Maximal Use Study of Tapinarof Cream, 1% in Adults With Extensive Plaque Psoriasis

Frequency and severity of AEs (local and systemic)

Changes in laboratory values, biomarker values, ECG results and vital signs were assessed for clinical relevance.

At each specified study visit, the Investigator (or qualified evaluator) assessed the presence and overall degree of irritation at the application sites, according to the LTS. The score will ideally represent an 'average' across all application sites. To the fullest extent possible, the same Investigator (or designated evaluator) will perform all tolerability assessments for an individual participant throughout the study.

The AUC in plasma is a pharmacokinetic parameter that describes the overall exposure of the drug.

The Cmax is a pharmacokinetic parameter that describes the highest concentration of the drug that is achieved after dosing.

The tmax is a pharmacokinetic parameter that describes the time point at which the highest concentration of the drug is achieved after dosing.

Identify clinically relevant effect of tapinarof on cardiac conduction

The relationship between tapinarof plasma concentrations and ∆QTcF was investigated using a linear mixed-effects modeling approach with ΔQTcF as the dependent variable. A linear model with an intercept was fitted for tapinarof plasma concentrations, which represented the data in an acceptable way. The slope of tapinarof plasma concentration in the concentration-QTc relationship was estimated.

The PGA is a clinical tool for assessing the current state/severity of a subject's psoriasis at a given timepoint. It is a static 5-point morphological assessment of overall disease severity, as determined by the investigator, using the clinical characteristics of erythema, scaling, and plaque thickness/elevation as guidelines. Higher PGA scores represent more severe disease. This scale ranges from 0 to 5, with 0 = best outcome.

The Psoriasis Area and Severity Index (PASI) scoring system combines the assessment of lesion severity and extent of affected area into a single score: 0 (no disease) to 72 (maximal disease). The body is divided into 4 areas for scoring (head, arms, trunk, and legs). Each area is assessed for 3 signs: erythema (redness), induration (plaque thickness), and scale. The severity of each sign in each body area is assessed and scored independently using a 5-point scale, where 0=none, 1=slight, 2=mild, 3=moderate, 4=severe. Each area is also assessed for percent of skin involved: 0 = (0%), 1 = (1-<10%), 2 = (10-<30%), 3 = (30-<50%), 4 = (50 -<70%), 5 = (70-<90%), 6 = (90-100%). The individual scores are multiplied by a weighted factor for each body region; the sum of these scores gives the overall PASI score. Higher scores indicate more severe disease. PASI is a static assessment made without reference to previous scores.

The assessment of %BSA affected is an estimate of the percentage of total involved skin with psoriasis. For the purpose of clinical estimation, the total palmar surface of the subject's palm and digits may be assumed to be approximately equivalent to 1% BSA. The %BSA affected by psoriasis will be evaluated (from 0% to 100%). %BSA is a static assessment made without reference to previous scores.