Overview

We are a clinical-stage biopharmaceutical company committed to discovering, developing and commercializing products targeting inflammation, bleeding and disorders of the central nervous system. Our most clinically advanced product candidates are derived from our proprietary PharmacoSurgery ^tm platform designed to improve clinical outcomes of patients undergoing arthroscopic, ophthalmological, urological and other surgical and medical procedures. Our PharmacoSurgery platform is based on low-dose combinations of therapeutic agents delivered directly to the surgical site throughout the duration of the procedure to preemptively inhibit inflammation and other problems caused by surgical trauma and to provide clinical benefits both during and after surgery. We currently have six ongoing clinical development programs, including four from our PharmacoSurgery platform and two from our addiction franchise. Our most advanced clinical development program is in a Phase 3 clinical program evaluating OMS103HP for arthroscopy in patients undergoing arthroscopic anterior cruciate ligament, or ACL, reconstruction. We expect to announce data from this program during the first quarter of 2011. In addition, we have a deep and diverse pipeline of preclinical programs as well as a platform capable of unlocking new drug targets. For each of our product candidates and programs, we have retained all manufacturing, marketing and distribution rights.

Our Product Candidates and Development Programs

Our clinical product candidates and pipeline of development programs consist of the following:

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Clinical Programs

PharmacoSurgery™ Platform

Current standards of care for the management and treatment of surgical trauma are limited in effectiveness. Surgical trauma causes a complex cascade of molecular signaling and biochemical changes, resulting in inflammation, pain, spasm, loss of function and other problems. As a consequence, multiple pharmacologic actions are required to manage the complexity and inherent redundancy of the cascade. Accordingly, we believe that single-agent treatments acting on single targets do not result in optimal therapeutic benefit. Further, current pre-operative treatments are not optimally effective because the administration of standard irrigation solution during the surgical procedure washes out pre-operatively delivered drugs. In addition, current postoperative therapies are not optimally effective because the cascade and resultant inflammation, pain, spasm, loss of function and other problems have already begun and are difficult to reverse and manage after surgical trauma has occurred. Also, drugs that currently are delivered systemically to target these problems, such as by oral or intravenous administration, are frequently associated with adverse side effects.

In contrast, we generate from our PharmacoSurgery platform proprietary product candidates that are combinations of therapeutic agents designed to act simultaneously at multiple discrete targets to preemptively block the molecular-signaling and biochemical cascade caused by surgical trauma and to provide clinical benefits both during and after surgery. Supplied in pre-dosed, pre-formulated, single-use containers, our PharmacoSurgery product candidates are added to standard surgical irrigation solutions and delivered intra-operatively to the site of tissue trauma throughout the surgical procedure. This results in the delivery of low concentrations of agents with minimal systemic uptake and reduced risk of adverse side effects, and does not require a surgeon to change his or her operating procedure. In addition to ease of use, we believe that the clinical benefits of our product candidates could provide surgeons a competitive marketing advantage and may facilitate third-party payor acceptance, all of which we expect will drive adoption and market penetration. Our current PharmacoSurgery product candidates are specifically comprised of active pharmaceutical ingredients, or APIs, contained in generic drugs already approved by the FDA, with established profiles of safety and pharmacologic activities, and are eligible for submission under the potentially less-costly and time-consuming Section 505(b)(2) New Drug Application, or NDA, process.

OMS103HP—Arthroscopy

Background. OMS103HP is our PharmacoSurgery product candidate being developed for use during arthroscopic procedures, including ACL reconstruction surgery and partial meniscectomy surgery, and was designed to provide a multimodal approach to preemptively block the inflammatory cascade induced by arthroscopy. OMS103HP is a proprietary combination of anti-inflammatory/analgesic APIs, each with well-known safety and pharmacologic profiles. Each of the APIs are components of generic, FDA-approved drugs that have been marketed in the United States as over-the-counter, or OTC, or prescription drug products for over 15 years and have established and well-characterized safety profiles.

Arthroscopy is a surgical procedure in which a miniature camera lens is inserted into an anatomic joint, such as the knee, through a small incision in the skin. Through similar incisions, surgical instruments are also introduced and manipulated within the joint. During any arthroscopic procedure, an irrigation solution, such as lactated Ringer’s solution or saline solution, is flushed through the joint to distend the joint capsule, allowing better visualization with the arthroscope, and to remove debris resulting from the operation.

One of the major challenges facing orthopedic surgeons in performing arthroscopic procedures is adequately controlling the local inflammatory response to surgical trauma, particularly the pain and swelling that lead to restricted joint motion and loss of function. Minimizing postoperative inflammation and pain may not only decrease the time to return to work and to activities of daily living, but also could decrease arthrofibrosis and other postoperative complications. Arthrofibrosis is a complication caused by surgical trauma in which excessive scar tissue forms within the joint and surrounding soft tissue spaces resulting in pain, restricted joint motion and loss of function.

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The inflammation associated with arthroscopic surgery, or any other procedure resulting in tissue trauma, is a complex reaction to tissue injury with multiple pathways, mechanisms and pro-inflammatory mediators, such as PGE2, involving three major components:

The key cellular events involved in these components include the synthesis and release of multiple pro-inflammatory mediators. Consequently, multiple pharmacologic actions are required to manage the complexity and inherent redundancy of the inflammatory cascade.

Added to standard irrigation solutions, OMS103HP is delivered directly to the joint throughout arthroscopy, and is designed to act simultaneously at multiple distinct targets to block preemptively the inflammatory cascade induced by arthroscopic surgery. OMS103HP contains the following three APIs, each of which is known to interact with different, discrete molecular targets that are involved in the acute inflammatory and pain response:

In combination, these APIs inhibit PGE2 production, decrease inflammation-induced vasodilation and prevent increased vascular permeability, as well as block the release of proinflammatory mediators from primary afferent nerve endings, or neurogenic inflammation, at the site of surgical trauma. Using an in vivo joint model of acute inflammation-induced plasma extravasation, preclinical studies showed that the combined activity of all three APIs in OMS103HP produced significant inhibition of plasma extravasation and was more effective than any of the two-API combinations or any single API administered alone, demonstrating that each API contributed to the effect of OMS103HP.

Market Opportunity.  According to SOR Consulting, approximately a total of: 4.0 million arthroscopic operations were performed in the United States in 2006, including 2.6 million knee arthroscopy operations. Based on independent reports that we commissioned from The Reimbursement Group, or TRG, and from Musculoskeletal Clinical Regulatory Advisers, we believe that OMS103HP will be favorably reimbursed both to the surgical facility for its utilization and to the surgeon for its administration and delivery. We believe that OMS103HP will, if approved, be the first commercially available drug delivered directly to the surgical site to improve function following arthroscopic surgery. Also, use of OMS103HP does not require a surgeon to change his or her operating procedure. In addition to ease of use, we believe that the clinical benefits of OMS103HP could provide surgeons a competitive marketing advantage and may facilitate third-party payor acceptance, all of which we expect will drive adoption and market penetration.

Clinical Trial Results—ACL Reconstruction.  We conducted a double-blind, vehicle-controlled, parallel-group, randomized Phase 1/Phase 2 clinical trial of OMS103HP in a total of 35 patients undergoing arthroscopic cadaveric, or allograft, ACL reconstruction surgery. 34 patients comprised the intent to treat population, 18 patients in the OMS103HP group and 16 patients in the vehicle group. 30 patients, 14 OMS103HP and 16

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vehicle patients, were included in the efficacy evaluable population. The intent-to-treat population consisted of all patients who were randomized into the study, received OMS103HP or vehicle control, and had at least one recovery room evaluation. The OMS103HP and vehicle groups showed no significant differences in demographics, or pre- or intra-operative findings. Patients were adults scheduled to undergo primary ACL reconstruction surgery, using patellar tendon-bone or Achilles tendon allografts, for an ACL tear occurring from two weeks to one year prior to the day of arthroscopic surgery. Patients were followed for 30 postoperative days and instructed to complete a patient diary each day.

Efficacy endpoints included assessments of range of motion, knee function, pain management, quadriceps and hamstring muscle strength, and return to work. Assessments were collected during clinic and rehabilitation visits and in the patient diary. At each clinic visit a visual analog scale, or VAS, pain score was obtained and passive range of motion measurements were taken. At the end of the 30-day evaluation period, physical and orthopedic examinations were also performed and quadriceps and hamstring strength testing was conducted. At each study rehabilitation visit, knee function and range of motion were assessed. Patients treated with OMS103HP demonstrated statistically significant: (1) improvement in postoperative knee range of motion, (2) improvement in postoperative knee function, (3) better pain management and (4) earlier return to work. No adverse events were determined to be related to the delivery of OMS103HP and there was no evidence of OMS103HP having any detrimental effect with respect to healing, either in soft tissue or bone.

