cstl-20210809
0001447362FALSE00014473622021-08-092021-08-09

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): August 9, 2021

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.)
505 S. Friendswood Drive, Suite 401
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 classTrading Symbol(s) Name of each exchange on which registered
Common Stock, $0.001 par value per shareCSTL 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 
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 August 9, 2021, Castle Biosciences, Inc. (the “Company”) issued a press release announcing its financial results for the quarter ended June 30, 2021. A copy of the press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

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 August 9, 2021, the Company made available the slide presentation attached hereto as Exhibit 99.2. Information from this slide presentation may also be used by the management of the Company in future meetings regarding the Company.

The information contained or incorporated in this Item 7.01 of 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.

Item 9.01    Financial Statements and Exhibits.
(d) Exhibits.
Exhibit
NumberDescription
99.1
99.2
104Inline XBRL for the cover page of this Current Report on Form 8-K.




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: August 9, 2021
 



Exhibit 99.1
cstllogo01a.jpg



Castle Biosciences Announces Second Quarter 2021 Results

Q2 2021 revenues of $22.8 million, compared to $12.7 million in Q2 2020
Q2 2021 total dermatology test report volume of 6,539
DecisionDx-Melanoma test reports increased 70%, compared to Q2 2020
Raising 2021 Revenue Guidance to $89-93 million from $80-83 million
Conference call and webcast today at 4:30 p.m. ET

FRIENDSWOOD, Texas- Aug. 9, 2021--Castle Biosciences, Inc. (Nasdaq: CSTL), a dermatologic diagnostics company providing personalized genomic information to improve treatment decisions, today announced its financial results for the second quarter and six months ended June 30, 2021.
“The Castle team delivered an exceptional quarter, which included record test report volume across each of our gene expression profile tests for a single quarter,” said Derek Maetzold, president and chief executive officer of Castle Biosciences. “We saw continued recovery trends throughout the second quarter, despite cutaneous melanoma diagnoses remaining below historical 2019 levels by approximately 12%. Our year-over-year growth in DecisionDx®-Melanoma test reports of 70% reflects both gains in diagnoses compared to 2020, as well as significant gains in market penetration. Due to our strong performance and expected continued momentum, we are raising our 2021 revenue guidance for the full year to $89-93 million.
"We continue to aggressively invest in our growth initiatives, including the expansion of our commercial team and accelerated R&D investments for our marketed and pipeline tests. Beginning on July 1, 2021, our dermatology-facing commercial team approximately doubled in size to the mid-60s, and each of our sales representatives will support all four of our skin cancer genomic tests. We believe our investments will continue to support our long-term value creation plans and the improvement of patient care.
“Finally, the acquisition of the myPath® Melanoma laboratory, and the resulting addition of the myPath Melanoma test to our skin cancer test services, was finalized in late May of 2021. We believe this acquisition furthers our position as the leader in dermatologic diagnostics and enables us to provide the most comprehensive offering for patients with skin cancer and difficult-to-diagnose melanocytic lesions.”
Second Quarter Ended June 30, 2021, Selected Results
Revenues were $22.8 million, an 79% increase compared to $12.7 million during the same period in 2020. Included in revenue for the period were revenue adjustments related to tests delivered in prior periods. These (negative) positive prior period revenue adjustments for the quarter ended June 30, 2021, were $(0.2) million, compared to $2.3 million for the same period in 2020.
Adjusted revenues were $22.9 million, a 120% increase, excluding the effects of revenue adjustments related to tests delivered in prior periods, compared to $10.4 million for the same period in 2020.
Total gene expression profile test reports delivered in the second quarter of 2021 were 7,007, compared to 3,314 in the same period of 2020:
DecisionDx-Melanoma test reports delivered in the second quarter of 2021 were 5,128, compared to 3,008, in the second quarter of 2020, an increase of 70%.
DecisionDx®-SCC test reports delivered in the second quarter of 2021 were 784.
MyPath Melanoma and DecisionDx® DiffDx™-Melanoma (Castle’s comprehensive diagnostic offering) aggregate test reports delivered in the second quarter of 2021 were 627.
DecisionDx®-UM test reports delivered in the second quarter of 2021 were 468, compared to 306 in the second quarter of 2020, an increase of 53%.
Gross margin for the quarter ended June 30, 2021, was 82.6%.
Adjusted gross margin for the quarter ended June 30, 2021, was 83.9%.
Operating cash flow was $(6.4) million, compared to $13.5 million for the same period in 2020.



Adjusted operating cash flow was $(4.3) million, excluding the effects of certain COVID-19-related government payments, compared to $3.3 million for the same period in 2020.

Six Months Ended June 30, 2021, Selected Results
Revenues were $45.6 million, a 51% increase compared to $30.1 million during the same period in 2020. Included in revenue for the period were positive revenue adjustments related to tests delivered in prior periods. These positive prior period revenue adjustments for the six months ended June 30, 2021, were $5.1 million, compared to $1.0 million for the same period in 2020.
Adjusted revenues were $40.5 million, a 39% increase, excluding the effects of revenue adjustments related to tests delivered in prior periods, compared to $29.1 million for the same period in 2020.
Total gene expression profile test reports delivered in the six months ended June 30, 2021, were 12,149, compared to 8,249 in the same period of 2020:
DecisionDx-Melanoma test reports delivered in the six months ended June 30, 2021, were 9,188, compared to 7,582, during the same period in 2020, an increase of 21%.
DecisionDx-SCC test reports delivered in the six months ended June 30, 2021, were 1,311.
MyPath Melanoma and DecisionDx DiffDx-Melanoma (Castle’s comprehensive diagnostic offering) aggregate test reports delivered in the six months ended June 30, 2021, were 845.
DecisionDx-UM test reports delivered in the six months ended June 30, 2021, were 805, compared to 667, during the same period in 2020, an increase of 21%.
Gross margin for the six months ended June 30, 2021, was 84.7%.
Adjusted gross margin for the six months ended June 30, 2021, was 83.4%.
Operating cash flow was $(10.1) million, compared to $13.3 million for the same period in 2020.
Adjusted operating cash flow was $(9.8) million, compared to $3.0 million for the same period in 2020.

Cash and Cash Equivalents
As of June 30, 2021, the Company’s cash and cash equivalents totaled $368 million, compared to $410 million at December 31, 2020. The decrease is primarily attributable to the acquisition of the Myriad myPath Laboratory for $33 million and cash used in operations of $10 million, including the effect of $2 million in recoupment of the Medicare advance payment the Company received last year.
2021 Revenue Guidance
Castle Biosciences is increasing its previously issued guidance for anticipated total revenue in 2021. The Company now anticipates generating $89-93 million in total revenue in 2021, compared to the previously provided guidance of $80-83 million.

Second Quarter and Recent Business and Clinical Evidence Highlights
In April, the Company announced it signed a definitive agreement to acquire the equity of Myriad myPath, LLC (Myriad myPath Laboratory), from Myriad Genetics. myPath Melanoma is a clinically validated gene expression profile (GEP) test designed to be used as an adjunct to histopathology when the distinction between a benign nevus and a malignant melanoma cannot be made confidently by histopathology alone (difficult-to-diagnose melanocytic lesions). With the acquisition, which closed in late May 2021, Castle provides the most comprehensive diagnostic offering for difficult-to-diagnose melanocytic lesions. See the Company’s news release from April 27, 2021, for more information.
In April, at the 10th World Congress of Melanoma, the Company presented data on three of its skin cancer tests, including from an independent validation study which demonstrated the i31-GEP artificial intelligence algorithm improved precision of sentinel lymph node positivity prediction in cutaneous melanoma. The poster, titled “Integration of the 31-gene expression profile test with clinicopathologic features (i31-GEP) to assess sentinel lymph node positivity risk in patients with cutaneous melanoma,” highlighted the i31-GEP validation study data and demonstrated that the algorithm provided a more precise, personalized likelihood of sentinel lymph node positivity. The poster can be accessed here.



