FRIENDSWOOD, Texas, July 14, 2026
Castle Biosciences, Inc. has announced that its AdvanceAD-Tx™ test has received assay approval from the New York State Department of Health (NYSDOH), expanding access to its innovative precision medicine solution for patients aged 12 years and older with moderate-to-severe atopic dermatitis (AD). The approval enables clinicians in New York to utilize the non-invasive gene expression profile (GEP) test to guide systemic treatment selection based on the underlying molecular biology of each patient’s disease. As New York is the only U.S. jurisdiction requiring formal regulatory review of laboratory-developed tests before clinical use, the approval highlights the scientific validity and regulatory rigor of Castle Biosciences’ molecular diagnostics portfolio. The milestone also means the company now holds New York State approval for all tests across its dermatology, ophthalmology, and gastroenterology portfolios, further strengthening its leadership in precision diagnostics. By helping physicians identify which patients are more likely to respond to Janus kinase (JAK) inhibitors or T helper type 2 (Th2)-targeted therapies, AdvanceAD-Tx aims to improve treatment outcomes while reducing unnecessary therapy switching and delays in disease control.
Precision Molecular Testing Personalizes Atopic Dermatitis Treatment
AdvanceAD-Tx has been developed to address one of the biggest challenges in managing moderate-to-severe atopic dermatitis—identifying the most effective systemic therapy for an individual patient before treatment begins. The test analyzes RNA expression from a simple, non-invasive skin scraping sample, eliminating the need for surgical biopsies while evaluating the activity of 487 genes across 12 inflammatory and skin biology pathways. Using advanced molecular profiling, the assay classifies patients into either a JAK Inhibitor Responder Profile or a Th2 Molecular Profile, providing clinicians with objective biological evidence to guide personalized therapy selection. This approach supports precision medicine by moving beyond traditional trial-and-error prescribing and allowing treatment decisions to be based on the molecular mechanisms driving each patient’s disease.
Clinical Validation Demonstrates Improved Patient Outcomes
The NYSDOH approval is supported by strong clinical validation demonstrating the potential of AdvanceAD-Tx to improve treatment outcomes for patients living with chronic inflammatory skin disease. Prospective clinical studies showed that patients identified with a JAK Inhibitor Responder Profile experienced faster skin clearance, greater achievement of EASI-90 response, improved itch relief, prolonged flare-free periods, and enhanced quality of life when treated with JAK inhibitors compared with patients receiving Th2-targeted biologic therapies. These findings reinforce the value of incorporating molecular diagnostics into routine dermatology practice, helping clinicians select the most appropriate systemic therapy earlier in the treatment journey. With approximately 16.5 million adults and 9.6 million children in the United States affected by atopic dermatitis, the availability of biology-driven treatment guidance could significantly reduce disease burden while improving long-term patient outcomes.
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Castle Biosciences Expands Leadership in Precision Diagnostics
The latest regulatory milestone reinforces Castle Biosciences’ position as a leading developer of molecular diagnostic tests designed to personalize patient care across multiple medical specialties. Beyond dermatology, the company has established clinically validated genomic testing platforms in ophthalmology and gastroenterology, helping physicians make more informed diagnostic and therapeutic decisions. By securing New York State Department of Health approval for AdvanceAD-Tx, Castle Biosciences further demonstrates its commitment to delivering scientifically rigorous diagnostic technologies that support precision medicine and evidence-based clinical decision-making. As molecular testing continues transforming healthcare by matching patients with the therapies most likely to provide benefit, the company remains well positioned to expand the use of advanced genomic diagnostics that improve treatment selection, reduce healthcare costs, and enhance patient outcomes across a growing range of diseases.
Source: Castle Biosciences press release
