UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 8-K
CURRENT REPORT
Pursuant to Section 13 or 15(d)
of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): January 9, 2020

Castle Biosciences, Inc.
(Exact name of registrant as specified in its charter) 
 
 
 
 
 
Delaware
 
001-38984
 
77-0701774
(state or other jurisdiction
of incorporation)
 
(Commission
File Number)
 
(I.R.S. Employer
Identification No.)

 
820 S. Friendswood Drive, Suite 201
Friendswood, Texas
 
77546
 
(Address of principal executive offices)
 
(Zip Code)

Registrant’s telephone number, including area code: (866) 788-9007

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: 

¨    Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
¨    Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) 
¨    Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) 
¨    Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) 
 
Securities registered pursuant to Section 12(b) of the Act: 
Title of each class
 
Trading Symbol(s)
 
Name of each exchange on which registered
Common Stock, $0.001 par value per share
 
CSTL
 
The Nasdaq Global Market

Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).
Emerging growth company x
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨ 
 




 

Item 2.02    Results of Operations and Financial Condition.

On January 9, 2020, Castle Biosciences, Inc. (the “Company”) issued a press release announcing certain preliminary performance results for the fourth quarter of 2019 and for the year ended December 31, 2019. A copy of the press release is attached hereto as Exhibit 99.1.

The information contained or incorporated in this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed to be incorporated by reference into any filing under the Exchange Act or the Securities Act of 1933, as amended (the “Securities Act”), except as expressly set forth by specific reference in such filing to this Current Report on Form 8-K.

Item 7.01    Regulation FD Disclosure.

On January 9, 2020, the Company made available via its website, www.castlebiosciences.com, an updated slide presentation for use in meetings with investors, analysts and others. A copy of the slide presentation is attached hereto as Exhibit 99.2.

The information contained or incorporated in this Current Report on Form 8-K, including Exhibit 99.2, shall not be deemed “filed” for purposes of Section 18 of the Exchange Act, or otherwise subject to the liabilities of that section, nor shall it be deemed to be incorporated by reference into any filing under the Exchange Act or the Securities Act, except as expressly set forth by specific reference in such filing to this Current Report on Form 8-K.

By filing this Current Report on Form 8-K, including Exhibit 99.2 attached hereto, and furnishing this information, the Company makes no admission as to the materiality of such information. The information contained in this report is intended to be considered in the context of the Company’s filings with the Securities and Exchange Commission (“SEC”) and other public announcements that the Company makes, by press release or otherwise, from time to time. The Company undertakes no duty or obligation to publicly update or revise the information contained in this report, although it may do so from time to time as its management believes is appropriate. Any such updating may be made through the filing of other reports or documents with the SEC, through press releases or through other public disclosure.

Item 9.01    Financial Statements and Exhibits.
(d) Exhibits.
Exhibit
 
 
Number
 
Description
99.1
 
99.2
 

 


SIGNATURES
 
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has caused this report to be signed on its behalf by the undersigned hereunto duly authorized.





 
CASTLE BIOSCIENCES, INC.
 
 
 
 
 
 
 
By:
/s/ Frank Stokes
 
 
Frank Stokes
 
 
Chief Financial Officer
Date: January 9, 2020
 
 
 





Exhibit 99.1
EX991PRESSRELEASE0109_IMAGE1.GIF     




Castle Biosciences Announces Preliminary Fourth Quarter and Full-Year 2019 Performance Results, Delivering 29% DecisionDx-Melanoma Test Report Volume Growth in 2019

Q4 2019 DecisionDx-Melanoma test report volume increased 37% compared to Q4 2018

Full-year 2019 DecisionDx-Melanoma test report volume increased 29% compared to full-year 2018

New Ordering Clinicians for Decision-Dx Melanoma increased 24% in 2019 compared to 2018

Year-end 2019 cash and cash equivalents balance of approximately $99 million


FRIENDSWOOD, TEXAS – Jan. 9, 2020 – Castle Biosciences, Inc. (Nasdaq: CSTL), a skin cancer diagnostics company providing personalized genomic information to improve cancer treatment decisions, today announced certain unaudited preliminary performance results for the fourth quarter and full-year 2019. The Company will report its full financial results and other metrics during its fourth quarter and year-end 2019 conference call, which is expected to be held in March 2020. Additionally, the Company expects to provide certain preliminary guidance for 2020 when it reports its final results for the fourth quarter and year-end 2019.

