Difamilast safe, efficacious in atopic dermatitis treatment

A Japanese study found difamilast ointment 1% to be efficacious and safe in the treatment of atopic dermatitis.

“Atopic dermatitis (AD), a chronic, pruritic inflammatory skin disease, occurs most frequently in children,” Hidehisa Saeki, MD, PhD, of the department of dermatology at Nippon Medical School in Tokyo, and colleagues wrote. “AD also frequently affects adults, with a reported prevalence of 8% to 9% in Japanese adults aged 20 to 30 years and 10% in adults in high-income countries globally.”

This phase 3, randomized, double-blind trial evaluated difamilast 1%, a selective phosphodiesterase 4 inhibitor, compared with vehicle in AD patients aged 15 to 70 years.

Patients were randomly assigned 1:1 to the treatment or vehicle groups. Application was twice daily for 4 weeks, and of 364 patients included in the trial, 300 completed the treatment course.

Investigator Global Assessment (IGA) scores were significantly improved in the difamilast group compared with the vehicle group (38.46% vs. 12.64%; 95% CI, 17.46-34.40).

The success rate in IGA score was 10.99% in the treatment group and 0.55% in the vehicle group at week 1 and 23.08% and 6.04%, respectively, at week 2.

Eczema Area and Severity Index (EASI) 50, 75 and 90 were also evaluated.

At week 4 the percentage of patients who reached EASI 50 was 58.24% in the treatment group and 25.82% in the vehicle group. EASI 75 was 42.86% in the difamilast group and 13.1% in the vehicle group and EASI 90 was 24.73% and 5.49%, respectively.

A mean change in pruritis score was –0.65 in the 1% difamilast group and –0.04 in

the vehicle group.

Treatment emergent adverse events occurred in 32 patients (17.6%) in the treatment group and 51 patients (28%) in the vehicle group. These included worsening AD, which occurred in seven of the 182 patients (3.8%) treated with difamilast and 22 of the 182 patients (12.1%) in the vehicle group, and nasopharyngitis, which occurred in nine patients (4.9%) in the treatment group and seven (3.8%) in the vehicle group.

Adverse events believed to be related to treatment included one patient in the treatment group and 16 patients in the vehicle group.

“Difamilast ointment 1% applied twice daily for 4 weeks shows superiority over its vehicle, with excellent safety for adult patients with AD,” the authors wrote. “Early effectiveness, as we show for difamilast, is important in the treatment of AD, although long-term evaluation is also relevant in assessing the value of treatments for chronic conditions.