Study methods and findings:
The study reviewed the development and validation of the i31-GEP, which deploys an artificial intelligence neural network algorithm to integrate the continuous DecisionDx-Melanoma score with histologic and clinical features on a development cohort of 1,398 patients. The i31-GEP algorithm was locked using these 1,398 patients and was then independently validated on an independent, U.S. based cohort of 1,674 patients.
The development phase identified that the DecisionDx-Melanoma score was the most important variable in predicting SLN positivity under both the variable importance assessment function (DecisionDx-Melanoma score = 100, Breslow thickness = 56, Mitotic rate = 25, ulceration = 83 and Age = 0; with 100 being the highest possible value) and log-likelihood value (DecisionDx-Melanoma score = 91.3, Breslow thickness = 53.5, Mitotic rate = 20.7, ulceration = 19.1 and Age = 10.5; with 100 being the highest possible value).
The independent validation phase showed that the i31-GEP provides a highly concordant prediction of SLN positivity rate compared to observed rates (linear regression slope of 0.999, with 1.0 representing complete concordance).
Of patients originally classified with 5-10% SLN positivity risk, i31-GEP reclassified 63% of those patients, whose actual risk of SLN positivity was outside that range in either direction (less than 5% or greater than 10%).
i31-GEP had a high negative predictive value of 98% in patients with T1-T4 tumors.
Information about the additional data presentations can be found here on the Company’s news release from April 16, 2021.
Data from an independent, prospective study was published in the American Journal of Surgery, which demonstrated DecisionDx-Melanoma’s utility for prediction of outcomes in patients with cutaneous melanoma. The publication, titled “Utility of a 31-gene expression profile for predicting outcomes in patients with primary cutaneous melanoma referred for sentinel node biopsy,” describes a study comparing tumor features, sentinel node biopsy (SLNB) results, and patient outcomes from a prospective database of 383 patients with cutaneous melanoma who both underwent SLNB and had their primary tumor assayed with DecisionDx-Melanoma. The study’s results demonstrated that a Class 2 (high-risk) DecisionDx-Melanoma result was significantly associated with higher rates of SLNB positivity compared to Class 1 (low risk). With respect to risk prognoses, patients who received a Class 2B DecisionDx-Melanoma result and were SLNB-positive experienced the highest recurrence rates (38%), compared to only a 2% recurrence rate for patients who were Class 1A and SLNB-negative. DecisionDx-Melanoma Class 2 results were significantly associated with poorer RFS and DMFS rates compared to Class 1 results, both in the entire cohort of 383 cases and in patients staged as “low risk” (IA-IIA) according to American Joint Committee on Cancer (AJCC) staging criteria. See the Company’s news release from April 14, 2021, for more information.
Publication of prospective, multi-center long-term outcomes data in cutaneous melanoma appeared in the peer-reviewed journal, JCO® Precision Oncology, and was titled “Long-term outcomes in a multicenter, prospective cohort evaluating the prognostic 31-gene expression profile for cutaneous melanoma.” The study’s key objective was to demonstrate the prognostic value of DecisionDx-Melanoma with long-term follow-up that extends the assessment time period for a previously studied cohort. The study achieved its key objective and expanded upon prior results to show the ability of the test to accurately identifying recurrence risk of patients with American Joint Committee on Cancer (AJCC) 8th Edition staging system early stage I-IIA disease. See the Company’s news release from April 13, 2021, for more information.
In May, the Company announced the launch of its innovative pipeline initiative to develop a genomic test aimed at predicting systemic therapy response in patients with moderate to severe psoriasis, atopic



dermatitis and related conditions. See the Company’s news release from May 10, 2021, for more information.
In May, the Company announced a publication describing the findings of a squamous cell carcinoma (SCC) GEP expert panel in the Journal of Drugs in Dermatology. The publication provides a framework for integrating DecisionDx-SCC into clinical practice. The article, titled “Clinical Considerations for Integrating Gene Expression Profiling into Cutaneous Squamous Cell Carcinoma Management,” describes the findings of a multidisciplinary expert panel, representing backgrounds from academic medical centers and community practices. The panel also included specialties clinicians, such as Mohs surgeons, surgical oncologists and a radiation oncologist. The panel reviewed traditional risk assessment practices, guidelines and expert recommendations on DecisionDx-SCC. The panel also focused on decision-making points, where information from DecisionDx-SCC might inform the clinical management of patients with SCC and one or more risk factors. See the Company’s news release from May 20, 2021, for more information.
In June, the Company announced that it received approval from the New York State Department of Health (NYSDOH) for its DecisionDx-SCC test. Castle’s laboratory in Phoenix is a NYSDOH permitted laboratory. This designation allows patients in New York to access the Company’s molecular diagnostic tests, designed to provide actionable molecular information to inform patient care decisions. The Company has previously received approvals in the state of New York for its other genomic tests, DecisionDx®-Melanoma, DecisionDx®-UM and DecisionDx®-PRAME, as well as its next generation sequencing panels, DecisionDx®-CMSeq and DecisionDx®-UMSeq. See the Company’s news release from June 9, 2021, for more information.
In July and August, the Company presented evidence on its family of skin cancer tests at numerous in-person, hybrid and virtual medical conferences, including American Head & Neck Society (AHNS) 2021 International Conference, Society of Dermatology Physician Assistants (SDPA) Annual Summer Dermatology Conference, DERM 2021 and 2021 American Academy of Dermatology Association (AAD) Summer Meeting.

Conference Call and Webcast Details
Castle Biosciences will hold a conference call on Monday, Aug. 9, 2021, at 4:30 p.m. Eastern time to discuss its second quarter 2021 results and provide a corporate update.

A live webcast of the conference call can be accessed here:
https://event.on24.com/wcc/r/3315443/658722E54799C7564600E9B3CB3E3EAE or via the webcast link on the Investor Relations page of the Company’s website (www.castlebiosciences.com). Please access the webcast at least 10 minutes before the conference call start time. An archive of the webcast will be available on the Company’s website until Aug. 31, 2021.

To access the live conference call via phone, please dial 844 200 6205 from the United States and Canada, or +1 646 904 5544 internationally, at least 10 minutes prior to the start of the call, using the conference ID 538115.

There will be a brief Question & Answer session following management commentary.

Use of Non-GAAP Financial Measures (UNAUDITED)
In this release, we use the metrics of Adjusted Revenue, Adjusted Gross Margin and Adjusted Operating Cash Flow, which are non-GAAP financial measures and are not calculated in accordance with generally accepted accounting principles in the United States (GAAP). Adjusted Revenue and Adjusted Gross Margin reflect adjustments to net revenues to exclude changes in variable consideration related to test reports delivered in previous periods. Adjusted Gross Margin also excludes acquisition-related intangible asset amortization. Adjusted Operating Cash Flow excludes the effects of cash activity associated with COVID-19 government relief payments to healthcare providers.




We use Adjusted Revenue, Adjusted Gross Margin and Adjusted Operating Cash Flow internally because we believe these metrics provide useful supplemental information in assessing our revenue and cash flow performance, respectively. We believe Adjusted Revenue and Adjusted Gross Margin are also useful to investors because they provide additional information on current-period performance by removing the effects of revenue adjustments related to tests delivered in previous periods and acquisition-related intangible asset amortization, which we believe may facilitate revenue and gross margin comparisons to historical periods. We believe Adjusted Operating Cash Flow is also useful to investors as a supplement to GAAP measures in the assessment of our cash flow performance by removing the effects of COVID-19 government relief payments, which we believe are not indicative of our ongoing operations. However, these non-GAAP financial measures may be different from non-GAAP financial measures used by other companies, even when the same or similarly titled terms are used to identify such measures, limiting their usefulness for comparative purposes. These non-GAAP financial measures are not meant to be substitutes for net revenues or net cash (used in) provided by operating activities reported in accordance with GAAP and should be considered in conjunction with our financial information presented on GAAP basis. Accordingly, investors should not place undue reliance on non-GAAP financial measures. Reconciliations of these non-GAAP financial measures to the most directly comparable GAAP financial measures are presented in the tables at the end of this release.

About Castle Biosciences

Castle Biosciences (Nasdaq: CSTL) is a commercial-stage dermatologic diagnostics 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), cutaneous squamous cell carcinoma (DecisionDx®-SCC), suspicious pigmented lesions (myPath® Melanoma, DecisionDx® DiffDx™-Melanoma) and uveal melanoma (DecisionDx®-UM, DecisionDx®-PRAME and DecisionDx®-UMSeq). For more information about Castle’s gene expression profile tests, visit www.CastleTestInfo.com.