“We are pleased with our solid execution in 2019, particularly the acceleration in DecisionDx®-Melanoma volume seen since our first quarter 2019 commercial expansion,” said Derek Maetzold, president and chief executive officer of Castle Biosciences. “We attribute this growth to a combination of ongoing evidence development, which included eight peer-reviewed publications, as well as the early 2019 commercial expansion. As a result of this growth, we executed a second commercial expansion on December 1, 2019. And as of December 31, 2019, we have more than doubled our commercial personnel compared to December 31, 2018. Evidence development continued in 2019, including prospective studies that further support the two intended uses of our DecisionDx-Melanoma test, which we believe contributed to the posting of a draft Medicare Local Coverage Determination (LCD) expansion, as well as the acceptance of our application for a Category I MAAA Current Procedural Terminology (CPT) code by the American Medical Association’s CPT Editorial Panel.

“We believe the substantial volume growth in our lead product, DecisionDx-Melanoma, is providing more patients diagnosed with early stage cutaneous melanoma the opportunity to have informed discussions with their doctors and potentially improve treatment decisions. Additionally, we remain on track for the commercial launch of our two additional skin cancer products – our DecisionDx®-SCC gene expression profile (GEP) test for use in patients diagnosed with high risk cutaneous squamous cell carcinoma, and our skin cancer product for


use in patients with a suspicious pigmented lesion – in the second half of 2020. We believe these two late stage pipeline products will increase our estimated total addressable U.S. market by more than $1.4 billion, for an estimated total addressable U.S. market of $2.0 billion for current and pipeline products.”

Fourth Quarter Ended December 31, 2019, Highlights

•
Delivered 4,480 DecisionDx-Melanoma test reports in the 2019 fourth quarter, compared to 3,270 reports during the fourth quarter of 2018, representing an increase of 37% compared to the same period in 2018.

•
Delivered 434 DecisionDx®-UM test reports in the 2019 fourth quarter, compared to 385 reports during the fourth quarter of 2018, representing an increase of 13% compared to the same period in 2018.

Year- Ended December 31, 2019, Highlights

•
Delivered 15,529 DecisionDx-Melanoma test reports for the full year 2019, compared to 12,032 reports during the full year 2018, representing an increase of 29%.

•
In 2019, new ordering clinicians for DecisionDx-Melanoma increased 24% year-over-year. Additionally, total ordering clinicians in 2019 for DecisionDx-Melanoma increased 32% to 3,927, year-over-year.

•
Delivered 1,526 DecisionDx-UM test reports for the full year 2019, compared to 1,413 reports during the full year 2018, representing an increase of 8%. On a combined basis, overall reports increased by 27% for both DecisionDx-Melanoma and DecisionDx-UM for the full year 2019, compared to 2018.

•
Year-end 2019 cash and cash equivalents balance was approximately $99 million.

•
More than 1,000 squamous cell carcinoma patients from 56 U.S. centers enrolled in the DecisionDx-SCC clinical validation and performance studies as of December 31, 2019. The Company reported positive data from the clinical validation cohort study (n=321) in October 2019, and expects to report data from the performance cohort in 2020. Castle expects to launch its DecisionDx-SCC gene expression profile (GEP) test for use in patients diagnosed with high risk cutaneous squamous cell carcinoma in the second half of 2020.

•
More than 1,000 patients were also enrolled in the clinical development, validation and performance cohort studies for Castle’s GEP test for patients with a suspicious


pigmented lesion as of December 31, 2019. The Company expects to announce data from these studies and launch this GEP test in the second half of 2020.

Castle Biosciences has not completed the preparation of its financial statements for the fourth quarter or full -year 2019. The preliminary, unaudited performance results presented in this news release for the quarter and year-ended December 31, 2019, are based on management’s initial review of the information presented and are subject to adjustment based on the completion of the Company’s end-of-period reporting processes and related activities, including the audit of the Company’s financial statements, as such, any financial information contained herein may differ from the information reflected in our financial statements as of and for the year-ended December 31, 2019. Additional information and disclosures would be required for a more complete understanding of the Company’s financial position and results of operations as of and for the quarter and year-ended December 31, 2019. Accordingly, undue reliance should not be placed on this preliminary information.


About Castle Biosciences

Castle Biosciences (Nasdaq: CSTL) is a commercial-stage dermatologic cancer company focused on providing physicians and their patients with personalized, clinically actionable genomic information to make more accurate treatment decisions. The Company currently offers tests for patients with cutaneous melanoma (DecisionDx®-Melanoma, DecisionDx®-CMSeq; www.SkinMelanoma.com) and uveal melanoma (DecisionDx®-UM, DecisionDx®-PRAME and DecisionDx®-UMSeq; www.MyUvealMelanoma.com), with products in development for other underserved cancers, the two most advanced of which are focused on patients with cutaneous squamous cell carcinoma, and patients who have a difficult-to-diagnose pigmented lesion. Castle Biosciences is based in Friendswood, Texas (Houston), and has laboratory operations in Phoenix, Arizona. For more information, visit www.CastleBiosciences.com.

