive and as a result, their potency is robust against the activated state of ERK. Based on this property, ERK inhibitors potentially can overcome drug resistance mechanisms that involve reactivation of RAS/MAPK pathway signaling, such as a rebound of RAS/MAPK signaling resulting from the alleviation of negative feedback or an upstream RAS/MAPK pathway protein adopting an acquired resistance mutation.

ULK

Autophagy is a metabolic process that cells use to break down and recycle cellular components. This process enables cells to renew cellular components whose functions are impaired due to age or malfunction. Autophagy also serves as a survival mechanism in nutrient deprived conditions, enabling the cell to continue to synthesize critical cellular components. RAS-driven tumor cells reconfigure many of their metabolic processes, including autophagy, to better fuel their growth and survival. Autophagy can act as a resistance mechanism to RAS/MAPK pathway inhibitors by becoming constitutively active and enabling the cell to survive metabolic stresses induced by the inhibition of RAS/MAPK pathway signaling. ULK1 and ULK2 are serine-threonine kinases that control the initiation of autophagy, thereby acting as gatekeepers of autophagy. Combining a RAS/MAPK pathway inhibitor with an ULK1 and/or ULK2 inhibitor can potentially inhibit tumor growth by blocking upregulation of autophagy, a potential escape route or adaptive resistance mechanism to the RAS/MAPK pathway inhibitor.

MYC

The MYC protein (also known as c-MYC) is a transcription factor that regulates the transcription of hundreds of genes that are associated with cell growth. Transcription factors guide the cellular machinery to transcribe specific genes in the nucleus and those transcribed genes are then translated into proteins in the cytoplasm. Transcription factors are regulated by multiple signaling pathways, including RAS/MAPK, and they integrate this signaling information to transcribe genes in a context-dependent manner. Dimerization is required for MYC transcription factor activity and MYC’s most frequent dimerization partner is MAX. The activity of the MYC-MAX complex is largely driven by the concentration of MYC protein in the nucleus but other factors, such as the phosphorylation status of MYC, also regulate MYC activity. Given MYC’s critical role in regulating genes that drive cell growth, MYC function is dysregulated in 40% of cancers and MYC overexpression is the most frequent form of MYC dysregulation. MYC’s role as a transcription factor and not an enzyme has made the development of inhibitors targeting the MYC protein challenging. We believe inhibiting the transcription of MYC and/or MYC-agonists, such as MAX, offers a promising alternative therapeutic approach to reduce MYC activity in tumors where the traditional direct targeting of the MYC protein has failed. MYC and RAS are two of the most commonly dysregulated genes in human cancer and are also downstream effectors for a range of other oncogenic mutations in a variety of tumor types. MYC and RAS also frequently cooperate with each other in tumor development, heightening the urgency of targeting these two pivotal oncogenes.

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Our approach is focused on comprehensively silencing the RAS/MAPK pathway by targeting these key signaling nodes, from upstream RTKs to downstream nuclear transcription factors, which have been shown to drive cell proliferation across a wide range of tumor types.

Patient lives at stake annually with RAS/MAPK pathway alterations

At Erasca, we are on a bold mission to erase cancer. The journey will be long, and it won’t be easy. But patients with cancer are waiting, and we are eager to make new therapies available as soon as possible. Our mission will involve delivering new therapies to patients in markets where there are limited or no approved therapies, which are referred to as “blue oceans” (adapted from Blue Ocean Strategy by Chan Kim & Renée Mauborgne), as well as markets where there are already approved or soon to be approved product offerings, or “red oceans.” Of the approximately 5.5 million new patients diagnosed globally per year with cancers driven by RAS/MAPK pathway alterations, over 90% (approximately 5 million patients) are in blue oceans with limited or no treatment options. In the United States and Europe, there are over 1.8 million patients per annum who could be treated with the therapies we are seeking to develop and commercialize. In other parts of the world, we intend to explore partnerships in selected geographies to maximize the worldwide commercial potential of our programs.

Our therapeutic strategies for shutting down the RAS/MAPK pathway

We believe that to effectively shut down a pathway that signals as promiscuously as RAS/MAPK, a holistic approach must be taken to target not just single nodes, but multiple nodes and cooperative mechanisms in parallel. We believe our internally and externally sourced RAS/MAPK pathway-focused pipeline, comprising 11 targeted therapy programs, is the deepest in the industry. The target breadth and molecular diversity represented in our pipeline enable us to pursue a systematic, data-driven clinical development effort to identify single agent and combination approaches that aim to prolong survival in numerous patient populations with high unmet medical needs. We are pursuing three therapeutic strategies that may be used in combination with the goal of comprehensively, and perhaps synergistically, shutting down the RAS/MAPK pathway:

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Our strategic focus on the RAS/MAPK pathway allows us to comprehensively target every critical node in the pathway that could drive signaling. As shown in the figure below, our wholly-owned or controlled pipeline targets, either directly or indirectly, each of the signaling nodes colored in purple.

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Our innovation model

Due to the magnitude of the challenge of erasing cancer, we are combining our robust internal discovery and development capabilities with a global in-licensing and acquisition strategy to assemble the industry’s deepest, modality-agnostic RAS/MAPK pathway-focused pipeline. We believe these complementary approaches to innovation provide us with important optionality, both therapeutically and strategically, as we endeavor to bring forth the next generation of potentially differentiated targeted therapies for RAS/MAPK pathway-driven cancers.

Internal discovery and development

We have built a productive and efficient internal discovery engine at the heart of which lies SBDD, a key tool for the discovery of novel small molecule therapeutics and protein degraders by elucidating the three-dimensional structure of the potential drug molecule or degrader bound to the target protein of interest, allowing scientists to better understand and iterate on the structure-activity relationship of their hit and lead compounds or degraders. Three of our senior scientists were early pioneers in the use of SBDD while at Agouron Pharmaceuticals (now Pfizer), the first biotechnology company to use protein structure to inform medicinal chemistry for drug discovery: Dr. Dave Matthews, the scientific founder of Agouron, is our Senior Crystallography Advisor; Dr. Michael Varney, one of the original employees at Agouron who built the team that developed SBDD, is our Chair of R&D, SAB member, and a member of our board of directors; and Dr. Ping Chen, our Senior Director of Crystallography, was a member of Dr. Matthews’ structural biology team at Agouron, and joined us from Pfizer to lead our internal structural biology efforts which generates more than 100 protein structures annually to guide our discovery research.

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We use computational biology and computational chemistry to accelerate our discovery activities. We have standardized how we characterize our compounds across in vitro/vivo activity, drug distribution, metabolism, and pharmacokinetics (PK), structural, and secondary pharmacology assays, and centralized the storage of these data for automated analyses. These data are continuously reviewed by our scientific teams, and promising trends, including unpredicted ones that arise serendipitously, are prioritized for future exploration.

We supplement our medicinal chemistry efforts with fragment screens, including DNA encoded library (DEL) screens, to identify novel chemical matter with promising activity against targets of interest. These “hits” give us starting points for our early-stage drug discovery programs, and also provide opportunities to diversify molecular designs for later-stage discovery programs. DEL screens interrogate the binding of billions of compounds against our targets and increase the likelihood that we will discover a fragment that we can eventually transform into a potent therapy.

Based on our previous collective experiences at Ignyta, Roche/Genentech, Pfizer, and elsewhere, our team has extensive precision oncology expertise with dynamic clinical trial designs such as adaptive trials, biomarker-based basket and umbrella studies, and master protocols. We will continue to leverage this experience, in collaboration with industry and academic partners, in order to quickly demonstrate clinical proof-of-concept in a variety of tumor types for both single agent and combination approaches.

External sources of innovation

We believe innovation in cancer therapy is a collective, global endeavor unlikely to emerge from a single company or a single platform. There are exciting product candidates, technologies, and approaches in development worldwide, and our innovation model gives us the flexibility to supplement our internal efforts with externally sourced assets through collaboration, in-license, or acquisition. We also established Erasca Ventures, our wholly-owned subsidiary, in March 2021 to make equity investments in early-stage biotechnology companies that are aligned with our mission and strategy. In March 2022, Erasca Ventures made an equity investment in Affini-T Therapeutics, Inc. (Affini-T) to develop Affini-T’s potential best-in-class T-cell receptor (TCR) cell therapies targeting multiple oncogenic driver mutations, including KRAS G12V and KRAS G12D. To date, we have in-licensed or acquired novel therapies from multiple geographic regions, including our clinical-stage, oral ERK1/2 inhibitor, ERAS-007, which we acquired from Asana.

We leverage our extensive network of preferred relationships with our Scientific and Research & Development Advisory Boards, as well as leading institutional investors, investment banks, academic institutions, and biopharmaceutical companies that keep us apprised of assets of strategic interest. We pursue the best science in the world, regardless of its origin, and will continue to evaluate additional opportunities to strengthen and diversify our pipeline through academic and biopharmaceutical collaborations, in-licenses, acquisitions, and strategic investments that meet our high scientific bar and can help us advance our mission to erase cancer.

Modality-agnostic pipeline

Cancer is a complex, heterogeneous disease that is unlikely to succumb to a one-size-fits-all approach. We believe shutting down the RAS/MAPK pathway in cancer requires a systematic, data-driven approach to development, part of which involves choosing the most appropriate technology for the target of interest, or what we call a modality-agnostic approach. We therefore seek to understand the biology of the target of interest first, and then choose the therapeutic modality best suited to optimally inhibit or degrade that target. We are currently utilizing several modalities to target the RAS/MAPK pathway, including small molecule therapeutics, large molecule therapeutics, and protein degraders.

For example, we are developing protein degraders in addition to our internal small molecule discovery capabilities, including proteolysis targeting chimeras (PROTACs), as a complementary strategy to modulate RAS/MAPK pathway proteins of interest. PROTAC-mediated degradation is a viable option for attenuating oncogenic RAS/MAPK pathway levels and downstream signaling in cancer cells, by utilizing the body’s own natural disposal system to remove oncogenic proteins selectively and efficiently.

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Our pipeline

We have assembled what we believe is the deepest, wholly-owned or controlled RAS/MAPK pathway-focused pipeline in the industry, comprising 11 modality-agnostic programs aligned with our three therapeutic strategies of: (1) targeting key upstream and downstream signaling nodes in the RAS/MAPK pathway; (2) targeting RAS directly; and (3) targeting escape routes that emerge in response to treatment. The table below summarizes our current pipeline. We have exclusive worldwide development and commercial rights for all of our programs (excluding programs in our pipeline that arise from an investment made by Erasca Ventures in a third party).

Importantly, we believe the target breadth and molecular diversity represented in our pipeline enable us to pursue a systematic, data-driven clinical development effort to identify single agent and combination approaches designed to comprehensively shut down the RAS/MAPK pathway in a range of underserved cancer indications. The figure below illustrates the overlay between our current pipeline and several key nodes in the RAS/MAPK pathway that we believe are attractive targets for therapeutic intervention. Our pipeline also provides potential solutions for patients with limited or no treatments available by directly targeting with single agents and/or clamping with combinations, the various nodes of the RAS/MAPK pathway.

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MAPKlamp: our therapeutic strategy targeting proximal and terminal nodes of the RAS/MAPK pathway

Our first therapeutic strategy to erase cancer with various combinations is MAPKlamp, our novel approach targeting upstream and downstream nodes in the RAS/MAPK pathway designed to shut down, or clamp, the signaling of various oncogenic drivers, such as RTKs, NF1, RAS, RAF, and MEK alterations trapped in between any nodes involving this pathway. With our MAPKlamp approach, we aim to induce tumor regression in RAS/MAPK pathway-driven cancers, while also blocking the main escape routes that lead to tumor resistance.

Our lead product candidates are ERAS-007 (our oral ERK1/2 inhibitor) and ERAS-601 (our oral SHP2 inhibitor), which together comprise our first, innovative MAPKlamp approach. ERK and SHP2 are the convergent downstream and upstream nodes of the RAS/MAPK pathway, respectively. ERK proteins propagate signaling for multiple cellular functions involved in cell growth and differentiation, which are often overactivated in RAS/MAPK pathway-driven cancers. We believe that targeting ERK, the terminal node of the RAS/MAPK pathway, is preferable to targeting MEK because it is less prone to MAPK pathway reactivation, which leads to greater suppression of signaling. The second prong of our first MAPKlamp, ERAS-601, is a potent and selective oral inhibitor of SHP2, a critical “on/off switch” that activates RAS-GTP signaling. Our SHP2 inhibitor is designed to block oncogenic signal transduction and delay the onset of therapeutic resistance. Targeting either or both of these key nodes thereby has the potential to serve as a backbone of combination therapy against RAS/MAPK pathway altered cancers.

As our portfolio advances, we anticipate additional MAPKlamp combinations to emerge. Given the breadth of our pipeline, we believe we are the only company that has the therapeutic and strategic flexibility to comprehensively target every critical node in the RAS/MAPK pathway that could drive cancer signaling.

ERAS-007: our ERK inhibitor

ERAS-007 is designed to be a potent and selective oral inhibitor of ERK1/2. We in-licensed ERAS-007 from Asana based in part on preclinical studies that demonstrated the highest potency and longest target residence time of ERK inhibitors of which we are aware. In a Phase 1 clinical trial completed by Asana, ERAS-007 demonstrated single-agent activity including objective responses in tumors harboring RAS/MAPK pathway alterations and was well tolerated. We are pursuing a broad clinical development plan across multiple tumor types for ERAS-007, which we refer to as our HERKULES series of clinical trials, that will include both monotherapy and combinations with approved and investigational agents, such as RTK, SHP2, RAS, and/or RAF inhibitors. The first four HERKULES Phase 1b/2 clinical trials are exploring both tissue agnostic and tissue specific indications in patients with solid tumors and hematologic malignancies. We dosed the first patient in HERKULES-1 in May 2021 and the first patients in HERKULES-2 and HERKULES-3 in September 2021. We believe that as many as 4.5 million patients worldwide per year could benefit from ERAS-007 combinations that include MAPKlamp, including 4.0 million patients with blue ocean indications where there are currently limited or no approved therapies.

Preclinical profile of ERAS-007

Asana completed a series of preclinical studies to characterize the differentiated attributes, namely high potency and long target residence time, of ERAS-007 in vivo and in vitro. In multiple assays, ERAS-007 achieved potent, reversible, and ATP-competitive inhibition of ERK1 and ERK2 with a biochemical IC50 (a measure of 50% inhibition) against both ERK1 and ERK2 of 2 nM and cell-based mechanistic IC50 against pRSK of 7 nM. In addition, ERAS-007 exhibited long biochemical residence time while bound to ERK, which has been measured as 550 minutes against ERK2. This longer target residence time compared to other clinical-stage ERK inhibitors may allow for longer intervals between doses in patients.

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ERAS-007 IC50s against ERK1 and ERK2 were characterized in a biochemical kinase activity. Cell-based IC50 was characterized by the ability of ERAS-007 to inhibit ERK from phosphorylating one of its downstream targets, RSK1. pRSK represents RSK1 phosphorylation.

The biochemical binding properties of three clinical-stage ERK inhibitors shown as both the rate at which each inhibitor dissociates from ERK2 (koff) and the period of time that each ERK inhibitor binds ERK2 (residence time).

This biochemical potency has translated into strong anti-proliferative activity in cell lines with mutations in the RAS/MAPK pathway compared to other clinical-stage ERK inhibitor compounds. In 14 out of 14 cell lines that harbored activating RAS/MAPK pathway alterations, ERAS-007 exhibited potent activity with a less than 1 µM IC50. In two KRAS G12C cell lines, ERAS-007 showed greater potency compared to ulixertinib, an ERK inhibitor, comparable potency to binimetinib, a MEK inhibitor, and sotorasib, a KRAS G12C inhibitor. Cellular signaling studies demonstrated that ERAS-007 inhibited phosphorylation of downstream targets of ERK such as ribosomal S6 kinases (RSK), Fos-related antigen (FRA), and ETS domain-containing protein (ELK) in the BRAF V600E CRC HT-29 cell line. Demonstrating its selectivity, in seven out of eight cell lines that did not harbor any activating RAS/MAPK pathway alterations, ERAS-007 showed weak inhibition with a greater than 10 µM IC50. Together, these results suggest that ERAS-007 is a potent and selective ERK inhibitor with the ability to inhibit cell growth in multiple models of RAS/MAPK pathway-driven cancers relative to other agents used in these settings.

ERAS-007, ulixertinib and ravoxertinib were profiled in 3 BRAF mutant, 1 HRAS mutant, 8 KRAS mutant, 2 NRAS mutant, and 8 wildtype RAS and wildtype RAF cell lines. Nanomolar IC50 values are represented on the y-axis. Lower IC50s denote stronger activity.

ERAS-007 inhibits cell viability of two KRAS G12C mutant cell lines, pancreatic carcinoma MIA PaCa-2 and NSCLC NCI-H358, with higher potency than a clinical-stage ERK inhibitor, ulixertinib, and comparable potency to an approved MEK inhibitor, binimetinib, and an approved KRAS G12C inhibitor, sotorasib.

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Inhibition of signaling by kinases is typically achieved by either: (1) ATP-competitive inhibition whereby an inhibitor blocks ATP binding or (2) allosteric inhibition whereby an inhibitor does not block ATP binding but rather binds to a different region to prevent the kinase from signaling downstream. Currently approved MEK inhibitors, trametinib, binimetinib, selumetinib, and cobimetinib, are allosteric MEK inhibitors. A potential limitation of these allosteric MEK inhibitors is that they preferentially bind MEK in the inactive state and have weaker inhibitory activity against activated MEK proteins. Another limitation is that some MEK inhibitors preferentially disrupt activation via one RAF family member (e.g., BRAF) but not another (e.g., CRAF). Due to negative feedback regulation in the RAS/MAPK pathway, inhibition of downstream signaling nodes can result in RAS/MAPK pathway feedback reactivation that is mediated through multiple members of the RAF family. This increased upstream signaling pressure can serve as a resistance mechanism to MEK inhibitors and has been observed in the clinic. As an ATP-competitive ERK inhibitor, ERAS-007 has been shown to more robustly block RAS/MAPK pathway reactivation than allosteric MEK inhibitors. As shown in the figure below, ERAS-007 continuously inhibited downstream ERK activity in a KRAS G12C mutant CRC cell line, whereas the RAS/MAPK pathway was reactivated beginning as early as 24 hours after treatment with each of the three MEK inhibitors, which is illustrated with the emergence of the dark P-RSK bands (darker intensity equates to higher signaling or reactivation) in the following Western blots.

Western blot characterization of three MEK inhibitors (selumetinib, binimetinib, and trametinib) and two ERK inhibitors (ulixertinib and ERAS-007) in the KRAS G12C mutant CRC cell line SW1463. The phosphorylation states of RSK (P-RSK), ERK (P-ERK), CRAF (P-CRAF) and MEK (P-MEK) are shown. Band intensity indicates level of phosphorylation. Total GAPDH (GAPDH), a housekeeping gene, is used as a protein loading control. Times, in hours, represent the duration of compound incubation. NT means “no treatment,” and this sample serves as a negative control. The level of P-RSK, highlighted in dotted red rectangles, indicates ERK signaling activity. The absence of a P-RSK band indicates inhibition of ERK signaling activity and thereby inhibition of RAS/MAPK pathway signaling.

In BRAF V600E colorectal cell lines, ERAS-007 also blocked the RAS/MAPK pathway feedback reactivation observed with MEK or other ERK plus BRAF inhibitor combinations at one-tenth the concentration used for the MEK and other ERK inhibitors. These results provide further support that inhibition of ERK by ERAS-007 may lead to more complete and durable blockade of the RAS/MAPK pathway relative to other inhibitors of ERK or MEK, either alone or in combination.

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Treatment of two BRAF V600E mutant CRC cell lines, RKO and HT-29, with encorafenib in combination with the MEK inhibitor binimetinib, the ERK inhibitor ERAS-007, the ERK inhibitor LY3214996, and the ERK inhibitor ravoxertinib. The Western blot gels depict phosphorylation of RSK (P-RSK) and ERK (P-ERK). Higher levels of phosphorylation are depicted by higher (i.e., darker) band intensity. Total GAPDH protein (GAPDH) serves as a loading control. ERK signaling activity is represented by the phosphorylation state of RSK (P-RSK), which is a downstream target of ERK. The column values indicate the duration of compound incubation of up to 72 hours.

To explore ERAS-007 activity in vivo, we measured tumor growth inhibition (TGI) in a melanoma patient-derived xenograft (PDX) model resistant to BRAF and MEK inhibitors. Whereas treatment with dabrafenib, a BRAF inhibitor, and vehicle showed similar tumor growth trajectories, ERAS-007 significantly inhibited tumor growth at the end of the 38-day treatment period at both 25 mg/kg twice a day (BID) (p-value < 0.001) and 50 mg/kg BID (p-value < 0.01). These data suggest ERAS-007 may be more potent than BRAF or MEK inhibitors in achieving inhibition of the RAS/MAPK pathway and may be able to overcome treatment resistance.

