Phase 3 trials of Tapinarof cream for plaque psoriasis
Tapinarof Cream is a topical aryl hydrocarbon receptor modulator being investigated for the treatment of psoriasis. Tapinarof modulates the expression of interleukin-17 and the skin barrier proteins filaggrin and loricrin.
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We conducted two identical phase 3 randomized trials of tapinarof in patients with mild to severe plaque psoriasis. Adults with a baseline Physician’s Global Assessment (PGA) score of 2 (mild) to 4 (severe) (on a scale of 0 to 4, with higher scores indicating more severe psoriasis) and a percentage of 3-20% affected total body surface area were randomly assigned in a 2: 1 ratio to use 1% tapinarof cream or vehicle cream once daily for 12 weeks. The primary endpoint, the PGA response, was a PGA score of 0 (clear) or 1 (almost clear) and a decrease of at least 2 points from baseline at week 12. Criteria for Secondary efficacy evaluations at week 12 were at least 75% reduction in Psoriasis Area and Severity Index (PASI) score, PGA score of 0 or 1, mean change from baseline in percentage affected body surface area and a reduction of at least 90% in the PASI score. The patient-reported outcomes were the mean changes between baseline and week 12 in the proportion of patients who had a 4-point or greater decrease in the Peak Pruritus Numerical Rating Scale score (PP- NRS) (range: 0 [no itch] to 10 [worst imaginable itch]), PP-NRS total score, Dermatology Life Quality Index total score, and Psoriasis Symptom Diary score.
In Trials 1 and 2, a total of 692 and 674 patients, respectively, were examined, with 510 and 515 patients included. A PGA response occurred in 35.4% of patients in the tapinarof group and in 6.0% of those in the vehicle group in Trial 1 and in 40.2% and 6.3%, respectively, in the trial 2 (P
Tapinarof 1% cream once daily was superior to vehicle control in reducing the severity of plaque psoriasis over a 12 week period, but was associated with local adverse events and headache. Larger and longer trials are needed to assess the efficacy and safety of tapinarof cream compared to existing treatments for psoriasis. (Funded by Dermavant Sciences; PSOARING issues 1 and 2 ClinicalTrials.gov, NCT03956355 and NCT03983980, respectively.)