DecisionDx-Melanoma, DecisionDx-CMSeq, DecisionDx-UM, DecisionDx-PRAME and DecisionDx-UMSeq are trademarks of Castle Biosciences, Inc.


Forward-Looking Statements

The information in this press release contains forward-looking statements and information 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. These forward-looking statements include, but are not limited to, statements regarding the expected announcement of the our financial results and preliminary guidance, the expected commercial availability of our pipeline products, estimated total addressable market attributable to these pipeline products, our plans for commercial expansion, the impact of our tests, including DecisionDx-Melanoma, on patient treatment plans, the announcement/reporting of data from certain of our studies, our prospects and plans and the objectives of management.


The words “anticipates,” “believes,” “estimates,” “expects,” “intends,” “may,” “plans,” “projects,” “will,” “would” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. We may not actually achieve the plans, intentions, or expectations disclosed in our forward-looking statements and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements that we make. These forward-looking statements involve risks and uncertainties that could cause our actual results to differ materially from those in the forward-looking statements, including, without limitation, the risks set forth in our final prospectus filed with the SEC on July 26, 2019 relating to our Registration Statements on Form S-1 (File Nos. 333-232369 and 333-232796) and our Quarterly Report on Form 10-Q for the quarter ended September 30, 2019, filed with the SEC on November 12, 2019, and in our other filings with the SEC. The forward-looking statements are applicable only as of the date on which they are made, and we do not assume any obligation to update any forward-looking statements, except as may be required by law.

Media and Investor Contact:

Camilla Zuckero
832-835-5158 
czuckero@castlebiosciences.com


The Skin Cancer Diagnostics Company COMPANY PRESENTATION January 2020 NASDAQ:CSTL

 
DISCLAIMERS › Forward-Looking Statements The information in this presentation contains forward-looking statements and information 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. These forward-looking statements include, but are not limited to, statements concerning the anticipated milestones, including expected commercial availability of our pipeline products, estimated total addressable market attributable to our pipeline products, including the number of clinicians and patients in such addressable market, and our plans for commercial expansion, including anticipated number of sales territories. The words “anticipates,” “believes,” “estimates,” “expects,” “intends,” “may,” “plans,” “projects,” “will,” “would” and similar expressions are intended to identify forward-looking statements, although not all forward- looking statements contain these identifying words. We may not actually achieve the plans, intentions, or expectations disclosed in our forward-looking statements and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements that we make. These forward-looking statements involve risks and uncertainties that could cause our actual results to differ materially from those in the forward-looking statements, including, without limitation, the risks set forth in our final prospectus filed with the SEC on July 26, 2019 relating to our Registration Statements on Form S-1 (File Nos. 333-232369 and 333-232796) and our Quarterly Report on Form 10-Q for the quarter ended September 30, 2019 and in our other filings with the SEC. The forward-looking statements are applicable only as of the date on which they are made, and we do not assume any obligation to update any forward-looking statements, except as may be required by law. DecisionDx, DecisionDx-UM, DecisionDx-Melanoma, and the Castle Biosciences logo are the registered trademarks of Castle Biosciences, Inc. This presentation may also contain trademarks and trade names that are the property of their respective owners. 2

 
PRELIMINARY FOURTH QUARTER AND YEAR-END 2019 PERFORMANCE RESULTS1 (unaudited) › High volume growth: › 4Q2019 DecisionDx-Melanoma increased by 37% over the same period in 2018 › Full-year 2019 DecisionDx-Melanoma increased by 29% year-over-year from 2018 › New ordering clinicians for DecisionDx-Melanoma increased by 24% year-over-year from 2018 › Strong cash position: › Year-end 2019 cash and cash equivalents of ~$99 million2 › Skin cancer products pipeline: › More than 1,000 squamous cell carcinoma patients enrolled in the DecisionDx-SCC clinical validation and performance studies (as of December 31, 2019) › More than 1,000 patients enrolled in the clinical development, validation and performance cohort studies for Castle’s GEP test for patients with a suspicious pigmented lesion (as of December 31, 2019) 1 Castle will report full financial results in March 2020. 2 This amount is preliminary and is subject to completion of financial closing procedures. As a result, this amount may differ from the amount that will be reflected in our financial statements 3 as of and for the year ended December 31, 2019.