A p-value is the probability that the reported result was achieved purely by chance, such that a p-value of less than or equal to 0.05 means that there is a less than or equal to 5% probability that the difference between the control group and the treatment group is purely due to chance. A p-value of 0.05 or less typically represents a statistically significant result. The FDA’s evidentiary standard of efficacy when evaluating the results of a clinical trial generally relies on a p-value of less than or equal to 0.05.

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ERAS-007 shows significant TGI relative to vehicle control at both 25 mg/kg BID (p-value < 0.001) and 50 mg/kg BID (p-value < 0.01) in a dabrafenib resistant melanoma PDX model.

Preclinical anti-tumor activity of ERAS-007

We further showed the breadth of ERAS-007 in vivo activity in CRC, NSCLC, pancreatic cancer, melanoma, and neuroblastoma models harboring alterations in the BRAF, NRAS, or KRAS nodes of the RAS/MAPK pathway. In the BRAF V600E mutant melanoma cell line-derived xenograft (CDX) A375 model, ERAS-007 showed dose-dependent tumor inhibition with a maximal 104% TGI at 30 mg/kg BID (p-value <0.001 across all ERAS-007 doses relative to vehicle control). In the NRAS Q61K mutant neuroblastoma CDX SK-N-AS model, ERAS-007 showed dose-dependent tumor inhibition with a maximal 82% TGI at 25 mg/kg BID (p-value < 0.001 across all ERAS-007 doses relative to vehicle control). In the KRAS G12D pancreatic CDX Panc-1 model, ERAS-007 showed dose-dependent TGI with a maximal 94% TGI at 40 mg/kg BID (p-value < 0.001 across all ERAS-007 doses relative to vehicle control). In the KRAS G13D CRC CDX HCT116 model, ERAS-007 showed 101% TGI at 25 mg/kg BID (p-value < 0.001 relative to vehicle control). ERAS-007 showed superior TGI to ulixertinib at 75 mg/kg QD in Panc-1 and MIA PaCa-2 at doses ranging from 20 mg/kg BID to 40 mg/kg BID. TGI values >100% indicated tumor regression.

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ERAS-007 showed significant TGI in pancreatic cancer, CRC, melanoma, and neuroblastoma CDX models at doses ranging from as low as 10 mg/kg BID (p-value < 0.001). At doses ranging from 20 mg/kg BID to 40 mg/kg BID, ERAS-007 showed superior TGI to a clinical-stage ERK inhibitor, ulixertinib, at 75 mg/kg QD, in pancreatic cancer Panc-1 and MIA PaCa-2 CDX models. ERAS-007 at 25 mg/kg BID also showed superior TGI to ravoxertinib at 50 mg/kg BID in the CRC HCT-116 CDX model. Relative to trametinib at 1.5 mg/kg QD, ERAS-007 showed superior TGI in the MIA PaCA-2 CDX model at doses ranging from 20 mg/kg BID to 40 mg/kg BID and in the pancreatic cancer CDX Panc-1 at 40 mg/kg BID. In the neuroblastoma S-K-NAS model, ERAS-007 showed superior TGI at doses as low as 12.5 mg/kg BID to trametinib at 0.15 mg/kg QD. Error bars represent standard error of the mean (SEM).

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ERAS-007 showed statistically significant TGI in BRAF V600E CRC, mutant EGFR NSCLC, and mutant KRAS NSCLC CDX models as a monotherapy and in combination with standard of care targeted therapies and with ERAS-601 (our first MAPKlamp). In the BRAF V600E CRC CDX model RKO, ERAS-007 exhibited 82% TGI as a monotherapy (p-value < 0.001), 88% TGI in combination with encorafenib (p-value <0.001) and 93% TGI in combination with encorafenib and cetuximab (p-value < 0.001). In the BRAF V600E CRC CDX model WiDr, ERAS-007 exhibited 102% TGI as a monotherapy (p-value < 0.001), 109% TGI in combination with encorafenib (p-value < 0.001), and 111% TGI in combination with encorafenib and cetuximab (p-value < 0.001). Indicated with an asterisk in the graphic, both ERAS-007 combinations achieved statistically significant TGI relative to either the encorafenib and cetuximab combination or ERAS-007 monotherapy (p-values < 0.01). In the EGFR exon 19 deletion and MET amplified CDX HCC827/ER1, ERAS-007 achieved 121% TGI as a monotherapy (p-value < 0.001), 123% in combination with osimertinib at 10 mg/kg BID (p-value <0.001), and 124% TGI in combination with osimertinib at 30 mg/kg QD (p-value < 0.001). In the EGFR exon 19 deletion, EGFR T790M, and MET amplified CDX NCI-H820, ERAS-007 achieved 117% TGI as monotherapy (p-value < 0.001), 107% TGI in combination with osimertinib at 10 mg/kg BID (p-value < 0.001), and 112% TGI in combination with osimertinib at 30 mg/kg QD (p-value < 0.001).

In the KRAS G12V NSCLC CDX model NCI-H441, the MAPKlamp combination of ERAS-007 at 30 mg/kg QD and ERAS-601 at 15 mg/kg QD achieved a statistically significant TGI of 113% (p-value < 0.001), demonstrating statistically significant benefit relative to the respective monotherapy doses of both ERAS-007 at 30 mg/kg QD and ERAS-601 at 15 mg/kg QD (p-value < 0.01). ERAS-007 as a monotherapy at 30 mg/kg BID and 30 mg/kg QD doses achieved statistically significant TGI of 115% (p-value < 0.001) and 94% (p-value < 0.001), respectively. ERAS-601 as a monotherapy at 30 mg/kg QD and 15 mg/kg QD doses achieved statistically significant TGI of 101% (p-value < 0.001) and 87% (p-value < 0.001), respectively. In the KRAS G12A NSCLC CDX model NCI-H2009, the MAPKlamp combination of ERAS-007 at 30 mg/kg QD and ERAS-601 at 15 mg/kg QD achieved statistically significant TGI of 107% (p-value < 0.001). MAPKlamp achieved a statistically significant combination benefit relative to the respective monotherapy doses of both ERAS-007 at 30 mg/kg QD and ERAS-601 at 15 mg/kg QD (p-value < 0.01). The MAPKlamp combination also showed statistically significant superior TGI relative to ERAS-007 monotherapy at 30 mg/kg BID (p-value < 0.05) and ERAS-601 monotherapy at 30 mg/kg QD (p-value < 0.01). These doses represent the maximum monotherapy nonclinical efficacious doses for ERAS-007 and ERAS-601. ERAS-007 as a monotherapy at 30 mg/kg BID achieved statistically significant TGI of 93%). ERAS-601 as a monotherapy at 30 mg/kg QD and 15 mg/kg QD doses achieved statistically significant TGI of 90% (p-value < 0.001) and 73% (p-value < 0.001), respectively. TGI values >100% indicated tumor regression.

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ERAS-007 was profiled in two BRAF V600E CRC CDX models, RKO, which was insensitive to encorafenib and cetuximab treatment, and WiDr, which was sensitive to encorafenib and cetuximab treatment. In both models, ERAS-007 combinations showed superior TGI to encorafenib (Encor.) and cetuximab (Cetux.) monotherapies and to the encorafenib and cetuximab combination (p-value < 0.01). The asterisk in the WiDr graphic indicates that the TGI of the ERAS-007 combinations relative to either the encorafenib and cetuximab combination or ERAS-007 monotherapy was statistically significant (p-value < 0.01). In two osimertinib-resistant mutant EGFR NSCLC CDX models, HCC827/ER1 and NCI-H820, ERAS- 007 showed superior TGI to osimertinib monotherapy both as a single agent and in combination with osimertinib (p-value < 0.001). In two mutant KRAS NSCLC CDX models, NCI-H441 and NCI-H2009, the MAPKlamp combination of ERAS-007 and ERAS-601 achieved statistically significant TGI relative to vehicle (p-values < 0.01) and showed statistically significant combination benefit relative to the respective monotherapy doses used in the MAPKlamp combination (p-values < 0.01). At their efficacious monotherapy doses, ERAS-007 and ERAS-601 also achieved significant TGI in both models as monotherapies (p-values < 0.01).

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In a panel of 41 CRC PDX models, which include the most common genetic alterations in CRC, ERAS-007 inhibited tumor growth by greater than 50% relative to untreated tumors in 30 out of the 41 CRC PDX models (73%). ERAS-007’s inhibitory activity was observed in 71% of KRAS mutant models (n=17 total), 73% of BRAF models (n=11 total), and 77% of KRAS wildtype and BRAF wildtype models (n=13 total). Together, these in vivo results suggest ERAS-007 exhibits strong single agent anti-tumor activity across a wide range of tumors with alterations in BRAF and KRAS relative to other agents in use today.

ERAS-007 inhibited tumor growth by greater than 50% in 73% of CRC PDX tumor models. The T/C (treated/control) ratio is calculated as the ratio of mean volume of ERAS-007 treated tumors to mean volume of untreated tumors in the control group. Lower values represent better TGI.

Phase 1 trial of single agent ERAS-007 in patients with advanced solid tumors

Asana completed a Phase 1 first-in-human clinical trial (ASN007-101) that evaluated the safety, tolerability, PK, pharmacodynamics (PD), and preliminary anti-tumor activity of ERAS-007 in patients with advanced cancers. Forty-nine patients were enrolled and administered ERAS-007 QD (17 patients) or QW (32 patients). Following dose escalation using both schedules, the recommended dose (RD) of 250 mg QW was selected. The maximum tolerated dose (MTD) on a daily schedule was 40 mg QD.

Phase 1 safety and tolerability

ERAS-007 showed a reversible and manageable adverse event profile, consistent with other RAS/MAPK-pathway inhibitors (e.g., MEK inhibitors). The ERAS-007 QW dosing schedule was better tolerated than QD dosing based on the treatment-related adverse events (TRAEs) reported. Transient nausea and vomiting observed with QW dosing were manageable. Skin toxicities have been noted as a class effect of inhibitors of RAF, MEK, or ERK. Less skin toxicity was observed with QW dosing of ERAS-007 compared to QD dosing. Ophthalmic toxicities have been observed during treatment with MEK targeted agents and occur with ERK inhibitors, and reversible retinopathy is a well-known MEK/ERK inhibitor class effect.

The ERAS-007 250 mg QW RD was well tolerated with minimal grade 3 and no grade 4 or 5 TRAEs, as shown in the table below. No grade 3 or higher eye toxicity was observed at this dose. We believe these safety results and QW dosing support combination strategies in our ERAS-007 clinical development plan.

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Phase 1 pharmacokinetics

As shown in the table below, the ERAS-007 Phase 1 data suggest that intermittent QW dosing is preferable to QD dosing. The duration of time in which mean concentration was above IC90 (%T>IC90), which correlates with tumor cell killing, was substantially longer for 250 mg QW (~29%) compared to 40 mg QD (~17%). The lower Cmin for 250 mg QW, compared to 40 mg QD, allows more time for RAS/MAPK pathway recovery, which gives normal cells a treatment break during each dosing interval.

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Optimizing dosing and scheduling

The observed long biochemical residence time of ERAS-007 bound to ERK (greater than 9 hours) and the observed human half-life (approximately 30 hours) offer flexibility in optimizing the dosing schedule. While the QW schedule of ERAS-007 demonstrated clinical activity with an acceptable adverse event profile, our exploratory PK/PD analyses suggest that increasing duration of exposure above IC90 (which increases tumor cell killing) may drive anti-tumor activity, and that maintaining Cmin near or below IC50 (which allows normal cells to recover) may improve safety and tolerability. Informed by the clinical data observed from the Phase 1 trial, we conducted PK simulations (projections based on the data) to explore alternative dosing regimens to provide additional flexibility for combinations with ERAS-601 (together, our first MAPKlamp) and other agents, as shown in the figure and table below.

The PK simulations suggest that the dosing regimen of twice daily on day 1 of each week (BID-QW) may potentially provide a meaningful extension of the duration of the PK exposure above the IC90 beyond what has been achieved with 250 mg QW to improve cancer cell killing, while still maintaining Cmin near or below the IC50, to give normal cells a treatment break during each dosing interval. Therefore, in the Phase 1b/2 trial of ERAS-007 in patients with advanced or metastatic cancers (HERKULES-1, described below), we plan to evaluate this BID-QW dosing schedule in the dose escalation cohort, in addition to the 250 mg QW expansion cohort.

Phase 1 clinical activity

Objective tumor responses and durable disease control of ERAS-007 were observed in diverse tumor types at doses ranging from 120 to 250 mg QW in patients with BRAF-, HRAS-, and NRAS-driven cancers. As of the December 21, 2020 data cutoff, the waterfall plot below illustrates the objective responses seen in all patients who had received at least one dose of ERAS-007 and underwent at least one tumor assessment (the efficacy-evaluable patients). Four responses were observed in patients with BRAF V600E thyroid cancer (180 mg QW), BRAF K601E NSCLC (120 mg QW), HRAS salivary gland cancer (250 mg QW), and BRAF rearranged melanoma (250 mg QW).

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“% Change from Baseline in Tumor Size” is defined as the maximum reduction in the sum of tumor diameters of selected target lesions measured after a patient started on study treatment compared to the baseline measurements of the same target lesions before study treatment was started. “Efficacy-Evaluable” is defined as patients who have a baseline tumor scan and at least one post-baseline scan after starting study treatment, to allow assessment of tumor response. Prior treatments in patients with objective responses included: HRAS salivary gland—radiation; BRAF rearranged melanoma—nivolumab/ipilimumab, radiation; BRAF V600E thyroid—radiation; BRAF K601E NSCLC—carboplatin/pemetrexed, carboplatin/paclitaxel plus durvalumab. The dashed lines represent the RECIST-defined definitions of response (30% decrease) or progression (20% increase) in tumor size.

As of the December 21, 2020 data cutoff, the swimmer plot below demonstrated encouraging duration of treatment, with three patients who achieved disease control that exceeded one year. One patient with BRAF V600E melanoma (7104-010) received ERAS-007 for a total of 71 weeks before experiencing disease progression, first on the ASN007-101 clinical trial (shown in this swimmer plot) and subsequently on a single patient IND (not shown in this swimmer plot), since the patient was deriving clinical benefit at the time the ASN007-101 trial had completed.

Examples of single agent activity of ERAS-007 from these responses in patients with melanoma and salivary gland adenocarcinoma are shown in the scan images below. On the left, a patient with a BRAF rearranged melanoma, who had prior progression on nivolumab/ipilimumab, showed complete regression of the target lesion. On the right, a patient with HRAS salivary gland cancer showed partial response of target lesions.

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Rationale for combining with other targeted agents

Since ERK is the terminal node of the RAS/MAPK pathway and activates hundreds to thousands of downstream proteins, we believe an ERK inhibitor is an attractive combination partner to achieve maximal inhibition of the RAS/MAPK pathway. In combination with RTK, SHP2, RAS, and/or RAF inhibitors, an ERK inhibitor has the potential to further inhibit RAS/MAPK pathway signaling and delay development of resistance. The RAS/MAPK pathway is regulated by negative feedback mechanisms that desensitize the pathway when active. In the presence of a RAS/MAPK pathway inhibitor, pathway signaling activity is reduced, alleviating negative feedback mechanisms and sensitizing the RAS/MAPK pathway to upstream signaling. This sensitization can prevent RAS/MAPK pathway inhibitors from achieving therapeutic levels of pathway inhibition. Another challenge for RAS/MAPK pathway inhibitors is the activation of RTKs that can generate sufficient upstream RAS/MAPK pathway signaling pressure that overwhelms RAS/MAPK pathway inhibitors. Combining upstream RAS/MAPK pathway inhibitors with an ERK inhibitor can potentially enable pathway inhibition in the absence of negative feedback and in the presence of additional upstream signaling pressure. The activity of RAS/MAPK pathway inhibitors can also be bypassed by the emergence of activating mutations in RAS/MAPK pathway proteins that lie downstream. For example, activating mutations in RAS can emerge as a resistance mechanism against EGFR inhibitors in mutant EGFR NSCLC, and MEK mutations can develop as a resistance mechanism against BRAF plus MEK inhibitors in melanoma. As the terminal node of the RAS/MAPK pathway, ERK inhibition can help address activating RAS, RAF, or MEK mutations that can act as resistance mechanisms to RAS/MAPK pathway inhibitors.

BRAF V600E CRC as an example that ERK inhibition can reduce the emergence of resistance

While the combination of a BRAF inhibitor and an EGFR inhibitor (encorafenib plus cetuximab) has been approved for the second- and third-line treatment of BRAF V600E CRC, only 20% of patients experience an objective response, and only half of these responses last more than 4 months. Therefore, emergence of resistance is a major therapeutic barrier to long-term clinical benefit. Analysis of post-progression biopsies and cell-free DNA samples revealed a heterogeneous collection of resistance mutations in the RAS/MAPK pathway, including KRAS, NRAS, MEK1, and MEK2. A set of published experiments conducted by researchers at Massachusetts General Hospital modeled this clinical resistance in a pooled clone model system and xenograft models. Seven different resistant BRAF V600E CRC cells, each engineered with one of these resistance mutations, were introduced at 1% allele frequency into a pool of sensitive BRAF V600E CRC cells. Of all combination therapies evaluated, a triple blockade of BRAF, EGFR, and ERK (identified with a red box around the image below) proved to be the most effective in reducing tumor volume and preventing the emergence of resistance clones.

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These data suggest that: (1) in tumors that are highly addicted to the RAS/MAPK pathway, such as BRAF V600E CRC, resistance mechanisms are dominated by reactivation of this critical pathway via mutations within the pathway, and (2) an ERK inhibitor can potentially overcome these resistance mechanisms by blocking the terminal node of the pathway. Therefore, ERAS-007 may be combined with other RAS/MAPK pathway inhibitors (e.g., KRAS G12C inhibitor and BRAF inhibitor) as either initial therapy or in the post-progression setting in patients who have been treated with RAS/MAPK pathway inhibitors.

Development strategy for ERAS-007

We are pursuing a broad clinical development plan for ERAS-007 across multiple tumor types that includes both monotherapy and combinations with approved and investigational agents. The first series of trials are four POC trials in solid tumors, NSCLC, CRC, and AML. While providing POC data, these trials may be expanded to enable potential accelerated approvals in their respective indications:

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We anticipate multiple data readouts from our HERKULES clinical trials beginning in 2022, including a Phase 1b monotherapy data readout from HERKULES-1 in the second half of 2022, a Phase 1b combination data readout from HERKULES-2 in 2023, and a Phase 1b combination data readout from HERKULES-3 between the fourth quarter of 2022 and the first half of 2023.

As shown in the schema below, HERKULES-1 is a Phase 1b/2 trial evaluating ERAS-007 monotherapy in patients with solid tumors. In Part A, a dose-finding portion will determine the maximum tolerated dose (MTD) and RD when ERAS-007 is given BID-QW, the rationale of which was described earlier in the Phase 1 PK pharmacokinetics section. The primary endpoint of this part is to characterize the safety profile of ERAS-007 when given on a BID-QW schedule. Testing this alternative intermittent dosing schedule will provide us with three schedules (QD, QW, and BID-QW) from which to select the optimal dose and schedule to combine with ERAS-601 (our first MAPKlamp) and other agents. When the ERAS-601 RD is identified from the FLAGSHP-1 trial (described below), we expect to amend the HERKULES-1 trial protocol to identify the optimal dose and schedule for the ERAS-007 and ERAS-601 combination and to evaluate the preliminary efficacy and safety of this MAPKlamp in multiple tumor types. In Part B, which is running in parallel with Part A (since monotherapy responses were observed with the QW schedule in the completed Phase 1 clinical trial of ERAS-007), separate cohorts are evaluating ERAS-007 QW in patients with NSCLC, pancreatic cancer, melanoma, and other solid tumors that harbor RAS/MAPK pathway alterations. These patient populations have high unmet medical needs, as they have exhausted all approved therapies. Patients in some cohorts have not been previously treated with any RAS/MAPK pathway inhibitors (e.g., KRAS, BRAF, or MEK inhibitors), since none of these inhibitors are approved for use in these patients. Patients in other cohorts have been previously treated with RAS/MAPK pathway inhibitors when these agents are part of standard of care. The primary endpoint is an assessment of anti-tumor activity of ERAS-007 in the patient populations. We dosed the first patient in HERKULES-1 in May 2021.

As shown in the schema below, HERKULES-2 is a Phase 1b/2 master protocol evaluating novel combination therapies for patients with NSCLC. Sub-Study A is focused on patients with EGFR mutant NSCLC, representing approximately 184,000 new patients worldwide each year, and Sub-Study B is focused on patients with KRAS G12C mutant NSCLC, representing approximately 240,000 new patients worldwide each year. The master protocol for this clinical trial may be expanded in the future to include other novel combinations and indications in NSCLC. We dosed the first patient in HERKULES-2 in September 2021.