The results of this Phase 1/Phase 2 clinical program were published in a peer-reviewed article titled “Novel Drug Product to Improve Joint Motion and Function and Reduce Pain After Arthroscopic Anterior Cruciate Ligament Reconstruction” that appeared in the June 2008 issue of Arthroscopy: The Journal of Arthroscopic and Related Surgery (Vol. 24, No. 6: pp. 625-636).

Clinical Trial Results—Meniscectomy.  We conducted a multicenter, randomized, double-blind, vehicle-controlled Phase 2 clinical trial of OMS103HP in patients undergoing arthroscopic partial meniscectomy surgery. Of the 161 patients who were enrolled and treated, 143 patients met the predetermined surgical criteria and were included in the data analysis (71 OMS103HP and 72 vehicle). There were no important differences in demographic characteristics between the two treatment groups. The protocol was amended to collect patient self-reports using the Knee Injury and Osteoarthritis Outcome Score, or KOOS, which consists of five subscale scores: symptoms, pain, activities of daily living, sport and recreation function, and knee-based quality of life. The KOOS subset consisted of 67 subjects (33 OMS103HP and 34 vehicle).

In this study, OMS103HP provided greater efficacy than vehicle as measured by patient-reported functional scores using the KOOS, passive knee flexion and VAS pain scores. The patient-reported outcomes showed a sustained benefit through postoperative Day 90. OMS103HP was well tolerated, and adverse events were more frequent in the vehicle dose group.

An article describing the results of this Phase 2 clinical study, titled “Novel Drug, OMS103HP, Reduces Pain and Improves Joint Motion and Function over 90 Days following Arthroscopic Meniscectomy,” has been accepted for publication in the peer-reviewed Arthroscopy: The Journal of Arthroscopic and Related Surgery .

Although these positive results from our clinical studies evaluating OMS103HP are encouraging, there can be no assurance that they will be predictive of the results obtained from later trials.

Development Plan.  OMS103HP is in two clinical programs. The first is a Phase 3 program evaluating OMS103HP’s safety and ability to improve postoperative joint function and reduce pain following ACL reconstruction surgery. This Phase 3 program consists of three multi-center trials, two evaluating efficacy and safety (approximately 280 patients in each) and a third evaluating safety only (approximately 480 patients). Enrollment in these three Phase 3 trials is complete. Two of the trials, each evaluating efficacy and safety of OMS103HP, were conducted in patients receiving grafts from cadavers or their own tissue, respectively. The safety only trial included patients receiving either graft type. Efficacy endpoints include assessments of postoperative knee function and range of motion, pain reduction and return to work. We expect to release the results from this program during the first quarter of 2011.

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The second program is evaluating OMS103HP’s safety and ability to improve postoperative joint function and reduce pain following arthroscopic meniscectomy surgery. We are finalizing preparations to begin enrollment in a Phase 3 clinical study of OMS103HP in patients undergoing partial meniscectomy surgery and will decide whether and when to begin enrollment in this study after we review the data from our Phase 3 ACL program.

OMS302—Ophthalmology

Background.  OMS302 is our PharmacoSurgery product candidate being developed for use during ophthalmological procedures including cataract and other lens replacement surgery. OMS302 is a proprietary combination of an anti-inflammatory API and an API that causes pupil dilation, or mydriasis, each with well-known safety and pharmacologic profiles. FDA-approved drugs containing each of these APIs have been used in ophthalmological clinical practice for more than 15 years, and both APIs are contained in generic, FDA-approved drugs.

Cataract and other lens replacement surgery involves replacement of the original lens of the eye with an artificial intraocular lens. These procedures are typically performed to replace a lens opacified by a cataract or to correct a refractive error of the lens. Added to standard irrigation solution used in cataract and other lens replacement surgery, OMS302 is being developed for delivery into the anterior chamber of the eye, or intracameral delivery, to maintain mydriasis, to prevent surgically induced pupil constriction, or miosis, and to reduce postoperative pain and irritation. Mydriasis is an essential prerequisite for these procedures and, if not maintained throughout the surgical procedure or if miosis occurs, risk of damaging structures within the eye increases as does the operating time required to perform the procedure.

Clinical Trial Results.  We conducted a Phase 1/Phase 2 clinical trial evaluating the efficacy and safety of OMS302 added to standard irrigation solution and delivered to patients undergoing cataract surgery. The purpose of the study was to demonstrate the proof of concept that a surgical irrigation solution containing a mydriatic API improves maintenance of mydriasis during cataract surgery and that a surgical irrigation solution containing an anti-inflammatory API improves pain control and lessens inflammation following surgery. In this study, 61 patients were randomized to receive one of three treatments: (1) OMS302, (2) the mydriatic API of OMS302 alone, or OMS302-mydriatic, and (3) vehicle control. For efficacy assessments, patients were monitored for pupil size during surgery and pain and inflammation for 14 days following the surgery.

Patients treated with OMS302 reported less postoperative pain than patients treated with either OMS302-mydriatic or vehicle control. Patients treated with either OMS302 or OMS302- mydriatic demonstrated statistically significant improvement in maintenance of mydriasis compared to patients treated with vehicle control. OMS302 was well tolerated with no serious adverse events and no discontinuations due to adverse events. The type and number of adverse events were similar across all three treatment groups. Three of the total 61 patients (two in the OMS302 group and one in the OMS302-mydriatic group) reported mild to moderate eye pain judged by the investigator to be either possibly or probably treatment-related.

Overall, this study suggests that OMS302 would be useful in helping maintain mydriasis during surgery and controlling pain immediately following surgery.

Development Plan.  We are conducting a Phase 2b clinical trial for OMS302 to assess the effect of a fixed concentration of the mydriatic API alone and in combination with the anti-inflammatory API in a full-factorial design. Enrollment for this study is complete and we expect to announce data from this Phase 2b trial in the first quarter of 2011. Approximately 200 patients were enrolled in the multicenter, randomized, double-blind, vehicle-controlled Phase 2b clinical trial. Patients were randomized into one of four parallel treatment groups of equal size. The first arm received OMS302, the second and third received only the mydriatic agent or the anti-inflammatory agent, respectively, and the fourth arm received a placebo of standard irrigation solution without drug. The co-primary endpoints of the study include the reduction of post-operative ocular pain and maintenance of mydriasis (pupil dilation).

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OMS201—Urology

Background.  OMS201 is our PharmacoSurgery product candidate being developed for use during urological procedures including ureterscopy for removal of ureteral or renal stones. OMS201 is a proprietary combination of an anti-inflammatory API and a smooth muscle relaxant API, and is intended for local delivery to the bladder, ureter, urethra, and other urinary tract structures during urological procedures. Both of the APIs in OMS201 are contained in generic, FDA-approved drugs that have been marketed in the United States for more than 15 years and have well-known profiles of safety and pharmacologic activities. Each of the APIs in OMS201 has been individually prescribed to manage the symptoms of ureteral and renal stones.

Uroendoscopic procedures are performed within the urinary tract using a flexible camera device, or endoscope, and cause tissue injury that activates local mediators of pain and inflammation, which results in inflamed tissue, pain, smooth muscle spasm and lower urinary tract symptoms including frequency, urgency and painful urination, and can prolong recovery. Added to standard irrigation solutions in urological surgery, OMS201 is being developed for delivery directly to the surgical site during uroendoscopic procedures, such as bladder endoscopy, or cystoscopy, minimally invasive prostate surgery and ureteroscopy, to inhibit surgically induced inflammation, pain and smooth muscle spasm, or excess contractility.

Clinical Trial Results.  We completed a Phase 1/Phase 2 study in 24 patients designed to evaluate the safety and systemic absorption of two sequentially higher concentrations of OMS201 added to standard irrigation solution and delivered to patients undergoing ureteroscopy for removal of ureteral or renal stones. This multicenter, double-blind, placebo-controlled study also explored potential efficacy endpoints but was not powered to assess efficacy. OMS201 was safe and well tolerated in this study. The incidence of adverse events was similar in the two OMS201-concentration arms and the group receiving vehicle. No adverse events were considered treatment-related by investigators. There were no deaths or discontinuations for adverse events. Only one serious adverse event was reported, which occurred in a vehicle-treated patient.