 
CASTLE’S LEAD PRODUCT, DECISIONDX-MELANOMA, INCREASED 29% IN 2019 YEAR-OVER-YEAR FROM 2018 DecisionDx-Melanoma DecisionDx-Melanoma Test DecisionDx-Melanoma Test Report Growth 4Q19 Report Growth New Ordering Clinicians 2019 4480 15,529 3270 12,032 24% 37% 9,300 29% 6,295 2,858 4Q18 4Q19 2015 2016 2017 2018 2019 2018 2019 4

 
The Skin Cancer Diagnostics Company COMPANY PRESENTATION November 14, 2019 NASDAQ:CSTL The following is the unedited presentation made available on the Company’s website, www.castlebiosciences.com, on November 14, 2019.

 
CASTLE BIOSCIENCES Improving Health Outcomes Of Patients With Skin Cancer Through Innovative, Clinically Actionable, Cost-effective Diagnostics › STRONG FINANCIALS › High volume growth: 3Q2019 = DecisionDx-Melanoma = 32%; 30% total GEP test reports › Strong revenue: 3Q2019 =$14.8 million; YTD2019 = $34.2 million › Gross Margin: 3Q2019=$13.1 million, or 88% › Cash at September 30, 2019, of $94.5 million › INNOVATIVE PRODUCTS › Two commercialized products that improve treatment decisions for patients with melanoma › 95% of commercial emphasis currently on skin melanoma › Pipeline products → Two addi�onal skin cancer products expected to launch in second half of 2020 › Will increase estimated U.S. total addressable market size by $1.4B to $2.0B › ADVANCING EVIDENCE DEVELOPMENT › We support our products with extensive studies on clinical validity, clinical utility and analytical validity › 22 peer-reviewed publications for DecisionDx-Melanoma › Both DecisionDx-Melanoma and DecisionDx-UM achieved Category I MAAA CPT code status › Recently presented clinical validation data for DecisionDx-SCC pipeline product 6

 
RECENT AND UPCOMING EXPECTED MILESTONES 2018 2019 2020 2021 7

 
CASTLE’S DERMATOLOGICAL CANCER PRODUCTS & CURRENT PIPELINE TARGET AN ESTIMATED $2.0B U.S. TOTAL ADDRESSABLE MARKET1 SQUAMOUS CELL SUSPICIOUS PIGMENTED MELANOMA CARCINOMA LESIONS TOTAL ANNUAL ~190,000 ~1 Million ~2 Million INCIDENCE Patients Patients Patients INITIAL CASTLE ~130,000 patients classified ~200,000 patients present ~300,000 patients with an ADDRESSABLE as Stage I, II or III with high-risk features indeterminant biopsy MARKET ~$540M Estimated U.S. TAM ~$820M Estimated U.S. TAM ~$600M Estimated U.S. TAM COMPANIES WITH Castle Castle (proj. 2H2020) Castle (proj. 2H2020) ADRESSABLE OFFERINGS Myriad Genetics: myPath®Melanoma 8 1U.S. TAM = Total addressable market based on estimated patient population assuming average reimbursement rate among all payors.

 
CASTLE’S PRODUCTS & PRODUCT PIPELINE DEVELOPMENT VALIDATION COMMERCIALIZATION Secure Assay Algorithm Analytical Clinical Clinical Physician Commercial Guideline Medicare1 Samples Development Development Validation Validation Utility Adoption Payors Inclusion LCD effective Dec 2018 In process Cutaneous Melanoma 7 published studies ~3,400 1 published 11 published 3 published ordering Covered lives: study studies systematic clinicians 60 million reviews/practice (2018) guideline available Currently LCD effective Jul 2017  Uveal Melanoma >130 ordering 2 published 10 published 2 published Covered lives: Covered lives: clinicians studies studies studies 60 million 83 million (2018) Squamous Cell  Carcinoma pipeline Suspicious Near term Near term  In process In process Pigmented Lesion 1Includes Medicare Advantage. 9

 
The Skin Cancer Diagnostics Company

 
TWO PRIMARY TREATMENT DECISIONS ARE REQUIRED FOLLOWING DIAGNOSIS OF CUTANEOUS MELANOMA Diagnosis of localized cutaneous melanoma 1 2 Is the risk of Is the risk of SLN- recurrence high positivity high enough to warrant enough to warrant initiation of imaging, referral for the high frequency SLNB surgery? follow-up, adjuvant therapy, and clinical trial enrollment? Traditionally, tumor thickness and Traditionally, tumor ulceration are used thickness, ulceration, to make this and SLN status are decision used to make this decision SLN = sentinel lymph node; SLNB = sentinel lymph node biopsy. 11

