Efficacy of Tapinarof Cream for Psoriasis
Tapinarof cream 1% once daily (QD) demonstrated statistically significant efficacy vs vehicle and was well tolerated in adults with mild to severe plaque psoriasis in the two 12-week, pivotal phase 3 trials, PSOARING 1 (N=510) and PSOARING 2 (N=515).22 Eligible patients had a PGA score of 2 (mild) to 4 (severe) and a percentage body surface area (%BSA) affected of 3% to 20% at baseline. Patients were randomly assigned 2:1 to tapinarof cream or vehicle cream QD for 12 weeks, after which eligible patients could enroll in PSOARING 3. The primary endpoint was PGA response, defined as a PGA score of 0 (clear) or 1 (almost clear), and a decrease of at least 2 points from baseline at week 12. This was achieved by a significantly higher proportion of patients in the tapinarof group vs vehicle in PSOARING 1 and 2: 35.4% vs 6.0% and 40.2% vs 6.3%, respectively (both P<0.0001).22,29 All secondary efficacy endpoints were met for tapinarof cream vs vehicle in PSOARING 1 and 2 (P≤0.0005). These included: the proportion of patients with a reduction of at least 75% in the Psoriasis Area and Severity Index (PASI) score (PASI75) at week 12 (36.1% vs 10.2% and 47.6% vs 6.9% in PSOARING 1 and 2, respectively); the proportion with a PGA score of 0 or 1 at week 12 (37.8% vs 9.9% and 43.6% vs 8.1%); the mean change from baseline in %BSA affected at week 12 (–3.5% vs –0.2% and –4.2% vs 0.1%); and the proportion with a reduction of at least 90% in the PASI score (PASI90) at week 12 (18.8% vs 1.6% and 20.9% vs 2.5%).22,29,30 Figure 3 shows a patient treated with tapinarof cream who achieved primary and secondary efficacy endpoints at week 12.
Improvements with tapinarof cream were seen as early as the first clinical assessment at week 2 and continued to week 12; additional efficacy was achieved in the long-term extension trial, PSOARING 3.30 The efficacy of tapinarof cream was consistent across a broad spectrum of disease severity (as evaluated by PGA score, %BSA affected, and duration of disease) and patient demographics (including sex, age, race, and country of enrollment [US or Canada]).31
PSOARING 3 assessed the safety, efficacy, and tolerability of tapinarof cream 1% QD, as well as durability of response on therapy (absence of tachyphylaxis), and duration of remittive effect off therapy.27 Patients received up to 40 weeks of open-label treatment followed by 4 weeks of follow-up off treatment. Therefore, patients could be treated with up to 52 weeks of tapinarof from PSOARING 1 and 2 baseline through PSOARING 3 completion.27
In PSOARING 3, patients were treated based on their PGA score. Those entering the trial with PGA≥1 received tapinarof cream until complete disease clearance was achieved (PGA=0). Patients entering with, or achieving, PGA=0 discontinued treatment and were monitored for the duration of remittive effect, defined as off-therapy maintenance of PGA=0 or 1. Patients with PGA≥2 were treated or re-treated until PGA=0.
In total, 91.6% (n=763) of eligible patients completing PSOARING 1 and 2 elected to enroll in PSOARING 3. Overall, 40.9% (n=312) achieved complete disease clearance (PGA=0) at least once during the trial. Among patients entering with PGA≥2, 58.2% (n=302) achieved PGA=0 or 1. Among patients achieving PGA=0 at any time during the trial (n=312), the mean total duration of remittive effect off treatment was approximately 4 months