Development Plan.  Based on the data from our recently completed Phase 1/Phase 2 clinical study, we are designing subsequent trials to evaluate the efficacy and safety of OMS201 in patients undergoing urologic procedures.

PPAR g Program

Overview . In our peroxisome proliferator-activated receptor gamma, or PPAR g , program, we are developing proprietary compositions that include PPAR g agonists for the treatment and prevention of addiction to substances of abuse, which may include opioids, nicotine and alcohol. We believe that Omeros is the first to demonstrate a link between PPAR g and addiction disorders. Data from European pilot clinical studies and animal models of addiction suggest that PPAR g agonists could be efficacious in the treatment of a wide range of addictions. Our collaborators at The New York State Psychiatric Institute are conducting two Phase 2 clinical trials for our PPAR g program. These studies are evaluating a PPAR g agonist, alone or in combination with other agents, for the abuse liability potential of oxycontin and for the treatment of addiction to heroin. The National Institute on Drug Abuse is providing substantially all of the funding for these clinical trials. We will have the right to reference the data obtained from these studies for subsequent submissions to the FDA and continue to retain all other rights in connection with the PPAR g program.

Patent Assignment Agreement with Roberto Ciccocioppo, Ph.D. We acquired the patent applications and related intellectual property rights for our PPAR g program in February 2009 from Roberto Ciccocioppo, Ph.D. of the Università di Camerino, Italy, pursuant to a Patent Assignment Agreement. In February 2010, we amended the agreement to include all intellectual property rights, including patent applications, related to nutraceuticals that increase PPAR g activity. Under the amended agreement, we have agreed to pay Dr. Ciccocioppo a low-single digit percentage royalty on net sales of any products that are covered by any patents that issue from the patent applications that we acquired from him. In addition, if we grant any third parties rights to manufacture, sell or distribute any such products, we must pay to Dr. Ciccocioppo a percentage of any associated fees we

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receive from such third parties in the range of low single-digits to low double-digits depending on stage of development at which such rights are granted. We have also agreed to make total milestone payments of up to $3.8 million to Dr. Ciccocioppo upon the occurrence of certain development events, such as patient enrollment in a Phase 1 clinical trial and receipt of marketing approval of a product covered by any patents that issue from the patent applications that we acquired from him. If we notify Dr. Ciccocioppo that we have abandoned all research and development and commercialization efforts related to the patent applications and intellectual property rights we acquired from him, Dr. Ciccocioppo has the right to repurchase those assets from us at a price equal to a double-digit percentage of our direct and indirect financial investments and expenditures in such assets. If he does not exercise his right to repurchase those assets within a limited period of time by paying the purchase price, we will have no further obligations to sell those assets to Dr. Ciccocioppo. The term of our agreement with Dr. Ciccocioppo ends when there are no longer any valid and enforceable patents related to the intellectual property rights we acquired from him, provided that either party may terminate the agreement earlier in case of an uncured breach by the other party. Under the terms of the agreement, we have agreed to pay a portion of the payments due to Dr. Ciccocioppo to the Università di Camerino without any increase to our payment obligations.

GPCR Program

Overview . G protein-coupled receptors, or GPCRs, comprise one of the largest families of proteins in the genomes of multicellular organisms. According to Insight Pharma Reports, or IPR, there are over 1,000 GPCRs in the human genome, comprising three percent of all human proteins. GPCRs are cell surface membrane proteins involved in mediating both sensory and nonsensory functions. Sensory GPCRs are involved in the perception of light, odors, taste and sexual attractants. Non-sensory GPCRs are involved in metabolism, behavior, reproduction, development, hormonal homeostasis and regulation of the central nervous system. The vast majority of GPCR drug targets are non-sensory. Although GPCRs form a super-family of receptors, individual GPCRs display a high degree of specificity and affinity for the molecules that bind to them, or their respective ligands. Ligands can either activate the receptor (agonists) or inhibit it (antagonists and inverse agonists). When activated by its ligand, the GPCR interacts with intracellular G proteins, resulting in a cascade of signaling events inside the cell that ultimately leads to the particular function linked to the receptor.

The high degree of specificity and affinity associated with GPCRs has contributed to their becoming the largest family of drug targets for therapeutics against human diseases. According to IPR, 30% to 40% of all drugs sold worldwide target GPCRs. Based on available data, we believe that there are 363 human non-sensory GPCRs, of which approximately 120 have no known ligands, or orphan GPCRs. Without a known ligand, there is no template from which medicinal chemistry efforts can be readily initiated nor a means to identify the GPCR’s signaling pathway and, therefore, drugs cannot easily be developed against orphan GPCRs. “Unlocking” these orphan GPCRs could lead to the development of drugs that act at these new targets. To our knowledge, despite efforts by others in the biopharmaceutical industry, Omeros’ technology is the first commercially viable technology capable of identifying ligands of orphan GPCRs in high throughput.

We have scientific expertise in the field of GPCRs and members of our scientific team were the first to identify and characterize all GPCRs common to mice and humans, with the exception of sensory GPCRs. Our work was published in a peer-reviewed article titled “The G protein-coupled receptor repertoires of human and mouse” that appeared in the April 2003 issue of Proceedings of the National Academy of Sciences (Vol. 100, No. 8: pp. 4903-4908) . In addition, our proprietary cellular redistribution assay, or CRA, can be used in a high-throughput manner to identify synthetic ligands, including antagonists, agonists and inverse agonists, that bind to and affect the function of orphan GPCRs. We also have developed a proprietary rapid mouse gene knock-out platform technology, which is described in a peer-reviewed article titled “Large-scale, saturating insertional mutagenesis of the mouse genome” that appeared in the September 2007 issue of Proceedings of the National Academy of Sciences (Vol. 104, No. 36: pp. 14406-14411). We have used this platform to create 61 different GPCR-specific strains of knock-out mice, and we have established a battery of behavioral tests that allows us to characterize these knock-out mice and identify candidate drug targets. The genes disrupted in these strains of knock-out mice include those linked to orphan GPCRs. In addition, we have developed a platform technology to

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efficiently produce reversible and inducible mouse gene knockout and rescue, which allows the mouse to fully develop before knocking out the gene rather than creating the knockout in the mouse embryo. As a result, we can evaluate the function of a gene even when its mutation would cause compensation by other genes or death during embryonic or neonatal development. This platform technology is described in a peer-reviewed article titled “An Inducible and Reversible Mouse Genetic Rescue System” that appeared in the May 2008 issue of PLoS Genetics (Vol. 4, Issue. 5) .

Using our expertise and these assets, we believe that we are the first to possess the capability to conduct high-throughput drug discovery for orphan GPCRs, and that there is no other existing high-throughput technology able to “unlock” orphan GPCRs. We have begun screening orphan GPCRs against our small-molecule chemical libraries using the CRA. Based on the limited screening of libraries to date, we have already announced that we have identified and confirmed sets of compounds that interact selectively with, and modulate signaling of a series of orphan GPCRs, including orphans linked to squamous cell carcinoma (GPR87), pancreatic cancer (GPR182), obesity (GPR85), appetite control (GPR101) and cognitive disorders (GPR12).

GPCR Platform Funding Agreements with Vulcan Inc. and the Life Sciences Discovery Fund. On October 21, 2010, we entered into a platform development funding agreement with Vulcan Inc. and its affiliate, which we refer to collectively as Vulcan, pursuant to which we received $20.0 million for our GPCR program from Vulcan. Also on October 21, 2010, we entered into an agreement with the Life Sciences Discovery Fund Authority, a granting agency of the State of Washington, or LSDF, under which we received a $5.0 million grant award from LSDF that will be used to reimburse us for expenses that we incur and equipment we purchase for our GPCR program. Pursuant to the Vulcan and LSDF agreements, we have agreed to pay Vulcan and LSDF tiered percentages of the net proceeds derived from the GPCR program. The percentage rates of net proceeds payable to Vulcan and LSDF decrease as the cumulative net proceeds reach specified thresholds, and the blended percentage rate payable to Vulcan and LSDF in the aggregate is in the mid-teens with respect to the first approximately $1.5 billion of cumulative net proceeds that we receive from our GPCR program. After we have received approximately $1.5 billion of cumulative net proceeds, the percentage rate payable to Vulcan and LSDF in the aggregate decreases to one percent. Pursuant to the agreement with Vulcan, at our option, we may pay a portion of Vulcan’s share of the one percent of net proceeds to a life sciences initiative, or LSI, to be established pursuant to LSDF agreement. The LSI will be a non-profit, tax-exempt organization with a mission to advance life sciences in the State of Washington.

