Castle Biosciences Launches AdvanceAD-Tx Gene Expression Test to Guide Atopic Dermatitis Treatment Selection
Key Insights
Castle Biosciences (search) has launched AdvanceAD-Tx (search), a 487-gene expression profile test designed to guide systemic treatment decisions in patients aged 12 and older with moderate-to-severe atopic dermatitis (search).
The IDENTITY study validation data showed that patients with a JAK inhibitor (search) responder profile achieved significantly higher EASI-90 response rates when treated with JAK inhibitors versus Th2-targeted therapies (45.5% vs 8.3%, p=0.021).
The test identifies approximately 30.4% of patients as having a JAKi responder profile, who also experienced faster skin clearance, reduced itch, and fewer flares compared to Th2-targeted therapy (search) recipients.
Castle Biosciences (search) has announced the commercial launch of AdvanceAD-Tx (search), a 487-gene expression profile test designed to guide systemic treatment selection in patients aged 12 years and older with moderate-to-severe atopic dermatitis (search). The molecular diagnostic aims to identify patients more likely to respond to Janus kinase (search) inhibitor therapy versus T helper type 2 (search)-targeted treatments, addressing a significant clinical challenge in personalized dermatologic care.
Addressing Treatment Selection Challenges
The launch addresses a persistent clinical challenge in atopic dermatitis (search) management, where empiric treatment approaches often result in sequential therapy trials before achieving optimal disease control. "Selecting the right systemic therapy for patients with atopic dermatitis can be a challenge, and too often patients end up cycling through multiple treatments before finding one that works," said Jonathan I. Silverberg, M.D., Ph.D., MPH, IDENTITY study author and associate professor of dermatology at the George Washington University School of Medicine and Health Sciences.
The test utilizes RNA expression data from lesional skin samples to evaluate 487 genes across 12 skin and inflammatory pathways, revealing the underlying immune biology driving individual patient disease. Results classify patients into one of two molecular profiles: Janus Kinases Inhibitor Responder Profile or T helper 2 Molecular Profile.
IDENTITY Study Validation Results
Clinical validation data from the IDENTITY study demonstrated significant treatment response differences based on molecular profiling. In the validation cohort, 30.4% of tested samples showed a JAKi responder profile. Patients with this profile who received JAK inhibitor (search) therapy achieved markedly superior outcomes compared to those treated with Th2-targeted therapies.
The primary endpoint showed patients with a JAKi responder profile achieved EASI-90 (90% or greater reduction in disease severity) at significantly higher rates when treated with JAK inhibitors versus Th2-targeted therapy (search) (45.5% vs 8.3%, p=0.021). Secondary endpoints reinforced these findings, with JAKi responders treated with JAK inhibitors achieving validated investigator global assessment scores of clear (vIGA-AD 0) at rates of 36.4% versus 0% for Th2-targeted therapy (p=0.006).
Additional clinical benefits included significantly higher rates of achieving "no itch" by three months (45.5% vs. 8.3%, p=0.021) and remaining flare-free during treatment (54.5% vs. 16.7%, p=0.041). Notably, these patients reached EASI-90 3.8 times faster than those receiving Th2-targeted therapy (search) (p=0.049).
Market Opportunity and Commercial Strategy
Castle Biosciences (search) estimates the U.S. total addressable market opportunity at approximately $33 billion, with an estimated 13.2 million patients aged 12 and older having moderate-to-severe atopic dermatitis (search) based on one-year prevalence data. "With AdvanceAD-Tx (search), we are extending the power of precision medicine into an additional dermatologic indication," said Derek Maetzold, chief executive officer of Castle Biosciences.
The test integrates with Castle's existing laboratory workflows, enabling streamlined adoption for dermatologists already familiar with DecisionDx testing platforms. The company is pursuing multiple reimbursement pathways to support clinical adoption.
Launch Timeline and Clinical Integration
AdvanceAD-Tx (search) is being made commercially available through a measured, limited access launch beginning November 2025, with phased, expanded availability anticipated throughout 2026. The test utilizes Castle's established molecular diagnostics infrastructure and standard biopsy workflows.
"AdvanceAD-Tx (search) underscores Castle's commitment to the dermatology community and developing clinically meaningful innovations that improve patient outcomes," said Matthew Goldberg, M.D., senior vice president, medical, at Castle Biosciences (search). "We're applying the same disciplined, data-driven approach that made our DecisionDx franchise successful to an area where patients and clinicians need better tools."
The launch represents Castle Biosciences (search)' strategic expansion beyond oncology and rare dermatologic indications into precision medicine applications for common inflammatory skin diseases, potentially reducing treatment trial-and-error approaches and improving time to optimal disease control.