Approval expands access to Castle's precision medicine test designed to guide systemic treatment decision making in patients with moderate-to-severe atopic dermatitis

FRIENDSWOOD, Texas, July 14, 2026 /PRNewswire/ -- Castle Biosciences, Inc. (NASDAQ:CSTL), a company improving health through innovative tests that guide patient care, today announced that it has received assay approval from the New York State Department of Health (NYSDOH) for its AdvanceAD-Tx test. AdvanceAD-Tx is a non-invasive gene expression profile test designed to guide systemic therapy selection for patients aged 12 years and older with moderate-to-severe atopic dermatitis (AD).

"We are proud to announce the final approval of our AdvanceAD-Tx test by the NYSDOH's Clinical Laboratory Evaluation Program. This approval makes it easier than ever for patients in New York with moderate-to-severe AD to access a test which helps identify the class of systemic therapy to which they are most likely to respond based on the underlying biology of their disease," said Kristen Oelschlager, chief operating officer at Castle Biosciences. "New York State is the only U.S. jurisdiction that conducts a formal review of laboratory-developed tests before they can be offered to patients; this approval further demonstrates the level of quality and regulatory rigor we seek to achieve with each of our test offerings."

With this approval, Castle has New York State approval for all tests within its dermatology and ophthalmology portfolios, its TissueCypher® test within gastroenterology and its clinical laboratories in Phoenix and Pittsburgh.

"Too often, patients with AD spend months on therapies that do not adequately control their disease," said Matthew Goldberg, M.D., senior vice president, medical, at Castle Biosciences. "AdvanceAD-Tx was developed to provide clinicians with objective molecular insight that can help guide a more confident and personalized treatment decision from the start, with the goal of helping patients achieve meaningful relief from their symptoms sooner."

AD is a chronic inflammatory skin disease that affects approximately 16.5 million adults and 9.6 million children in the United States. Despite a rapidly expanding treatment landscape, including T helper type 2 (Th2)-targeted biologics and Janus kinase (JAK) inhibitor therapies, identifying the most appropriate systemic therapy for an individual patient remains a major clinical challenge. Patients frequently experience treatment switching and modification due to inadequate response, highlighting the need for molecular tools to guide therapy selection.

AdvanceAD-Tx analyzes a patient's individual disease biology from a simple, non-invasive skin sample to classify them into one of two molecular profiles — a JAK Inhibitor Responder Profile or a Th2 Molecular Profile — providing clinicians with objective molecular insight to help guide systemic treatment selection.

About AdvanceAD-Tx

AdvanceAD-Tx is a non-invasive gene expression profile (GEP) test designed to guide systemic treatment decisions for patients aged 12 years and older with moderate-to-severe atopic dermatitis (AD). Using RNA expression data from lesional skin scraping samples—no biopsy required—the test evaluates 487 genes across 12 inflammatory and cutaneous biology pathways to reveal the underlying immune biology driving an individual patient's disease. Results classify patients into one of two molecular profiles: a Janus kinase (JAK) Inhibitor Responder Profile or a T helper 2 (Th2) Molecular Profile.

The prospective, clinical validation study showed that patients with a JAK Inhibitor Responder Profile given JAK inhibitor therapy experience significantly greater clinical benefit — including improved and faster skin clearance (EASI-90), greater likelihood of achieving no itch and remaining flare-free, and better quality of life by three months — compared to those treated with a Th2-targeted therapy.¹AdvanceAD-Tx provides clinicians with objective, molecular-based insights to help personalize systemic treatment decisions and improve care for patients. Learn more at https://castlebiosciences.com/tests/therapy-guidance/advancead-tx/overview.

About Castle Biosciences

Castle Biosciences (NASDAQ:CSTL) is a leading diagnostics company improving health through innovative tests that guide patient care. With a primary focus in dermatologic and gastroenterological disease, we develop personalized, clinically actionable solutions that help improve disease management and patient outcomes.

We put people first—empowering patients and clinicians and informing care decisions through rigorous science and advanced molecular tests that support more confident treatment planning. To learn more, visit www.CastleBiosciences.com and connect with us on LinkedIn, Instagram, Facebook and X. 

DecisionDx-Melanoma, DecisionDx-CMSeq, i31-SLNB, i31-ROR, DecisionDx-SCC, MyPath Melanoma, AdvanceAD-Tx, TissueCypher, Esopredict, DecisionDx-UM, DecisionDx-PRAME and DecisionDx-UMSeq are trademarks of Castle Biosciences, Inc.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, which are subject to the "safe harbor" created by those sections. These forward-looking statements include, but are not limited to, statements concerning: expanded access to diagnostic testing; and AdvanceAD-Tx's ability to (i) extend personalized, molecularly guided care into inflammatory skin disease, (ii) help clinicians select treatments that can improve patient outcomes and reduce unnecessary treatment cycling, (iii) transform how moderate-to-severe AD is managed, (iv) enable biology-informed treatment decisions and (v) help patients achieve meaningful relief from their symptoms. The words "believe," "can," "may" 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: subsequent study or trial results and findings may contradict earlier study or trial results and findings or may not support the results obtained in these studies, including with respect to the discussion of our tests in this press release; actual application of our tests may not provide the aforementioned benefits to patients; and the risks set forth under the heading "Risk Factors" in our Annual Report on Form 10-K for the year ended December 31, 2025, and our subsequent Quarterly Reports on Form 10-Q, each as filed or to be filed with the SEC, 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.

¹Silverberg JI, Eichenfield LF, Armstrong AW, et al. The 487-gene expression profile test guides systemic therapy selection to improve outcomes for patients with atopic dermatitis: results from a prospective trial. J Am Acad Dermatol. 2026. doi:10.1016/j.jaad.2026.02.034

Investor Contact:

Camilla Zuckero

czuckero@castlebiosciences.com

Media Contact:

Allison Marshall

amarshall@castlebiosciences.com

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SOURCE Castle Biosciences, Inc.