Efficacy and Safety of Zabedosertib, an Interleukin-1 Receptor-Associated Kinase 4 Inhibitor, in Patients with Moderate-to-Severe Atopic Dermatitis: A Phase II Randomized Study

Abstract Introduction Interleukin-1 receptor-associated kinase 4 (IRAK4) is expressed in various immune cells and regulates proinflammatory cytokine production. Its inhibition represents a novel, promising therapeutic option in the treatment of atopic dermatitis (AD). Zabedosertib (BAY1834845) is a potent, selective IRAK4 inhibitor that suppresses markers of local and systemic immune responses. This study aimed to evaluate the efficacy and safety of zabedosertib in adults with moderate-to-severe AD. Methods DAMASK was a randomized, double-blind, 12-week, placebo-controlled, phase 2a, proof-of-concept study. Patients were randomized 2:1 to receive oral zabedosertib 120 mg twice daily or placebo. The primary efficacy endpoint was a composite of 75% reduction from baseline on the Eczema Area and Severity Index (EASI-75), no discontinuation of study medication for lack of efficacy, no rescue medication during the 4 weeks before Day 84, and no initiation of systemic AD treatment. Other efficacy assessments included validated Investigator’s Global Assessment for Atopic Dermatitis (vIGA-AD), Peak Pruritus numerical rating scale score, and affected body surface area (BSA); for safety, it included frequency and severity of treatment-emergent adverse events (TEAEs). Results Of 77 randomized patients, 69 were included in the primary efficacy analysis (zabedosertib, n = 47; placebo, n = 22); 55 patients completed treatment. At Week 12, there was no significant difference between zabedosertib and placebo in the primary efficacy endpoint (32.3% vs. 37.4%) or percentage change in EASI from baseline (− 44.6% vs. − 55.9%). There were also no significant differences between zabedosertib and placebo at Week 12 in vIGA-AD response (15.9% vs. 28.5%), Peak Pruritus response (16.4% vs. 25.0%), percentage change in Peak Pruritus (− 20.7% vs. − 27.3%), or percentage change in BSA affected by AD (− 13.3% vs. − 20.3%). No severe or serious TEAEs were reported throughout the study. Conclusions Zabedosertib was safe and well tolerated in adults with moderate-to-severe AD but showed no evidence of efficacy in reducing disease severity or pruritus in this placebo-controlled study. Trial Registration ClinicalTrials.gov identifier, NCT05656911.