Tapinarof cream for the treatment of plaque psoriasis: Efficacy and safety results from 2 Japanese phase 3 trials

Tapinarof is a non-steroidal, topical, aryl hydrocarbon receptor agonist. We evaluated the efficacy and safety of tapinarof cream (1%) in Japanese patients aged ≥18 years with plaque psoriasis in two phase 3 trials, ZBA4-1 and ZBA4-2. ZBA4-1 (N = 158) consisted of a 12-week, double-blind, vehicle-controlled treatment period (period 1) and a 12-week extension treatment period (period 2). Patients were randomized 2:1 to tapinarof or vehicle in period 1; subsequently, all patients who were enrolled in period 2 received tapinarof. ZBA4-2 (N = 305) was a 52-week, open-label, uncontrolled trial in which all patients received tapinarof. In period 1 of ZBA4-1, the proportion of patients who achieved a Physician Global Assessment (PGA) score of 0 (clear) or 1 (almost clear) with ≥2-grade improvement from baseline at week 12 (PGA treatment success, the primary endpoint) was 20.06% in the tapinarof group and 2.50% in the vehicle group (p = 0.0035). The proportion of patients with ≥75% improvement from baseline in the Psoriasis Area and Severity Index (PASI) score at week 12 (PASI75 response, a key secondary endpoint) was 37.7% in the tapinarof group and 3.8% in the vehicle group (p < 0.0001). In ZBA4-2, PGA treatment success rate was 30.0% at week 12, 51.3% at week 24, and 56.3% at week 52, and PASI75 response rate was 50.4% at week 12, 77.5% at week 24, and 79.9% at week 52, indicating that efficacy responses improved over time and were maintained over 52 weeks. Across the two trials, most adverse events (AEs) were mild or moderate; common AEs included folliculitis and contact dermatitis. In summary, tapinarof cream (1%) was efficacious and generally safe for up to 52 weeks of treatment in Japanese patients with plaque psoriasis.