Castle also has active research and development programs for tests in other dermatologic diseases with high clinical need, including its test in development to predict systemic therapy response in patients with moderate to severe psoriasis, atopic dermatitis and related conditions. Castle Biosciences is based in Friendswood, Texas (Houston), and has laboratory operations in Phoenix. Additionally, in May of 2021, Castle acquired the myPath Melanoma laboratory in Salt Lake City.

For more information, visit www.CastleBiosciences.com.

DecisionDx-Melanoma, DecisionDx-CMSeq, DecisionDx-SCC, DecisionDx DiffDx-Melanoma, myPath Melanoma, 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 concerning the effects of the COVID-19 pandemic on our business and our efforts to address its impact on our business, the impact, accuracy and effectiveness of our tests, including DecisionDx-Melanoma, DecisionDx-SCC, myPath Melanoma and DecisionDx DiffDx-Melanoma, on physicians, patients and their treatment plans, our prospects and plans and the objectives of management, Castle’s ability to integrate the myPath Melanoma test into its commercial offerings and deliver the most comprehensive molecular testing offering for difficult-to-diagnose melanocytic lesions, our increased total revenue guidance for 2021, and the ability of our investments in our growth initiatives to continue to support our long-term value creation plans and the improvement of patient care. 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 effects of the COVID-19 pandemic on our business and our efforts to address its impact on our business, subsequent study results and findings that contradict earlier study results and findings, our tests, including DecisionDx-Melanoma, DecisionDx-SCC, myPath Melanoma and DecisionDx DiffDx-Melanoma, ability to provide the aforementioned benefits to patients and the risks set forth in our Quarterly Report on Form 10-Q for the quarter ended June 30, 2021, 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.

The COVID-19 situation continues to evolve and brings along with it a high level of uncertainty surrounding potential future impacts. Therefore, trends in test report volumes, order data and new ordering clinician data is not necessarily indicative of the Company’s results of operations that can be expected for future interim periods or for the year ending December 31, 2021.

Investor and Media Contact:
Camilla Zuckero
+1 832-835-5158
[email protected]







CASTLE BIOSCIENCES, INC.
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
(UNAUDITED)
(in thousands, except per share data)
Three Months Ended
June 30,
Six Months Ended
June 30,
2021202020212020
NET REVENUES$22,758 $12,715 $45,571 $30,133 
OPERATING EXPENSES AND OTHER OPERATING INCOME
Cost of sales (exclusive of amortization of acquired intangible asset)3,697 2,146 6,725 4,537 
Research and development6,793 2,704 12,701 5,617 
Selling, general and administrative20,822 10,392 38,983 21,470 
Amortization of acquired intangible asset256 — 256 — 
Other operating income— (1,882)— (1,882)
Total operating expenses, net31,568 13,360 58,665 29,742 
Operating (loss) income(8,810)(645)(13,094)391 
Interest income24 38 28 336 
Interest expense— (769)— (1,533)
Loss before income taxes(8,786)(1,376)(13,066)(806)
Income tax expense— — 
Net loss and comprehensive loss$(8,791)$(1,376)$(13,071)$(806)
Loss per share:
Basic$(0.35)$(0.08)$(0.52)$(0.05)
Diluted$(0.35)$(0.08)$(0.52)$(0.05)
Weighted-average shares outstanding:
Basic25,091 17,544 25,002 17,458 
Diluted25,091 17,544 25,002 17,458 





CASTLE BIOSCIENCES, INC.
CONDENSED CONSOLIDATED BALANCE SHEETS
(in thousands)
June 30, 2021December 31, 2020
(unaudited)
ASSETS  
Current Assets  
Cash and cash equivalents$368,339 $409,852 
Accounts receivable, net17,817 12,759 
Inventory2,124 2,217 
Prepaid expenses and other current assets3,419 4,766 
Total current assets391,699 429,594 
Long-term accounts receivable, net1,313 1,096 
Property and equipment, net8,092 7,102 
Intangible asset, net32,798 — 
Other assets – long-term1,631 1,536 
Total assets$435,533 $439,328 
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current Liabilities
Accounts payable$1,368 $2,098 
Accrued compensation8,584 9,108 
Medicare advance payment6,177 6,615 
Other accrued liabilities2,525 3,055 
Total current liabilities18,654 20,876 
Noncurrent portion of Medicare advance payment— 1,735 
Deferred rent and other liabilities963 1,026 
Total liabilities19,617 23,637 
Stockholders’ Equity
Common stock
25 25 
Additional paid-in capital491,458 478,162 
Accumulated deficit(75,567)(62,496)
Total stockholders’ equity415,916 415,691 
Total liabilities and stockholders’ equity$435,533 $439,328 






CASTLE BIOSCIENCES, INC.
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
(UNAUDITED)
(in thousands)
Six Months Ended
June 30,
20212020
OPERATING ACTIVITIES
Net loss$(13,071)$(806)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization867 193 
Stock compensation expense9,679 3,230 
Amortization of debt discounts and issuance costs— 452 
Other69 — 
Change in operating assets and liabilities:
Accounts receivable(5,275)2,337 
Prepaid expenses and other current assets1,347 234 
Inventory223 (430)
Other assets(95)(62)
Accounts payable(683)444 
Accrued compensation(523)(1,127)
Medicare advance payment(2,173)8,350 
Other accrued liabilities(306)263 
Deferred rent and other liabilities(128)172 
Net cash (used in) provided by operating activities(10,069)13,250 
INVESTING ACTIVITIES
Purchases of property and equipment(1,663)(2,256)
Asset acquisition(33,184)— 
Proceeds from sale of property and equipment— 
Net cash used in investing activities(34,845)(2,256)
FINANCING ACTIVITIES
Proceeds from public offerings of common stock, net of underwriting discounts, commissions and offering costs— 69,530 
Payment of common stock offering costs(336)— 
Repayments on term debt— (833)
Proceeds from exercise of common stock options2,345 400 
Proceeds from contributions to the employee stock purchase plan1,392 823 
Net cash provided by financing activities3,401 69,920 
NET CHANGE IN CASH AND CASH EQUIVALENTS(41,513)80,914 
Beginning of period409,852 98,845 
End of period$368,339 $179,759 




CASTLE BIOSCIENCES, INC.
Reconciliation of Non-GAAP Financial Measures (UNAUDITED)
The table below presents the reconciliation of adjusted revenue and adjusted gross margin, which are non-GAAP measures. See "Use of Non-GAAP Financial Measures (UNAUDITED)" above for further information regarding the Company's use of non-GAAP financial measures.
Three Months Ended
June 30,
Six Months Ended
June 30,
2021202020212020
(in thousands)
Adjusted revenue
Net revenues (GAAP)$22,758 $12,715 $45,571 $30,133 
Revenue associated with test reports delivered prior periods166 (2,291)(5,092)(1,048)
Adjusted revenue (Non-GAAP)$22,924 $10,424 $40,479 $29,085 
Adjusted gross margin
Gross margin (GAAP)1
$18,805 $10,569 $38,590 $25,596 
Amortization of acquired intangible asset256 — 256 — 
Revenue associated with test reports delivered prior periods166 (2,291)(5,092)(1,048)
Adjusted gross margin (Non-GAAP)$19,227 $8,278 $33,754 $24,548 
Gross margin percentage (GAAP)2
82.6 %83.1 %84.7 %84.9 %
Adjusted gross margin percentage (Non-GAAP)3
83.9 %79.4 %83.4 %84.4 %
________________________
1.Calculated as net revenues (GAAP) less the sum of cost of sales (exclusive of amortization of acquired intangible asset) and amortization of acquired intangible asset.
2.Calculated as gross margin (GAAP) divided by net revenues (GAAP).
3.Calculated as adjusted gross margin (Non-GAAP) divided by adjusted revenue (Non-GAAP).