Net proceeds are defined in the Vulcan and LSDF agreements as (1) all consideration received by us in any form relating directly to the GPCR program, such as from license fees, milestone fees, royalties, product sales, partnerships and a transfer of the GPCR program to a third party, subject to exceptions specified in such agreements, less (2) all expenses and expenditures in excess of $25.0 million incurred by us in connection with the GPCR program such as for research and development, related overhead, milestone and royalty payments, legal expenses, cost of goods sold and product sales deductions. Any consideration that we receive (a) from government entities (subject to specified exceptions), (b) from third parties that have designated such consideration for the purpose of funding research and development expenses and related overhead or (c) in the form of grants, as well as any expenses or expenditures that we incur that are paid for with such consideration, are excluded for purposes of determining net proceeds.

Pursuant to our agreement with Vulcan, we issued to Vulcan three warrants to purchase our common stock, each exercisable for 133,333 shares, with exercise prices of $20, $30 and $40 per share, respectively. The warrants may be exercised for cash or on a “cashless” basis through the surrender at the time of exercise of a number of shares that would otherwise be issuable equal to the fair market value of our common stock at the time of exercise. In addition, we agreed to purchase from Patobios Limited, or Patobios, intellectual property assets related to the CRA for consideration consisting of approximately $10.8 million CAD. We completed the acquisition of these assets on November 22, 2010 by paying to Patobios $7.8 million CAD ($7.6 million USD) in cash and the remaining $3.0 million CAD ($3.2 million USD) in the form of 379,039 shares of our common stock.

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Under our agreement with Vulcan, we granted Vulcan a security interest in our personal property related to the GPCR program, other than intellectual property, which security interest shall be junior to any existing or future security interests granted in connection with a financing transaction and which shall be released automatically after Vulcan receives $25.0 million under the agreement. We also agreed not to grant any liens on intellectual property related to the GPCR program. The term of our agreement with Vulcan is 35 years, provided that the term will automatically extend until the cumulative net proceeds that we receive from the GPCR program are approximately $1.5 billion.

Under our agreement with LSDF, after LSDF receives $25.0 million from us, any remaining amounts that would be payable by us to LSDF pursuant to the agreement will instead be paid to LSI. If for any reason LSDF does not provide the full $5.0 million to us, LSDF’s percentage share of net proceeds will be reduced in proportion to the amount it actually pays to us. Our obligations with respect to LSI are limited to creating LSI’s charter documents, incorporating LSI, selecting directors and applying for tax exempt status, all in consultation with LSDF. We have no other obligations, funding or otherwise, to LSI. The term of our agreement with LSDF expires on the six-month anniversary following the last date that we deliver a report related to our incurrence of grant-funded expenses described in the agreement, provided that certain obligations will survive the expiration of the term. The term of our payment obligations to LSDF is the same as that under our agreement with Vulcan.

In addition, pursuant to our agreements with Vulcan and LSDF, we have agreed (1) to use commercially reasonable efforts to screen at least 75% of the currently known human Class A orphan GPCRs within 19 months of October 21, 2010, subject to possible extensions and (2) to commence a medicinal chemistry effort focused on developing a product candidate with respect to one orphan GPCR for which compounds were identified using the GPCR assay technology.

Preclinical Programs

Plasmin Program

Overview. We are developing antifibrinolytic agents for the control of blood loss during surgery or resulting from trauma. Excessive bleeding during cardiac surgery is known to increase overall morbidity and mortality. In an attempt to control this bleeding, patients undergoing cardiac and other extensive surgery often receive antifibrinolytic compounds. These drugs inhibit plasmin, an enzyme present in blood that degrades fibrin clots. Because plasmin degrades fibrin clots, an agent that inhibits plasmin may have potential utility for reducing blood loss due to trauma or surgery.

Prior to withdrawal from the market in 2008 for safety concerns, the antifibrinolytic Trasylol ^® (aprotinin) had been shown in a number of studies to be more effective at reducing blood loss than the other two most commonly used antifibrinolytics on the market today, tranexamic acid and epsilon aminocaproic acid. While Trasylol ^® is a potent inhibitor of plasmin, it is non-selective. In addition to plasmin, it significantly inhibits kallikrein and Factor XIa, two enzymes important in promoting clotting, and their inhibition can increase bleeding. Trasylol ^® was found to be associated with a number of safety issues, including increased mortality. Further, it is a bovine protein associated with anaphylactic reactions. While the specific cause of increased death remains unknown, an often-cited explanation is the lack of specificity of Trasylol ^® .

Our proprietary agents are derived from tissue factor pathway inhibitor-2, or TFPI-2. A single domain of TFPI-2, referred to as KD1, inhibits plasmin but, like Trasylol ^® , also inhibits kallikrein and Factor XIa. Researchers demonstrated that a minimal change to the sequence of the KD1 protein increases its activity against plasmin approximately 6-fold, while dramatically reducing its inhibition of kallikrein and Factor XIa by more than 100-fold. This work appears in a peer-reviewed article titled “Engineering Kunitz Domain 1 (KD1) of Human Tissue Factor Pathway Inhibitor-2 to Selectively Inhibit Fibrinolysis: Properties of KD1-L17R Variant” that was published in the February 11, 2011 issue of the Journal of Biological Chemistry . Because the variant KD1 proteins developed by the authors and exclusively licensed to Omeros are more selective than Trasylol ^® ,

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they could provide more effective bleeding control with fewer side effects. Additionally, as a human protein derivative, these agents are expected to reduce the potential for immunological side effects. We believe the efficacy and improved selectivity of the variant KD1 provides a novel approach to the control of bleeding from surgery and trauma.

Exclusive License Agreement with The Regents of the University of California. On December 14, 2010, we entered into a license agreement with The Regents of the University of California, or The Regents, pursuant to which we received an exclusive license to a series of antifibrinolytic agents claimed in certain patents owned by The Regents in exchange for our agreement to make royalty and development milestone payments.

PDE7 Program

Overview. Our phosphodiesterase 7, or PDE7, program is based on our discoveries of previously unknown links between PDE7 and any addiction or compulsive disorder and between PDE7 and any movement disorders, such as Parkinson’s disease. PDE7 appears to modulate the dopaminergic system, which plays a significant role in regulating both addiction and movement. We believe that PDE7 inhibitors could be effective therapeutics for the treatment of addiction and compulsive disorders as well as movement disorders. Data generated in preclinical studies support both of these potential indications. We have selected a clinical candidate and currently are conducting additional studies evaluating the effects of potential clinical candidates in models of addiction and compulsive disorders as well as Parkinson’s disease. Our collaborators on this program include the National Institute on Drug Abuse and The Michael J. Fox Foundation.

Exclusive License Agreement with Daiichi Sankyo Co., Ltd. Under an agreement with Daiichi Sankyo Co., Ltd. (successor-in-interest to Asubio Pharma Co., Ltd.), or Daiichi Sankyo, we hold an exclusive license to PDE7 inhibitors claimed in certain patents and pending patent applications owned by Daiichi Sankyo for use in the treatment of movement disorders and other specified indications, or Indication 1, as well as for use in the treatment of addiction and compulsive disorders, or Indication 2. Under the agreement, we agreed to make milestone payments to Daiichi Sankyo of up to an aggregate total of $30.2 million upon the achievement of certain events related to Indication 1 and Indication 2; however, if only one of the two indications is advanced through the milestones, the total milestone payments would be $23.5 million. The milestone payment events include successful completion of preclinical toxicology studies; dosing of human subjects in Phase 1, 2 and 3 clinical trials; receipt of marketing approval of a PDE7 inhibitor product; and reaching specified sales milestones. In addition, Daiichi Sankyo is entitled to receive from us a low single-digit percentage royalty of any net sales of a PDE7 inhibitor licensed under the agreement by us and/or our sublicensee(s), provided that if the sales are made by a sublicensee, then the amount payable by us to Daiichi Sankyo is capped at an amount equal to a low double-digit percentage of all royalty and specified milestone payments received by us from the sublicensee.

The term of the agreement with Daiichi Sankyo continues so long as there is a valid, subsisting and enforceable claim in any patents covered by the agreement. The agreement may be terminated sooner by us, with or without cause, upon 90 days advance written notice or by either party following a material breach of the agreement by the other party that has not been cured within 90 days or immediately if the other party is insolvent or bankrupt. Daiichi Sankyo also has the right to terminate the agreement if we and our sublicensee(s) cease to conduct all research, development and/or commercialization activities for a PDE7 inhibitor covered by the agreement for a period of six consecutive months, in which case all rights held by us under Daiichi Sankyo’s patents will revert to Daiichi Sankyo.