Sub-Study A. For patients with EGFR mutant NSCLC, the standard of care for newly diagnosed patients with metastatic disease is osimertinib, an EGFR inhibitor. While 77% of patients respond initially, nearly all patients experience disease progression while on osimertinib treatment, and no other targeted therapy is approved in the post-osimertinib setting. Biomarker analyses of tumors that developed resistance to osimertinib showed that RAS/MAPK pathway alterations make up a substantial portion of resistance mechanisms. With the ERAS-007 plus osimertinib combination, we are evaluating in this trial whether combined ERK and EGFR inhibition can overcome osimertinib resistance in EGFR mutant NSCLC with RAS/MAPK pathway alterations. In Part A1, an ERAS-007 QW RD will be identified in combination with osimertinib. The primary endpoint will be a safety assessment of this combination. In Part A2, this combination regimen will be evaluated in EGFR mutant NSCLC patients who have progressed on initial osimertinib monotherapy. The primary endpoint will be an assessment of anti-tumor activity. Part A3 will identify the RD of ERAS-007 on a BID-QW schedule in combination with osimertinib, with a safety assessment as the primary endpoint. Part A4 will evaluate this combination with BID-QW schedule in a larger patient population, with a preliminary assessment of anti-tumor activity as the primary endpoint.

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HERKULES-2 Sub-Study A: EGFR mutant NSCLC

Sub-Study B. For patients with KRAS G12C NSCLC, the standard of care for previously-treated patients with metastatic disease is sotorasib, a KRAS G12C inhibitor. Only 36% of patients respond initially, and nearly all patients experience disease progression. Biomarker analyses of tumors that developed resistance to a KRAS G12C inhibitor showed that RAS/MAPK pathway alterations make up a substantial portion of resistance mechanisms, highlighting the strong reliance of KRAS G12C NSCLC on this pathway. With the ERAS-007 plus sotorasib and ERAS-601 plus sotorasib combinations in Sub-Study B, we are evaluating whether combined ERK and KRAS G12C inhibition can lead to broader and deeper responses than sotorasib monotherapy, as well as prolonged efficacy and SHP2 and KRAS G12C inhibition. In Part B1 and Part B3, the RDs for ERAS-007 on QW and BID-QW schedules will be identified in combination with sotorasib, respectively. The primary endpoint will be a safety assessment of combinations. In Part B2 and Part B4, these combination regimens will be evaluated in KRAS G12C mutant NSCLC patients who are naïve to KRAS G12C inhibitor treatment. The primary endpoint will be an assessment of anti-tumor activity. Part B5 and Part B7 will identify the RDs of ERAS-601 dosing schedules in combination with sotorasib, respectively. The primary endpoint will be a safety assessment of the combinations. Part B6 and Part B8 will evaluate these combinations in a larger patient population, respectively, with a preliminary assessment of anti-tumor activity as the primary endpoint.

HERKULES-2 Sub-Study B: KRAS G12C NSCLC

As shown in the schema below, HERKULES-3 is a Phase 1b/2 master protocol evaluating novel combination therapies for patients with GI malignancies. Sub-Study A is focused on patients with BRAF V600E mutant CRC, representing approximately 180,000 new patients worldwide each year, and Sub-Study B, on patients with KRAS or NRAS mutant CRC and KRAS mutant pancreatic cancer, representing over 1.1 million new patients worldwide each year. The master protocol for this clinical trial may be expanded in the future to include other novel combinations and indications in GI cancers. We dosed the first patient in HERKULES-3 in September 2021.

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Sub-Study A. The standard of care for patients with BRAF V600E CRC in the second-/third-line metastatic setting is encorafenib plus cetuximab, an anti-BRAF and anti-EGFR doublet therapy. Only 20% of patients respond, nearly all patients experience disease progression, and the median overall survival is less than 9 months. The prognosis for patients in the post-encorafenib plus cetuximab setting is worse. In preclinical models of BRAF V600E CRC, the addition of an ERK inhibitor to BRAF inhibitor plus EGFR inhibitor substantially enhanced anti-tumor activity and reduced the development of resistance to BRAF inhibitor plus EGFR inhibitor. In Part A1, the ERAS-007 QW RD will be identified in combination with encorafenib plus cetuximab, with a safety assessment of the combination as the primary endpoint. The RD will be evaluated further in two patient populations: BRAF V600E CRC patients who are naïve to encorafenib plus cetuximab treatment and who have been treated with encorafenib plus cetuximab. The primary endpoint will be an assessment of anti-tumor activity. Parts A2 and A3 contain optional cohorts that would allow us to evaluate alternative dosing schedules of ERAS-007 in combination with encorafenib and cetuximab, depending on the results from Part A1.

HERKULES-3 Sub-Study A: BRAF V600E CRC

Sub-Study B. The standard of care for patients with KRAS or NRAS mutant CRC in the third-line metastatic setting is typically chemotherapy. However, when treated with regorafenib (a multi-kinase inhibitor) or TAS-102 (chemotherapy), less than 5% of patients respond, nearly all patients experience disease progression, and the median overall survival is around 6 months. In preclinical models of KRAS or NRAS mutant CRC, the combined inhibition of cycle and RAS/MAPK pathways demonstrated substantial anti-tumor activity in these highly resistant tumor types. In Part B1 and Part B2, the ERAS-007 QW RD will be identified in combination with two different schedules of palbociclib, with a safety assessment of the combination as the primary endpoint. In Part B3 and Part B4, the alternative schedule of ERAS-007 given BID-QW may be evaluated. One RD and schedule will be evaluated further in previously-treated patients with KRAS or NRAS mutant CRC. The primary endpoint will be an assessment of anti-tumor activity.

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HERKULES-3 Sub-Study B: KRAS or NRAS mutant CRC

As shown in the schema below, HERKULES-4 is a Phase 1b/2 clinical trial evaluating novel combination therapies for patients with hematological malignancies. Sub-Study A is focused on patients with FLT3 mutant AML, which represents 30-40% of all AML, or approximately 61,000 new patients worldwide each year. The standard of care for patients with relapsed/refractory AML is gilteritinib, a FLT3 inhibitor. Only 14% of patients achieve a complete remission, nearly all patients experience disease progression, and the median overall survival is less than 10 months. While FLT3 is the most commonly altered gene in AML, alterations along the entire RAS/MAPK pathway are also prevalent, including SHP2, KRAS, NRAS, and BRAF, suggesting dual FLT3 and SHP2 inhibition or FLT3 and ERK inhibition may improve the efficacy of gilteritinib monotherapy. In Part A1, the RD of ERAS-007 in two schedules in combination with gilteritinib will be identified, with a safety assessment as the primary endpoint. In Part A2, a selected RD and schedule of ERAS-007 will be evaluated further in an expansion cohort of patients with relapsed/refractory FLT3 mutant AML. The primary endpoint will be an assessment of anti-tumor activity. In Part A3, the RD of ERAS-601 in two schedules in combination with gilteritinib will be identified, with a safety assessment as the primary endpoint. A selected RD and schedule of ERAS-601 will be evaluated further in an expansion cohort of patients with relapsed/refractory FLT3 mutant AML. The master protocol may be expanded in the future to include additional sub-studies of other novel combinations and indications in hematological malignancies.

These and other trial designs may be modified based on evolving clinical and nonclinical data, as well as feedback from regulatory agencies.

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ERAS-601: our SHP2 inhibitor

ERAS-601 is designed to be a potent and selective oral inhibitor of SHP2. In preclinical studies, ERAS-601 has demonstrated strong in vitro potency relative to other SHP2 inhibitors (RMC-4550 and TNO155) and favorable absorption, distribution, metabolism, and excretion (ADME) and PK properties, which we believe support its use in a broad range of combination therapies. ERAS-601 is the second prong of our first MAPKlamp with ERAS-007. In our first-in-human trial, FLAGSHP-1, we are evaluating the safety, tolerability, PK, PD, and preliminary anti-tumor activity of ERAS-601 in patients with advanced or metastatic solid tumors. We believe that approximately 4.9 million patients worldwide per year could benefit from ERAS-601 in combination with other agents, including ERAS-007.

Preclinical profile of ERAS-601

In a biochemical assay, ERAS-601 potently and selectivity inhibited full length SHP2 with an IC50 value of 4.6 nM as shown in the table on the left below. By binding to an allosteric pocket that is present only in the inactive conformation of SHP2, ERAS-601 inhibited SHP2 activity by stabilizing the protein in the inactive state. No ERAS-601 activity was observed against 10 other phosphatases (including SHP1), and ERAS-601 showed no strong inhibition of any kinase in a 300-kinase panel (i.e., less than 30% inhibition at 1 µM), demonstrating high selectivity as shown in the table on the right below.

Biochemical on-target activity of ERAS-601 against SHP2 (left) and biochemical activity of ERAS-601 in a panel of 12 phosphatases (right). PTPN11 (SHP2) catalytic domain protein is a truncated form of SHP2 (246 aa – 593 aa). This truncated form contains a phosphatase domain and is missing two regulatory domains. The PTPN11 (SHP2) catalytic domain does not harbor the binding site of ERAS-601 due to these missing domains, while the PTPN11 (SHP2) full length protein does harbor ERAS-601’s binding site.

ERAS-601’s activity against SHP2 was shown in a cell-based assay using a SHP2 inhibitor-sensitive cell line, NCI-H1666, which was transduced with either wildtype SHP2 or mutant SHP2 (T253M / Q257L). ERAS-601 inhibited RAS/MAPK pathway signaling, shown by a decrease of phosphorylated ERK (pERK) relative to total ERK in the figure below, but ERAS-601 had no effect on RAS/MAPK pathway signaling in the double mutant SHP2 cell line. These cell data support that ERAS-601’s cellular activity is due to SHP2 binding and not due to off-target activity. In vitro cell line screening revealed potent ERAS-601 activity in EGFR, KRAS, NF1, and class III BRAF mutant cell lines. Generally, ERAS-601 showed greater activity in RAS/MAPK pathway mutant cell lines that relied on upstream RTK signaling, such as EGFR, NF1 loss-of-function, and class III BRAF mutants. ERAS-601 did not show activity in cell lines that harbored activating RAS/MAPK pathway activating mutations that were not dependent on upstream signaling, such as the melanoma BRAF V600E mutant cell line A375.

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Western blot of the NCI-H1666 cell line transduced with empty vector (EV), wildtype SHP2 (WT), and double mutant SHP2 (T253M and Q257L). The two T253M and Q257L mutations in SHP2 prevent ERAS-601 from binding SHP2 via steric hindrance. ERAS-601 at 1 µM inhibited pERK in empty vector and SHP2 wildtype transduced cells. ERAS-601 at 1 µM did not inhibit pERK in cells transduced with double mutant SHP2, thereby suggesting that ERAS-601’s cellular activity is due to SHP2 binding.

The ADME/PK properties of ERAS-601 have been extensively evaluated in non-clinical studies. As shown in the table below, ERAS-601 demonstrated favorable physicochemical and PK properties, including low risk of drug-drug interaction (DDI), negligible CYP enzyme inhibition, and moderate plasma protein binding. It also showed high oral bioavailability and low clearance across multiple animal species. We believe these properties support ERAS-601’s use in a broad range of combination therapies.

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Preclinical anti-tumor activity of ERAS-601

As shown in the table below, ERAS-601 significantly inhibited tumor growth as a monotherapy in 25 in vivo models, including KRAS G12C, KRAS G12D, KRAS G12V, EGFR, BRAF class I and III, and NF1 loss-of-function mutations. In 21 models, ERAS-601 was well tolerated and showed significant TGI at QD and BID dose schedules. In a PK/PD study, ERAS-601 also achieved time and dose-dependent increases in plasma concentrations and concomitant reductions in RAS/MAPK pathway signaling, as measured by pERK, in the KRAS G12C mutant NSCLC xenograft model NCI-H358. Tumor pERK1/2 levels were reduced by more than 50% when ERAS-601 total plasma concentrations exceeded or approximated the IC50/fu, which is the in vitro cellular pERK IC50 unbound fraction in plasma.

ERAS-601 exhibited significant TGI relative to vehicle control (p-value < 0.05) in 11 KRAS mutant, four EGFR mutant, three BRAF mutant, four NF1 LOF mutant, and three triple wildtype (KRAS/NRAS/BRAF wildtype) CDX and PDX models. Significant TGI was observed at both 30 mg/kg QD and 10 mg/kg BID doses. *p-value < 0.05 **p-value < 0.01 ***p-value < 0.001 (p-values assessed relative to vehicle control)

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Preclinical activity of ERAS-601 combination therapies

As shown in the figures below, when combined with KRAS G12C and EGFR inhibitors, ERAS-601 showed significantly greater TGI than dosing of these inhibitors as monotherapies. This benefit was observed in models that harbored mutations both upstream and downstream of SHP2. These ERAS-601 combinations were generally well tolerated across the tested models as demonstrated by the minimal percentage body weight changes observed.

ERAS-601 combined with sotorasib and cetuximab showed significant TGI in five CDX and PDX models. The ERAS-601 + sotorasib (KRAS G12C inhibitor) showed significant TGI relative to vehicle control (p-value < 0.01) and monotherapy arms (p-value < 0.05) in KRAS G12C mutant CRC PDX and esophageal CDX models. The ERAS-601 + cetuximab (EGFR inhibitor) combination showed significant TGI in three triple wildtype (KRAS/NRAS/BRAF wildtype) CRC PDX models relative to vehicle control (p-value < 0.01) and cetuximab monotherapy arms (p-value < 0.001).

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Development strategy for ERAS-601

Our clinical development plan aims to advance ERAS-601 in combination with other targeted agents to prevent and overcome adaptive resistance mechanisms in order to achieve more durable clinical benefit. In the fourth quarter of 2020, we began evaluating the safety and tolerability of ERAS-601 in a first-in-human dose escalation trial in patients with advanced or metastatic solid tumors in our FLAGSHP-1 trial. The primary endpoints of this trial are assessments of safety and anti-tumor activity. After we have identified the monotherapy RD of ERAS-601, we will evaluate rational combinations with ERAS-601, including dual SHP2 and EGFR inhibition focused on CRC (cetuximab combination in FLAGSHP-1), dual SHP2 and KRAS G12C inhibition in NSCLC (sotorasib combination in HERKULES-2), and dual SHP2 and FLT3 inhibition in AML (gilteritinib combination in HERKULES-4), as well as dual SHP2 and ERK inhibition with ERAS-007 (our first, innovative MAPKlamp approach) in our HERKULES series of clinical trials. Other agents for potential combinations include approved RTK inhibitors, RAS/MAPK pathway inhibitors, and/or investigational agents we are developing, such as ERAS-3490. Given the wide range of cancers that are dependent on SHP2, we believe ERAS-601 could serve as a backbone for compelling combination therapies to prolong survival for patients.

We anticipate a Phase 1 monotherapy data readout from our FLAGSHP-1 trial in the second half of 2022 and a Phase 1b combination data readout in triple wildtype (KRAS/NRAS/BRAF wildtype) CRC between the fourth quarter of 2022 and the first half of 2023.

ERAS-3490: our CNS-penetrant KRAS G12C inhibitor program

RAS proteins are the most frequently mutated oncoproteins, with KRAS being the most abundantly expressed RAS isoform. Despite decades of research focused on KRAS as a target of interest in oncology, it was generally deemed to be undruggable until 2013, when Dr. Shokat and his colleagues at UCSF identified a new binding pocket, the "switch II pocket" (S-IIP), via crystallography studies. Importantly, they also described the discovery of small molecules that irreversibly bound to this pocket on KRAS G12C – a finding that turned an undruggable target into a druggable one.

This historic discovery spurred multiple companies to develop KRAS G12C inhibitors, including the recently approved sotorasib and others that are currently in clinical trials. While single agent activity to date has been most promising in NSCLC, opportunities remain for improvement in CNS penetration to be able to address the propensity of NSCLC to metastasize to the brain. Worldwide, KRAS G12C mutations affect approximately 350,000 patients with cancer, with NSCLC comprising two-thirds of these patients, and CRC one-sixth of these patients. NSCLC has the highest rate of CNS metastases, and the CNS is a site of progression in approximately 25% to 50% of patients on standard of care therapies. Hence, we believe a CNS-penetrant KRAS G12C inhibitor, either as a monotherapy or in combination therapies, would represent an important advance in maintaining systemic disease control, prolonging response, and preventing CNS progression. In preclinical in vivo experiments, an approved KRAS G12C inhibitor and a late clinical-stage KRAS G12C inhibitor (sotorasib and adagrasib, respectively, and together, the reference compounds) were poorly CNS-penetrant, detectable in the CNS at less than 10% of the plasma level. We have been designing and optimizing KRAS G12C inhibitors that have shown comparable or superior anti-tumor activity to the reference compounds and robust ability to cross the blood-brain barrier (BBB) in order to address this key limitation.

Preclinical profile of ERAS-3490 and other pre-candidates

Our team discovered a novel scaffold that binds the S-IIP in a different configuration which allows us to optimize potency while also enabling high CNS penetration. We have discovered and are characterizing five KRAS G12C inhibitor pre-candidates based on this scaffold that have promising potency, selectivity, and physicochemical properties relative to the reference compounds.

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Importantly, all five pre-candidates (ERAS-3490, ERAS-3691, ERAS-3599, ERAS-3537, and ERAS-3788) have shown attractive physicochemical properties relative to the reference compounds, especially with respect to in vitro CNS penetration:

Five CNS-penetrant KRAS G12C pre-candidates showed comparable in vitro and in vivo PK characteristics and in vitro potency to the reference compounds. ERAS-3490 and ERAS-3599 exhibited superior exposure and CNS penetration relative to the reference compounds, and ERAS-3537 and ERAS-3788 exhibited superior CNS penetration relative to the reference compounds. A green arrow indicates a favorable value relative to the reference compounds, an orange arrow indicates a comparable value, and a red arrow indicates an inferior value. P-gp substrate ratios were characterized in a P-gp expressing MDCK cell line. The P-gp substrate ratio for a single reference compound is shown. Per compound, a P-gp substrate ratio was calculated by dividing its efflux ratio in absence of a P-gp inhibitor by its efflux ratio in presence of a P-gp inhibitor. Compounds with lower P-gp substrate ratios are less likely to have CNS penetration limited by P-gp mediated efflux. LM stands for liver microsome and CL stands for clearance. Liver microsome stability is normalized to hepatic blood flow to better enable cross-species comparisons. In vitro potency was characterized by both pERK inhibition and cell viability. Both potency assays used the RAS Initiative KRAS G12C cell line.

We are aiming to optimize CNS penetration while maintaining comparable potency and metabolic stability to the reference compounds. This is a highly challenging balancing act to achieve because typically, the attributes of a molecule that endow it with potency against the S-IIP (e.g., hydroxyl group moiety for one of the reference compounds) are the very properties that compromise its ability to cross the BBB. Our goal with our CNS-penetrant KRAS G12C inhibitor discovery program has been to significantly increase CNS penetration as measured by the rat braintotal/plasmatotal ratio (RBP, measured in percent). Reference compounds have RBPs ranging from 1% to 6%. Our pre-candidates have RBPs ranging from 11% to 68% (ERAS-3537 [68%], ERAS-3599 [66%], ERAS-3490 [52%], ERAS-3691 [13%], and ERAS-3788 [11%]), and therefore have the potential to demonstrate better CNS penetration in the clinic than the reference compounds. Our team has significant experience developing targeted CNS-penetrant compounds, including entrectinib (ROZLYTREK), an FDA-approved product for ROS1 fusion-positive NSCLC and NTRK fusion-positive solid tumors, including those in patients with CNS metastases. Using the rat brain assays, entrectinib has an RBP of 16% and an absolute value of 80 ng/g rat brain concentration.

Furthermore, ERAS-3490 and ERAS-3599 are not P-glycoprotein (P-gp) substrates, meaning they are less likely to be effluxed, or pumped, from the brain back out into the blood. This feature further enhances the potential for high CNS penetration of these two pre-candidates relative to the other three pre-candidates and reference compounds that are P-gp substrates.

Selection of ERAS-3490 as DevCan

ERAS-3490 was derived from a novel scaffold and potently inhibited the proliferation of 17 KRAS G12C cell lines with IC50s ranging from 1.4 nM to 82 nM. These values were comparable to reference compounds, which showed IC50s ranging from 2 nM to 35 nM in the same cell line panel.

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ERAS-3490 was also a highly selective inhibitor of KRAS G12C, which is supported by ERAS-3490 adducting with only one other peptide when incubated for 4 hours in the KRAS G12C mutant cell line NCI-H358. The figure below shows that KRAS G12C was strongly (x-axis) and significantly depleted (y-axis) when incubated with ERAS-3490, indicating that it strongly and selectively bound to KRAS G12C.

ERAS-3490 selectively bound to KRAS G12C protein in cell-based Cysteine Enrichment Proteome (CEP) assays. This assay quantifies the covalent binding activity of cysteine-targeting compounds, like ERAS-3490, after being incubated with NCI-H358 cells for 4 hours at 1 µM. The depletion of cysteine-containing proteins in the compound treatment sample relative to vehicle treatment indicates that the compound is covalently binding to that peptide. The x-axis represents the magnitude of protein depletion, and the y-axis represents the significance of depletion. Proteins in the shaded green region are significantly depleted by at least 4-fold (p-value < 1.0e-4) and proteins in the shaded red region are significantly enriched by at least 4-fold (p-value < 1.0e-4). Both compounds were profiled in the KRAS G12C mutant NSCLC cell line NCI-H358. In the ERAS-3490 study, KRAS G12C and one other protein, PDS5, were the only two proteins out of 2,602 detected proteins that were significantly depleted.