The table below presents the reconciliation of adjusted operating cash flow, which is a non-GAAP measure. See "Use of Non-GAAP Financial Measures (UNAUDITED)" above for further information regarding the Company's use of non-GAAP financial measures.
Three Months Ended
June 30,
Six Months Ended
June 30,
2021202020212020
(in thousands)
Adjusted operating cash flow
Net cash (used in) provided by operating activities (GAAP)$(6,438)$13,501 $(10,069)$13,250 
Medicare advance payment1
2,173 (8,350)2,173 (8,350)
HHS provider relief funds2
— (1,882)(1,882)(1,882)
Adjusted operating cash flow (Non-GAAP)$(4,265)$3,269 $(9,778)$3,018 
________________________
1.In April 2020, we received an advance payment of $8.3 million from the Centers for Medicare & Medicaid Service (CMS), for which recoupment has commenced in April 2021. We recorded the receipt of the payment as a liability on our balance sheet and, in accordance with GAAP, it is included in net cash provided by operating activities in the period received. We have excluded receipt of the advance payment from adjusted operating cash flow, but as claims are submitted for reimbursement and applied against this balance, we include the advance payment in adjusted operating cash flow to the extent that Medicare claims submitted for reimbursement have been applied to the balance.
2.In April 2020, we received a one-time payment of $1.9 million in relief funds automatically allocated to Medicare providers under the Coronavirus Aid, Relief and Economic Security Act (CARES Act) from the U.S. Department of Health and Human Services (HHS).





A u g u s t 9 , 2 0 2 1 Tr a n s f o r m i n g t h e m a n a g e m e n t o f d e r m a t o l o g i c c a n c e r s a n d o t h e r d e r m a t o l o g i c d i s e a s e s w i t h h i g h u n m e t n e e d


 
D i s c l a i m e rs F O R W A R D - L O O K I N G S T A T E M E N T S 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 effects of the COVID-19 pandemic on our business and our efforts to address its impact on our business, statements concerning the estimated size of our total addressable market or our existing and pipeline products, statements concerning our increased total revenue guidance for 2021, the impact, accuracy and effectiveness of our tests, including DecisionDx-Melanoma, DecisionDx-SCC, DecisionDx DiffDx-Melanoma and myPath Melanoma, on physicians, patients and their treatment plans, 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 effects of the COVID-19 pandemic on our business and our efforts to address its impact on our business, subsequent study results and findings that contradict earlier study results and findings, our tests, including DecisionDx-Melanoma, DecisionDx-SCC, DecisionDx DiffDx-Melanoma and myPath Melanoma, their ability to provide the aforementioned benefits to patients, and the risks set forth in our Quarterly Report on Form 10-Q for the quarter ended June 30, 2021, 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. 2


 
Transforming the management of skin cancer and other dermatologic diseases with high unmet clinical need Expansive Body of Evidence Suite of Dermatologic Prognostic And Diagnostic Tests Strong Financial Position Robust Pipeline L e a d i n g D e r m a t o l o g i c D i a g n o s t i c s C o m p a ny 3 Culture of Teamwork and Innovation


 
F i n a n c i a l S u m m a r y 2 Q 2 0 2 1 2Q21 2Q20 Revenue $22.8M $12.7M Adj. Revenue1 $22.9M $10.4M Total GEP test reports2 7,007 3,314 Total Derm test reports2 6,539 3,008 Operating Cash Flow $(6.4)M $13.5M Adj. Operating Cash Flow1 $(4.3)M $3.3M Gross Margin 83% 83% Adj. Gross Margin1 84% 79% Cash & Cash Equivalents $368M as of 6/30/2021 $180M as of 6/30/2020 1See Non-GAAP reconciliations at the end of this presentation. 2Castle had two commercially available GEP tests as of 6/30/2020. 4


 
Indication/ Test outcome Trade Name Reimbursement Status Peer-Reviewed Publications Primary Customers Initial Launch Targets Initial addressable market, patients2 Estimated U.S. TAM Cutaneous melanoma/ Risk of metastasis MCR, MCRA Commercial – in process 30+ Derms (including Mohs), Surgeons __ ~130k patients classified as Stage I, II or III ~$540M Cutaneous squamous cell carcinoma/ Risk of metastasis Expected draft LCD in 2021 Commercial – in process 5 Derms (including Mohs) ~4,709 current customers3 ~200k w/ high-risk features ~$820M Suspicious pigmented lesions/ Melanoma status MCR, MCRA Commercial – in process Expected draft LCD in 2021 Commercial – in process 9 2 Dermpaths, Derms ~1,778 current dermpath customers4 ~300k patients w/indeterminant biopsy ~$600M Pipeline Test- Inflammatory Target launch anticipated by the end of 2025 N/A N/A Expected to utilize existing dermatologic sales channels ~4,709 current customers3 ~450k patients eligible for systemic therapies ~$1.9B Other Pipeline Tests Target launches anticipated by the end of 2025 N/A N/A Expected to utilize existing dermatologic sales channels To be announced To be announced ~$1.7B E s t i m a t e d ~ $ 5 . 5 B U. S . To t a l A d d re s s a b l e M a r ke t 1 I n m a r k e t a n d p i p e l i n e t e s t s , l e v e r a g i n g e s t a b l i s h e d d e r m a t o l o g i c s a l e s c h a n n e l s 1U.S. TAM = Total addressable market based on estimated patient population assuming average reimbursement rate among all payors. 2 Annual U.S. incidence for Stage I, II or III melanoma estimated at 130,000; annual U.S. incidence for squamous cell carcinoma estimated at 1,000,000 with addressable market limited to carcinomas with one or more high risk features; annual U.S. incidence for suspicious pigmented lesion biopsies estimated at 2,000,000 with addressable market limited to the 15% with an indeterminant biopsy. 3Clinicians who ordered DecisionDx-Melanoma in last twelve months (as of 6/30/2021). 4Pathologists who provided clinical specimens for DecisionDx-Melanoma in last twelve months (as of 6/30/2021). -MCR = Medicare. MCRA = Medicare Advantage; current customer estimates based on last twelve months. 5


 
6 C l i n i c a l Po r t fo l i o A n d P i p e l i n e Te s t s P o t e n t i a l t o l a u n c h 3 - 5 n e w t e s t s b y t h e e n d o f 2 0 2 5 Skin Cancer Cutaneous melanoma/ Risk of metastasis Cutaneous squamous cell carcinoma/ Risk of metastasis Suspicious pigmented lesions/ Melanoma status Eye Cancer Uveal Melanoma/ Risk of metastasis Pipeline Target launch anticipated by the end of 2025 AD, PSO/ Prediction of systemic therapy response Pipeline Target launches anticipated by the end of 2025 Other clinical conditions Discovery Development Commercial Payer coverage Indication/ Test outcome 1U.S. TAM = Total addressable market based on estimated patient population assuming average reimbursement rate among all payors. AD= Atopic Dermatitis, PSO= Psoriasis


 
2022 C a s t l e ’s L o n g - Te r m Re v e n u e G r o w t h Po t e n t i a l 7 Cutaneous Melanoma 2021 Squamous Cell Carcinoma Cutaneous Melanoma Additional Tests for Dermatologic Diseases 2025 (Expanded LCD effective Dec 2020) (Potential LCD effective in 2022) (Acquired in May 2021; LCD in effect) (Potential LCD effective in 2022) Pipeline Expansion (Expected launches ~2025)


 
T h e C a s t l e A p p ro a c h 8 Identify dermatologic diseases with high unmet medical need, where genomic information has the potential to improve management decisions Leveraging artificial intelligence, tests are designed to provide clinically actionable information based on tumor gene expression patterns Designed to improve patient outcomes, test results inform management decisions within nationally accepted treatment guidelines Suite of skin cancer tests designed to provide clinicians with precise, personalized information, enabling more accurate treatment plan decisions


 
Informing clinical decision making for patients with invasive melanoma


 
If melanoma, clinician orders to answer SLNB and/or management questions: • Is the risk of SLN-positivity high enough to warrant referral for the SLNB surgery? • What is the individual risk of recurrence? D e c i s i o n D x - M e l a n o m a : A f t e r D i a g n o s i s O f C a n c e r 10 Patient presents with mole/melanocytic lesion Biopsy performed Potential Diagnosis: • Positive for melanoma • Negative • Uncertain malignant potential Physician may order SLNB, if warranted per clinicopathological features and Management plan determined, based on personalized risk