 
DECISIONDX-MELANOMA INFORMS THESE TWO IMPORTANT CLINICAL DECISIONS AND IMPACTS TREATMENT PLANS Diagnosis of localized cutaneous LIMITATIONS OF CURRENT melanoma STAGING TO INFORM BOTH DECISIONS 1 SLNB Surgery: • SLNB is prognostic only – no melanoma-specific survival benefit 1 2 • Surgery is often based upon a 5% or Is the risk of greater likelihood of SLN positivity Is the risk of SLN- recurrence high • Only 12% will be SLN-positive on positivity high enough to warrant average; SLNB also has an 18% enough to warrant initiation of imaging, median false negative rate referral for the high frequency • 11.3% complication rate and average SLNB surgery? follow-up, adjuvant reimbursed cost between $20,000 to therapy, and clinical $24,000 trial enrollment? Tumor thickness, 2 age, and Tumor thickness, DecisionDx- ulceration, SLN status Risk of recurrence management: Melanoma and DecisionDx- • 2 out of 3 deaths occur in the Melanoma “low-risk” group 12 • Many in the “high-risk” SLN = sentinel lymph node; SLNB = sentinel lymph node biopsy. group do well Source: AJCC v7 J Clin Oncol 2009; SEER data release 2017; Morton et al. N Engl J Med 2014; Whiteman et al. J Invest Dermatol 2015; Shaikh et al. J Natl Cancer Inst 2016; Poklepovic and Carvajal. Oncology 2018; Sondak and Zager. Ann Surg Oncol 2010. Moody et al. Euro Jrnl Surg Onc 2017.

 
DECISIONDX-MELANOMA WORKFLOW: AFTER DIAGNOSIS FOR MORE ACCURATE PREDICTION OF RISK Primary CM Tissue Class 1: 1A (FFPE) Lowest risk Low risk of SLN positivity (eligible T1-T2) Castle CAP/CLIA 1B Low risk of melanoma Low risk Patients with Certified Lab recurrence (T1-T4) Stage I – III Melanoma RNA Isolation Class 2: 2A 31 Gene Expression High-risk Profile Higher risk of SLN positivity (eligible T1-T2) High-risk of melanoma 2B Proprietary recurrence (T1-T4) Highest risk Algorithm Predicts Class 13 Gerami et al. Clin Cancer Res 2015; Gerami et al. JAAD 2015; Zager et al. BMC Cancer 2018; Gastman et al. JAAD 2019

 
DECISION 1 : SLNB SURGERY RULE OUT IN T1-T2 MELANOMAS Probability of a Positive Sentinel Lymph Node1 DecisionDx- DecisionDx-Melanoma Class 1A identifies a Melanoma All Ages ≥65 years 55-64 years <55 years low risk for SLN positivity similar to stage Result (n=1065) (n=448) (n=247) (n=370) T1a patients (for whom SLNB is not Class 1A 4.6% 1.6% 4.9% 7.6% recommended) Class 1B/2A 10.8% 6.9% 7.7% 19.6% Class 2B 18.8% 11.9% 30.8% 24.0% Class 1A Outcomes (all ages) Median follow-up MSS OS DMFS RFS Class 1A patients show excellent 5-year survival outcomes in long-term archival studies1 >5 years 99.6% 98.2% 95.3% 93.5% Outcomes confirmed in prospective, multi-center study2 3.2 years n/r 99.4% 98.8% 96.8% Data shows DecisionDx-Melanoma could result in 74% fewer SLNB surgeries, potentially saving U.S. healthcare system $250M1,3 1Vetto et al. Future Oncol 2019. 2Hsueh et al. Poster discussion abstract, ASCO 2019. 3Clearview health economic model, data on file. T1-T2 tumors are ≤2.0mm thick (“Breslow’s” thickness or depth). 14 MSS = melanoma specific survival. OS = overall survival. DMFS = distant metastasis free survival. RFS = recurrence free survival. n/r = not reported.