In an exploratory intracranial KRAS G12C NSCLC CDX NCI-H1373 model in panel (A) of the figure below, ERAS-3490 demonstrated that its superior physicochemical properties and PK profile enabled it to significantly outperform a reference compound in anti-tumor activity, both at the initial dose of 100 mg/kg QD for the first nine days and upon lowering the dose to 30 mg/kg for the remainder of the study. In panel (B), ERAS-3490 demonstrated comparable to superior anti-tumor activity at two different doses relative to a reference compound in a subcutaneous pancreatic cancer model (MIA PaCa-2).

The PK/PD profile help explain why ERAS-3490 outperforms a reference compound in the intracranial model with its superior PK profile, with high oral bioavailability (mean plasma AUC0-lastof 21,606 ng*h/g vs. 10,065 ng*h/g) and high brain bioavailability (mean brain AUC0-last of 1985 ng*h/g vs. ND) at the 30 mg/kg dose. In these in vivo studies, ERAS-3490 was well tolerated, as body weights remained constant across all in vivo studies.

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(A) ERAS-3490 and a reference compound were dosed in an intracranially injected and luciferase labeled KRAS G12C mutant CDX model, NCI-H1373. All compounds were dosed at 100 mg/kg QD on days 1-9 and then at 30 mg/kg QD on days 10-42. ERAS-3490 significantly inhibited tumor growth relative to vehicle control (p-value < 0.01). (B) ERAS-3490 and a reference compound were dosed in a KRAS G12C inhibitor sensitive pancreatic cancer CDX, MIA PaCa-2, for 28 days. ERAS-3490 significantly inhibited tumor growth at both 30 mg/kg QD (p-value < 0.01) and 100 mg/kg QD (p-value < 0.001) relative to vehicle control. ERAS-3490 showed minimal body weight change at doses up to 100 mg/kg QD, demonstrating good tolerability.

We believe ERAS-3490 is the only KRAS G12C inhibitor specifically designed to cross the BBB. We nominated ERAS-3490 as our DevCan in June 2021 and expect to file an IND in the second half of 2022.

Development strategy for ERAS-3490

The initial development of ERAS-3490 as a monotherapy will be in KRAS G12C mutant NSCLC. We will evaluate the hypothesis that improved CNS penetration will enhance clinical activity, broaden the patient population, prolong response, delay disease progression, and extend survival. Our deep pipeline within the RAS/MAPK pathway will allow a number of combination therapies to be developed in NSCLC and other solid tumors, such as CRC and pancreatic cancer. One of the initial combinations to be assessed will be with ERAS-601, as preclinical and clinical data support the synergistic effect of inhibiting KRAS and SHP2. We intend to explore additional combinations of ERAS-3490 with other approved and investigational agents.

Our RAS-GTP franchise

Over 2 million patients annually worldwide are affected by RAS mutations other than KRAS G12C. Like KRAS G12C, these mutations hyperactivate RAS/MAPK pathway signaling by diminishing RAS’s ability to transition from the active to the inactive state. Nearly 700,000 of these 2 million patients are affected by tumors that harbor KRAS G12D, which is the most prevalent KRAS mutation. This mutation results in hyperactive RAS/MAPK pathway signaling and is frequently observed in NSCLC, CRC, endometrial cancer, and pancreatic cancer. Targeting non-G12C RAS mutations (the focus of our RAS-GTP franchise, including ERAS-4 and ERAS-2/3) is more challenging than targeting KRAS G12C because: (1) KRAS G12D and other non-G12C RAS mutations are more commonly found in the active RAS-GTP state; (2) non-G12C mutations do not have a mutant-specific site for irreversible inhibitor binding; and (3) these mutations alter the conformation dynamics of RAS, hindering the ability of small molecules to target the same binding site as KRAS G12C inhibitors, S-IIP.

ERAS-4: our KRAS G12D program

Our ERAS-4 program endeavors to develop small molecules that potently and selectivity bind KRAS G12D. When bound to KRAS G12D, these inhibitors will prevent RAS-mediated signaling by locking KRAS G12D in the inactive GDP-bound state and/or obstructing KRAS G12D’s ability to bind downstream effector proteins, such as BRAF and CRAF. We are accelerating advancement of this program by leveraging our in-house chemistry, biology, and structural biology expertise gained from working on our RAS-GDP and other RAS-GTP programs.

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We have generated molecules with low nanomolar IC50 potency against KRAS G12D in the biochemical RAS-cRAF binding assay and high selectivity vs. KRAS wildtype (WT). As shown in the figure below, ERAS-4057 has strong potency of 10.8 nM, with 66-fold selectivity vs. KRAS WT. We are optimizing the properties of these molecules utilizing SBDD and structure-activity relationships while continuing to focus on generating other highly potent and selective compounds against KRAS G12D, with the intention to nominate and advance a DevCan into IND-enabling activities.

ERAS-4057 potently and selectively bound KRAS G12D with an IC50 of 10.8 nM (blue) and KRAS WT, an off-target protein, with an IC50 of 717.3 nM (green). Lower values on the y-axis indicate stronger inhibition of KRAS-RAF1 Ras binding domain (RBD) binding. Higher values on the x-axis indicate higher concentrations of ERAS-4057. In this assay, GDP-bound KRAS was converted to GTP-bound KRAS via an interaction with SOS1 and GTP-bound KRAS then bound the RAF1 RBD protein. A compound that inhibited the transition of KRAS from the GDP-bound to GTP-bound state and/or inhibited the protein-protein binding of KRAS and RAF1 resulted in a lower fraction of KRAS-RAF1 RBD binding.

ERAS-2/3: our other RAS-GTP programs

Our ERAS-2/3 program is focused on the development of small molecule inhibitors that target a novel region on RAS called the "switch II groove" (S-IIG). Unlike the S-IIP, the S-IIG is accessible in both the GDP-bound and GTP-bound states of RAS, making it a robust binding region across multiple RAS mutants.

Dr. Shokat identified a new binding site called S-IIG, as shown in the figure below. The original S-IIP that was the binding site for KRAS G12C inhibitors is present in the RAS-GDP state only. When RAS cycles to the RAS-GTP state, the S-IIP becomes obscured by switch II. Unlike the S-IIP, the S-IIG is not obscured by switch II, which enables small molecules to access the S-IIG independently of the phosphorylation state of the bound guanosine. Therefore, S-IIG is present in both the RAS-GTP and RAS-GDP states. Disruption of these switch regions can inhibit RAS signaling since GTP-bound RAS binds to effector proteins at these switch regions. We entered into an exclusive worldwide license agreement with UCSF for certain intellectual property derived from Dr. Shokat’s work related to RAS-GTP, which guides our ERAS-2/3 programs.

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The small molecule tool compound binds to the S-IIG region on GDP-bound KRAS M72C in this surface representation of RAS. The S-IIG is less obstructed by switch II, and this feature allows small molecules to bind to the S-IIG independently of the phosphorylation state of the bound guanosine. Unlike S-IIG, access to S-IIP is influenced by the phosphorylation state of the bound guanosine. Most selective KRAS G12C inhibitors in development bind to the S-IIP. Switch II is flexible in the GDP-bound state, allowing small molecule inhibitors to access the S-IIP. In the GTP-bound state, switch II rigidly folds over the S-IIP and occludes access to the S-IIP, thereby preventing most selective KRAS G12C inhibitors from accessing the S-IIP. Binding of GDP to RAS is coordinated by a magnesium ion, shown in green.

Our EGFR franchise

EGFR is a transmembrane protein and member of the ErbB family of receptor tyrosine kinases (RTKs) that under normal conditions bind various growth factors to activate cellular signaling to regulate homeostasis. However, when the receptor is overexpressed, amplified, and/or mutated, it becomes oncogenic, thereby contributing to cell survival, proliferation, and metastasis.

We are developing a differentiated portfolio of programs that target EGFR, including ERAS-801, our CNS-penetrant small molecule EGFR inhibitor, and ERAS-12, our EGFR domain II/domain III (D2/D3) targeting bispecific antibody.

ERAS-801: our CNS-penetrant EGFR inhibitor

EGFR-mediated signaling plays a key role in the growth of many tumor types. Targeting of wildtype EGFR (wtEGFR) and mutant variants of EGFR (EGFRm) by small molecules and antibodies has resulted in improved patient outcomes in NSCLC, CRC, and HNSCC. However, the ability of these agents to effectively target wtEGFR and EGFRm in the CNS remains an unmet medical need. For example, in primary CNS tumors like GBM that have amplification of wtEGFR as well as expression of a mutation in the extracellular domain, the most common of which is epidermal growth factor receptor variant III (EGFRvIII), approved small molecule EGFR inhibitors have not demonstrated clinical activity.

The lack of clinical activity is likely multifactorial, but we believe there are two primary reasons why approved EGFR inhibitors are not effective: (1) the molecules do not penetrate the CNS well, and (2) the molecules are weak inhibitors of the EGFRvIII mutant protein as homodimers or heterodimers that include wildtype EGFR.

ERAS-801 is designed to be a potent, selective, reversible, and orally available small molecule with both: (1) highly enhanced CNS penetration (3.7:1 brain:plasma ratio in mice) and (2) the ability to target both EGFR alterations such as EGFRvIII, the most common mutant form of EGFR found in GBM, and wtEGFR, which heterodimerizes with EGFRvIII.

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High CNS penetration of ERAS-801

As shown below, following administration of a single oral dose of 10 mg/kg in mice, ERAS-801 demonstrated substantially higher brain concentrations than erlotinib, an approved EGFR inhibitor:

Brain concentrations and exposures of ERAS-801 and erlotinib in mice when administered a single 10 mg/kg dose. The x-axis represents time when brain concentration was assessed post-dose. The y-axis represents total concentration of compound in nanomolars.

Whereas approved EGFR inhibitors have suboptimal CNS penetration for primary brain tumors, as shown below, ERAS-801 showed substantially higher values of Kpand Kp,uu (partition coefficients that measure bound and unbound drug concentration, respectively) compared to osimertinib, afatinib, erlotinib, gefitinib, and dacomitinib. The figure below is for illustrative purposes only and is not a head-to-head comparison. These data were generated from different studies, and caution should be exercised when comparing data across studies.

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Dual targeting of EGFR alterations and wtEGFR in GBM to address heterodimerization

The most common mutant form of EGFR found in GBM is EGFRvIII. Given the promiscuous nature of EGFR signaling, ERAS-801 has been specifically designed to have activity against both EGFR alterations such as EGFRvIII and wildtype EGFR, as we believe that wtEGFR inhibition is critical to impairing the growth of EGFR altered GBM because of the propensity of wtEGFR to heterodimerize with EGFRvIII to drive oncogenic signaling, as seen below with substantial co-expression of EGFRvIII and wtEGFR.

Panel A showed that the EGFR splice variant mutant EGFRvIII may be expressed in a subset of GBM tumor cells and that it can be co-expressed with wildtype EGFR. Panel B showed a zoomed in diagram of a GBM tumor cell membrane that harbors both wildtype EGFR and EGFRvIII. Wildtype EGFR can homodimerize with another wildtype EGFR protein or heterodimerize with EGFRvIII, in each case potentially leading to oncogenic signaling. In panels C and D, an immunohistochemistry-stained section of GBM tumor tissue shows wildtype EGFR-expressing tumor cells in brown and EGFRvIII-expressing tumor cells in blue. Regions that are stained both brown and blue express both wildtype EGFR and EGFRvIII proteins while regions that are stained brown but not blue express wildtype EGFR only.

Preclinical profile of ERAS-801

In preclinical studies, ERAS-801 has demonstrated strong biochemical and cell-based potency, as well as strong biochemical selectivity. ERAS-801 has shown high potency against EGFR with a biochemical IC50 of 0.3 nM and high CNS penetration. It also showed high selectivity for EGFR based on a biochemical screen of 484 kinases in which ERAS-801 at 10 µM inhibited only two non-EGFR family kinases at greater than 90%.

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The biochemical activities of ERAS-801 and two approved compounds that are active against EGFR, erlotinib and lapatinib, were characterized at a single concentration (10 µM) in kinome screens. Inhibitory activity has been mapped onto a kinase phylogenetic tree where related kinases within 8 kinase groups are grouped by color (top row). Red circles indicate kinases where inhibitory activity has been observed; the diameter of the circle represents the strength of inhibition (i.e., large circles mean greater inhibitory activity). Activity against atypical and mutant kinases are shown in the bottom row.

In cell-based assays, ERAS-801 was potent against wildtype EGFR with an IC50 of 1.1 nM and EGFRvIII with an IC50 of 0.7 nM. In a 31 patient-derived glioma cell panel, ERAS-801 inhibited the growth of 65% of glioma cells with IC50 values less than 3 µM. This glioma cell panel included the most frequent types of EGFR alterations observed in GBM: amplification, EGFRvIII, extracellular domain mutations (e.g., A289V and A289D), and chromosome 7 polysomy. ERAS-801 showed no activity in normal human astrocytes (i.e., IC50 greater than 25 µM), which is the most common cell type in the human brain. ERAS-801’s lack of activity against this normal brain cell type demonstrated that ERAS-801 selectively inhibited EGFR and that these normal brain cells were not dependent on EGFR signaling.

ERAS-801 showed broad activity in a panel of 31 patient-derived glioma cell lines. Demonstrating selectivity, ERAS-801 showed no activity in normal human astrocyte cells. Lower IC50 values, in blue, indicated stronger activity. The EGFR mutation status of the GBM patient-derived cells is indicated by symbols. Mutations include extracellular domain EGFR mutations and EGFR splice variants, such as EGFRvIII. Focal amplification indicates a high-level gain of the chromosomal region that includes the EGFR gene locus. Polysomy indicates cells that harbor more copies of chromosome 7, which contained the EGFR gene, than expected in a normal cell. Two copies of chromosome 7 are expected in normal cells.

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In vivo studies showed that total ERAS-801 concentration was present in the brain by a factor of 3.7x relative to plasma, and its unbound concentration in the brain was 1.2x higher than in plasma. This high CNS penetration translated into enhanced in vivo survival benefit, which was observed in the EGFRvIII mutant patient-derived glioma model GBM39. In this study, ERAS-801 significantly extended the survival of mice at 10 mg/kg, 25 mg/kg, and 75 mg/kg doses relative to vehicle control (p-value < 0.05). Relative to vehicle control, significant survival benefit was observed in four additional patient-derived glioma models that harbor EGFRvIII, EGFR amplified, or chromosome 7 polysomy mutations (p-value < 0.001). ERAS-801 showed significant survival benefit and TGI in 93% of 14 patient-derived glioma models that harbored EGFR amplifications +/- EGFRvIII and extracellular domain EGFR mutations. These preclinical in vivo data highlight ERAS-801’s potent CNS activity against EGFR mutant GBM, which comprises 40-60% of all GBM.

ERAS-801 plasma and brain concentrations in mice that have been administered a single dose of ERAS-801 at 10 mg/kg or 25 mg/kg. The table summarizes the PK profiles shown in the graph.

ERAS-801 showed dose-dependent survival benefit in the in vivo GBM PDX model GBM39, which harbored the EGFRvIII splice variant.

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ERAS-801 showed significant survival benefit in multiple glioma PDX models that harbored a variety of EGFR mutations.

***p-value < 0.001.

Development strategy for ERAS-801

We believe that ERAS-801 could provide benefit to approximately 125,000 patients with newly diagnosed GBM worldwide per year. GBM is a difficult-to-treat, aggressive cancer that can occur in the brain or spinal cord. Current therapy consists primarily of surgical resection of the tumor, followed by radiation and chemotherapy. Once GBM recurs, therapeutic options for patients are limited. EGFR amplifications and mutations are detected in 40-60% of GBM cases and are generally indicative of poor prognosis. In the fourth quarter of 2021, our IND was cleared by FDA to proceed with a Phase 1 clinical trial of ERAS-801. In February 2022, we dosed the first patient in our THUNDERBBOLT-1 Phase 1 clinical trial in recurrent GBM that will evaluate the safety, PK, and PD effects of ERAS-801 as a single agent. Preliminary evaluation of anti-tumor activity will also be performed in patients who have tumors harboring alterations in EGFR.

ERAS-12: our EGFR D2/D3 bispecific antibody program

Inhibition of wildtype EGFR signaling mediated by overexpression of EGFR has shown promise in treating various tumors, including HNSCC and CRC. In tumors where overexpression of EGFR is thought to be the primary driver of EGFR signaling, an antibody-based approach is the most effective way to target the receptor, and approved antibodies have demonstrated good tolerability as well as activity by inhibiting EGFR activation and mediating antibody-dependent cellular cytotoxicity (ADCC), a process by which the antibody alerts the immune system to attack the bound tumor cell. However, all approved anti-EGFR antibodies target domain III (D3) only, which is the inactive conformation of wildtype EGFR, and no approved antibodies target domain II (D2), which is the active, ligand binding, conformation of wildtype EGFR. Antibodies targeting D2 are expected to be more effective when epidermal growth factor (EGF) or other members of the EGF family are overexpressed.

We are developing a bispecific antibody that is active against both the inactive and active conformations of wildtype EGFR, and we anticipate filing an IND for this program by 2024.

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Diagram (A) visualizes the EGFR antibody ER-2a binding to the extracellular domain II of EGFR wildtype (purple), which is accessible when EGFR is in the active state. EGFR assumes an active state conformation when its ligand is bound (the bound ligand is shown in blue). Diagram (B) visualizes the EGFR antibody ER-3a binding to the extracellular domain III of EGFR wildtype (purple), which is accessible when EGFR is in the inactive state. In the rectangle, the portion of ER-2b that recognizes domain II of EGFR and the portion of ER-3b that recognizes domain III of EGFR are combined into a bispecific antibody that binds EGFR in both states.

By binding to EGFR in the active D2 state, our D2/D3 bispecific antibody can likely better prevent EGFR dimerization and can potentially achieve higher levels of EGFR inhibition than currently approved EGFR antibodies. Achieving a higher level of EGFR inhibition may better control tumor growth and delay the emergence of resistance mechanisms involving EGFR that spends more time in the active conformation.

Targeting D2 via the ER-3a/2a and ER-2a antibodies show a concentration-dependent inhibition of cancer cell proliferation.

The bispecific antibody ER-3a/ER-2a and EGFR active state-binding antibody ER-2a inhibited cell growth in FaDu, an HNSCC cell line, and HCT-8, a CRC cell line, and the NSCLC cell line H1975. FaDu and HCT-8 expressed wildtype EGFR and H1975 expressed EGFR with two kinase domain mutations, L858R and T790M. EGFR’s ligand, EGF, was added to these cells to further stimulate EGFR activity and model environments where EGF is expressed. As expected, only the two antibodies that recognized the active state of EGFR, ER-3a/ER-2a, inhibited the proliferation of all three cell lines, as indicated by a reduced confluency percentage.

ERAS-5: our ULK program

The ULK1 and ULK2 kinases are key regulators of the metabolic process known as autophagy. Under physiological conditions, cells utilize autophagy to recycle cellular components, breaking down older components that may be malfunctioning due to age and stress into subunits that are combined to form new components. This process can act as a survival mechanism during stress, such as nutrient starvation, by enabling cells to break down non-critical cellular components to support critical functions. Autophagy can be upregulated in tumor cells where RAS/MAPK pathway signaling is inhibited, acting as an escape route mechanism by preventing tumor cell death.

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To pursue our therapeutic strategy of targeting escape routes, our ERAS-5 program is focused on developing potent, selective inhibitors of ULK1/2 so that we can further boost tumor cell death in combination with our RAS/MAPK pathway inhibitors. We have identified a promising ERAS-5 compound that showed strong potency, target engagement, inhibition of autophagy, and selectivity. In a biochemical assay, it exhibited IC50s of 2.4 nM and 2.6 nM against ULK1 and ULK2, respectively. In cell-based assays, this compound showed an IC50 of 13.4 nM in an ULK1 target engagement assay and an IC50 of 5.9 nM in an autophagy pathway activity assay that visualized GFP-labeled LC3 puncta (LC3 proteins localize on autophagosomes and, when labeled with a fluorophore, can enable quantification of autophagosomes by microscopy; higher numbers of autophagosomes in the cell, which are generated during the autophagy process, indicate higher levels of autophagy). Our promising ERAS-5 compound also showed biochemical selectivity—greater than 375x selectivity against TBK1 and greater than 240x selectivity against AMPK, two off-target kinases that are commonly inhibited by other ULK inhibitors with published structures.

We believe that agents targeting the RAS/MAPK pathway could benefit from combination with an ULK1/2 inhibitor, addressing up to 2.6 million patients with cancer annually worldwide. This includes over 400,000 patients with RAS mutant pancreatic cancer since pancreatic cancer tumors have upregulated RAS/MAPK pathway signaling and autophagy may already be upregulated due to these tumors growing in nutrient poor environments. As shown below, a promising clinical case report showed that combining a non-specific autophagy inhibitor, hydroxychloroquine, with a RAS/MAPK pathway inhibitor, trametinib, meaningfully reduced tumor burden in a patient with metastatic pancreatic cancer. The patient’s level of CA19-9, a blood-based marker of overall tumor burden, rapidly decreased upon initiation of this combination therapy and remained low through 5 months of treatment. This patient had previously progressed on multiple chemotherapy regimens and an mTOR inhibitor, everolimus.