MASP-2 Program

Overview. Mannan-binding lectin-associated serine protease-2, or MASP-2, is a novel pro-inflammatory protein target involved in activation of the complement system, which is an important component of the immune system. The complement system plays a role in the inflammatory response and becomes activated as a result of tissue damage or trauma or microbial pathogen invasion. MASP-2 appears to be unique to, and required for the

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function of, one of the principal complement activation pathways, known as the lectin pathway. Importantly, inhibition of MASP-2 does not appear to interfere with the antibody-dependent classical complement activation pathway, which is a critical component of the acquired immune response to infection, and its abnormal function is associated with a wide range of autoimmune disorders. MASP-2 is generated by the liver and is then released into the circulation. Adult humans who are genetically deficient in one of the proteins that activate MASP-2 do not appear to be detrimentally affected by the deficiency. Therefore, we believe that it may be possible to deliver MASP-2 antibodies systemically.

We have completed a series of in vivo studies using proprietary MASP-2 knock-out mice or MASP-2 antibodies in established models of disease previously linked to activation of the complement system. Our findings suggest that antibody-blockade of MASP-2 may have a preventive or therapeutic effect in the treatment of wet age-related macular degeneration, ischemia-reperfusion injury, transplant-related complications and radiation injury. We are continuing to evaluate the role of MASP-2 in other complement-mediated disorders. We hold worldwide exclusive licenses to rights related to MASP-2, the antibodies targeting MASP-2 and the therapeutic applications for those antibodies from the University of Leicester, from its collaborator, Medical Research Council at Oxford University, and from Helion Biotech ApS.

Exclusive License Agreements with the University of Leicester and the Medical Research Council at Oxford University. Under our exclusive license agreements with the University of Leicester and the Medical Research Council at Oxford University, or MRC, we have agreed to pay royalties to each of the University of Leicester and MRC that are a percentage of any proceeds we receive from the licensed technology during the terms of the agreements. We must pay low single-digit percentage royalties with respect to proceeds that we receive from products incorporating the licensed technology that are used, manufactured, directly sold or directly distributed by us, and we must pay royalties, in the range of a low single-digit percentage to a low double-digit percentage, with respect to proceeds we receive from sublicense royalties or fees that we receive from third parties to which we grant sublicenses to the licensed technology. We did not make any upfront payments for these exclusive licenses nor are there any milestone payments or reversion rights associated with these license agreements. We also agreed to sponsor research of MASP-2 at these institutions at pre-determined rates for maximum terms of approximately three years. If mutually agreed, we may sponsor additional research of MASP-2 at these institutions. We retain worldwide exclusive licenses from these institutions to develop and commercialize any intellectual property rights developed in the sponsored research. The term of each license agreement ends when there are no longer any pending patent applications, applications in preparation or unexpired issued patents related to any of the intellectual property rights we are licensing under the agreement. Both of these license agreements may be terminated prior to the end of their terms by us for convenience or by one party if the other party (1) breaches any material obligation under the agreement and does not cure such breach after notice and an opportunity to cure or (2) is declared or adjudged to be insolvent, bankrupt or in receivership and materially limited from performing its obligations under the agreement.

Exclusive License Agreement with Helion Biotech ApS. Pursuant to our exclusive license agreement with Helion Biotech ApS, or Helion, we received a royalty-bearing, worldwide exclusive license in and to all of Helion’s intellectual property rights related to MASP-2 antibodies, polypeptides and methods in the field of inhibition of mannan-binding lectin-mediated activation of the complement system for the prevention, treatment or diagnosis of any disease or condition. Upon execution of the agreement on April 23, 2010, we made a one-time payment to Helion of $500,000 and agreed to make development and sales milestone payments to Helion of up to an additional $6.9 million upon the achievement of certain events, such as the filing of an IND application with the FDA; initiation of Phase 2 and 3 clinical trials; receipt of marketing approval; and reaching specified sales milestones. In addition, Helion is entitled to receive a low single-digit percentage royalty of any net sales of a MASP-2 inhibitor product that is covered by the patents licensed under the agreement. The term of the agreement continues so long as there is a valid, subsisting and enforceable claim in any patents or patent applications covered by the agreement. The agreement may be terminated sooner by either party following a material breach of the agreement by the other party that has not been cured within 90 days.

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PDE10 Program

Overview. Phosphodiesterase 10, or PDE10, is an enzyme that is expressed in areas of the brain strongly linked to schizophrenia and other psychotic disorders and has been recently identified as a target for the development of anti-psychotic therapeutics. We are developing proprietary compounds that inhibit PDE10 for the treatment of schizophrenia and other psychotic disorders. In multiple animal models of psychotic behavior, PDE10 inhibitors have been shown to be as effective as current anti-psychotic drugs. In addition, results from preclinical studies suggest that PDE10 inhibitors may address the limitations of currently used anti-psychotic drugs by avoiding the associated weight gain, improving cognition and, potentially, reducing the risk of associated sudden cardiac death.

Funding Agreement with The Stanley Medical Research Institute. Our preclinical development is supported by funds from The Stanley Medical Research Institute, or SMRI, a non-profit corporation that supports research on the causes and treatment of schizophrenia and bipolar disorder. Under our funding agreement with SMRI, we may receive grant and equity funding upon achievement of product development milestones through Phase I clinical trials totaling $9.0 million, subject to our mutual agreement with SMRI. Through December 31, 2010, we have received $5.7 million from SMRI, $3.2 million of which was recorded as equity funding, $2.3 million was recorded as revenue and $227,000 remains in deferred revenue. We have agreed to pay royalties to SMRI based on any net income we receive from sales of a PDE10 product until we have paid a maximum aggregate amount that is a low single-digit multiple of the amount of grant funding that we have received from SMRI. This multiple increases as time elapses from the date we received the grant funding. There are no minimum payment obligations under our agreement with SMRI. Based on the amount of grant funding that we have received as of December 31, 2010, the maximum amount of royalties payable to SMRI is $12.8 million. The funding agreement and our obligation to pay a royalty to SMRI terminate when we have repaid such amount in the form of royalties.

Sales and Marketing

We have retained all marketing and distribution rights to our product candidates and programs, which provides us the opportunity to market and sell any of our product candidates independently, make arrangements with third parties to perform these services for us, or both. For the commercial launch of our lead product candidate, OMS103HP, we intend to use a combination of orthopedic specialty distributors and our own internal sales and marketing organization to market OMS103HP in North America and, for markets outside of North America, we intend to utilize similar distribution networks or work with third parties to perform these services. Because OMS103HP, if approved, will be used principally by surgeons in hospital-based and freestanding ambulatory surgery centers, we believe that commercializing OMS103HP will only require a limited sales and marketing force.

We expect that an OMS103HP sales and marketing force is potentially scalable for both of our other PharmacoSurgery product candidates, OMS302 and OMS201. For the sales and marketing of other product candidates, we generally expect to retain marketing and distribution rights in those for which we believe that it will be possible to access markets through an internal sales and marketing force. If we do not believe that we can cost-effectively access markets for any approved product candidate through an internal sales and marketing force, we expect that we will make arrangements with third parties to perform these services with us.

Manufacturing

We have laboratories in-house for analytical method development, bioanalytical testing, formulation, stability testing and small-scale compounding of laboratory supplies of product candidates, which need not be manufactured in compliance with current Good Manufacturing Practices, or cGMPs. We utilize outside contract manufacturers to produce sufficient quantities of product candidates for use in preclinical studies.

We rely on third-party manufacturers to produce, store and distribute our product candidates for clinical use and currently do not own or operate manufacturing facilities. We require that these manufacturers produce active pharmaceutical ingredients, or APIs, and finished drug products in accordance with cGMPs and all other applicable

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laws and regulations. We anticipate that we will rely on contract manufacturers to develop and manufacture our products for commercial sale. We maintain agreements with potential and existing manufacturers that include confidentiality and intellectual property provisions to protect our proprietary rights related to our product candidates.

We contracted with Catalent Pharma Solutions, Inc. to manufacture three batches of OMS103HP in freeze-dried, or lyophilized, form. Ongoing stability programs for these batches will be used to support the planned filing of a New Drug Application, or NDA, for OMS103HP. Pursuant to our stability study agreements with Catalent, we have agreed to pay Catalent for its performance of stability studies of three lots of lyophilized OMS103HP in accordance with cGMPs. These agreements terminate upon completion of the stability studies, provided that we may terminate these agreements at any time upon notice to Catalent. We have received guidance from the FDA that submission of three months of stability data from one registration batch of lyophilized OMS103HP would be sufficient to qualify any other facility for commercial manufacturing purposes.