 
Cutaneous melanoma diagnosis F o l l o w i n g D i a g n o s i s , Tw o P r i m a r y C l i n i c a l Q u e s t i o n s H e l p G u i d e M e l a n o m a M a n a g e m e n t C h o o s i n g r i s k - a p p r o p r i a t e l e v e l o f m a n a g e m e n t i s k e y SLN = sentinel lymph node; SLNB = sentinel lymph node biopsy. Source: NCCN Guidelines for Cutaneous Melanoma v3.2020 What is the individual risk of recurrence? Higher RiskLower Risk 11 Traditionally estimated with tumor thickness, ulceration and SLN status Traditionally estimated with tumor thickness and age Is the risk of SLN-positivity high enough to warrant referral for the SLNB surgery? Potential Sentinel lymph node biopsy surgical procedure


 
Gerami et al. Clin Cancer Res 2015; Gerami et al. JAAD 2015; Zager et al. BMC Cancer 2018; Gastman et al. JAAD 2019 D e c i s i o n D x - M e l a n o m a : A f t e r D i a g n o s i s F o r M o r e A c c u ra t e R i s k A s s e s s m e n t s qPCR: open array card, 31-gene expression profile CM tumor tissue RNA isolation RT-PCR: cDNA generation and amplification, RT-PCR GEP analysis with a proprietary algorithm to predict class Stage I – III melanoma diagnosis Class 1A Lowest risk of recurrence and/or metastasis within 5 years Class 2B Highest risk of recurrence and/or metastasis within 5 years 12 Class 1B/2A Increased risk of recurrence and/or metastasis within 5 years


 
1Ellis et al. Am J Surg 2010; 2Bamboat et al. Ann Surg Oncol 2014; 3Morton et al. N Engl J Med 2014; 4Sondak et al. Ann Surg Oncol 2009; 5Moody et al. Eur J Surg Oncol 2017, SEER data release 2017 18% median false negative rate for nodal recurrence4 Majority of patients (~88%) subjected to a SLNB are negative and derive little to no benefit1-2 MSLT-I demonstrated no survival benefit and low sensitivity (2/3 of melanoma deaths in SLN negative group)3 Reduce exposure to anesthesia risks and surgical complications (rate = 11%)5 P ro b l e m O n e : T h e re I s A N e e d F o r B e t t e r S t ra t i f i c a t i o n O f R i s k O f Po s i t i v e S L N To I n fo r m S u r g e r y D i s c u s s i o n s T h e r e a r e l i m i t a t i o n s o f c u r r e n t s t a g i n g Average reimbursed cost of SLNB is $20-24k 13


 
› DecisionDx-Melanoma i31-GEP accurately identifies low risk (<5%) of SLN positivity in patients with T1-T4 staged disease1 › i31-GEP accurately identifies patients within the 5-10% and >10% ranges of SLN positivity risk1 › In T1aHR cases, patients with a Class 2B (highest risk) could be more reliably and appropriately considered for SLNB1 D e c i s i o n D x - M e l a n o m a I d e n t i f i e s T h o s e At L o w R i s k F o r A Po s i t i v e S L N 14 DecisionDx-Melanoma could result in 74% fewer SLNB surgeries, potentially saving the U.S. healthcare system $250M 2,3 I n t e g r a t e s c l i n i c o p a t h o l o g i c f e a t u r e s t o o f f e r p r e c i s e a n d p e r s o n a l i z e d l i k e l i h o o d o f s e n t i n e l l y m p h n o d e p o s i t i v i t y i n T 1 - T 4 p a t i e n t s 1Whitman, JCO Precision Oncology, 2021 accepted for publication 2Vetto et al. Future Oncol 2019. 3Clearview health economic model, data on file. Highly concordant prediction of SLN positivity rate compared to observed rates


 
1Whitman, JCO Precision Oncology, 2021 accepted for publication Variable Variable importance assessment function Log-likelihood value (G2) DecisionDx- Melanoma 100 Most important 91.3 P<.001 Breslow thickness 56 53.5 P<.001 Mitotic rate 25 20.7 P<.001 Ulceration 83 19.1 P<.001 Age 0 10.5 P=.001 Lowest Best Decreasing explanatory variables D e c i s i o n D x - M e l a n o m a I s T h e M o s t I m p o r ta n t Va r i a b l e I n P r e d i c t i n g S L N Po s i t i v i t y i 3 1 - G E P u t i l i z e s a r t i f i c i a l i n t e l l i g e n c e - b a s e d n e u r a l n e t w o r k s i31-GEP incorporates robust clinicopathologic variables along with a patient’s biological risk as assessed by DecisionDx-Melanoma 15


 
V i g n e t t e : Pa t i e n t W i t h T 2 b M e l a n o m a With the DecisionDx-Melanoma Class designation of Class 1A and an i31-GEP of 2.9%, this patient is within the range to forgo SLNB DecisionDx-Melanoma: Class 1A 31-GEP continuous score: 0.12 Likelihood of SLNB Positivity: 2.9% Likelihood of 5-Year Survival (MSS): 98% • Female, age 68 • Breslow thickness = 1.1 mm • Ulceration: present • Mitotic Rate = 1/mm2 • No other high-risk features 16 MSS=Melanoma-specific survival


 
Text sources:1Poklepovic and Carvajal. ONCOLOGY 2018; 2Ribas et al. JAMA 2016; 3Schadendorf et al. Eur J Can 2017; 4Robert et al. J Clin Oncol 2017; 5Joseph et al. Clin Cancer Res 2018; 6SEER data release 2017; 7Whiteman et al. J Invest Dermatol 2015; 8Shaikh et al. J Natl Cancer Inst 2016 Graph sources: 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. P r o b l e m 2 : T h e r e I s A N e e d F o r I m p r o v e d P r o g n o s t i c A c c u r a c y To D e t e r m i n e T h e M o s t A p p r o p r i a t e M e l a n o m a M a n a g e m e n t S t r a t e g y C u r r e n t r i s k a s s e s s m e n t s m i s s p a t i e n t s w i t h a g g r e s s i v e t u m o r b i o l o g y 34% 66% “High-risk” patients “Low-risk” patients DEATHS FROM MELANOMAEarly detection, lower tumor burden associated with better therapy responses, survival outcomes1-5 Appropriate surveillance, including imaging of high-risk patients, is critical1-5 AJCC clinicopathologic factors are helpful clinically, but the majority of deaths occur in patients diagnosed with early-stage disease6-8 17


 
0 1 2 3 4 5 6 7 8 9 10 Archival, Multi-center1 Disease-Free Survival Stage I-II AJCC high risk DecisionDx-Melanoma Class 2 0 5 10 15 20 25 30 Prospective, Multi-center4 Recurrence-Free Survival Stage I-II 0 1 2 3 4 5 6 7 8 9 10 Archival, Multi-center2 Melanoma Specific Survival Stage I-III 0 1 2 3 4 5 6 7 8 9 10 Prospective, Multi-center3 Recurrence-Free Survival Stage I-III H az ar d R at io ( m u lt iv ar ia te )* H az ar d R at io ( m u lt iv ar ia te )* ** ** ** ** ** ** ** ** ** ** D e c i s i o n D x - M e l a n o m a I s A S i g n i f i c a n t , I n d e p e n d e n t P r e d i c t o r O f O u t c o m e s *Hazard ratio is continuous for thickness, categorical for other endpoints; **Statistically significant Data shown are from the first and most recent publications for archival and prospective studies 1Gerami et al. Clin Cancer Res 2015. 2Gastman et al. Jrnl Amer Acad Dermatol 2019. 3Hsueh et al. Jrnl Hematol Oncol 2017. 4Podlipnik et al. Jrnl Eur Asso Veneral and Derm 2019. AJCC high risk Age DecisionDx-Melanoma Class 2 Thickness Mitotic rate Ulceration SLN+ DecisionDx-Melanoma Class 2 Thickness Mitotic rate Ulceration SLN+ DecisionDx-Melanoma Class 2 18


 
Low Risk Stage I-IIA High Risk Stage IIB-III NCCN Risk Category Prado et al. SKIN J Cutan Med 2018:suppl 2. n=690 D e c i s i o n D x - M e l a n o m a F u r t h e r S t ra t i f i e s R i s k O f Re c u r re n c e B e y o n d A J C C ( 8 T H E d . ) S t a g i n g 19 STAGE M el an o m a- Sp ec if ic S u rv iv al ( M SS ) (% ) 100% 90% 80% 70% 60% I 99.6% ≈AJCC IA 89.5% ≈AJCC IIIA 98% II >99% ≈AJCC IA 84.7% ≈AJCC IIIB 90% III 94.8% ≈AJCC IIA 61.2% ≈AJCC IIIC+ 77% Castle Class 1A MSS Castle Class 2B MSS AJCC MSS