 
DECISION 2 : 50% OF PATIENTS HAD A CHANGE IN MANAGEMENT % Change in Study Design # of Patients Management 4 consecutive clinical impact studies have Prospectively tested cohort, Berger1 multi-center. Retrospective pre 156 53% shown 47-53% change in risk of test / post test management. recurrence management Prospective, multi-center: Dillon2 247 49% Changes in patient management include: pre test / post test management › Imaging and labs 169 physician impact study: › Sentinel lymph node biopsy guidance Farberg3 patient vignettes with pre test / n/a 47-50% › Clinical visit frequency post test management › Referrals Prospectively tested cohort, single center. Retrospective Schuitevoerder4 pre test / post test management; 91 52% and modeling of prospective cohort 1Berger, et al. Curr Med Res Opin 2016; 2Dillon et al. Skin 2018; 3Farberg et al. Jrnl Drugs Derm 2017; 4Schuitevoerder, et al. Jrnl Drugs Derm 2018. 15

 
DECISIONDX-MELANOMA INFORMS BOTH PRIMARY TREATMENT DECISIONS, ADDRESSING THE ISSUES OF OVER- AND UNDER-TREATMENT 1 Rule-out SLNB for T1-T2 melanoma Class 1A: <5% SLN positivity and favorable prognosis patients, including T1a with adverse Class 1B-2B: ≥5% SLN positivity and higher rates of metastasis features SLNB decision: T1a with adverse features and T1b-T2 T1a T1a HR T1b T2 T3 T4 Risk of recurrence: Any T ≥0.3 mm Class 1A: lowest risk 2 Guide follow-up, referrals, imaging and adjuvant therapy Class 1B: low risk decisions for patients with any T ≥0.3 mm. Class 2A: high-risk Class 2B: highest risk Vetto et al. Future Oncol 2019; Marks et al SKIN J Cutaneous Med 2019 13

 
22 STRONG PEER-REVIEWED PUBLICATIONS SINCE 2015 FOR DECISIONDX-MELANOMA Validation & Validation & Prospective Studies Clinical Impact Studies Performance Studies Performance Studies • Vetto et al. Future Oncol 2019 • Keller et al. Cancer Med 2019 • Marks et al. SKIN 2019 • Gastman et al. JAAD 2019 • Podlipnik et al. JEADV 2019 • Mirsky et al. J Drugs Dermatol 2018 • Dillon et al. SKIN 2018 • Gastman et al. Head & Neck 2019 • Greenhaw et al. Dermatol Surg 2018 • Schuitevoerder et al. J Drugs • Zager et al. BMC Cancer 2018 Dermatol 2018 • Hsueh et al. J Hematol Oncol • Ferris et al. JAAD 2017 • Svoboda et al. J Drugs Dermatol 2017 • Gerami et al. CCR 2015 2018 • Gerami et al. JAAD 2015 • Farberg et al. J Drugs Dermatol 2017 • Berger et al. CMRO 2016 • Cook et al. Diagn Pathol 2018 Systematic Reviews and Practice Guidelines • Berman et al. SKIN 2019 • Dubin et al. Am J Clin Dermatol 2019 • Winkelmann et al. Derm Clin 2017 17

 
PRODUCT PIPELINE The Skin Cancer Diagnostics Company

 
TREATMENT PATHWAYS IN SQUAMOUS CELL CARCINOMA OF THE SKIN (SCC) ARE BASED UPON RISK OF METASTASIS “Low” Risk Treatment plans may include: 80% of › Curettage and electrodesiccation patients or Mohs or WLE Clinicopathologic factors determine Biopsy high vs low-risk based diagnosis of SCC high-risk is defined as having one or more clinicopathologic factors Treatment plans may include: “High” Risk › Mohs or WLE 20% of › Radiation therapy patients › Chemotherapy › Some centers perform SLNB LIMITATIONS OF CURRENT STAGING SYSTEMS (AJCC [head/neck only], BWH, NCCN): LOW POSITIVE PREDICTIVE VALUE (PPV): AJCC = 14-17%. BWH = 24-38%. NCCN <10%. NCCN Guidelines v2.2019 19

 
DECISIONDX-SCC APPROPRIATE USE IS TARGETED TO THE HIGH-RISK PATIENT AND PROVIDES FOR DIFFERENTIAL ACTIONS “Low” Risk Treatment plans may include: 80% of › Curettage and electrodesiccation patients or Mohs or WLE Clinicopathologic factors determine Biopsy high vs low risk based diagnosis of SCC High-risk is defined as having one or more clinicopathologic factors Class 2A Treatment plans may include: “High” Risk result › Mohs or WLE 20% of › Radiation therapy patients Class 2B › Chemotherapy result › Some centers perform SLNB Clinical Validation Study presented at Amer Soc Derm Surgery (Oct 2019): • n=321. 93% of patients were staged as “high-risk”. 16% overall metastatic rate. • NPV of Class 1 test result = 91%. 63% of patients were Class 1. • PPV of Class 2B test result = 60%. 20

