Improvement effects of tapinarof on the skin barrier function in Japanese patients with atopic dermatitis

Abstract

Background: Tapinarof is a nonsteroidal, topical, aryl hydrocarbon receptor agonist. Tapinarof has been shown to be efficacious and have acceptable safety profile in the treatment of atopic dermatitis (AD). Objective: We sought to evaluate the improvement effect of tapinarof on skin barrier function in patients with AD. Methods: This was an open-label, uncontrolled, single-center study. Japanese patients aged ≥20 years with AD (N = 30) were included in this study. Patients applied tapinarof cream 1% once daily to the target areas on the volar forearm for 8 weeks. The primary endpoints were changes from baseline in stratum corneum hydration (SCH) and transepidermal water loss (TEWL) at the target affected area at week 8. Results: The mean SCH value at the target affected area was 13.656 AU at baseline, 16.904 AU at week 4, and 16.423 AU at week 8. The SCH at the target affected area significantly increased from baseline to week 8, with a mean change of 2.826 AU ( p = 0.0433). The mean TEWL value at the target affected area was 17.35 g/m 2 /hr at baseline, 10.01 g/m 2 /hr at week 4, and 9.52 g/m 2 /hr at week 8. The TEWL at the target affected area significantly decreased from baseline to week 8, with a mean change of −8.03 g/m 2 /hr ( p < 0.0001). Clinical signs of AD at the target affected area were improved over time. No serious, severe, or treatment-related AEs were reported. Conclusion: Treatment with tapinarof led to an increase in SCH and a decrease in TEWL in patients with AD, indicating the potential improvement effect of tapinarof on skin barrier function.