 
D e c i s i o n D x - M e l a n o m a C h a n g e d M a n a g e m e n t F o r 5 0 % O f Pa t i e n t s 1Berger, et al. 2016 Curr Med Res Opin; 2Dillon et al. 2018 Skin; 3Farberg et al. 2017 Jrnl Drugs Derm; 4Schuitevoerder, et al. 2018 Jrnl Drugs Derm. Changes in patient management include: Imaging and labs Sentinel lymph node biopsy guidance Clinical visit frequency Referrals Study Design # of Patients % Change in Management Berger1 Prospectively tested cohort, multi-center. Retrospective pre-test / post-test management. 156 53% Dillon2 Prospective, multi-center: pre-test / post-test management 247 49% Farberg3 169 physician impact study: patient vignettes with pre-test / post-test management n/a 47-50% Schuitevoerder4 Prospectively tested cohort, single center. Retrospective pre-test / post-test management; modeling of prospective cohort 91 52% 4 consecutive clinical impact studies: 47-53% change in risk-of-recurrence-based management 20


 
D e c i s i o n D x - M e l a n o m a : We l l - s t u d i e d , I n fo r m s C a n c e r M a n a g e m e n t D e c i s i o n s * A c c o r d i n g t o s o r t s y s t e m , u s e d b y A A D Patients included in studies including independent validation >5,700 Peer-reviewed, published studies including 2 meta-analyses 30+ Demonstrated change in management for 1 of 2 patients tested 50% Level 1A evidence* 1A Patients with a DecisionDx-Melanoma order from more than 8,000 clinicians 73,000+ Covered by Medicare and multiple private insurers with an industry- leading patient assistance program Medicare+ 21


 
Identifying the risk of metastasis in patients with cutaneous squamous cell carcinoma with one or more risk factors


 
Pa t i e n t J o u r n e y : W h e re D e c i s i o n D x - S C C F i t s 23 Patient referred to a dermatologist who performs a skin exam History and physical • Complete skin exam • Regional lymph node exam Skin biopsy Lesion suspicious for skin cancer discovered by patient or PCP Diagnosis of SCC with ≥1 risk factor Order placed for Test results received for Treatment plan defined • Curettage and electrodesiccation • Standard excision • Excision with wide margins • Mohs


 
~20% of SCC patients (200,000 annually) have one or more clinical or pathological risk factors, and a subset will develop metastasis They suffer the majority of SCC mortality These factors alone are often not specific enough to determine risk-appropriate treatment and further management P ro b l e m : T h e U n m e t N e e d I n H i g h - R i s k S C C Pa t i e n t s W h o i s r e a l l y a t l o w r i s k o r h i g h r i s k f o r m e t a s t a s i s ? NCCN=National Comprehensive Cancer Network; BWH = Brigham and Women’s Hospital; AJCC = American Joint Committee on Cancer SCC treatment plans are guided by risk of metastasis Risk-appropriate SCC management is currently limited by classification systems (NCCN, BWH, AJCC) with low positive predictive value (PPV) Deaths from SCC are now estimated to exceed those from melanoma 24


 
200,000 high-risk patients annually; $820M U.S TAM1 Validated in 420- patient cohort of high- risk SCC from 33 U.S. centers 5 peer-reviewed publications to date; Over 2,320 patients enrolled in studies to date from 110 centers D e s i g n e d To P r e d i c t I n d i v i d u a l M e t a s t a t i c R i s k To I n fo r m R i s k - A p p ro p r i a t e M a n a g e m e n t 1 based on Castle estimates Incorporation of DecisionDx-SCC with traditional risk factors can improve patient classification compared to traditional risk factors alone For high-risk SCC patients with one or more risk factors Utilizing existing sales channels: dermatologists (including Mohs surgeons) 25


 
Wo r k f l o w F o r D e c i s i o n D x - S C C : P ro c e s s I d e n t i c a l To D e c i s i o n D x - M e l a n o m a qPCR: open array card 34 discriminant gene targets and 6 control genes Class 1 low metastatic risk (~50% of results)a Class 2A moderate metastatic risk (~40% of results) Class 2B high metastatic risk (<10% of results) SCC tumor tissue RNA isolation RT-PCR: cDNA generation and amplification Analysis of GEP with a proprietary algorithm to determine Class and metastatic risk Wysong et al. JAAD 2020; Data on file, Castle Biosciences NCCN Guidelines for Squamous Cell Skin Cancer v1.2020, Likhacheva et al. Pract Radiat Oncol 2020, Farberg et al. CMRO 2020, Litchman et al. CMRO 2020, Teplitz et al. JDD 2019, Alam et al. JAAD 2018 . D e c i s i o n D x - S C C r e s u l t s c a n i n f o r m m a n a g e m e n t d e c i s i o n s w i t h i n e s t a b l i s h e d g u i d e l i n e s • Surgery, if feasible • Consider nodal imaging / staging • Consider oncology referral • Surgery, if feasible • Nodal imaging / staging • Consultation: radiation oncology • Consultation: medical oncology Treatment plans may include • Surgery, if feasible • Clinical nodal exam Follow-up plans may include • Clinical follow-up: 1-2x per year • Clinical nodal exam • Clinical follow-up: 2-4x per year for 3 years • Baseline and annual nodal US/CT for 2 years • Clinical follow-up: 4-12x per year for 3 years • Baseline and 4x per year nodal US/CT for 2 years Patient diagnosed with SCC and one or more risk factors 26


 
M et as ta si s- fr ee s u rv iv al ( M FS ) Years Kaplan-Meier Estimated MFS n = 420 p < 0.0001 D e c i s i o n D x - S C C I s Va l i d at e d To P r e d i c t M e t a s ta t i c R i s k F o r I n d i v i d u a l S C C Pa t i e n t s W i t h O n e O r M o r e R i s k Fa c t o rs Wysong et al. JAAD 2020; Ibrahim et al. submitted; Data on file, Castle Biosciences. Class 1 – Low Biological Risk Less than half the general study population risk Class 2A – Moderate Biological Risk Similar to the strongest traditional factors Class 2B – High Biological Risk ≥50% risk of metastasis 27


 
C l a s s 2 A A n d C l a s s 2 B A r e I n d e p e n d e n t P r e d i c t o rs O f M e ta s ta s i s Deep invasion: beyond subcutaneous fat, depth >6mm, or Clark level V. Wysong et al. JAAD 2020; Ibrahim et al. submitted; Data on file, Castle Biosciences. W h a t i s t h e i m p a c t o f D e c i s i o n D x - S C C ? Immunosuppression Tumor diameter (per cm) Perineural invasion Deep invasion Poor differentiation Class 2A Class 2B Univariate Analysis Multivariate Analysis NA 1.1 (ns) 1.2 (ns) 2.1 (p<0.001) 2.3 (p<0.001) 2.3 (p<0.001) 6.9 (p<0.001) 1.5 (ns) 1.2 (p<0.001) 3.3 (p<0.001) 3.1 (p<0.001) 3.9 (p<0.001) 3.2 (p<0.001) 11.6 (p<0.001) Hazard Ratio (HR) Hazard Ratio (HR) 0 5 10 Hazard Ratio 0 5 10 azard Ratio An SCC with deep invasion is 2.1x more likely to metastasize than without Adding a Class 2A results shifts that to 4.8x more likely to metastasize Adding a Class 2B result shifts that to 14.5x more likely to metastasize 28


 
Highly accurate and objective tests for melanocytic lesions of unknown malignant potential Comprehensive Diagnostic Offering Comprehensive Diagnostic Offering


 
D e r m a t o p at h o l o g i s t s A n d D e r m a t o l o g i s t s Wo r k To g e t h e r To D i a g n o s e M e l a n o m a 30 Patient presents with mole to PCP or dermatologist Biopsy results received: • Positive for melanoma • Negative • Indeterminate If biopsy results show uncertain malignant potential, physician orders Comprehensive Diagnostic Offering Melanoma diagnosis confirmed; physician can initiate management plan with Physician may order biopsy