In a patient with metastatic pancreatic cancer, the combination of an autophagy inhibitor, hydroxychloroquine, with a RAS/MAPK pathway inhibitor, trametinib, resulted in a steep reduction of overall tumor burden as represented by a decrease in CA19-9. Higher tumor burden levels are shown as higher concentrations of CA19-9. The x-axis represents dates within the patient’s treatment journey and the y-axis is the detected concentration of CA19-9. Prior to initiation of trametinib and hydroxychloroquine treatment, the patient was treated with chemotherapy regimens mFOLFIRINOX (folinic acid [leucovorin], fluorouracil, irinotecan, and oxaliplatin), gemcitabine, and capecitabine, and gemcitabine, abraxane, and cisplatin. After progressing on the gemcitabine, abraxane, and cisplatin triplet, the patient was treated with an mTOR inhibitor, everolimus. The patient progressed on everolimus and was then treated with trametinib at 2 mg QD in combination with escalating doses of hydroxychloroquine up to 1,200 mg QD. The combination of trametinib at 2 mg QD with hydroxychloroquine at 1,200 mg resulted in a significant decrease in overall tumor burden that continued through 5 months of treatment.

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ERAS-9: our SOS1 program

SOS1 is a protein that binds to RAS and enables it to transition from the inactive RAS-GDP state to the active RAS-GTP state. RAS proteins bind GDP tightly, and a cofactor, such as a SOS1, is required to facilitate RAS’s release of GDP followed by its binding to GTP. Without this cofactor, RAS will accumulate in the inactive state as active state RAS hydrolyzes bound GTP. We are developing small molecule inhibitors in our ERAS-9 program that obstruct SOS1-RAS binding and thereby prevent RAS from cycling to the active RAS-GTP state. SOS1-RAS inhibition can prevent RAS activation mediated by upstream signaling (e.g., via EGFR activation) and can be combined with downstream RAS/MAPK pathway inhibitors to potentially address RAS and RAF mutations that result in constitutive RAS/MAPK pathway signaling. SOS1-RAS inhibitors can address as many as 4.9 million patients with cancer who harbor RAS/MAPK pathway activating mutations annually worldwide either as a monotherapy or in combination therapies.

ERAS-10: our protein degrader program

We are exploring protein degradation as an alternative mechanism to complement our approach of enzymatically inhibiting oncogenic proteins. Degrader molecules bind to a target oncogenic protein and cellular machinery that label proteins for degradation. Within proximity of each other, the degrader machinery labels the target protein through a process called ubiquitination, and the labeled protein is degraded. Degraders can offer advantages over enzymatic inhibitors, such as the ability of a single degrader molecule to tag many copies of the target oncoprotein for degradation and the ability of a degrader to more effectively inhibit the function of non-enzymatic proteins. We think this approach will allow us to target a broader range of proteins within the RAS/MAPK pathway and may help us more effectively target a subset of oncogenic proteins than via enzymatic inhibition alone.

ERAS-11: our MYC program

MYC is a transcription factor that is mutated in 40% of cancers, affecting approximately 7.7 million patients with cancer annually worldwide. These mutations promote cancer by hyperactivating MYC and/or its protein dimerization partners (e.g., MAX). Inhibiting MYC by disrupting its ability to dimerize with other proteins or bind DNA has been pursued for over 20 years but has not yet been successful. We are exploring novel approaches to targeting MYC utilizing our internal discovery expertise complemented with partnerships to overcome the challenges that have prevented the successful development of MYC protein inhibitors.

Our acquisition and license agreements

Asana BioSciences

In November 2020, we entered into an agreement and plan of merger with Asana and ASN Product Development, Inc. (ASN) (the Asana Merger Agreement), pursuant to which ASN became our wholly-owned subsidiary. Asana and ASN had previously entered into a license agreement, which was amended and restated prior to the closing of the merger transaction (the Asana License Agreement, and collectively with the Asana Merger Agreement, the Asana Agreements), pursuant to which ASN acquired an exclusive, worldwide license to certain intellectual property rights relating to inhibitors of ERK1 and ERK2 owned or controlled by Asana to develop and commercialize ERAS-007 and certain other related compounds for all applications. We have the right to sublicense (through multiple tiers) the licensed rights under the Asana Agreements, subject to certain conditions. The foregoing license is subject to Asana’s non-exclusive right to practice the licensed rights to research and conduct preclinical pharmacology activities with a specified combination of compounds, subject to certain specified conditions. Pursuant to the Asana License Agreement, neither Asana nor ASN can directly or indirectly exploit certain classes of competing products, subject to specified exceptions. In addition, we are required to use commercially reasonable efforts to develop and obtain regulatory approval for ERAS-007 in the United States, at least one major market country in Europe, and either China or Japan.

Under the Asana Merger Agreement, we made an upfront payment of $20 million and issued 4,000,000 shares of our Series B-2 convertible preferred stock to Asana. In connection with our IPO, these shares of Series B-2 convertible preferred stock were converted into 3,333,333 shares of our common stock. We are obligated to make future development and regulatory milestone cash payments for a licensed product in an amount of up to $90 million. Additionally, upon achieving a development milestone related to demonstration of successful proof-of-concept in a specified clinical trial, we will be required to issue 3,888,889 shares of our common stock to Asana. We are not obligated to pay royalties on the net sales of licensed products.

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Upon our payment to Asana of all merger consideration, including upfront cash and equity payments, the milestone payments, the equity payment related to the proof-of-concept development milestone, and all other development milestone payments, with the exception of a specific milestone that does not need to be achieved at such time and will remain subject to payment in the event that such milestone occurs at a later time, all licensed rights will become fully paid-up, perpetual, and irrevocable. The License Agreement may be terminated by either Asana or us in the event of an uncured material breach by the other party. Asana also has the right to terminate the Asana License Agreement if we fail to engage in material activities in support of clinical development and commercialization of ERAS-007 for a period of 12 consecutive months, excluding reasons outside of our reasonable control and subject to certain limitations. However, Asana’s right to terminate the Asana License Agreement for any reason ends once we have paid to Asana all merger consideration, or if Asana’s equity interest in us is publicly traded and exceeds a certain threshold value. We may terminate the Asana License Agreement at any time upon the provision of prior written notice to Asana.

NiKang Therapeutics

In February 2020, we entered into a license agreement (the NiKang Agreement) with NiKang Therapeutics, Inc. (NiKang) under which we were granted an exclusive, worldwide license to certain intellectual property rights owned or controlled by NiKang related to certain SHP2 inhibitors to develop and commercialize ERAS-601 and certain other related compounds for all applications. We have the right to sublicense (through multiple tiers) our rights under the NiKang Agreement, subject to certain conditions, and are required to use commercially reasonable efforts to develop and commercialize licensed products. The parties are obligated to negotiate in good faith for a certain period of time to grant NiKang the exclusive commercial distribution rights in greater China once a licensed product reaches a certain development stage.

Under the NiKang Agreement, we made an upfront payment of $5 million to NiKang and reimbursed NiKang $0.4 million for certain initial manufacturing costs. In addition, we paid an additional $7 million after publication of a US patent application that covered the composition of matter of ERAS-601. We are also obligated to pay (i) development and regulatory milestone payments in an aggregate amount of up to $16 million for the first licensed product and $12 million for a second licensed product, and (ii) commercial milestone payments in an aggregate amount of up to $157 million for the first licensed product and $151 million for a second licensed product. We are also obligated to: (i) pay tiered royalties on net sales of all licensed products in the mid-single digit percentages, subject to certain reductions; and (ii) equally split net sublicensing revenues earned under sublicense agreements that we enter into with any third party before commencement of the first Phase I clinical trial for a licensed product.

The NiKang Agreement will expire upon the last to expire royalty term, which is determined on a licensed product-by-licensed product and country-by-country basis, and is the later of: (i) ten years from the date of first commercial sale, (ii) the last to expire valid claim within the licensed patent rights covering such licensed product, or (iii) the expiration of all regulatory exclusivity for the licensed product in such country. Upon expiration of the NiKang Agreement, on a licensed product-by-licensed product and country-by-country basis, we will have a fully paid-up, non-exclusive license to conduct research and to develop and commercialize the licensed products.

The NiKang Agreement may be terminated in its entirety by NiKang in the event of our uncured material breach, which includes our failure to use commercially reasonable efforts to satisfy certain specified clinical development diligence milestones. In addition, NiKang may terminate if we, directly or indirectly, commence a legal action challenging the validity or enforceability of any licensed patents. Further, if we acquire more than 50% of the equity or assets of a company that owns a competing small molecule that is designed to prevent the same target as set forth in the NiKang Agreement from switching to an enzymatically active state, then we must either divest such competing product or terminate the NiKang Agreement. We may terminate the NiKang Agreement at any time upon the provision of prior written notice to NiKang. Upon termination of the NiKang Agreement for any reason, all rights and licenses granted to us, as well as any sublicenses that we granted thereunder, will terminate. In addition, upon any termination (but not expiration) of the NiKang Agreement and upon NiKang’s request, the parties are obligated to meet and negotiate in good faith the terms of a license from us to NiKang to allow NiKang’s continued development, manufacture, and commercialization of the licensed products.

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Katmai Pharmaceuticals

In March 2020, we entered into a license agreement (the Katmai Agreement) with Katmai Pharmaceuticals, Inc. (Katmai) under which we were granted an exclusive, worldwide, royalty-bearing license to certain patent rights and know-how controlled by Katmai related to the development of small molecule therapeutic and diagnostic products that modulate EGFR and enable the identification, diagnosis, selection, treatment, and/or monitoring of patients for neuro-oncological applications to develop, manufacture, use, and commercialize ERAS-801 and certain other related compounds in all fields of use. We have the right to sublicense (through multiple tiers) our rights under the Katmai Agreement, subject to certain limitations and conditions, and are required to use commercially reasonable efforts to develop, manufacture, and commercialize licensed products and to meet certain specified development and launch milestones by certain dates. We are obligated to use commercially reasonable efforts to develop the licensed products first for use within the neuro-oncology field before expanding our development efforts to include other indications in the oncology field. Following the first achievement of a clinical proof-of-concept for any indication, we have the right to submit a non-binding offer to Katmai for: (i) the purchase of all licensed patent rights, know-how, and other assets owned by Katmai that are necessary or useful for the exploitation of the licensed products, or (ii) for the purchase of Katmai. Pursuant to the Katmai Agreement, neither Katmai nor we can directly or indirectly exploit certain specified classes of competing products.

The license granted under the Katmai Agreement is subject to The Regents of the University of California’s reserved right to: (i) use the licensed patent rights and know-how for educational and non-commercial research purposes, and to publish results arising therefrom, and (ii) grant licenses to the licensed know-how to third parties without notice because the licensed know-how is non-exclusively licensed to Katmai by The Regents of the University of California. Further, the license granted under the Katmai Agreement is subject to the rights of the United States government under the Bayh-Dole Act, including: (i) a non-exclusive, non-transferable, irrevocable, paid-up license to practice or have practiced the invention claimed by the licensed patent rights throughout the world, and (ii) the obligation that any licensed products used or sold in the United States be manufactured substantially in the United States.

Under the Katmai Agreement, we made an upfront payment of $5.7 million and Katmai agreed to purchase shares of our Series B-1 convertible preferred stock and Series B-2 convertible preferred stock having an aggregate value of $2.7 million. In connection with our IPO, these shares of Series B-1 convertible preferred stock and Series B-2 convertible preferred stock were converted into 395,555 shares of our common stock, in the aggregate. We are obligated to make future development and regulatory milestone payments of up to $26 million and commercial milestone payments of up to $101 million. We are also obligated to pay tiered royalties on net sales of each licensed product, at rates ranging from the mid- to high-single digit percentages, subject to a minimum annual royalty payment in the low six figures and certain permitted deductions.

Our royalty obligations and the Katmai Agreement will expire, on a licensed product-by-licensed product and country-by-country basis, on the earlier of: (i) the ten-year anniversary of the expiration of all valid claims included in the licensed patents covering the composition of matter or method of use of such licensed product in such country, or (ii) the twentieth anniversary of the first commercial sale of such licensed product in such country. Upon the expiration of the Katmai Agreement, we will have a fully paid-up and irrevocable license.

The Katmai Agreement may be terminated in its entirety by either party: (i) in the event of an uncured material breach by the other party, or (ii) in the event the other party becomes subject to specified bankruptcy, insolvency, or similar circumstances. Provided that we are in full compliance with the Katmai Agreement, we may terminate the Katmai Agreement upon written notice to Katmai. Upon termination of the Katmai Agreement for any reason, all rights and licenses granted to us thereunder will terminate. Upon termination of the Katmai Agreement, we are obligated, among other things, to: (i) grant an exclusive license to Katmai under all of our right, title and interest in all inventions and know-how developed under the Katmai Agreement existing at the time of termination that are specific to the licensed compounds or products, including without limitation all data and results related to their exploitation, and (ii) transfer to Katmai ownership and possession of all regulatory filings related to the licensed compounds and products. Unless the Katmai Agreement is terminated for our material breach, the parties will negotiate in good faith the financial terms pursuant to which the foregoing actions will be conducted, provided that our performance of such actions may not be conditioned upon the conduct or completion of such negotiations. If the parties are unable to agree upon such terms within the specified time period, then the parties will submit all unresolved matters for resolution by arbitration.

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Emerge Life Sciences

In March 2021, we entered into an asset purchase agreement (the ELS Purchase Agreement) with ELS wherein we purchased all rights, title, and interest (including all patent and other intellectual property rights) to ELS’s EGFR antibodies directed against the EGFR domain II (EGFR-D2) and domain III (EGFR-D3) as well as a bispecific antibody where one arm is directed against EGFR-D2 and the other is directed against EGFR-D3 (the Antibodies). Under the ELS Purchase Agreement, we issued to ELS 500,000 shares of our common stock and made an upfront payment of $2 million. We are not obligated to pay royalties on the net sales of products covered by the acquired intellectual property. Under the ELS Purchase Agreement, ELS is committed to performing certain studies on the Antibodies to assist in development activities, the costs of which shall be mutually agreed upon and for which we will be responsible.

Pursuant to the ELS Purchase Agreement, at any time between 12 months and 36 months after the effective date of the ELS Purchase Agreement, if we reasonably determine that none of the Antibodies should be taken into human clinical trials due to safety, efficacy or CMC issues, then we have the option to select another antibody developed and solely owned by ELS that is not the subject of a license, collaboration, or option to a third party (the Option). If we elect to exercise the Option, then ELS will provide us with a list of all available antibodies that meet the aforementioned requirements, and we have the right to select one antibody from the list. Upon our selection of an antibody, ELS will assign us all rights, title and interest to such antibody (including patent and other intellectual property rights) subject to any pre-existing obligations or restrictions. In the event that we wish to have ELS conduct any studies on such optioned antibody, then after mutual agreement as to the scope of the studies, we will be responsible for the cost for such studies.

LifeArc

In April 2020, we entered into a license agreement with LifeArc (the LifeArc Agreement) under which we were granted an exclusive, worldwide license to certain materials, know-how, and intellectual property rights owned or controlled by LifeArc to develop, manufacture, use, and commercialize certain ULK inhibitors for all applications. We also have the right to sublicense (through multiple tiers) our rights under the LifeArc Agreement, subject to certain conditions. The foregoing license is subject to LifeArc’s retained non-exclusive, irrevocable, worldwide, sublicensable (to its academic collaborators), royalty-free right to use the licensed intellectual property rights within all fields of use for LifeArc’s own non-commercial, non-clinical academic research. Notwithstanding its retained rights, LifeArc will not seek to develop or undertake any other ULK1/2 therapeutic development programs either in-house or via third parties until April 2025. We are required to use diligent efforts to achieve certain development and regulatory milestones with respect to submission of an IND, initiation of clinical trials, submission of a new drug application (NDA), and commencement of commercial sales.

Under the LifeArc Agreement, we were granted the license at no upfront cost and a period of three months after the effective date to conduct experiments on LifeArc’s compounds. Upon completion of this initial testing period, we had the option to continue the license and make a one-time license payment of $75,000 to LifeArc, which payment was subsequently made. We are obligated to make future development milestone payments for a licensed product of up to $11 million and sales milestone payments of up to $50 million. We are also obligated to pay royalties on net sales of all licensed products, in the low-single digit percentages, subject to certain reductions.

Our royalty obligations and the LifeArc Agreement will expire, on a licensed product-by-licensed product and country-by-country basis, on the later of: (i) ten years from the date of first commercial sale, and (ii) when there is no longer a valid patent claim covering such licensed product, or expiration of regulatory exclusivity for the licensed product in such country. Upon expiration of the LifeArc Agreement, all rights and licenses granted to us and under the LifeArc Agreement will continue on a fully paid-up basis.

The LifeArc Agreement may be terminated in its entirety by either LifeArc or us in: (i) the event of an uncured material breach by the other party, or (ii) in the event the other party becomes subject to an order by a court of competent jurisdiction for winding-up or dissolution or similar circumstances. Further, LifeArc may terminate the LifeArc Agreement by giving written notice to us if: (i) we fail to comply with our diligence obligations and fail to take remedial actions, (ii) we fail to agree on a mechanism to cure a persistent breach, or (iii) we fail to provide proof of the insurance coverage as required under the LifeArc Agreement. We may terminate the agreement at any time upon the provision of written notice to LifeArc.

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Upon termination of the LifeArc Agreement for any reason, all rights and licenses granted to us, as well as any sublicenses we granted thereunder, will terminate. In addition, upon termination of the LifeArc Agreement for any reason other than its natural expiration or termination by us for LifeArc’s material breach, LifeArc has an option to negotiate an exclusive, worldwide, sublicensable license to commercialize any patent rights, technical and clinical data, and any development results relating to the licensed products that are owned or controlled by us for the purpose of developing, manufacturing and commercializing the licensed products on terms to be negotiated between the parties.

University of California, San Francisco

In December 2018, we entered into a license agreement, as amended (the UCSF Agreement), with The Regents of the University of California, San Francisco (the Regents), under which we were granted an exclusive, worldwide, royalty-bearing license under certain patent rights claiming novel covalent inhibitors of GTP- and GDP-bound RAS for the development and commercialization of products covered by such patent rights for the prevention, treatment and amelioration of human cancers and other diseases and conditions. We have the right to sublicense (through multiple tiers) our rights under the UCSF Agreement, subject to certain conditions. The UCSF Agreement was amended in May 2021. The foregoing license is subject to various retained rights and restrictions, including: (i) the Regents’ reserved right to make, use and practice the licensed patent rights and any technology relating thereto for educational and research purposes, (ii) Howard Hughes Medical Institute’s non-exclusive, fully paid-up, irrevocable worldwide license to use the licensed patent rights for research purposes, (iii) Howard Hughes Medical Institute’s statement of policy on research tools, and (iv) the obligations to the US government under the Bayh-Dole Act, including the obligation to report on the utilization of the invention covered by the licensed patent rights and a non-exclusive, non-transferable, irrevocable, paid-up license to practice or have practiced such invention throughout the world. We are required to use diligent efforts to proceed with the development and commercialization of licensed products including by achieving certain milestone events within the specified time periods.

Under the UCSF Agreement, we made upfront payments of $50,000 to the Regents and pay the Regents an annual license maintenance fee, but such fee will not be due on any anniversary if, on that date, we are making royalty payments to the Regents. We are obligated to make future development and regulatory milestone payments of up to $6.4 million and a sales milestone payment of $2 million for either of the first two licensed products. We are also obligated to pay royalties on net sales of all licensed products in the low-single digit percentages, subject to a minimum annual royalty payment in the low six figures, commencing on the year of the first sale of a licensed product and continuing, on a licensed product-by-licensed product and country-by-country basis, until there are no valid claims of the licensed patent rights covering the licensed product in such country. Additionally, we are obligated to pay tiered sublicensing fees, with the first two tiers in the low-to-mid teen percentages and the third tier at 30%, on certain fees we receive from any sublicense that we grant, depending on the stage of development of a licensed product when such sublicense is granted. Prior to the execution of the amendment, we were obligated to make a cash payment to the Regents in the event of our initial public offering, a change of control transaction or a reverse merger (the Corporate Milestone). In the amendment, the amount of the cash payment payable upon our achievement of a Corporate Milestone was reduced and we agreed to issue the Regents 944,945 shares of our common stock, which issuance is not contingent upon the achievement of a Corporate Milestone and occurred in May 2021. In August 2021, following the achievement of the Corporate Milestone, we made a cash payment to the Regents in the amount of $1.7 million.

The UCSF Agreement will expire upon the expiration of the last of the licensed patent rights. The UCSF Agreement may be terminated in its entirety by the Regents: (i) for our uncured breach, (ii) for our bankruptcy, or (iii) if we challenge, directly or indirectly, the validity or enforceability of any licensed patents. Further, if we fail to satisfy any diligence milestones, the Regents has the right and option to either terminate the UCSF Agreement or modify the exclusive license granted thereunder to a non-exclusive license. We may terminate the UCSF Agreement in its entirety or on a country-by-country basis at any time upon the provision of written notice to the Regents. Upon termination of the UCSF Agreement for any reason, all rights and licenses granted to us thereunder will terminate.

