March 26, 2020
Otsuka Pharmaceutical Co., Ltd.
Otsuka Pharmaceutical Co., Ltd. (Otsuka) is pleased to announce top-line results from two phase 3 trials conducted in Japan for difamilast (OPA-15406) in patients with atopic dermatitis. One study was in adult patients and the other was in pediatric patients.
Difamilast is a novel atopic dermatitis drug candidate discovered by Otsuka that has phosphodiesterase 4 (PDE4) inhibitory activity. PDE4 inhibitors are believed to improve the symptoms of atopic dermatitis through suppression of the production of chemical mediators such as pro-inflammatory cytokines and through other anti-inflammatory effects.
The two trials were conducted as multicenter, randomized, double-blind, vehicle-controlled (i.e., comparator), 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), a standard methodology in atopic dermatitis clinical trials that uses severity scoring to evaluate systemic symptoms.
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.
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.
Information in this news release was current as of the original release date.