Molecular Skin Test May Help Guide Treatment Selection in Atopic Dermatitis
Posted on 28 Sep 2026
Patients with atopic dermatitis (eczema) often struggle to achieve consistent symptom control, leading many to alter or switch systemic therapies when treatment is ineffective. Newly published survey data show that more than half of patients using targeted systemic therapies modified treatment because of inadequate efficacy, while interest in molecular tools to guide treatment selection was high. These findings underscore the need for objective biomarkers that can support more informed therapy discussions and decisions.
AdvanceAD-Tx from Castle Biosciences (Austin, TX, USA) 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 from lesional skin scraping samples, without the need for biopsy, the assay evaluates 487 genes across 12 inflammatory and cutaneous biology pathways to characterize the immune drivers of disease. Based on these molecular patterns, the test classifies patients into one of two profiles: a Janus kinase (JAK) Inhibitor Responder Profile or a T helper type 2 (Th2) Molecular Profile.
A study published in Dermatology and Therapy evaluated treatment experiences and preferences among 43 patients with AD and caregivers who completed a 32-question assessment at the 2024 National Eczema Association Eczema Expo. Among participants who had used targeted systemic therapies, 55% had modified treatment because of inadequate efficacy. Overall, 83% expressed interest in molecular testing to guide treatment selection, increasing to 94% among those open to starting a new systemic therapy.
The leading treatment priorities were itch control (70%), effective skin clearance (58%), and safety or absence of side effects (50%). Inadequate clearance and persistent itching were the most common reasons for switching or adding therapies.
These patient-reported findings complement results from a prospective, multicenter clinical validation study published in the Journal of the American Academy of Dermatology, which showed that AdvanceAD-Tx can identify differences in response to systemic therapy classes in patients with moderate-to-severe AD.
Patients with a JAK Inhibitor Responder Profile who received a JAK inhibitor were 5.5 times more likely to achieve at least 90% improvement in Eczema Area and Severity Index (EASI-90) by three months and reached that response 3.8 times faster than patients with the same profile treated with a Th2-targeted therapy. By contrast, patients with a Th2 Molecular Profile showed comparable clinical outcomes with either treatment class.
“One thing came through clearly in this study: patients want better control of their disease and more information to help guide their treatment decisions. AdvanceAD-Tx gives us an opportunity to bring objective molecular information into those conversations, helping personalize systemic treatment decisions and expedite the path to an effective therapy and symptom relief,” said Diego Ruiz Dasilva, M.D., board-certified dermatologist at Forefront Dermatology in Virginia Beach, Virginia.
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