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Commercialization

We intend to maintain exclusive worldwide development and commercialization rights to our product candidates (excluding programs in our pipeline that arise from an investment made by Erasca Ventures in a third party) and, if marketing approval is obtained, to commence commercialization activities by building a focused sales and marketing organization to sell our products on our own in the United States and potentially other regions such as Europe. We will likely seek commercialization partnerships for our product candidates in other regions beyond the United States and Europe. We currently have no sales, marketing, or commercial product distribution capabilities. We intend to build the necessary infrastructure and capabilities over time for commercialization in the United States and potentially other regions, following further advancement of our product candidates. Clinical data, the size of the addressable patient population, the size of the commercial infrastructure and manufacturing needs, and the status of our pipeline, may all influence or alter our commercialization plans.

Competition + Cooperation (“Coopetition”)

Although the biotechnology and pharmaceutical industries, and the oncology sector, are characterized by rapid evolution of technologies, fierce competition, and strong defense of intellectual property rights, we believe the most fearsome competitor of all is cancer itself. As such, we view other companies in this sector more as potential allies and collaborators than as competitors, as we all have a common cause: to defeat cancer. Many of the companies that are developing or marketing treatments for cancer, including major pharmaceutical and biotechnology companies that are working on therapies targeting the RAS/MAPK pathway, are companies with whom we endeavor to collaborate in our mission to erase cancer.

Collaborating with these companies alleviates some of the traditional challenges that emerging companies face with respect to financial resources, established presence in the market, expertise in research and development, manufacturing, preclinical and clinical testing, obtaining regulatory approvals and reimbursement, and marketing approved products. Similarly, recruiting and retaining qualified scientific and management personnel, establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, programs are challenges for all companies developing or marketing treatments for cancer.

That said, our commercial potential could be reduced or eliminated if other companies develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than products that we may develop. Other companies also may obtain FDA or other regulatory approval for their products more rapidly than we may obtain approval for ours, which could result in these companies establishing a strong market position before we are able to enter the market or make our development more complicated.

There are numerous companies developing or marketing treatments for cancer, including many major pharmaceutical and biotechnology companies. These treatments consist of small molecule drug products, biologics, cell-based therapies, and traditional chemotherapy. There are also a number of pharmaceutical companies with product candidates in development that target the nodes involving the RAS/MAPK pathway. These include, among others, Amgen, AstraZeneca, Black Diamond Therapeutics, BioMed Valley Discoveries, Boehringer Ingelheim, Deciphera Pharmaceuticals, Eli Lilly, Jacobio Pharmaceuticals (in collaboration with AbbVie), Janssen, Merck, Mirati Therapeutics, Navire Pharma (a subsidiary of BridgeBio), Novartis, Pfizer, Relay Therapeutics (in collaboration with Genentech), Revolution Medicines, Roche/Genentech, Sanofi, and Schrödinger (in collaboration with Bristol Myers Squibb).

Intellectual property

We strive to protect the proprietary technology, inventions, and improvements that are commercially or strategically important to our business, including seeking, maintaining, and defending patent rights, whether developed internally or in-licensed/acquired from third parties. We also rely on trade secrets and know-how relating to our proprietary technology and product candidates and continuing innovation to develop, strengthen and maintain our proprietary position. We also plan to rely on data exclusivity, market exclusivity and patent term adjustments or extensions when available. Our commercial success will depend in part on our ability to obtain and maintain patent and other intellectual property protection for our proprietary technology, inventions and improvements; to preserve the confidentiality of our trade secrets; to defend and enforce our proprietary rights, including any patents or trademarks that we may own in the future; and to operate without infringing on the valid and enforceable patents and other proprietary rights of third parties. Intellectual property rights may not address all potential threats to our competitive advantage.

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We continually assess and refine our intellectual property strategy as we develop new product candidates. To that end, we are prepared to file additional patent applications in any appropriate fields if our intellectual property strategy includes such filings, or where we seek to adapt to competition or seize business opportunities. Further, we are prepared to file patent applications, as we consider appropriate under the circumstances, relating to the new technologies that we develop.

We cannot be sure that patents will be granted with respect to any of our pending patent applications or with respect to any patent applications we may own or license in the future, nor can we be sure that any of our existing patents or any patents we may own or license in the future will be useful in protecting our technology.

To cover our proprietary technologies and our current pipeline of proprietary product candidates and related methods, such as methods of use, we have issued patents and patent applications representing thirty-eight patent families. As of December 31, 2021, our patent estate, which consists of owned and in-licensed patent families, includes seven issued US patents, eleven pending US non-provisional patent applications, fifty-one pending US provisional patent applications, three issued foreign patents, eleven pending international patent applications filed under the Patent Cooperation Treaty (PCT application), and ninety-four pending foreign patent applications in various markets outside of the United States. In particular, we have patent applications pending for each of our product candidates.

ERAS-007

As of December 31, 2021, we have in-licensed three patent families from Asana. The three patent families relate to ERK 1/2 inhibitors, their preparation, and methods of use. One of the families covers the ERAS-007 product candidate compound and additional ERK1/2 inhibitor compounds, their preparation and method of use, and includes four issued US patents, one pending US non-provisional patent application, three issued foreign patents, and fourteen pending foreign patent applications. The second and third families cover methods of using ERAS-007, and includes one pending US provisional patent application, one pending PCT application and two pending foreign patent applications. The issued US patents are expected to expire in June 2036, absent any patent term adjustments or extensions. Any patents issued from the patent applications related to ERAS-007 are expected to expire between 2036 and 2042, absent any patent term adjustments or extensions.

As of December 31, 2021, we also own six patent families relating to ERAS-007. The patent families include fifteen pending US provisional patent applications. Any patents issued from these patent applications are expected to expire in 2042, absent any patent term adjustments or extensions.

ERAS-601

As of December 31, 2021, we have in-licensed two patent families from NiKang. The two patent families relate to SHP2 inhibitor compositions, their preparation, and methods of use. One of the families covers the ERAS-601 product candidate compound, its preparation and method of use, and includes two issued US patents, two pending US non-provisional patent applications, and twenty-six pending foreign patent applications. The second family covers additional SHP2 inhibitor compositions, their preparation and methods of use, and includes one pending US non-provisional application and six pending foreign patent applications. The granted patent and any further patents that issue from these applications from the two families are expected to expire in 2039, absent any patent term adjustments or extensions.

As of December 31, 2021, we also own seven patent families relating to ERAS-601. These families include ten pending US provisional patent applications and three pending PCT applications. Any patents issued from these applications are expected to expire between 2041 and 2042, absent any patent term adjustments or extensions.

ERAS-3490

As of December 31, 2021, we own six patent families relating to KRAS G12C inhibitors, their preparation, and method of use. These patent families include four pending US non-provisional patent applications, eight pending US provisional patent applications, five pending PCT applications, and two pending foreign applications. Any patents issued from these applications are expected to expire between 2040 and 2042, absent any patent term adjustments or extensions.

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ERAS-801

As of December 31, 2021, we have sub-licensed three patent families from Katmai, which Katmai in-licensed from the University of California, Los Angeles (UCLA). Two of the patent families relate to EGFR inhibitor compositions, their preparation, and methods of use. The first patent family includes one pending US non-provisional patent application, and eight pending foreign patent applications. The second patent family covers the ERAS-801 product candidate and includes one pending US non-provisional application and twenty-three pending foreign patent applications. The third patent family relates to a functional companion assay for brain cancer therapy and includes one pending PCT application. Any patents issued from the first family of applications are expected to expire in 2038, any patents issued from the second family of applications are expected to expire in 2040, and any patents issued from the third family of applications are expected to expire in 2041, in each case, absent any patent term adjustments or extensions.

As of December 31, 2021, we also co-own with UCLA one patent family relating to EGFR inhibitor compositions, their preparation and methods of use. This patent family includes one pending PCT application. Any patents issued from this application are expected to expire in 2041, absent any patent term adjustments or extensions.

As of December 31, 2021, we also own one patent family relating to EGFR inhibitor polymorph forms. This patent family includes one pending US provisional patent application. Any patents issued from this application are expected to expire in 2042, absent any patent term adjustments or extensions.

ERAS-2/3

As of December 31, 2021, we have in-licensed one patent family from UCSF relating to covalent inhibitors of GTP- and GDP-bound RAS, their preparation, and method of use. This patent family includes one issued US patent, one pending US non-provisional patent application and 13 pending foreign patent applications. The granted patent and any further patents that issue from these applications are expected to expire in 2037, absent any patent term adjustments or extensions.

ERAS-4

As of December 31, 2021, we own three patent families relating to KRAS G12D inhibitors, their preparation, and method of use. These patent families include six pending US provisional patent applications. Any patents issued from these applications are expected to expire in 2042, absent any patent term adjustments or extensions.

ERAS-5

As of December 31, 2021, we have in-licensed one patent family from LifeArc relating to ULK1/2 inhibitors, their preparation, and method of use. The patent family includes one pending US provisional patent application. Any patents issued from this application are expected to expire in 2042, absent any patent term adjustments or extensions.

As of December 31, 2021, we also own one patent family relating to ULK1/2 inhibitors, their preparation and method of use. This family includes one pending US provisional patent application. Any patents that issue from this application are expected to expire in 2042, absent any patent term adjustments or extensions.

ERAS-10

As of December 31, 2021, we own two patent families relating to PROTAC conjugates with undisclosed RAS/MAPK pathway target(s), their preparation, and method of use. These patent families includes seven pending US provisional patent applications. Any patents issued from these applications are expected to expire in 2042, absent any patent term adjustments or extensions.

ERAS-12

As of December 31, 2021, we own one patent family relating to EGFR D2/D3 bispecific antibodies, their preparation, and method of use. The patent family includes one pending US provisional patent application. Any patents issued from this application are expected to expire in 2042, absent any patent term adjustments or extensions.

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Other IP programs or patents

With respect to our product candidates and processes we intend to develop and commercialize in the normal course of business, we intend to pursue patent protection covering, when possible, compositions, methods of use, dosing and formulations. We may also pursue patent protection with respect to manufacturing and drug development processes and technologies. Obtaining and maintaining patent protection depends on compliance with various procedural, document submission, fee payment, and other requirements imposed by governmental patent agencies. We may not be able to obtain patent protections for our compositions, methods of use, dosing and formulations, manufacturing and drug development processes and technologies throughout the world. Issued patents can provide protection for varying periods of time, depending upon the date of filing of the patent application, the date of patent issuance and the legal term of patents in the countries in which they are obtained. In general, patents issued for applications filed in the United States can provide exclusionary rights for 20 years from the earliest effective filing date. In addition, in certain instances, the term of an issued US patent that covers or claims an FDA-approved product can be extended to recapture a portion of the term effectively lost as a result of the FDA regulatory review period, which is called patent term extension. The restoration period cannot be longer than five years and the total patent term, including the restoration period, must not exceed 14 years following FDA approval. The US Patent and Trademark Office (USPTO) may also adjust the term of a US patent to accommodate for delays caused by the USPTO during the prosecution of a US patent application. Congress has defined the conditions upon which an applicant can receive an adjustment to the term and such requirements are established in 35 USC 154(b). Similar provisions are available in Europe and other jurisdictions to extend the term of a patent that covers an approved drug. The term of patents outside of the United States varies in accordance with the laws of the foreign jurisdiction, but typically is also 20 years from the earliest effective filing date. However, the actual protection afforded by a patent varies on a product-by-product basis, from country-to-country, and depends upon many factors, including the type of patent, the scope of its coverage, the availability of regulatory-related extensions, the availability of legal remedies in a particular country, and the validity and enforceability of the patent. Patent terms may be inadequate to protect our competitive position on our products for an adequate amount of time. In the future, if and when our therapeutic candidates receive FDA approval, we expect to apply for patent term extensions on patents covering those therapeutic candidates. We intend to seek patent term extensions in any jurisdiction where these are available and where we also have a patent that may be eligible; however, there is no guarantee that the applicable authorities, including the USPTO and FDA, will agree with our assessment of whether such extensions should be granted, and even if granted, the length of such extensions.

The patent positions of companies like ours are generally uncertain and involve complex legal and factual questions. No consistent policy regarding the scope of claims allowable in patents in the field of biopharmaceuticals has emerged in the United States. The relevant patent laws and their interpretation outside of the United States is also uncertain. Changes in either the patent laws or their interpretation in the United States and other countries may diminish our ability to protect our technology or product candidates and could affect the value of such intellectual property. In particular, our ability to stop third parties from making, using, selling, offering to sell or importing products that infringe our intellectual property will depend in part on our success in obtaining and enforcing patent claims that cover our technology, inventions and improvements. We cannot guarantee that patents will be granted with respect to any of our pending patent applications or with respect to any patent applications we may file in the future, nor can we be sure that any patents that may be granted to us in the future will be commercially useful in protecting our products, the methods of use or manufacture of those products. Moreover, even our issued patents do not guarantee us the right to practice our technology in relation to the commercialization of our products. Patent and other intellectual property rights in the pharmaceutical and biotechnology space are evolving and involve many risks and uncertainties. For example, third parties may have blocking patents that could be used to prevent us from commercializing our product candidates and practicing our proprietary technology, and our issued patents may be challenged, invalidated or circumvented, which could limit our ability to stop competitors from marketing related products or could limit the term of patent protection that otherwise may exist for our product candidates. In addition, the scope of the rights granted under any issued patents may not provide us with protection or competitive advantages against competitors with similar technology. Furthermore, our competitors may independently develop similar technologies that are outside the scope of the rights granted under any issued patents. For these reasons, we may face competition with respect to our product candidates. Moreover, because of the extensive time required for development, testing and regulatory review of a potential product, it is possible that, before any particular product candidate can be commercialized, any patent protection for such product may expire or remain in force for only a short period following commercialization, thereby reducing the commercial advantage the patent provides.

We also rely on trade secrets to protect aspects of our technology and business not amenable to, or that we do not consider appropriate for, patent protection. We seek to protect this intellectual property, in part, by requiring our employees, consultants, outside scientific collaborators, sponsored researchers and other service providers and advisors to execute confidentiality agreements upon the commencement of employment or other relationship with us. In general, these agreements provide that confidential information concerning our business or financial affairs developed or made

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known to the individual during the course of the individual’s relationship with us is to be kept confidential and not disclosed to third parties except in specific circumstances. In the case of employees, the agreements further provide that inventions and discoveries conceived or reduced to practice by the individual that are related to our business, or actual, or demonstrably anticipated, research or development, or made during normal working hours, on our premises or using our equipment, supplies, or proprietary information, are our exclusive property. In many cases our agreements with consultants, outside scientific collaborators, sponsored researchers and other service providers and advisors require them to assign, or grant us licenses to, inventions resulting from the work or services they render under such agreements or grant us an option to negotiate a license to use such inventions.

We seek trademark protection in the United States and in certain other jurisdictions where available and when we deem appropriate. We currently have registrations for our “ERASCA” mark in the United States as well as in over 20 foreign jurisdictions, including the European Union. We have also filed a trademark application in the United States as well as over 20 foreign jurisdictions for registration of our “MAPKLAMP” mark.

Manufacturing

We do not own or operate, and currently have no plans to establish, any manufacturing facilities. We rely, and expect to continue to rely, on third parties for the manufacture of our product candidates for preclinical and clinical testing, as well as for commercial manufacture if any of our product candidates obtain marketing approval. We are working with our current manufacturers to ensure that we will be able to scale up our manufacturing capabilities to support our clinical plans. We are also in the process of locating and qualifying additional manufacturers to build redundancies into our supply chain. In addition, we rely on third parties to package, label, store, and distribute our product candidates, and we intend to rely on third parties for our commercial products if marketing approval is obtained. We believe that this strategy allows us to maintain a more efficient infrastructure by eliminating the need for us to invest in our own manufacturing facilities, equipment, and personnel while also enabling us to focus our expertise and resources on the design and development of our product candidates.

Government Regulation

The FDA and comparable regulatory authorities in state and local jurisdictions and in other countries impose substantial and burdensome requirements upon companies involved in the clinical development, manufacture, marketing and distribution of drugs and biologics such as those we are developing. These entities regulate, among other things, the research and development, testing, manufacture, quality control, safety, effectiveness, labeling, storage, record keeping, approval, advertising and promotion, distribution, post-approval monitoring and reporting, sampling and export and import of our product candidates.

US regulation of drugs and biologics

In the United States, the FDA regulates drugs under the Federal Food, Drug, and Cosmetic Act (FDCA), and its implementing regulations, and biologics under the FDCA and the Public Health Service Act and their implementing regulations. FDA approval of a new drug application (NDA) or biologics license application (BLA) or supplement is required before any new unapproved drug, biologic or dosage form, including a new use of a previously approved drug or biologic, can be marketed in the United States.

The process required by the FDA before such product candidates may be marketed in the United States generally involves the following:

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Preclinical studies include laboratory evaluation of product chemistry, toxicity and formulation, as well as in vitro and animal studies to assess potential safety and efficacy. The conduct of preclinical studies is subject to federal regulations and requirements, including GLP regulations applicable to certain safety/toxicology studies.

An IND is a request for authorization from the FDA to administer an investigational new drug product to humans. The central focus of an IND submission is on the general investigational plan and the protocol or protocols for preclinical studies and clinical trials. The IND also includes results of animal and in vitro studies assessing the toxicology, pharmacokinetics, pharmacology and pharmacodynamic characteristics of the product, chemistry, manufacturing and controls (CMC) information, and any available human data or literature to support the use of the investigational product. An IND must become effective before human clinical trials may begin. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA, within the 30-day period, raises safety concerns or questions about the proposed clinical trial. In such a case, the IND may be placed on clinical hold and the IND sponsor and the FDA must resolve any outstanding concerns or questions before the clinical trial can begin. Submission of an IND therefore may or may not result in FDA authorization to begin a clinical trial.

Clinical trials involve the administration of the investigational product to human subjects under the supervision of qualified investigators in accordance with GCP, which includes the requirement that all research subjects, or their legal representative, provide their informed consent for their participation in any clinical study. Clinical trials are conducted under protocols detailing, among other things, the inclusion and exclusion criteria, the objectives of the study, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated. A separate submission to the existing IND must be made for each successive clinical trial conducted during product development and for any subsequent protocol amendments. Furthermore, an independent IRB for each site proposing to conduct the clinical trial must review and approve the plan for any clinical trial and its informed consent form before the clinical trial begins at that site, and must monitor the study until completed. An IRB is charged with protecting the welfare and rights of trial participants and considers such items as whether the risks to individuals participating in the clinical trials are minimized and are reasonable in relation to anticipated benefits. Regulatory authorities, the IRB or the sponsor may suspend a clinical trial at any time on various grounds, including a finding that the subjects are being exposed to an unacceptable health risk or that the trial is unlikely to meet its stated objectives. Some studies also include oversight by an independent group of qualified experts organized by the clinical study sponsor, known as a data safety monitoring board or committee, which provides authorization for whether or not a study may move forward at designated check points based on access to certain data from the study and may recommend that the clinical trial be halted if it determines that there is an unacceptable safety risk for subjects or other grounds, such as no demonstration of efficacy. There are also requirements governing the reporting of clinical trials and clinical study results to public registries.

The clinical investigation of a drug is generally divided into three phases. Although the phases are usually conducted sequentially, they may overlap or be combined.

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Post-marketing studies, sometimes referred to as Phase 4 clinical trials, may be conducted after initial marketing approval. These clinical trials are used to gain additional experience from the treatment of patients in the intended therapeutic indication. In certain instances, such as with accelerated approval drugs, the FDA may mandate the performance of Phase 4 clinical trials as a condition of approval.

Concurrent with clinical trials, companies may complete additional animal studies and develop additional information about the biological characteristics of the product candidate, and must finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the product candidate and, among other things, must develop methods for testing the identity, strength, quality and purity of the final product, or for biologics, the safety, purity and potency.

While the IND is active, progress reports summarizing the results of the clinical trials and nonclinical studies performed since the last progress report, among other things, must be submitted at least annually to the FDA, and written IND safety reports must be submitted to the FDA and investigators for serious and unexpected suspected adverse events, findings from other studies suggesting a significant risk to humans exposed to the same or similar drugs or biologics, findings from animal or in vitro testing suggesting a significant risk to humans, and any clinically important increased incidence of a serious suspected adverse reaction compared to that listed in the protocol or investigator brochure.

In addition, during the development of a new drug or biologic, sponsors are given opportunities to meet with the FDA at certain points. These points may be prior to submission of an IND, at the end of Phase 2, and before an NDA or BLA is submitted. Meetings at other times may be requested. These meetings can provide an opportunity for the sponsor to share information about the data gathered to date, for the FDA to provide advice, and for the sponsor and the FDA to reach agreement on the next phase of development. Sponsors typically use the meetings at the end of the Phase 2 trial to discuss Phase 2 clinical results and present plans for the pivotal Phase 3 clinical trials that they believe will support approval of the new drug or biologic.