 
SUSPICIOUS PIGMENTED LESIONS: PRODUCT CANDIDATE ADJUNCT DIAGNOSTIC SUPPORT FOR HISTOPATHOLOGICALLY CHALLENGING LESIONS Attractive Market Implications of Over- and Undercalling Melanoma ~2 million suspicious pigmented Overcalling can lead to: lesions biopsied annually › Unnecessary surgery potentially including SLNB › Unnecessary follow-up including imaging, and potentially adjuvant ~300,000 biopsies cannot be therapy and/or clinical trial participation confidently confirmed as melanoma or benign lesion Undercalling can miss: through histopathology alone › The most dangerous form of skin cancer Our Development Goal: Improve decision points through increased positive predictive value and identification of low-risk patients actually at high-risk of recurrence 21

 
The Skin Cancer Diagnostics Company

 
: STANDARD OF CARE Strong Evidence Base Uveal Melanoma – A Rare Eye Cancer › 14+ peer-reviewed publications, 2,000+ patients ~1,600 patients diagnosed in the U.S. annually Widespread adoption ~97% of patients – no evidence of metastatic › 90%+ of U.S. ocular oncology institutions order disease at the time of diagnosis › 1,413 reports issued in 2018 ~30% will develop metastases within 3 years Broad Coverage › 143+ million total lives covered › Medicare LCD covers patients with a confirmed diagnosis and no evidence of metastatic disease (Uveal Melanoma) 15-Gene Expression Profile (GEP) Test › “Existing ADLT” status effective May 2019 AJCC and NCCN Guideline Inclusion Low-risk: ~67% High-risk: ~33% Low Intensity Management High Intensity Management 23

 
FINANCIAL OVERVIEW The Skin Cancer Diagnostics Company

 
KEY PERFORMANCE INDICATORS DRIVING GROWTH › 1Q19: Expanded sales territories from 14 to 23 Report › Further expansion from 23 to 32 planned for Dec 2019 Volume › 3Q19 vs 3Q18, DecisionDx-Melanoma report volume up 32% and new ordering clinicians up 26% Revenue › DecisionDx-Melanoma ASP: Significant growth 2018 vs 2017. Medicare rate increased in July 2019 to $7,193 for 3Q19 through 1Q20, thereafter PAMA rate. Reimbursement › Expanded draft LCD posted Aug 22, 2019 › DecisionDx-UM ASP: Continued 2018 over 2017 growth. PAMA rate effective Jan 1, 2021 Gross › 88% in 3Q19 vs 64% in 3Q18 Margin › Expect continued margin expansion driven by increasing ASPs and efficiencies of scale Profitability › 2 pipeline products expected to commercially launch in the second half of 2020 with New Product additional estimated $1.4B+ U.S. TAM Development Pipeline › Expect to leverage our existing sales channel to support the launch of additional products 25

 
1Q19 SALES EXPANSION SUPPORTED STRONG TEST REPORT GROWTH AND NEW ORDERING PHYSICIANS GROWTH Outside Sales Territories DecisionDx-Melanoma DecisionDx-Melanoma 32 Test Report Growth New Ordering Physicians 4126 23 3136 32% 26% 16 15 15 14 2015 2016 2017 2018 Feb 19 Dec 19 3Q18 3Q19 3Q18 3Q19 Expanded by an additional 9 outside sales territories in December 2019 26

 
PIPELINE PRODUCTS FIT INTO EXISTING COMMERCIAL CHANNEL DecisionDx-Melanoma Call Points Test Report Growth 13,445 Product Primary Secondary 12,032 Dermatology (including Mohs), Dermatopathology 9,300 Surgeons Medical Oncology 6,295 * Dermatology (including Mohs), Dermatopathology 2,858 Surgeons Medical Oncology Suspicious * Dermatopathology Dermatology 2015 2016 2017 2018 Pigmented Lesions * Expected commercial launch in 2H20 27

 
STRONG THIRD QUARTER 2019 ADJUSTED REVENUE AND ADJUSTED GROSS MARGIN Adj. Net Revenue ($ in millions) Adj. Gross Margin ($ in millions) $14.8 $13.1 $5.91 $4.51 3Q18 3Q19 3Q18 3Q19 Adj. Gross Margin % 77% 1 88% Source: Company financials. Unaudited. 1 See Non-GAAP Reconciliation at end of presentation. 28