 
T h e C l i n i c a l I s s u e : U n c e r ta i n t y C r e a t e s A n O v e r - O r U n d e r - Tre a t m e n t D i l e m m a Definitive melanoma diagnoses (invasive or in situ) Definitive benign diagnoses SLNB Imaging Increased Follow-up No additional treatment Routine follow-up Clinically evaluated suspicious pigmented lesions Wide Local Excision ~2 million melanocytic skin biopsies Uncertain malignant potential Primary treatment Staging, surveillance, and follow-up options Histopathologic evaluation 31


 
C o m p re h e n s i v e D i a g n o s t i c O f fe r i n g I s D e s i g n e d F o r U s e F o l l o w i n g I m m u n o h i s t o c h e m i s t r y ( I H C ) A n d / O r L o c a l C o n s e n s u s Uncertain malignant potential IHC stains/recuts or local consensus conference/colleagues Uncertain malignant potential Benign Malignant Additional ancillary testing 32


 
*For purposes of reporting and consistency in the Comprehensive Diagnostic Offering, the term “indeterminate” will be now be referred to as “intermediate” for myPath Melanoma. **If both GEP tests result as intermediate, myPath Melanoma will be reported with a note stating that DiffDx- Melanoma was also intermediate. C o m p re h e n s i v e D i a g n o s t i c O f fe r i n g F o r C l a r i t y i n C l i n i c a l D e c i s i o n s Melanocytic lesion of unknown potential Benign Intermediate* Benign Intermediate** MalignantMalignant With an order of Castle’s comprehensive diagnostic offering, upon receipt at our lab, Castle will perform myPath Melanoma on submitted cases. If the case results in an intermediate result or fails to produce a result, we now have the ability to perform DecisionDx DiffDx to provide additional diagnostic clarity. 33


 
L e v e ra g i n g T h e S t r e n gt h s O f my Pa t h M e l a n o m a A n d D e c i s i o n D x D i f f D x - M e l a n o m a F o r T h e B e n e f i t O f Pa t i e n t C a r e Interpreted in the context of other clinical, laboratory and histopathologic information, the Comprehensive Diagnostic Offering is designed to add diagnostic clarity and confidence for dermatopathologists, while helping dermatologists better understand the clinical implications for more informed patient care Estrada et al. (2020) J Cut Med SKIN Designed to be used as an adjunct to histopathology when the distinction between a benign nevus and a malignant melanoma cannot be made confidently by histopathology alone A definitive result is received in ≥96% of lesions submitted for testing After melanoma diagnosis, clinicians can order DecisionDx-Melanoma; uses same tissue sample 34 Both tests included in NCCN guidelines; myPath Melanoma is currently covered under a MolDX LCD through Noridian 5-7 day turnaround time/similar to other ancillary tests


 
Pipel ine 35


 
Factors Defining Success Committed to dermatology and informing clinical management decisions Robust development pipeline and proven track record of AI-informed GEP algorithms Steering committee with world-class KOLs Large study investment for development and validation E x p a n d i n g C a s t l e ’s G e n o m i c Te s t s To N o n - S k i n C a n c e r M e d i c a l D e r m a t o l o g y 36 I n n o v a t i v e p i p e l i n e t e s t f o r p r e d i c t i n g s y s t e m i c t h e r a p y r e s p o n s e Psoriasis Atopic Dermatitis Related Conditions Psoriasis Atopic Dermatitis Gender 49% Female 53% Female Age at Diagnosis (average) Early fifties Mid thirties Severity ~30% moderate to severe >50% moderate to severe


 
37 Patient presents with skin signs and symptoms to PCP or dermatologist Clinical diagnosis of psoriasis, atopic dermatitis or related condition is made Patient achieves faster treatment response time resulting in improved patient outcomes and QoL Personalized therapy guidance leads to reduced medication switches and health care savings Management plan determined, based on individual biological profile Typically, topical treatment is initiated, while some proceed directly to systemic therapy based on disease severity Depending on initial treatment efficacy or disease severity, systemic treatment is considered Clinician orders innovative test to support decision making P a t i e n t J o u r n e y F o r P s o r i a s i s , A t o p i c D e r m a t i t i s A n d R e l a t e d C o n d i t i o n s E x p a n d s o u r r e a c h i n t o n o n - s k i n c a n c e r, m e d i c a l d e r m a t o l o g i c d i s e a s e s


 
P r o b l e m : T h e U n m e t N e e d I n M o d e r a t e To S e v e r e P s o r i a s i s A n d A t o p i c D e r m a t i t i s C o m m o n s k i n d i s e a s e s w i t h s i g n i f i c a n t p a t i e n t i m p a c t s a n d c o s t s t o h e a l t h c a r e s y s t e m Treatments are significantly different for PSO and AD. Previously, treatments for AD were inexpensive (e.g., topical steroids), but are now costly (e.g., Dupixent for ~$38k/year). Costly therapies for moderate/severe psoriasis are common (e.g., Humira for ~$68k/year) Systemic therapy guidance tools have the potential to streamline therapeutic interventions for patients and avoid ineffective, expensive medication courses Psoriasis (PSO) and Atopic Dermatitis (AD) are among the most frequently seen skin rashes, and their diagnosis is most often made clinically by the treating clinician 38 Cutaneous T Cell Lymphoma (CTCL) can mimic clinical presentation of AD and PSO. A subset of patients with PSO (approximately 20-30% of affected individuals) will go on to develop psoriatic arthritis, which can produce irreversible joint damage and significant patient morbidity


 
The Standard of Care for Evaluating Metastatic Risk in Uveal Melanoma


 
z D e c i s i o n D x - U M : S t a n d a r d O f C a r e ~2,000 patients diagnosed in the U.S. annually ~97% of patients – no evidence of metastatic disease at the time of diagnosis ~30% will develop metastases within 3 years Low-risk: ~67% Low Intensity Management High-risk: ~33% High Intensity Management (Uveal Melanoma) Strong Evidence Base • 20 peer-reviewed publications, 2,500+ patients Widespread adoption • 85-90%+ of U.S. ocular oncology institutions order • 1,395 reports issued in 2020 Broad Coverage • 156+ million total lives covered • Medicare LCD covers patients with a confirmed diagnosis and no evidence of metastatic disease • “Existing ADLT” status effective May 2019 • 2021 Medicare rate of ~$7800 AJCC and NCCN Guideline Inclusion Uveal Melanoma – A Rare Eye Cancer 15-Gene Expression Profile (GEP) Test 40


 
Market And F inancial Overview


 
Indication/ Test outcome Trade Name Reimbursement Status Peer-Reviewed Publications Primary Customers Initial Launch Targets Initial addressable market, patients2 Estimated U.S. TAM Cutaneous melanoma/ Risk of metastasis MCR, MCRA Commercial – in process 30+ Derms (including Mohs), Surgeons __ ~130k patients classified as Stage I, II or III ~$540M Cutaneous squamous cell carcinoma/ Risk of metastasis Expected draft LCD in 2021 Commercial – in process 5 Derms (including Mohs) ~4,709 current custome rs3 ~200k w/ high-risk features ~$820M Suspicious pigmented lesions/ Melanoma status MCR, MCRA Commercial – in process Expected draft LCD in 2021 Commercial – in process 9 2 Dermpaths, Derms ~1,778 current dermpath customers4 ~300k patients w/indeterminant biopsy ~$600M Pipeline Test- Inflammatory Target launch anticipated by the end of 2025 N/A N/A Expected to utilize existing dermatologic sales channels ~4,709 current custome rs3 ~450k patients eligible for systemic therapies ~$1.9B Other Pipeline Tests Target launches anticipated by the end of 2025 N/A N/A Expected to utilize existing dermatologic sales channels To be announced To be announced ~$1.7B E s t i m a t e d ~ $ 5 . 5 B U. S . To t a l A d d re s s a b l e M a r ke t 1 I n m a r k e t a n d p i p e l i n e t e s t s , l e v e r a g i n g e s t a b l i s h e d d e r m a t o l o g i c s a l e s c h a n n e l s 42 1U.S. TAM = Total addressable market based on estimated patient population assuming average reimbursement rate among all payors. 2 Annual U.S. incidence for Stage I, II or III melanoma estimated at 130,000; annual U.S. incidence for squamous cell carcinoma estimated at 1,000,000 with addressable market limited to carcinomas with one or more high risk features; annual U.S. incidence for suspicious pigmented lesion biopsies estimated at 2,000,000 with addressable market limited to the 15% with an indeterminant biopsy. 3Clinicians who ordered DecisionDx-Melanoma in last twelve months (as of 6/30/2021). 4Pathologists who provided clinical specimens for DecisionDx-Melanoma in last twelve months (as of 6/30/2021). -MCR = Medicare. MCRA = Medicare Advantage; current customer estimates based on last twelve months.