NDA and BLA review process

Assuming successful completion of all required testing in accordance with all applicable regulatory requirements, the results of product development, nonclinical studies and clinical trials are submitted to the FDA as part of an NDA or BLA requesting approval to market the product for one or more indications. The submission of an NDA or BLA requires payment of a substantial application user fee to the FDA, unless a waiver or exemption applies.

The NDA or BLA must include all relevant data available from pertinent preclinical studies and clinical trials, including negative or ambiguous results as well as positive findings, together with detailed information relating to the product’s CMC and proposed labeling, among other things. Data can come from company-sponsored clinical studies intended to test the safety and effectiveness of the product, or from a number of alternative sources, including studies initiated and sponsored by investigators.

In addition, under the Pediatric Research Equity Act (PREA), an NDA or BLA or supplement to an NDA or BLA must contain data to assess the safety and effectiveness of the biological product candidate for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. The Food and Drug Administration Safety and Innovation Act requires that a sponsor who is planning to submit a marketing application for a drug or biological product that includes a new active ingredient, new indication, new dosage form, new dosing regimen or new route of administration submit an initial pediatric study plan within sixty days after an end-of-Phase 2 meeting or as may be agreed between the sponsor and FDA. Unless otherwise required by regulation, PREA does not apply to any drug or biological product for an indication for which orphan designation has been granted.

Within 60 days following submission of the application, the FDA reviews the submitted BLA or NDA to determine if the application is substantially complete before the agency accepts it for filing. The FDA may refuse to file any NDA or BLA that it deems incomplete or not properly reviewable at the time of submission and may request additional information. In this event, the NDA or BLA must be resubmitted with the additional information. Once an NDA or BLA has been accepted for filing, the FDA’s goal is to review standard applications within ten months after the filing date, or, if the application qualifies for priority review, six months after the FDA accepts the application for filing. In both standard and priority

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reviews, the review process may also be extended by FDA requests for additional information or clarification. Once accepted for filing, the FDA reviews an NDA to determine, among other things, whether a product is safe and effective for its intended use and whether its manufacturing is sufficient to assure and preserve the product’s identity, strength, quality and purity. The FDA reviews a BLA to determine, among other things, whether a product is safe, pure and potent and the facility in which it is manufactured, processed, packed or held meets standards designed to assure the product’s continued safety, purity and potency. When reviewing an NDA or BLA, the FDA may convene an advisory committee to provide clinical insight on application review questions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions.

Before approving an NDA or BLA, the FDA will typically inspect the facility or facilities where the product is manufactured. The FDA will not approve an application unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. Additionally, before approving an NDA or BLA, the FDA will typically inspect one or more clinical sites to assure compliance with GCP.

After the FDA evaluates the NDA or BLA and conducts inspections of manufacturing facilities where the investigational product and/or its drug substance will be produced, the FDA may issue an approval letter or a Complete Response Letter (CRL). An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A CRL signals that the review cycle is complete and the application cannot be approved in its present form. The CRL will generally describe all of the deficiencies that the FDA has identified in the NDA or BLA, except that where the FDA determines that the data supporting the application are inadequate to support approval, the FDA may issue the CRL without first conducting required inspections, testing submitted product lots and/or reviewing proposed labeling. In issuing the CRL, the FDA may recommend actions that the applicant might take to place the NDA or BLA in condition for approval, including requests for additional information or clarification. The FDA may delay or refuse approval of an NDA or BLA if applicable regulatory criteria are not satisfied, require additional testing or information and/or require post-marketing testing and surveillance to monitor safety or efficacy of a product.

If regulatory approval of a product is granted, such approval will be granted for particular indications and may entail limitations on the indicated uses for which such product may be marketed. For example, the FDA may approve the NDA or BLA with a Risk Evaluation and Mitigation Strategy (REMS) to ensure the benefits of the product outweigh its risks. A REMS is a safety strategy to manage a known or potential serious risk associated with a product and to enable patients to have continued access to such medicines by managing their safe use, and could include medication guides, physician communication plans, or elements to assure safe use, such as restricted distribution methods, patient registries and other risk minimization tools. The FDA also may condition approval on, among other things, changes to proposed labeling or the development of adequate controls and specifications. Once approved, the FDA may withdraw the product approval if compliance with pre- and post-marketing requirements is not maintained or if problems occur after the product reaches the marketplace. The FDA may require one or more Phase 4 post-market studies and surveillance to further assess and monitor the product’s safety and effectiveness after commercialization, and may limit further marketing of the product based on the results of these post-marketing studies.

Expedited development and review programs

The FDA offers a number of expedited development and review programs for qualifying product candidates. For example, the fast track program is intended to expedite or facilitate the process for reviewing product candidates that meet certain criteria. Specifically, product candidates are eligible for fast track designation if they are intended to treat a serious or life-threatening disease or condition and demonstrate the potential to address unmet medical needs for the disease or condition. Fast track designation applies to the combination of the product candidate and the specific indication for which it is being studied. The sponsor of a fast track product candidate has opportunities for more frequent interactions with the review team during product development and, once an NDA or BLA is submitted, the product may be eligible for priority review, if the relevant criteria are met. A fast track product candidate may also be eligible for rolling review, where the FDA may consider for review sections of the NDA or BLA on a rolling basis before the complete application is submitted, if the sponsor provides a schedule for the submission of the sections of the NDA or BLA, the FDA agrees to accept sections of the NDA or BLA and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the NDA or BLA.

A product candidate intended to treat a serious or life-threatening disease or condition may also be eligible for breakthrough therapy designation to expedite its development and review. A product can receive breakthrough therapy designation if preliminary clinical evidence indicates that the product candidate, alone or in combination with one or more other drugs or biologics, may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The designation

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includes all of the fast track program features, as well as more intensive FDA interaction and guidance beginning as early as Phase 1 and an organizational commitment to expedite the development and review of the product candidate, including involvement of senior managers.

Any marketing application for a drug or biologic submitted to the FDA for approval, including a product candidate with a fast track designation and/or breakthrough therapy designation, may be eligible for other types of FDA programs intended to expedite the FDA review and approval process, such as priority review and accelerated approval. An NDA or BLA is eligible for priority review if the product candidate has the potential to provide a significant improvement in the treatment, diagnosis or prevention of a serious disease or condition. For new molecular entity NDAs and original BLAs, priority review designation means the FDA’s goal is to take action on the marketing application within six months of the 60-day filing date (as compared to 10 months under standard review).

Additionally, product candidates studied for their safety and effectiveness in treating serious or life-threatening diseases or conditions may receive accelerated approval upon a determination that the product candidate has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. As a condition of accelerated approval, the FDA will generally require the sponsor to perform adequate and well-controlled post-marketing clinical studies to verify and describe the anticipated effect on irreversible morbidity or mortality or other clinical benefit. Products receiving accelerated approval may be subject to expedited withdrawal procedures if the sponsor fails to conduct the required post-marketing studies or if such studies fail to verify the predicted clinical benefit. In addition, the FDA currently requires as a condition for accelerated approval pre-approval of promotional materials, which could adversely impact the timing of the commercial launch of the product.

Fast track designation, breakthrough therapy designation, priority review, and accelerated approval do not change the standards for approval but may expedite the development or approval process. Even if a product qualifies for one or more of these programs, the FDA may later decide that the product no longer meets the conditions for qualification or decide that the time period for FDA review or approval will not be shortened.

Orphan drug designation

Under the Orphan Drug Act, the FDA may grant orphan designation to a drug or biologic intended to treat a rare disease or condition, which is a disease or condition that affects fewer than 200,000 individuals in the United States, or more than 200,000 individuals in the United States for which there is no reasonable expectation that the cost of developing and making available in the United States a drug or biologic for this type of disease or condition will be recovered from sales in the United States for that drug or biologic. Orphan drug designation must be requested before submitting an NDA or BLA. After the FDA grants orphan drug designation, the generic identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. The orphan drug designation does not convey any advantage in, or shorten the duration of, the regulatory review or approval process.

If a product candidate that has orphan drug designation subsequently receives the first FDA approval for the disease for which it has such designation, the product is entitled to orphan drug exclusive approval (or exclusivity), which means that the FDA may not approve any other applications, including a full NDA or BLA, to market the same drug or biologic for the same indication for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or if the FDA finds that the holder of the orphan drug exclusivity has not shown that it can assure the availability of sufficient quantities of the orphan drug to meet the needs of patients with the disease or condition for which the drug or biologic was designated. Orphan drug exclusivity does not prevent the FDA from approving a different drug or biologic for the same disease or condition, or the same drug or biologic for a different disease or condition. Among the other benefits of orphan drug designation are tax credits for certain research and a waiver of the NDA or BLA application user fee.

A designated orphan drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan designation. In addition, exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition.

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Post-approval requirements

Any products manufactured or distributed pursuant to FDA approvals are subject to pervasive and continuing regulation by the FDA, including, among other things, requirements relating to record-keeping, reporting of adverse experiences, periodic reporting, product sampling and distribution, and advertising and promotion of the product. After approval, most changes to the approved product, such as adding new indications or other labeling claims, are subject to prior FDA review and approval. There also are continuing user fee requirements, under which the FDA assesses an annual program fee for each product identified in an approved NDA or BLA. Drug and biologic manufacturers and their subcontractors are required to register their establishments with the FDA and certain state agencies, and are subject to periodic unannounced inspections by the FDA and certain state agencies for compliance with cGMPs, which impose certain procedural and documentation requirements upon us and our third-party manufacturers. Changes to the manufacturing process are strictly regulated, and, depending on the significance of the change, may require prior FDA approval before being implemented. FDA regulations also require investigation and correction of any deviations from cGMPs and impose reporting requirements upon us and any third-party manufacturers that we may decide to use. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain compliance with cGMPs and other aspects of regulatory compliance.

The FDA may withdraw approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with manufacturing processes, or failure to comply with regulatory requirements, may result in revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical studies to assess new safety risks; or imposition of distribution restrictions or other restrictions under a REMS program. Other potential consequences include, among other things:

The FDA closely regulates the marketing, labeling, advertising and promotion of drug products. A company can make only those claims relating to safety and efficacy, purity and potency that are approved by the FDA and in accordance with the provisions of the approved label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses. Failure to comply with these requirements can result in, among other things, adverse publicity, warning letters, corrective advertising and potential civil and criminal penalties. Physicians may prescribe, in their independent professional medical judgment, legally available products for uses that are not described in the product’s labeling and that differ from those tested by us and approved by the FDA. Physicians may believe that such off-label uses are the best treatment for many patients in varied circumstances. The FDA does not regulate the behavior of physicians in their choice of treatments. The FDA does, however, restrict manufacturer’s communications on the subject of off-label use of their products. The federal government has levied large civil and criminal fines against companies for alleged improper promotion of off-label use and has enjoined companies from engaging in off-label promotion. The FDA and other regulatory agencies have also required that companies enter into consent decrees or permanent injunctions under which specified promotional conduct is changed or curtailed. However, companies may share truthful and not misleading information that is otherwise consistent with a product’s FDA-approved labeling.

In addition, the distribution of prescription biopharmaceutical products is subject to the Prescription Drug Marketing Act (PDMA) which regulates the distribution of drugs and drug samples at the federal level, and sets minimum standards for the registration and regulation of drug distributors by the states. Both the PDMA and state laws limit the distribution of prescription pharmaceutical product samples and impose requirements to ensure accountability in distribution.

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Drug product marketing exclusivity

Market exclusivity provisions under the FDCA can delay the submission or the approval of certain marketing applications. For example, the FDCA provides a five-year period of non-patent marketing exclusivity within the United States to the first applicant to obtain approval of an NDA for a new chemical entity. A drug is a new chemical entity if the FDA has not previously approved any other new drug containing the same active moiety, which is the molecule or ion responsible for the action of the drug substance. During the exclusivity period, the FDA may not approve or even accept for review an abbreviated new drug application (ANDA), or an NDA submitted under Section 505(b)(2), or 505(b) (2) NDA, submitted by another company for another drug based on the same active moiety, regardless of whether the drug is intended for the same indication as the original innovative drug or for another indication, where the applicant does not own or have a legal right of reference to all the data required for approval. However, an application may be submitted after four years if it contains a certification of patent invalidity or non-infringement to one of the patents listed with the FDA by the innovator NDA holder.

The FDCA alternatively provides three years of marketing exclusivity for an NDA, or supplement to an existing NDA if new clinical investigations, other than bioavailability studies, that were conducted or sponsored by the applicant are deemed by the FDA to be essential to the approval of the application, for example new indications, dosages or strengths of an existing drug. This three-year exclusivity covers only the modification for which the drug received approval on the basis of the new clinical investigations and does not prohibit the FDA from approving ANDAs or 505(b)(2) NDAs for drugs containing the active agent for the original indication or condition of use. Five-year and three-year exclusivity will not delay the submission or approval of a full NDA. However, an applicant submitting a full NDA would be required to conduct or obtain a right of reference to any preclinical studies and adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness.

Pediatric exclusivity is another type of marketing exclusivity available in the United States. Pediatric exclusivity provides for an additional six months of marketing exclusivity attached to another period of exclusivity if a sponsor conducts clinical trials in children in response to a Written Request from the FDA. The issuance of a written request does not require the sponsor to undertake the described clinical trials. In addition, orphan drug exclusivity, as described above, may offer a seven-year period of marketing exclusivity, except in certain circumstances.

Biosimilars and reference product exclusivity

The Biologics Price Competition and Innovation Act of 2009 (BPCIA) created an abbreviated approval pathway for biological products that are highly similar, or “biosimilar,” to or interchangeable with an FDA-approved reference biological product. Biosimilarity, which requires that there be no clinically meaningful differences between the biological product and the reference product in terms of safety, purity, and potency, is generally shown through analytical studies, animal studies, and a clinical study or studies. Interchangeability requires that a product is biosimilar to the reference product and the product must demonstrate that it can be expected to produce the same clinical results as the reference product in any given patient and, for products that are administered multiple times to an individual, the biologic and the reference biologic may be alternated or switched after one has been previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biologic. A product shown to be biosimilar or interchangeable with an FDA-approved reference biological product may rely in part on the FDA’s previous determination of safety and effectiveness for the reference product for approval, which can potentially reduce the cost and time required to obtain approval to market the product.

Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date that the reference product was first licensed by the FDA. In addition, the approval of a biosimilar product may not be made effective by the FDA until 12 years from the date on which the reference product was first licensed. During this 12-year period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product containing that applicant’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of its product. The BPCIA also created certain exclusivity periods for biosimilars approved as interchangeable products. At this juncture, it is unclear whether products deemed “interchangeable” by the FDA will, in fact, be readily substituted by pharmacies, which are governed by state pharmacy law.

A biological product can also obtain pediatric market exclusivity in the United States. Pediatric exclusivity, if granted, adds six months to existing exclusivity periods and patent terms. This six-month exclusivity, which runs from the end of other exclusivity protection or patent term, may be granted based on the voluntary completion of a pediatric study in accordance with an FDA-issued “Written Request” for such a study.

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FDA regulation of companion diagnostics

If safe and effective use of a drug or biologic depends on an in vitro diagnostic, then the FDA may require approval or clearance of that diagnostic, known as a companion diagnostic, at the same time that the FDA approves the therapeutic product. In August 2014, the FDA issued final guidance clarifying the requirements that will apply to approval of therapeutic products and in vitro companion diagnostics. According to the guidance, if FDA determines that a companion diagnostic device is essential to the safe and effective use of a novel therapeutic product or indication, FDA may will not approve the drug or new indication if the companion diagnostic device is not also approved or cleared for that indication. Approval or clearance of the companion diagnostic device will ensure that the device has been adequately evaluated and has adequate performance characteristics in the intended population. The review of in vitro companion diagnostics in conjunction with the review of our product candidates will, therefore, likely involve coordination of review by the FDA’s Center for Drug Evaluation and Research or the FDA’s Center for Biologics Evaluation and Research and the FDA’s Center for Devices and Radiological Health Office of In Vitro Diagnostics and Radiological Health.

Under the FDCA, in vitro diagnostics, including companion diagnostics, are regulated as medical devices. In the United States, the FDCA and its implementing regulations, and other federal and state statutes and regulations govern, among other things, medical device design and development, preclinical and clinical testing, premarket clearance or approval, registration and listing, manufacturing, labeling, storage, advertising and promotion, sales and distribution, export and import, and post-market surveillance. Unless an exemption applies, diagnostic tests require marketing clearance or approval from the FDA prior to commercial distribution. The two primary types of FDA marketing authorization applicable to a medical device are clearance of a premarket notification pursuant to Section 510(k) of the FDCA, also called 510(k) clearance, and approval of a premarket approval application (PMA).

The PMA process, including the gathering of clinical and preclinical data and the submission to and review by the FDA, can take several years or longer. It involves a rigorous premarket review during which the applicant must prepare and provide the FDA with reasonable assurance of the device’s safety and effectiveness and information about the device and its components regarding, among other things, device design, manufacturing and labeling. PMA applications are subject to an application fee. In addition, PMAs for certain devices must generally include the results from extensive preclinical and adequate and well-controlled clinical trials to establish the safety and effectiveness of the device for each indication for which FDA approval is sought. As part of the PMA review, the FDA will typically inspect the manufacturer’s facilities for compliance with the Quality System Regulation (QSR) which imposes elaborate testing, control, documentation and other quality assurance requirements.

If the FDA’s evaluation of the PMA application is favorable, the FDA typically issues an approvable letter requiring the applicant’s agreement to specific conditions, such as changes in labeling, or specific additional information, such as submission of final labeling, in order to secure final approval of the PMA. If the FDA’s evaluation of the PMA or manufacturing facilities is not favorable, the FDA will deny approval of the PMA or issue a not approvable letter. A not approvable letter will outline the deficiencies in the application and, where practical, will identify what is necessary to make the PMA approvable. The FDA may also determine that additional clinical trials are necessary, in which case the PMA approval may be delayed for several months or years while the trials are conducted and then the data submitted in an amendment to the PMA. If the FDA concludes that the applicable criteria have been met, the FDA will issue a PMA for the approved indications, which can be more limited than those originally sought by the applicant. The PMA can include post-approval conditions that the FDA believes necessary to ensure the safety and effectiveness of the device, including, among other things, restrictions on labeling, promotion, sale and distribution. Once granted, PMA approval may be withdrawn by the FDA if compliance with post-approval requirements, conditions of approval or other regulatory standards are not maintained or problems are identified following initial marketing.

After a device is placed on the market, it remains subject to significant regulatory requirements. Medical devices may be marketed only for the uses and indications for which they are cleared or approved. Device manufacturers must also establish registration and device listings with the FDA. A medical device manufacturer’s manufacturing processes and those of its suppliers are required to comply with the applicable portions of the QSR, which cover the methods and documentation of the design, testing, production, processes, controls, quality assurance, labeling, packaging and shipping of medical devices. Domestic facility records and manufacturing processes are subject to periodic unscheduled inspections by the FDA. The FDA also may inspect foreign facilities that export products to the United States.

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Other US regulatory requirements

In addition to FDA regulation of pharmaceutical products, pharmaceutical companies are also subject to additional healthcare regulation and enforcement by the federal government and by authorities in the states and foreign jurisdictions in which they conduct their business and may constrain the financial arrangements and relationships through which we research, as well as sell, market and distribute any products for which we obtain marketing authorization. Such laws include, without limitation, state and federal anti-kickback, fraud and abuse, false claims, data privacy and security, and transparency laws and regulations related to drug pricing and payments and other transfers of value made to physicians and other healthcare providers. If their operations are found to be in violation of any of such laws or any other governmental regulations that apply, they may be subject to penalties, including, without limitation, administrative, civil and criminal penalties, damages, fines, disgorgement, the curtailment or restructuring of operations, integrity oversight and reporting obligations, exclusion from participation in federal and state healthcare programs and imprisonment.

US coverage and reimbursement

Significant uncertainty exists as to the coverage and reimbursement status of any product candidate for which we may seek regulatory approval. Sales in the United States will depend, in part, on the availability of sufficient coverage and adequate reimbursement from third-party payors, which include government health programs such as Medicare, Medicaid, TRICARE and the Veterans Administration, as well as managed care organizations and private health insurers. Prices at which we or our customers seek reimbursement for our product candidates can be subject to challenge, reduction or denial by third-party payors.

The process for determining whether a third-party payor will provide coverage for a product is typically separate from the process for setting the reimbursement rate that the payor will pay for the product. In the United States, there is no uniform policy among payors for coverage or reimbursement. Decisions regarding whether to cover any of a product, the extent of coverage and amount of reimbursement to be provided are made on a plan-by-plan basis. Third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own coverage and reimbursement policies, but also have their own methods and approval processes. Therefore, coverage and reimbursement for products can differ significantly from payor to payor. As a result, the coverage determination process is often a time-consuming and costly process that can require manufacturers to provide scientific and clinical support for the use of a product to each payor separately, with no assurance that coverage and adequate reimbursement will be applied consistently or obtained in the first instance. In addition, companion diagnostic tests require coverage and reimbursement separate and apart from the coverage and reimbursement for their companion pharmaceutical or biological products. Similar challenges to obtaining coverage and reimbursement, applicable to pharmaceutical or biological products, will apply to companion diagnostics.