We have also formulated OMS103HP as a liquid solution to take advantage of the reduced cost of goods for manufacturing a liquid as compared to a lyophilized drug product and, if approved for marketing, intend to launch OMS103HP as a liquid solution. Although we do not believe that the inactive ingredients in liquid OMS103HP, which are included in the FDA’s Inactive Ingredient Guide due to being present in drug products previously approved for parenteral use, impact its safety or effectiveness, the FDA will require us to provide comparative information and complete a stability study in connection with a potential NDA submission. We completed a nonclinical study that demonstrated that liquid OMS103HP is as safe as lyophilized OMS103HP; however, the FDA may require us to conduct additional studies. We have entered into agreements with Hospira Worldwide, Inc., pursuant to which Hospira has manufactured three registration batches of liquid OMS103HP at its facility in McPherson, Kansas, and agreed to manufacture and supply commercial supplies of liquid OMS103HP, if approved for marketing. Pursuant to our commercial supply agreement with Hospira, Hospira has agreed to supply, and we have agreed to purchase, a minimum quantity of our commercial supply needs of OMS103HP at a price based on the volume of our purchases. If Hospira is unable to supply a minimum quantity of our commercial supply needs, we have the right to reduce our minimum purchase and, in some cases, require Hospira to provide reasonable technology assistance to qualify an alternate supplier or terminate the agreement. We are obligated to provide Hospira with the APIs necessary to manufacture OMS103HP as a liquid solution. Except for our obligation to purchase a minimum quantity of our commercial supply needs of OMS103HP from Hospira, our agreement with Hospira does not limit our ability to use another manufacturer to supply OMS103HP.

The term of the commercial supply agreement continues past the commercial launch of OMS103HP for a five-year period that automatically extends for up to two additional one-year periods unless a party gives notice that it intends to terminate the agreement at least two years prior to the beginning of an extension period. The commercial supply agreement may be terminated at any time prior to the end of its term by a party if the other party (1) materially breaches the agreement and does not cure such breach after notice and an opportunity to cure or (2) goes into liquidation, seeks the benefit of any bankruptcy or insolvency act, or a receiver or trustee is appointed for its property or estate, or it makes an assignment for the benefit of creditors, and such procedures are not terminated within ninety days. We also have the unilateral right to terminate the agreement in whole or in part at any time prior to the end of its term upon the occurrence of specified events such as a regulatory or development set back to OMS103HP that may prevent us from marketing OMS103HP or if we reasonably determine that OMS103HP will not be commercially viable or profitable. In addition, we have the right to terminate the agreement if we are acquired by an independent third party or if we enter into a marketing, promotion or distribution agreement with an independent third party, provided that we may be obligated to continue to purchase liquid OMS103HP from Hospira for a limited amount of time and pay an associated break-up fee. The manufacturing facilities of Hospira have been inspected and approved by the FDA for the commercial manufacture of several third-party drug products.

We utilized three suppliers for the three APIs used in our clinical supplies of OMS103HP. We have not yet signed commercial agreements with any suppliers for the supply of commercial quantities of these APIs,

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although we intend to do so prior to the commercial launch of OMS103HP. Given the large amount of these APIs manufactured annually by these and other suppliers, we anticipate that we will be capable of attaining our commercial API supply needs for OMS103HP.

We have undertaken the development of MASP-2 antibodies with two independent antibody developers, Affitech AS and North Coast Biologics, LLC. In March 2010 we amended our antibody development agreement with Affitech. Under the terms of the amendment, Affitech has released us from any future obligations to make royalty or milestone payments in exchange for $500,000. Our antibody development agreement with North Coast requires us to pay a low single-digit percentage royalty on net sales of any product containing an antibody developed for us by North Coast and milestone payments of up to $4.0 million. The milestone payments are payable upon the occurrence of certain development events, such as the delivery of a product candidate meeting certain criteria, initiation of clinical trials and receipt of marketing approval. The terms of these agreements continue until all of the services called for in the applicable agreement have been provided by the antibody developer and there are no pending patent applications or valid and enforceable claims included with any patent related to MASP-2 antibodies developed by such developer under the agreement, except that our agreement with North Coast may not terminate earlier than October 31, 2020. These agreements may be terminated prior to the end of their terms upon the occurrence of certain events such as breach of contract. We have the right under these agreements to require these developers to transfer the materials they create for us to third parties for further development and manufacturing of MASP-2 antibodies. In addition, under our North Coast antibody development agreement, North Coast has agreed to develop additional antibodies for us against targets that we select on or before October 31, 2020. If we do select additional targets, we may have to pay North Coast a technology access fee and we will have royalty and milestone payment obligations of up to $4.1 million per target for any related antibodies that are similar to our obligations for any MASP-2 antibody developed by North Coast. We intend to enter into an agreement with a third-party contract manufacturer for the scale-up and production of a MASP-2 monoclonal antibody product candidate for clinical testing and potentially commercial supply.

Competition

The pharmaceutical industry is highly competitive and characterized by a number of established, large pharmaceutical companies, as well as smaller companies like ours. If our competitors’ market products that are less expensive, safer or more effective than any future products developed from our product candidates, or that reach the market before our approved product candidates, we may not achieve commercial success. We are not aware of any products that directly compete with our PharmacoSurgery product candidates that are approved for intra-operative delivery in irrigation solutions during surgical procedures; however, our PharmacoSurgery product candidates could compete with preoperative and postoperative treatments for pain and inflammation. If approved, we expect that the primary constraint to market acceptance of our PharmacoSurgery product candidates will be surgeons who continue with their respective current treatment practices and do not adopt the use of these product candidates as well as the level of reimbursement surgeons receive for the administration of our product candidates.

Our other clinical and preclinical product candidates may face competing products. For example, we are developing PDE10 inhibitors for use in the treatment of schizophrenia and other psychotic disorders. Other pharmaceutical companies, many with significantly greater resources than us, are also developing PDE10 inhibitors for the treatment of schizophrenia and other psychotic disorders and these companies may be further along in development. In addition, we believe that other companies are attempting to de-orphanize orphan GPCRs. If any of these companies is able to de-orphanize an orphan GPCR before we do, we may be unable to establish an exclusive or commercially valuable intellectual property position around that orphan GPCR. We expect to compete with other pharmaceutical and biotechnology companies, and our competitors may:

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We expect to compete for market share against large pharmaceutical and biotechnology companies, smaller companies that are collaborating with larger pharmaceutical companies, new companies, academic institutions, government agencies and other public and private research organizations. In addition, the pharmaceutical and biotechnology industry is characterized by rapid technological change. Because our research approach integrates many technologies, it may be difficult for us to remain current with the rapid changes in each technology. If we fail to stay at the forefront of technological change, we may be unable to compete effectively. Our competitors may render our technologies obsolete by advancing their existing technological approaches or developing new or different approaches.

Intellectual Property

As of March 7, 2011, we owned a total of 27 issued or allowed patents and 37 pending patent applications in the United States and 112 issued or allowed patents and 122 pending patent applications in foreign markets directed to therapeutic compositions and methods related to our PharmacoSurgery platform, GPCR program and preclinical development programs. As of March 7, 2011, we also held worldwide exclusive licenses to five issued or allowed patents and two pending patent applications, in the United States and 17 issued or allowed patents and 18 pending patent applications in foreign markets. For each program, our decision to seek patent protection in specific foreign markets, in addition to the U.S., is based on many factors, including one or more of the following: our available resources, the size of the commercial market, the presence of a potential competitor or a contract manufacturer in the market and whether the legal authorities in the market effectively enforce patent rights.

Our patent portfolio for our PharmacoSurgery technology is directed to locally delivered compositions and treatment methods using agents selected from broad therapeutic classes. These patents cover combinations of agents, generic and/or proprietary to us or others, delivered locally and intra-operatively to the site of any medical or surgical procedure. As of March 7, 2011, our patent portfolio included 14 U.S. and 24 foreign issued or allowed patents, and seven U.S. and 24 foreign pending patent applications, directed to our PharmacoSurgery product candidates and development programs. Our issued PharmacoSurgery patents have terms that will expire December 12, 2014 and, assuming issuance of currently pending patent applications, October 20, 2019 for OMS103HP, July 30, 2023 for OMS302 and March 17, 2026 for OMS201. We intend to file additional patent applications directed to our specific drug products which, if issued, are expected to provide patent terms ending 2031 or later.