 
CASTLE BIOSCIENCES Improving Health Outcomes Of Patients With Skin Cancer Through Innovative, Clinically Actionable, Cost-effective Diagnostics › STRONG FINANCIALS › High volume growth: 3Q2019 = DecisionDx-Melanoma = 32%; 30% total GEP test reports › Strong revenue: 3Q2019 =$14.8 million; YTD2019 = $34.2 million › Gross Margin: 3Q2019=$13.1 million, or 88% › Cash at September 30, 2019, of $94.5 million › INNOVATIVE PRODUCTS › Two commercialized products that improve treatment decisions for patients with melanoma › 95% of commercial emphasis currently on skin melanoma › Pipeline products → Two addi�onal skin cancer products expected to launch in second half of 2020 › Will increase estimated U.S. total addressable market size by $1.4B to $2.0B › ADVANCING EVIDENCE DEVELOPMENT › We support our products with extensive studies on clinical validity, clinical utility and analytical validity › 22 peer-reviewed publications for DecisionDx-Melanoma › Both DecisionDx-Melanoma and DecisionDx-UM achieved Category I MAAA CPT code status › Recently presented clinical validation data for DecisionDx-SCC pipeline product 29

 
The Skin Cancer Diagnostics Company THANK YOU

 
NON-GAAP FINANCIAL MEASURES In this presentation, we use the metrics of Adjusted Revenues, Adjusted Gross Margin and Adjusted Gross Margin Percentage, whichare non-GAAP financial measures and are not calculated in accordance with generally acceptance accounting principles in the United States, or GAAP. These non-GAAP financial measures reflect adjustments of revenues associated with test reports delivered in one reporting period, that were not recognizable until a later reporting period because all of the criteria for revenue recognition were not met under GAAP. Specifically, we did not have a Medicare Local Coverage Determination, or LCD, in place for our DecisionDx-Melanoma test until the fourth quarter of 2018. When issued, the LCD also provided coverage for payment of claims beginning in February 2018. Therefore, all the revenues covered by the LCD associated with tests delivered in the first through third quarters of 2018 were not recognized in our reported GAAP revenue until the fourth quarter of 2018. We use Adjusted Revenues, Adjusted Gross Margin and Adjusted Gross Margin percentage because we believe these metrics provide useful supplemental information in understanding changes in our year-over-year financial performance. However, our non-GAAP financial measures may be different from non-GAAP financial measures used by other companies, even when similar terms are used to identify such measures, limiting their usefulness for comparative purposes. These non-GAAP financial measures are not meant to be a substitutefor those reported in accordance with GAAP and should be considered in conjunction with financial information presented on a GAAP basis. Reconciliations of the non-GAAP financial measures to the most directly comparable GAAP financial measure are presented on the following slide.

 
RECONCILIATION OF NON-GAAP FINANCIAL MEASURES Three Months Ended September 30, 2019 2018 (in thousands) Adjusted Revenues Adjusted Revenues (Non-GAAP)$ 14,775 $ 5,898 DecisionDx-Melanoma Medicare revenue associated with test reports delivered in 3Q18 not recognizable until 4Q18 - (2,186) Net Revenues (GAAP)$ 14,775 $ 3,712 Adjusted Gross Margin Adjusted Gross Margin (Non-GAAP)$ 13,066 $ 4,547 DecisionDx-Melanoma Medicare revenue associated with test reports delivered in 3Q18 not recognizable until 4Q18 - (2,186) Gross Margin (GAAP)$ 13,066 $ 2,361 Adjusted Gross Margin Percentage Adjusted Gross Margin Percentage (Non-GAAP) 88% 77% DecisionDx-Melanoma Medicare revenue associated with test reports delivered in 3Q18 not recognizable until 4Q18 0% -13% Gross Margin Percentage (GAAP) 88% 64%

 
Appendix 33

 
LEADERSHIP TEAM Board of Directors Name Prior Experience Name Derek Maetzold Dan Bradbury, Founder, Director, Castle Chairman, President and CEO Equillium CEO Frank Stokes Derek Maetzold Chief Financial Officer Bernhard Spiess Bonnie Anderson, Chief Business Officer Veracyte CEO Toby Juvenal Mara Aspinall, Stuart Senior Vice President, Pharmaceuticals Bluestone Sales Managing Director Kristen Brad Cole, Oelschlager, RN, CHC Exact Sciences Senior Vice President, General Manager Operations Precision Oncology Federico Monzon, MD, Joe Cook, III FCAP MGP Managing Chief Medical Officer Director Robert Cook, PhD David Kabakoff, Vice President, Research & HealthQuest Development Partner 34