Difamilast ointment in adult patients with atopic dermatitis: A phase 3 randomized, double-blind, vehicle-controlled trial

Background: Difamilast is a selective phosphodiesterase 4 inhibitor. Phosphodiesterase 4 is involved in cytokine production linked with inflammatory disorders, including atopic dermatitis. Objective: To demonstrate the superiority of difamilast ointment 1% to vehicle in adult Japanese patients with atopic dermatitis. Methods: In this phase 3, randomized, double-blind trial, patients aged 15-70 years with an investigator global assessment score of 2 or 3 received topical difamilast ointment 1% (n = 182) or a vehicle (n = 182) twice daily for 4 weeks. Results: The success rate in investigator global assessment score at week 4 (primary endpoint)-the percentage of patients achieving an investigator global assessment score of 0 or 1 with >= 2-grade improvement-was significantly higher with 1% difamilast than with the vehicle (38.46% vs 12.64%, respectively, P < .0001). The success rates in >= 50%, >= 75%, and >= 90% improvement in overall eczema area and severity index score at week 4 followed the same trend. Difamilast at 1% provided significant mean percent improvement from baseline in overall eczema area and severity index score versus vehicle from week 1 to 4. Treatment-emergent adverse events were mostly mild or moderate and less frequent with difamilast. Limitations: Study treatment was limited to 4 weeks. Conclusion: Difamilast ointment 1% demonstrated superiority to the vehicle and favorable safety in adult Japanese patients with atopic dermatitis.

Automated summary

The study demonstrated that 1% Difamilast ointment had superior efficacy compared to the vehicle in treating adult Japanese patients with atopic dermatitis. It significantly improved the investigator global assessment score and overall eczema area and severity index score, and showed favorable safety profile.