Third-party payors are increasingly challenging the price and examining the medical necessity and cost-effectiveness of medical products and services, in addition to their safety and efficacy. Third-party payors may not consider our product candidates to be medically necessary or cost-effective compared to other available therapies. Adoption of price controls and cost-containment measures, and adoption of more restrictive policies in jurisdictions with existing controls and measures, could further limit sales of any product that receives approval.

US healthcare reform

In the United States, there have been, and continue to be, legislative and regulatory changes and proposed changes regarding the healthcare system that could prevent or delay marketing approval of product candidates, restrict or regulate post-approval activities, and affect the profitable sale of product candidates. Among policy makers and payors in the United States, there is significant interest in promoting changes in healthcare systems with the stated goals of containing healthcare costs, improving quality and/or expanding access. In the United States, the pharmaceutical industry has been a particular focus of these efforts and has been significantly affected by major legislative initiatives.

By way of example, in March 2010, the Patient Protection and Affordable Care Act (the ACA) was passed, which substantially changed the way healthcare is financed by both governmental and private insurers, and significantly affected the pharmaceutical industry. The ACA, among other things, increased the minimum level of Medicaid rebates payable by manufacturers of brand name drugs from 15.1% to 23.1% of the average manufacturer price; required collection of rebates for drugs paid by Medicaid managed care organizations; required manufacturers to participate in a coverage gap discount program, in which manufacturers must agree to offer point-of-sale discounts off negotiated prices of applicable brand drugs to eligible beneficiaries during their coverage gap period, as a condition for the manufacturer’s outpatient drugs to be covered under Medicare Part D; imposed a non-deductible annual fee on pharmaceutical manufacturers or importers who sell certain “branded prescription drugs” to specified federal government programs; implemented a new methodology by which rebates owed by manufacturers under the Medicaid Drug Rebate Program are calculated for drugs

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that are inhaled, infused, instilled, implanted, or injected; expanded eligibility criteria for Medicaid programs; creates a new Patient-Centered Outcomes Research Institute to oversee, identify priorities in, and conduct comparative clinical effectiveness research, along with funding for such research; and established a Center for Medicare Innovation at the Centers for Medicare & Medicaid Services (CMS) to test innovative payment and service delivery models to lower Medicare and Medicaid spending, potentially including prescription drug spending.

Since its enactment, there have been judicial, executive and political challenges to certain aspects of the ACA. On June 17, 2021, the US Supreme Court dismissed a challenge on procedural grounds that argued the ACA is unconstitutional in its entirety because the “individual mandate” was repealed by Congress. Thus, the ACA will remain in effect in its current form. Prior to the US Supreme Court ruling, President Biden issued an executive order that initiated initiate a special enrollment period from February 15, 2021 through August 15, 2021 for purposes of obtaining health insurance coverage through the ACA marketplace. The executive order also instructed certain governmental agencies to review and reconsider their existing policies and rules that limit access to healthcare, including among others, reexamining Medicaid demonstration projects and waiver programs that include work requirements, and policies that create unnecessary barriers to obtaining access to health insurance coverage through Medicaid or the ACA. It is unclear how other healthcare reform measures of the Biden administration will impact our business.

In addition, other legislative changes have been proposed and adopted since the ACA was enacted. These changes included aggregate reductions to Medicare payments to providers of 2% per fiscal year, which went into effect on April 1, 2013 and, due to subsequent legislative amendments to the statute, will remain in effect through 2030, with the exception of a temporary suspension from May 1, 2020 through March 31, 2022, unless additional Congressional action is taken. On January 2, 2013, the American Taxpayer Relief Act of 2012 was signed into law, which, among other things, reduced Medicare payments to several providers, including hospitals, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years.

Moreover, there has recently been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for pharmaceutical products. Further, we expect that additional healthcare reform measures will be adopted in the future, particularly in light of the new presidential administration.

Individual states in the United States have also become increasingly active in implementing regulations designed to control pharmaceutical product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. In addition, regional healthcare authorities and individual hospitals are increasingly using bidding procedures to determine which drugs and suppliers will be included in their healthcare programs Furthermore, there has been increased interest by third party payors and governmental authorities in reference pricing systems and publication of discounts and list prices.

EU drug regulation

In order to market any product outside of the United States, we would need to comply with numerous and varying regulatory requirements of other countries and jurisdictions regarding quality, safety and efficacy and governing, among other things, clinical trials, marketing authorization, commercial sales and distribution of our products. Whether or not we obtain FDA approval for a product, we would need to obtain the necessary approvals by the comparable foreign regulatory authorities before we can commence clinical trials or marketing of the product in foreign countries and jurisdictions such as in China and Japan. Although many of the issues discussed above with respect to the United States apply similarly in the context of the European Union (EU), the approval process varies between countries and jurisdictions and can involve additional product testing and additional administrative review periods. The time required to obtain approval in other countries and jurisdictions might differ from and be longer than that required to obtain FDA approval. Regulatory approval in one country or jurisdiction does not ensure regulatory approval in another, but a failure or delay in obtaining regulatory approval in one country or jurisdiction may negatively impact the regulatory process in others. Failure to comply with applicable foreign regulatory requirements, may be subject to, among other things, fines, suspension or withdrawal of regulatory approvals, product recalls, seizure of products, operating restrictions and criminal prosecution.

Non-clinical studies and clinical trials

Similarly to the United States, the various phases of non-clinical and clinical research in the EU are subject to significant regulatory controls.

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Non-clinical studies are performed to demonstrate the health or environmental safety of new chemical or biological substances. Non-clinical studies must be conducted in compliance with the principles of good laboratory practice (GLP) as set forth in EU Directive 2004/10/EC. In particular, non-clinical studies, both in vitro and in vivo, must be planned, performed, monitored, recorded, reported and archived in accordance with the GLP principles, which define a set of rules and criteria for a quality system for the organizational process and the conditions for non-clinical studies. These GLP standards reflect the Organization for Economic Co-operation and Development requirements.

Clinical trials of medicinal products in the EU must be conducted in accordance with EU and national regulations and the International Conference on Harmonization (ICH) guidelines on GCP as well as the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki. Additional GCP guidelines from the European Commission, focusing in particular on traceability, apply to clinical trials of advanced therapy medicinal products. If the sponsor of the clinical trial is not established within the EU, it must appoint an entity within the EU to act as its legal representative. The sponsor must take out a clinical trial insurance policy, and in most EU member states, the sponsor is liable to provide ‘no fault’ compensation to any study subject injured in the clinical trial.

Certain countries outside of the United States, including the EU, have a similar process that requires the submission of a clinical study application (CTA) much like the IND prior to the commencement of human clinical studies. A CTA must be submitted to each country’s national health authority and an independent ethics committee, much like the FDA and the IRB, respectively. Once the CTA is approved by the national health authority and the ethics committee has granted a positive opinion in relation to the conduct of the trial in the relevant member state(s), in accordance with a country’s requirements, clinical study development may proceed.

The CTA must include, among other things, a copy of the trial protocol and an investigational medicinal product dossier containing information about the manufacture and quality of the medicinal product under investigation. Currently, CTAs must be submitted to the competent authority in each EU member state in which the trial will be conducted. Under the new Regulation on Clinical Trials, which is currently expected to become applicable by early 2022, there will be a centralized application procedure where one national authority takes the lead in reviewing the application and the other national authorities have only a limited involvement. Any substantial changes to the trial protocol or other information submitted with the CTA must be notified to or approved by the relevant competent authorities and ethics committees. Medicines used in clinical trials must be manufactured in accordance with good manufacturing practice (GMP). Other national and EU-wide regulatory requirements also apply.

Marketing Authorizations

To market a medicinal product in the EU and in many other foreign jurisdictions, we must obtain separate regulatory approvals. More concretely, in the EU, medicinal product candidates can only be commercialized after obtaining a Marketing Authorization (MA). To obtain regulatory approval of an investigational medicinal product under EU regulatory systems, we must submit a marketing authorization application (MAA.) The process for doing this depends, among other things, on the nature of the medicinal product. There are two types of MAs:

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Under the above-described procedures, in order to grant the MA, the EMA or the competent authorities of the EU member states make an assessment of the risk-benefit balance of the product on the basis of scientific criteria concerning its quality, safety and efficacy.

Under the Centralized Procedure, the maximum timeframe for the evaluation of a MAA by the EMA is 210 days. Where there is a major public health interest and an unmet medical need for a product, the CHMP may perform an accelerated review of a MA in no more than 150 days (not including clock stops). Innovative products that target an unmet medical need and are expected to be of major public health interest may be eligible for a number of expedited development and review programs, such as the PRIME scheme, which provides incentives similar to the breakthrough therapy designation in the US PRIME is a voluntary scheme aimed at enhancing the EMA’s support for the development of medicines that target unmet medical needs. It is based on increased interaction and early dialogue with companies developing promising medicines, to optimize their product development plans and speed up their evaluation to help them reach patients earlier. Product developers that benefit from PRIME designation can expect to be eligible for accelerated assessment but this is not guaranteed. The benefits of a PRIME designation include the appointment of a CHMP rapporteur before submission of a MAA, early dialogue and scientific advice at key development milestones, and the potential to qualify products for accelerated review earlier in the application process.

MAs have an initial duration of five years. After these five years, the authorization may be renewed for an unlimited period on the basis of a reevaluation of the risk-benefit balance, unless the EMA decides, on justified grounds relating to pharmacovigilance, to mandate one additional five-year renewal period.

Data and marketing exclusivity

The EU also provides opportunities for market exclusivity. Upon receiving MA, new chemical entity, or reference product candidates, generally receive eight years of data exclusivity and an additional two years of market exclusivity. If granted, the data exclusivity period prevents generic or biosimilar applicants from relying on the pre-clinical and clinical trial data contained in the dossier of the reference product when applying for a generic or biosimilar MA in the EU during a period of eight years from the date on which the reference product was first authorized in the EU. The market exclusivity period prevents a successful generic or biosimilar applicant from commercializing its product in the EU until 10 years have elapsed from the initial authorization of the reference product in the EU. The overall 10-year market exclusivity period can be extended to a maximum of eleven years if, during the first eight years of those 10 years, the MA holder obtains an authorization for one or more new therapeutic indications which, during the scientific evaluation prior to their authorization, are held to bring a significant clinical benefit in comparison with existing therapies. However, there is no guarantee that a product will be considered by the EU’s regulatory authorities to be a new chemical entity, and products may not qualify for data exclusivity.

Pediatric Development

In the EU, MAAs for new medicinal products candidates have to include the results of trials conducted in the pediatric population, in compliance with a pediatric investigation plan (PIP) agreed with the EMA’s Pediatric Committee (PDCO). The PIP sets out the timing and measures proposed to generate data to support a pediatric indication of the drug for which MA is being sought. The PDCO can grant a deferral of the obligation to implement some or all of the measures of the PIP until there is sufficient data to demonstrate the efficacy and safety of the product in adults. Further, the obligation to provide pediatric clinical trial data can be waived by the PDCO when these data is not needed or appropriate because the product is likely to be ineffective or unsafe in children, the disease or condition for which the product is intended occurs only in adult populations, or when the product does not represent a significant therapeutic benefit over existing treatments for pediatric patients. Once the MA is obtained in all EU Member States and study results are included in the product information, even when negative, the product is eligible for six months’ supplementary protection certificate extension (if any is in effect at the time of authorization).

Post-Approval Requirements

Similar to the United States, both MA holders and manufacturers of medicinal products are subject to comprehensive regulatory oversight by the EMA, the European Commission and/or the competent regulatory authorities of the member states. The holder of a MA must establish and maintain a pharmacovigilance system and appoint an individual qualified person for pharmacovigilance who is responsible for oversight of that system. Key obligations include expedited reporting of suspected serious adverse reactions and submission of periodic safety update reports (PSURs).

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All new MAA must include a risk management plan (RMP) describing the risk management system that the company will put in place and documenting measures to prevent or minimize the risks associated with the product. The regulatory authorities may also impose specific obligations as a condition of the MA. Such risk-minimization measures or post-authorization obligations may include additional safety monitoring, more frequent submission of PSURs, or the conduct of additional clinical trials or post-authorization safety studies.

The advertising and promotion of medicinal products is also subject to laws concerning promotion of medicinal products, interactions with physicians, misleading and comparative advertising and unfair commercial practices. All advertising and promotional activities for the product must be consistent with the approved summary of product characteristics, and therefore all off-label promotion is prohibited. Direct-to-consumer advertising of prescription medicines is also prohibited in the EU. Although general requirements for advertising and promotion of medicinal products are established under EU directives, the details are governed by regulations in each member state and can differ from one country to another.

The aforementioned EU rules are generally applicable in the European Economic Area (EEA) which consists of the 27 EU member states plus Norway, Liechtenstein and Iceland.

For other countries outside of the EU, such as countries in Latin America or Asia (e.g., China and Japan), the requirements governing the conduct of clinical studies, product licensing, pricing and reimbursement vary from country to country. In all cases, again, the clinical studies are conducted in accordance with GCP and the applicable regulatory requirements and the ethical principles that have their origin in the Declaration of Helsinki. If we fail to comply with applicable foreign regulatory requirements, we may be subject to, among other things, fines, suspension or withdrawal of regulatory approvals, product recalls, seizure of products, operating restrictions and criminal prosecution.

Data Privacy and Security Laws

Numerous state, federal and foreign laws, regulations and standards govern the collection, use, access to, confidentiality and security of health-related and other personal information, and could apply now or in the future to our operations or the operations of our partners. In the United States, numerous federal and state laws and regulations, including data breach notification laws, health information privacy and security laws and consumer protection laws and regulations govern the collection, use, disclosure, and protection of health-related and other personal information. In addition, certain foreign laws govern the privacy and security of personal data, including health-related data. For example, the GDPR imposes strict requirements for processing the personal data of individuals within the EEA. Companies that must comply with the GDPR face increased compliance obligations and risk, including more robust regulatory enforcement of data protection requirements and potential fines for noncompliance of up to €20 million or 4% of the annual global revenues of the noncompliant company, whichever is greater. Further, from January 1, 2021, companies have had to comply with the GDPR and also the UK GDPR, which, together with the amended UK Data Protection Act 2018, retains the GDPR in UK national law. The UK GDPR mirrors the fines under the GDPR, i.e., fines up to the greater of €20 million (£17.5 million) or 4% of global turnover. Privacy and security laws, regulations, and other obligations are constantly evolving, may conflict with each other to complicate compliance efforts, and can result in investigations, proceedings, or actions that lead to significant civil and/or criminal penalties and restrictions on data processing.

Japanese drug regulation

Non-clinical studies and clinical trials

Being a member of the International Conference on Harmonization (ICH), Japan has pharmaceutical regulations fundamentally similar to those of the United States or EU.

Non-clinical studies are performed to demonstrate the health safety of new chemical or biological substances. Non-clinical studies must be conducted in compliance with the principles of Japanese good laboratory practice (GLP) which reflect the Organization for Economic Co-operation and Development requirements. Currently, Japan and EU have a mutual recognition agreement for GLP, and data generated compliant with EU requirements will be accepted by the Japanese authorities. There is no similar agreement with the United States.

Clinical trials of medicinal products in Japan must be conducted in accordance with Japanese regulations based on ICH guidelines governing good clinical practices (GCP). They focus on ethics of the clinical trial and protection of the privacy of the trial subjects. If the sponsor of the clinical trial is not established within Japan, it must appoint an entity within the country to act as its caretaker who should be authorized to act on the sponsor’s behalf. The sponsor must take out a clinical trial insurance policy, and, according to the industry agreement, should put in place a common compensation policy for the injuries from the trial.

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Prior to the commencement of human clinical studies, the sponsor must complete evaluation of the safety of the investigative product, and submit a clinical trial notification and the protocol to the authorities in advance, upon agreement of the IRB of the participating institutions. When the authorities do not comment on the notification, the sponsor may proceed with the clinical trial.

Any substantial changes to the trial protocol or other information submitted must be cleared by the IRB and notified to the authorities. Medicines used in clinical trials must be manufactured in accordance with good manufacturing practice (GMP).

Product approval

To market a medicinal product in Japan, we must obtain regulatory approval. To obtain regulatory approval of an investigational medicinal product, we must submit a new drug application. The process for doing this depends, among other things, on the nature of the medicinal product and there are currently a few different pathways for approval. If the product is designed for treating certain “difficult diseases” or those whose patient size is limited, we may be able to obtain designation as an orphan drug product if it demonstrates unique therapeutic value. Approval application for such designated orphan products will be processed on an expedited basis and the authorities’ requirement for clinical data will be much limited. Separately, the latest amendment to the law introduced separate pathways for: (i) truly innovative products with a unique mode of action, and (ii) those which will satisfy unmet medical needs. These products will also be processed on an expedited basis.

The evaluation of applications will be based on an assessment of the risk-benefit balance of the product on the basis of scientific criteria concerning its quality, safety and efficacy. Once the review organization completes its review task, the matter will be considered by the advisory committee of experts, and the government will grant approval upon positive recommendation from the committee.

The volume and quality of the clinical data will be the key determinant of the approval decision. Clinical trial data generated overseas will be accepted as part of the data package consistent with the ICH recommendation. Typically, a limited dose response clinical trial for Japanese subjects is required to ensure that data are extrapolatable for the Japanese population. In a more recent development, the authorities encourage manufacturers to organize an international joint clinical trial with some Japanese participation under a joint protocol, to expedite the clinical trial process. Regulatory approval does not expire.

Licensing requirement

Separate from the approval requirement, it is also mandatory to possess a distribution license of an appropriate class for the manufacturer to commercially distribute the product in Japan. Non-Japanese companies who possess only the product approval may designate an appropriate license holder in Japan to commercially distribute the product, rather than distributing it on its own. The license is valid for 5 years.

Facilities

Our corporate headquarters are located in San Diego, California, where we currently lease approximately 16,153 square feet of office and laboratory space pursuant to a lease that expires April 1, 2022, with the option to holdover the lease month-to-month following such date. We plan to exercise this holdover option until we move into our new corporate headquarters, which is anticipated to occur in the second quarter of 2022. In September 2020, we entered into a lease of approximately 59,407 square feet of office and laboratory space in a facility in San Diego, California that is currently under construction, and scheduled to be completed in the second quarter of 2022. In March 2021, we amended this lease to include an additional 18,421 square feet of office space, resulting in 77,828 square feet of total leased space within this facility. The lease has an initial term of 10.5 years and commenced in August 2021. We believe our existing facilities are adequate to meet our current business requirements for the near term, and that additional space will be available on commercially reasonable terms, if required.

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Employees

As of February 28, 2022, we had 123 full-time employees (FTEs), 50 of whom have doctorate degrees. Of our FTEs, 87 are engaged in research and development activities, and 36 are engaged in general and administrative activities. Substantially all of our employees are located in San Diego County, California. None of our employees are represented by labor unions or covered by collective bargaining units. We consider our relationship with our employees to be good.

Our human resources objectives include, as applicable, identifying, recruiting, retaining, incentivizing, and integrating our existing and additional employees. The principal purposes of our equity incentive plans are to attract, retain, and motivate selected employees, consultants, and directors through the granting of stock-based compensation awards.

Corporate Information

We were incorporated under the laws of the State of Delaware on July 2, 2018 as Erasca, Inc. Our principal executive offices are located at 10835 Road to the Cure, Suite 140, San Diego, California 92121, and our telephone number is 858-465-6511. Our website address is www.erasca.com. Our website and the information contained on, or that can be accessed through, the website will not be deemed to be incorporated by reference in, and are not considered part of, this Annual Report on Form 10-K.

In July 2021, we completed our IPO pursuant to which we issued and sold 21,562,500 shares of common stock at a public offering price of $16.00 per share, resulting in net proceeds of $317 million, after deducting underwriting discounts and commissions and other offering costs.

We are an "emerging growth company" as defined in the Jumpstart Our Business Startups Act of 2012. We will remain an emerging growth company until the earlier of: (i) the last day of the fiscal year: (a) following the fifth anniversary of the completion of the IPO, (b) in which we have total annual gross revenue of at least $1.07 billion, or (c) in which we are deemed to be a large accelerated filer, which means the market value of our common stock that is held by non-affiliates exceeds $700.0 million as of the prior June 30th, and (ii) the date on which we have issued more than $1.0 billion in nonconvertible debt during the prior three-year period.

Available Information

Our website address is www.erasca.com. Our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, including exhibits, proxy and information statements and amendments to those reports filed or furnished pursuant to Sections 13(a), 14, and 15(d) of the Exchange Act are available through the “Investors” portion of our website free of charge as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. In addition, our filings with the SEC may be accessed through the SEC’s Interactive Data Electronic Applications system at www.sec.gov. All statements made in any of our securities filings, including all forward-looking statements or information, are made as of the date of the document in which the statement is included, and we do not assume or undertake any obligation to update any of those statements or documents unless we are required to do so by law.

We use the “Investors” portion of our website as a means of disclosing material non-public information and for complying with our disclosure obligations under Regulation FD. Investors should monitor such website, in addition to following our press releases, SEC filings and public conference calls and webcasts. Information relating to our corporate governance is also included on our website. The information in or accessible through the SEC and our website are not incorporated into, and are not considered part of, this Annual Report on Form 10-K.

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