 
Re c e n t A c h i e v e m e n t s A n d E x p e c t e d F u t u re M i l e s t o n e s 2 0 2 1 m i l e s t o n e s o n t r a c k Oct 2020: LCD expansion finalized for DecisionDx-Melanoma, effective date 12/6/20 2021: Potential draft LCD for DecisionDx-SCC and DecisionDx DiffDx-Melanoma 2020 2021 2019 2022 2H2020: Initiation of work on additional dermatology pipeline products 4Q2020: Launch of DecisionDx DiffDx-Melanoma 2022: Potential effective LCD for DecisionDx-SCC and DecisionDx DiffDx- Melanoma 3Q2020: Commercial team expansion Sept 2020: Launch of DecisionDx-SCC July 2019: IPO Dec 2019: Expanded outside sales territories to 32 = Achieved Feb 2019: Expanded outside sales territories to 23 Aug 2019: Expanded draft LCD for DecisionDx- Melanoma posted 43 1H2021: Planned commercial team expansion to mid-60s 2018 Dec 2018: Initial LCD effective for DecisionDx-Melanoma 2021+: Continued evidence development for all commercialized products 2021+: Continued development of dermatologic pipeline products; potential launches in 2025 2021: Acquired myPath® Melanoma 2021: Planned announcement of pipeline indications


 
Fa c t o rs D r i v i n g N e a r - A n d L o n g - Te r m G ro w t h REVENUE PROFITABILITY PIPELINE Gross Margins • 83% in Q2 2021 • Continued margin expansion of existing products (increasing ASPs and efficiencies of scale) could be offset by uptake of pipeline products ahead of reimbursement New Product Development • Launched two skin cancer tests in 2020 with estimated $1.4B+ U.S. TAM • Leverage of our existing skin cancer sales channels to support new products • Initiated new pipeline products in dermatologic diseases with high unmet need; potential to launch 3-5 new tests by the end of 2025 Test Report Volume • Commercial sales team expansion in 1H21 to mid-60s Reimbursement • Strong ASP growth • DecisionDx-Melanoma $7,193 PAMA rate through 2021 • DecisionDx-UM $7,776 PAMA rate through 2021 44


 
7 9 % I n c re a s e I n Re v e n u e I n Q 2 2 0 2 1 , D r i v e n B y Te s t Re p o r t A n d A S P G ro w t h * 2Q2019 2Q2020 2Q2021 Revenue *2Q2021 ASP growth over 2020 and 2019 $22.8m $12.7m $10.7m 45


 
Asian Black or African American Hispanic or Latino Two or more races (not Hispanic or Latino) White Othe (n t Hispanic r Latino) Female Male Female Male C o m m i t m e n t To D i v e rs i t y 46 37.3% 62.7% 68.2% 31.8% 79.1% 5% 9.5 4.9% 1.5% A ll Em p lo ye e s Ex ec u ti ve s E T H N I C I T Y/ R A C E G E N D E R Data as of 12/31/20, Executive= Executive Director or Regional Business Director level and above American Indian or Alaska Native Two or more races (not Hispanic or Latino) White Hispanic or Latino 86.36% 4.55% 4.55% 4.55%


 
C o m m i t t e d t o c u l t i v a t i n g a c u l t u r e o f i n n o v a t i o n , c o n t i n u o u s g r o w t h a n d a d v a n c e m e n t A w a r d - W i n n i n g C o m p a ny 47 “Market Value, Market Return & Revenue Growth” Awarded for the DecisionDx®-SCC and DecisionDx® DiffDx™- Melanoma genomic tests 2019 Technology Innovation in Melanoma Award Winner “New on Wall Street”


 
Tr a n s f o r m i n g t h e m a n a g e m e n t o f s k i n c a n c e r a n d o t h e r d e r m a t o l o g i c d i s e a s e s w i t h h i g h u n m e t c l i n i c a l n e e d Expansive Body of Evidence Suite of Dermatologic Prognostic And Diagnostic Tests Strong Financial Position Robust Pipeline L e a d i n g D e r m a t o l o g i c D i a g n o s t i c s C o m p a ny 48 Culture of Teamwork and Innovation


 
THANK YOU


 
U s e O f N o n - G A A P F i n a n c i a l M e a s u re s ( U n a u d i t e d ) 50 In this presentation, we use the metrics of Adjusted Revenue, Adjusted Gross Margin and Adjusted Operating Cash Flow, which are non-GAAP financial measures and are not calculated in accordance with generally accepted accounting principles in the United States (GAAP). Adjusted Revenue and Adjusted Gross Margin reflect adjustments to net revenues to exclude changes in variable consideration related to test reports delivered in previous periods. Adjusted Gross Margin also excludes acquisition-related intangible asset amortization. Adjusted Operating Cash Flow excludes the effects of cash activity associated with COVID-19 government relief payments to healthcare providers. We use Adjusted Revenue, Adjusted Gross Margin and Adjusted Operating Cash Flow internally because we believe these metrics provide useful supplemental information in assessing our revenue and cash flow performance, respectively. We believe Adjusted Revenue and Adjusted Gross Margin are also useful to investors because they provide additional information on current-period performance by removing the effects of revenue adjustments related to tests delivered in previous periods and acquisition-related intangible asset amortization, which we believe may facilitate revenue and gross margin comparisons to historical periods. We believe Adjusted Operating Cash Flow is also useful to investors as a supplement to GAAP measures in the assessment of our cash flow performance by removing the effects of COVID-19 government relief payments, which we believe are not indicative of our ongoing operations. However, these non-GAAP financial measures may be different from non-GAAP financial measures used by other companies, even when the same or similarly titled terms are used to identify such measures, limiting their usefulness for comparative purposes. These non-GAAP financial measures are not meant to be substitutes for net revenues or net cash (used in) provided by operating activities reported in accordance with GAAP and should be considered in conjunction with our financial information presented on GAAP basis. Accordingly, investors should not place undue reliance on non-GAAP financial measures. Reconciliations of these non-GAAP financial measures to the most directly comparable GAAP financial measures are presented in the next slide.


 
Re c o n c i l i a t i o n O f N o n - G A A P F i n a n c i a l M e a s u r e s ( U n a u d i t e d ) The table below presents the reconciliation of adjusted revenue and adjusted gross margin, which are non-GAAP measures. See "Use of Non-GAAP Financial Measures (UNAUDITED)" on the previous slide for further information regarding the Company's use of non-GAAP financial measures. 51


 
Re c o n c i l i a t i o n O f N o n - G A A P F i n a n c i a l M e a s u r e s ( U n a u d i t e d ) The table below presents the reconciliation of adjusted operating cash flow, which is a non-GAAP measure. See "Use of Non-GAAP Financial Measures (UNAUDITED)" on the previous slide for further information regarding the Company's use of non-GAAP financial measures. 52


 
APPENDIX


 
Stuart Pharmaceuticals Robert Cook, PhD Senior Vice President, Research & Development L E A D E RS H I P T E A M O V E RV I E W M A N A G E M E N T T E A M Derek Maetzold Founder, Director, President and CEO Frank Stokes Chief Financial Officer Bernhard Spiess Chief Business Officer Toby Juvenal Chief Commercial Officer Kristen Oelschlager, RN, CHC Chief Operating Officer Dan Bradbury Derek Maetzold Mara Aspinall Brad Cole Miles D. Harrison 54 Matthew Goldberg, MD Medical Director Tiffany Olson Kimberlee Caple Ellen Goldberg B O A R D O F D I R E C T O R S