Difamilast is a novel topical, non-steroidal phosphodiesterase IV (PDE4) inhibitor for the treatment of mild to moderate AD.

Medimetriks Pharmaceuticals, Inc. and Otsuka Pharmaceuticals Co. Ltd.’s MM36 (difamilast) performed well in two Phase 3 Japanese clinical trials in adult and pediatric atopic dermatitis (AD) patients.

Difamilast is a novel topical, non-steroidal phosphodiesterase IV (PDE4) inhibitor for the treatment of mild to moderate AD. Otsuka entered into a licensing agreement with Medimetriks, Inc. in 2016 which granted Medimetriks development, marketing, and manufacturing rights for difamilast in the United States.

The two trials were conducted as multicenter, randomized, double-blind, vehicle-controlled parallel-group studies. In the adult study, 1% difamilast ointment or the vehicle was applied twice daily for four weeks. In the pediatric study, 0.3% or 1% difamilast ointment or the vehicle was applied twice daily for four weeks.

Therapeutic effects were assessed using the Investigator's Global Assessment (IGA). In both the adult and pediatric trials, the IGA success rates, the primary endpoints as defined as the proportion of subjects whose IGA score was 0 (clear) or 1 (almost clear) and with improvement by at least 2 grades, were higher in the active-drug-treatment groups than in the vehicle groups, and the differences were statistically significant. No major adverse reactions were identified. Trial outcomes will be analyzed further and findings will be announced at a scientific conference.

"We are excited about the results announced today by Otsuka and believe these results further validate the potential for MM36 (difamilast) as a best- in-class treatment for patients suffering from mild to moderate atopic dermatitis," says Bradley Glassman, Chairman and Chief Executive Officer of Medimetriks, in a news release.  "We are preparing for our US Phase 3 MM36 (difamilast) trials and are committed to our goal of helping improve the lives of atopic dermatitis patients in the United States."