CSTL

EX-99.1

2 exhibit991q12026earningsre.htm

EX-99.1

Document

Exhibit 99.1

Castle Biosciences Reports First Quarter 2026 Results

Delivered Q1 2026 revenue of $83.7 million

Q1 2026 total test reports for our core revenue drivers (DecisionDx®-Melanoma, TissueCypher®) increased 36% over Q1 2025

Raising full-year 2026 revenue guidance to $345-355 million from $340-350 million

Conference call and webcast today at 4:30 p.m. ET

FRIENDSWOOD, Texas – May 6, 2026 – Castle Biosciences, Inc. (Nasdaq: CSTL), a company improving health through innovative tests that guide patient care, today announced its financial results for the first quarter ended March 31, 2026.

“The Castle Biosciences team delivered outstanding results to start 2026, delivering $83.7 million in revenue,” said Derek Maetzold, president and chief executive officer of Castle Biosciences. “I thank our team for their dedication and focus, which translates directly to our performance. Our momentum this quarter reflects our robust execution and the strength of our core revenue drivers, with both DecisionDx-Melanoma and TissueCypher achieving double digit year-over-year test volume growth, 16% and 58%, respectively. As a result of our first quarter performance and continued confidence in the business, we are raising our 2026 total revenue guidance to $345-355 million, compared to the previously provided guidance of $340-350 million.

“In addition, during the quarter we expanded the body of evidence supporting our market-leading DecisionDx-Melanoma test. Specifically, we announced new data from a prospective, multicenter, U.S. based study demonstrating that patients with a less than 5% predicted risk of sentinel lymph node positivity had an actual positivity rate of just 2.6%, reinforcing DecisionDx-Melanoma’s ability to guide sentinel lymph node biopsy decision-making in line with guideline thresholds. Our substantial body of evidence is a key driver of adoption and an important differentiator for DecisionDx-Melanoma and our innovative test portfolio more broadly, reinforcing our position of strength as we continue to execute across the business.”

First Quarter Ended Mar. 31, 2026, Financial and Operational Highlights

•Revenues were $83.7 million, compared to $88.0 million in the first quarter of 2025. Affecting first quarter 2026 revenue was the change in DecisionDx-SCC Medicare coverage effective April 24, 2025, the re-focus of our commercial efforts, as well as the discontinuation of IDgenetix in May 2025.

◦Revenues for our non-dermatologic tests were $42.6 million, compared to $25.0 million during the same period in 2025.

Core revenue drivers:

•First quarter 2026 total test reports for our core revenue drivers (DecisionDx-Melanoma, TissueCypher) increased 36% over the first quarter of 2025:

◦DecisionDx-Melanoma test reports delivered in the quarter were 10,021, compared to 8,621 in the first quarter of 2025.

◦TissueCypher Barrett’s Esophagus test reports delivered in the quarter were 11,745, compared to 7,432 in the first quarter of 2025.

Additional tests:

◦DecisionDx-SCC test reports delivered in the quarter were 3,702, compared to 4,375 in the first quarter of 2025.

◦MyPath® Melanoma test reports delivered in the quarter were 973, compared to 926 in the first quarter of 2025.

◦DecisionDx®-UM test reports delivered in the quarter were 492, compared to 470 in the first quarter of 2025.

•Gross margin was 73%, and Adjusted Gross Margin was 76%, compared to 49% and 81%, respectively, for the same periods in 2025. Affecting first quarter 2025 gross margin was the one-time adjustment of an acceleration of amortization expense of approximately $20.1 million.

•Net cash used in operations was $22.1 million, compared to net cash used in operations of $6.0 million for the same period in 2025. First quarter 2026 cash use reflects payout of employee annual cash bonuses as well as certain health care benefit payments, totaling $28.8 million, that are not expected to recur during the remainder of 2026.

•Net loss, which includes non-cash stock-based compensation expense of $9.8 million, was $14.5 million, compared to net loss of $25.8 million for the same period in 2025.

•Net loss per share, Basic and Diluted, was $0.49, compared to net loss per share, Basic and Diluted of $0.90 and Adjusted Net Loss per Share, Basic and Diluted, of $0.20, for the same period in 2025.

•Adjusted EBITDA was $(5.1) million, compared to $13.0 million for the same period in 2025.

Cash, Cash Equivalents and Marketable Investment Securities

As of Mar. 31, 2026, the Company’s cash, cash equivalents and marketable investment securities totaled $261.7 million.

2026 Outlook

Castle Biosciences is raising its guidance for anticipated total revenue in 2026. The Company now anticipates generating between $345-355 million in total revenue in 2026, compared to the previously provided guidance of between $340-350 million.

First Quarter and Recent Accomplishments and Highlights

cstl-202602260001447362FALSE00014473622026-02-262026-02-26

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): February 26, 2026

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.)

1500 W. Parkwood Ave, Suite 400 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 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 February 26, 2026, Castle Biosciences, Inc. (the “Company”) issued a press release announcing its financial results for the fourth quarter and year ended December 31, 2025. 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 February 26, 2026, the Company made available the slide presentation attached hereto as Exhibit 99.2. Information from these slide presentations 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 99.1Press release issued February 26, 2026.

99.2Slide presentation.

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: February 26, 2026

cstl-202601110001447362FALSE00014473622026-01-112026-01-11

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 11, 2026

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 shareCSTLThe 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 January 11, 2026, Castle Biosciences, Inc. (the “Company”) issued a press release announcing certain preliminary performance results for the fourth quarter of 2025 and for the year ended December 31, 2025. 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 January 11, 2026, 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 99.1Press release issued January 11, 2026.

99.2Slide presentation.

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: January 11, 2026