Castle Biosciences has published clinical validation data demonstrating that its AdvanceAD-Tx gene expression profile test can identify patients with moderate-to-severe atopic dermatitis who are likely to respond effectively to JAK inhibitor therapy. The prospective validation study, published in the Journal of the American Academy of Dermatology, showed that approximately 30% of patients exhibited a JAK Inhibitor Responder Profile, meaning they were significantly more responsive to this treatment class.
Patients identified by the test as JAK inhibitor responders achieved substantially better outcomes compared to those on Th2-targeted therapies. Within three months, 45.5% of patients with the JAK Inhibitor Responder Profile achieved EASI-90 improvement—a 90% reduction in disease severity—compared to just 8.3% of patients on alternative Th2-targeted treatments. This represents a 5.5-fold increased likelihood of achieving significant clinical improvement within the first quarter of treatment.
The AdvanceAD-Tx test entered limited commercial availability in late 2025, providing dermatologists with a molecular tool to guide treatment selection for atopic dermatitis patients. By identifying which patients are most likely to benefit from JAK inhibitor therapy, the test may help optimize clinical outcomes and treatment efficiency in this patient population.