Our initial issued patents in our PharmacoSurgery portfolio are directed to combinations of agents, drawn from therapeutic classes such as pain and inflammation inhibitory agents, spasm inhibitory agents, restenosis inhibitory agents and tumor cell adhesion inhibitory agents. We expanded our initial patent position with a series of patent applications directed to what we believe are the key physiological and technical elements of selected surgical procedures, and to the therapeutic classes that provide opportunities to improve clinical benefit during and after these procedures. Accordingly, our pending PharmacoSurgery patent applications are directed to combinations of agents, drawn from therapeutic classes such as pain and inflammation inhibitory agents, spasm inhibitory agents, vasoconstrictive agents, mydriatic agents and agents that reduce intraocular pressure, that are

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preferred for use in arthroscopic procedures, ophthalmologic procedures including intraocular procedures, and urologic procedures including ureteroscopy, for OMS103HP, OMS302 and OMS201, respectively, as well as covering the specific combinations of agents included in each of these product candidates.

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All of our employees enter into our standard Employee Proprietary Information and Inventions Agreement, which includes confidentiality provisions and provides us ownership of all inventions and other intellectual property made by our employees that pertain to our business or that relate to our employees’ work for us or result from the use of our resources. Our commercial success will depend in part on obtaining and maintaining patent protection and trade secret protection of the use, formulation and structure of our product candidates, and the methods used to manufacture them, as well as successfully defending these patents against third-party challenges. Our ability to protect our product candidates from unauthorized making, using, selling, offering to sell or importing by third parties is dependent on the extent to which we have rights under valid and enforceable patents that cover these activities.

The patent positions of pharmaceutical, biotechnology and other life sciences companies can be highly uncertain and involve complex legal and factual questions for which important legal principles remain unresolved. No consistent policy regarding the breadth of claims allowed in biotechnology patents has emerged to date in the United States, and tests used for determining the patentability of patent claims in all technologies are in flux. The pharmaceutical, biotechnology and other life sciences patent situation outside the United States is even more uncertain. Changes in either the patent laws or in interpretations of patent laws in the United States and other countries may diminish the value of our intellectual property. Accordingly, we cannot predict the breadth of claims that may be allowed or enforced in the patents that we own or have licensed or in third-party patents.

We have retained all manufacturing, marketing and distribution rights for each of our product candidates and programs. Some of our product candidates and programs are based on inventions and other intellectual property rights that we acquired through assignments, exclusive licenses or our acquisition of nura, inc. in August 2006 for an aggregate purchase price of $14.4 million.

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Government Regulation

Government authorities in the United States and other countries extensively regulate, among other things, the research, development, testing, manufacture, labeling, promotion, advertising, distribution, marketing, and export and import of drug products such as those we are developing. Failure to comply with applicable requirements, both before and after approval, may subject us, our third-party manufacturers, and other partners to administrative and judicial sanctions, such as a delay in approving or refusal to approve pending applications, warning letters, product recalls, product seizures, civil and other monetary penalties, total or partial suspension of production or distribution, injunctions, and/or criminal prosecutions.

In the United States, our products are regulated by the FDA as drugs under the Federal Food, Drug, and Cosmetic Act, or the FDCA, and implementing regulations. Before our drug products may be marketed in the United States, each must be approved by the FDA. Our product candidates are in various stages of testing and none have been approved.

The steps required before a drug product may be approved by the FDA generally include the following:

Preclinical Tests.  Preclinical tests include laboratory evaluations of product chemistry, toxicity, formulation, and stability, as well as animal studies to assess the potential efficacy and safety of the product candidate. The results of the preclinical tests, together with manufacturing information, analytical data, and other available information are submitted to the FDA as part of an IND.

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The IND Process.  An IND must become effective before human clinical trials may begin. An IND will automatically become effective 30 days after receipt by the FDA, unless before that time the FDA raises concerns or questions and imposes a clinical hold. In such a case, the IND sponsor and the FDA must resolve any outstanding FDA concerns or questions before clinical trials can proceed. There can be no assurance that submission of an IND will result in FDA authorization to commence clinical trials. Once an IND is in effect, the protocol for each clinical trial to be conducted under the IND must be submitted to the FDA, which may or may not allow the trial to proceed.

Clinical Trials.  Clinical trials involve the administration of the investigational drug to human subjects under the supervision of qualified personnel. Clinical trials are conducted under protocols detailing, for example, the parameters to be used in monitoring patient safety, and the efficacy criteria, or end points, to be evaluated. Each trial must be reviewed and approved by an independent Institutional Review Board or Ethics Committee before it can begin. Clinical trials are typically conducted in three defined phases, but the phases may overlap or be combined:

We, our product development partners, or the FDA may suspend clinical trials at any time on various grounds, including a belief that the subjects are being exposed to an unacceptable health risk.

The NDA Process.  If the necessary clinical trials are successfully completed, the results of the preclinical trials and the clinical trials, together with other detailed information, including information on the manufacture and composition of the product, are submitted to the FDA in the form of an NDA requesting approval to market the product for one or more indications. Before approving an NDA, the FDA usually will inspect the facility(ies) at which the product is manufactured, and will not approve the product unless it finds that cGMP compliance is satisfactory. If the FDA determines the NDA is not acceptable, the FDA may outline the deficiencies in the NDA and often will request additional information. Notwithstanding the submission of any requested additional testing or information, the FDA ultimately may decide that the application does not satisfy the criteria for approval. After approval, certain changes to the approved product, such as adding new indications, manufacturing changes, or additional labeling claims will require submittal of a new NDA or, in some instances, an NDA supplement, for further FDA review and approval. Post-approval marketing of products in larger patient populations than were studied during development can lead to new findings about the safety or efficacy of the products. This information can lead to a product sponsor’s requesting approval for and/or the FDA requiring changes in the labeling of the product or even the withdrawal of the product from the market. The testing and approval process requires substantial time, effort, and financial resources, and we cannot be sure that any approval will be granted on a timely basis, if at all.

Some of our drug products may be eligible for submission of applications for approval under the Section 505(b)(2) process. Section 505(b)(2) applications may be submitted for drug products that represent a modification, such as a new indication or new dosage form, of a previously approved drug. Section 505(b)(2) applications may rely on the FDA’s previous findings for the safety and effectiveness of the previously approved drug as well as information obtained by the 505(b)(2) applicant to support the modification of the previously approved drug. Preparing Section 505(b)(2) applications may be less-costly and time-consuming than preparing an NDA based entirely on new data and information.

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The FDA regulates certain of our candidate products as combination drugs under its Combination Drug Policy because they are comprised of two or more active ingredients. The FDA’s Combination Drug Policy requires that we demonstrate that each active ingredient in a drug product contributes to the product’s effectiveness.

In addition, we, our suppliers, and our contract manufacturers are required to comply with extensive FDA requirements both before and after approval. For example, we are required to report certain adverse reactions and production problems, if any, to the FDA, and to comply with certain requirements concerning advertising and promotion for our products. Also, quality control and manufacturing procedures must continue to conform to cGMP after approval, and the FDA periodically inspects manufacturing facilities to assess compliance with cGMP. Accordingly, manufacturers must continue to expend time, money, and effort in all areas of regulatory compliance, including production and quality control to comply with cGMP. In addition, discovery of problems such as safety problems may result in changes in labeling or restrictions on a product manufacturer or NDA holder, including removal of the product from the market.

Outside of the United States, our ability to market our products will also depend on receiving marketing authorizations from the appropriate regulatory authorities. The foreign regulatory approval process includes similar requirements and many of the risks associated with the FDA approval process described above. The requirements governing marketing authorization and the conduct of clinical trials vary widely from country to country.

Research and Development

We have built a research and development organization that includes expertise in discovery research, preclinical development, product formulation, analytical and medicinal chemistry, manufacturing, clinical development and regulatory and quality assurance. We operate cross-functionally and are led by an experienced research and development management team. We use rigorous project management techniques to assist us in making disciplined strategic research and development program decisions and to limit the risk profile of our product pipeline. We also access relevant market information and key opinion leaders in creating target product profiles and, when appropriate, as we advance our programs to commercialization. We engage third parties on a limited basis to conduct portions of our preclinical research; however, we are not substantially dependent upon any third parties for our preclinical research nor do any of these third parties conduct a major portion of our preclinical research. In addition, we engage multiple clinical sites to conduct our clinical trials; however we are not substantially dependent upon any one of these sites for our clinical trials nor do any of them conduct a major portion of our clinical trials. Research and development expenses were $23.5 million, $16.9 million and $17.9 million in 2010, 2009 and 2008, respectively.

Employees

As of February 28, 2011, we had 70 full-time employees, 55 of whom are in research and development and 15 of whom are in finance, legal, business development and administration, including three with M.D.s and 17 with Ph.D.s. None of our employees is represented by a labor union and we consider our employee relations to be good.

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Gregory A. Demopulos, M.D.  is one of our founders and has served as our president, chief executive officer and chairman of the board of directors since June 1994 and, in an interim capacity, as our chief financial officer and treasurer since January 2009. He also served as our chief medical officer from June 1994 to March 2010. Prior to founding Omeros, Dr. Demopulos completed his residency in orthopedic surgery at Stanford University and his fellowship training at Duke University. Dr. Demopulos currently serves on the board of directors of Onconome, Inc., a privately held company developing biomarkers for early cancer detection. Dr. Demopulos received his M.D. from the Stanford University School of Medicine and his B.S. from Stanford University. Dr. Demopulos is the brother of Peter A. Demopulos, M.D., a member of our board of directors.

Marcia S. Kelbon, J.D.  has served as our vice president, patent and general counsel since October 2001 and as our secretary since September 2007. Prior to joining us, Ms. Kelbon was a partner with the firm of Christensen O’Connor Johnson & Kindness, PLLC, where she specialized in U.S. and international intellectual property procurement, management, licensing and enforcement issues. Ms. Kelbon received her J.D. and her M.S. in chemical engineering from the University of Washington and her B.S. from The Pennsylvania State University.

Timothy M. Duffy has served as our vice president, business development since March 2010. From November 2008 to March 2010, Mr. Duffy served as the managing director of Pacific Crest Ventures, a life science consulting firm that he founded. From June 2004 through September 2008, Mr. Duffy served at MDRNA, Inc. (formerly Nastech Pharmaceutical Company, Inc.), a biotechnology company. At MDRNA, he held roles of increasing responsibility in marketing and business development, most recently as the chief business officer. Prior to MDRNA, Mr. Duffy served as vice president, business development at Prometheus Laboratories, Inc., a specialty pharmaceutical company, and as a customer marketing manager at The Procter & Gamble Company. Mr. Duffy received his B.S. from Loras College.

Kenneth M. Ferguson, Ph.D. has served as our vice president, development since November 2010. From August 2008 to November 2010, Dr. Ferguson served in various positions, including president, chief executive officer and executive director as well as a consultant, for VacTX International Inc., a biotechnology company. From 1990 to 2007, Dr. Ferguson served at ICOS Corporation. Prior to its acquisition in 2007 by Eli Lilly and Company, Dr. Ferguson served at ICOS as vice president, therapeutic development. He also served as chief operating officer, chief scientific officer and a member of the board of managers of Lilly ICOS LLC, the joint

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venture of Eli Lilly and ICOS that developed and marketed Cialis ^® . Following the acquisition of ICOS by Eli Lilly, he served as president of ICOS from January 2007 to December 2007, managing its integration into Eli Lilly. Before joining ICOS, Dr. Ferguson worked for Cold Spring Harbor Laboratory. He holds a Ph.D. in pharmacology from the University of Texas Health Science Center and a B.S. in biological sciences from Cornell University.

George A. Gaitanaris, M.D., Ph.D.  has served as our vice president, science since August 2006. From August 2003 to our acquisition of nura, inc. in August 2006, Dr. Gaitanaris served as the chief scientific officer of nura, a company that he co-founded and that developed treatments for central nervous system disorders. From 2000 to 2003, Dr. Gaitanaris served as president and chief scientific officer of Primal, Inc., a biotechnology company that was acquired by nura in 2003. Prior to co-founding Primal, Dr. Gaitanaris served as staff scientist at the National Cancer Institute. Dr. Gaitanaris received his Ph.D. in cellular, molecular and biophysical studies and his M.Ph. and M.A. from Columbia University in New York and his M.D. from the Aristotelian University of Greece.

Wayne R. Gombotz, Ph.D.  has served as our vice president, pharmaceutical operations since March 2005. From 2002 to 2005, Dr. Gombotz served as vice president, process science and pharmaceutical development at Corixa Corporation, a company that developed immunotherapeutic products and which was acquired by GlaxoSmithKline plc in July 2005. From 1995 to 2002, Dr. Gombotz served as senior director, analytical chemistry and formulation at Immunex Corporation, a company that developed immunotherapeutic products and was acquired by Amgen, Inc. in July 2002. Dr. Gombotz received his Ph.D. and M.S. in bioengineering from the University of Washington and his B.A. from Colby College.

J. Greg Perkins, Ph.D.  has served as our vice president, regulatory affairs and quality systems since April 2006. From 2004 to 2005, Dr. Perkins served as president of Bioderm Sciences, Inc., a company engaged in the development of wound management, first aid and sports medicine products. From 1994 to 2004, Dr. Perkins served in various positions at Solvay Pharmaceuticals, Inc., a pharmaceutical company, most recently as senior vice president, global scientific affairs and milestone review. Dr. Perkins received his Ph.D. in biochemistry and B.S. from Indiana University and completed a postdoctoral fellowship in neurochemistry at the University of Iowa.

David R. Toll has served as our senior director of finance since March 2009. He previously served as our director of finance and controller from January 2006 to March 2009. Mr. Toll also served as our controller and operations manager from November 2000 to January 2006. From 1998 to 2000, he served as the accounting manager at aQuantive, Inc., a publicly traded digital marketing company that was acquired by Microsoft Corporation. From 1992 to 1998, Mr. Toll served in various positions at Ostex International, Inc., a publicly traded biotechnology company and manufacturer of diagnostic kits for osteoporosis that was acquired by Inverness Medical Innovations, Inc. From 1990 to 1992, Mr. Toll served as a staff accountant with Deloitte & Touche LLP. Mr. Toll received his B.A. in business administration from Seattle University.

J. Steven Whitaker, M.D., J.D.  has served as our vice president, clinical development and chief medical officer since March 2010. From May 2008 to March 2010, Dr. Whitaker served as the chief medical officer, vice president of clinical development at Allon Therapeutics, Inc., a biotechnology company focused on developing drugs for neurodegenerative diseases. From August 2007 to May 2008, he served as a medical consultant to Accelerator Corporation, a biotechnology investment and development company. From May 1994 to May 2007, Dr. Whitaker served at ICOS Corporation, which was acquired by Eli Lilli & Company in 2007. At ICOS, he held roles of increasing responsibility in clinical research and medical affairs, most recently as divisional vice president, clinical research as well as medical director of the Cialis ^® global product team. Dr. Whitaker received his M.D. from the Indiana University School of Medicine, his J.D. from the University of Washington and his B.S. from Butler University.

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Corporate Information

We were incorporated as a Washington corporation on June 16, 1994. Our principal executive offices are located at 1420 Fifth Avenue, Suite 2600, Seattle, Washington, 98101, and our telephone number is (206) 676-5000. Our web site address is www.omeros.com. We make available, free of charge through our web site, our annual report on Form 10-K, our quarterly reports on Form 10-Q, our current reports on Form 8-K and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. Our web site and the information contained therein or incorporated therein are not intended to be incorporated into this Annual Report on Form 10-K. In addition, the public may read and copy any materials we file or furnish with the SEC at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549 or may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330. Moreover, the SEC maintains a web site that contains reports, proxy and information statements, and other information regarding reports that we file or furnish electronically with them at www.sec.gov.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, which are subject to the “safe harbor” created by those sections. Forward-looking statements are based on our management’s beliefs and assumptions and on information currently available to our management. All statements other than statements of historical facts are “forward-looking statements” for purposes of these provisions. In some cases you can identify forward-looking statements by terms such as “may,” “will,” “should,” “could,” “would,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “project,” “predict,” and “potential,” and similar expressions intended to identify forward-looking statements. Examples of these statements include, but are not limited to, statements regarding:

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Our actual results could differ materially from those anticipated in these forward-looking statements for many reasons, including the risks, uncertainties and other factors described in this Annual Report on Form 10-K under the heading “Risk Factors” and in our other filings with the Securities and Exchange Commission. Given these risks, uncertainties and other factors, you should not place undue reliance on these forward-looking statements. Also, these forward-looking statements represent our management’s estimates and assumptions only as of the date of the filing of this Annual Report on Form 10-K. You should read this Annual Report on Form 10-K completely and with the understanding that our actual future results may be materially different from what we expect. Except as required by law, we assume no obligation to update these forward-looking statements publicly, or to update the reasons actual results could differ materially from those anticipated in these forward-looking statements, even if new information becomes available in the future.

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