Screening period After obtaining informed consent, the investigator will perform a screening examination. The screening period is defined as the period between the day of obtaining informed consent and the day of baseline visit (0 - 30 days).~Assessment period (treatment period) The assessment period is defined as the period between the day of baseline visit and the end of Week 4 visit (or the end of withdrawal visit). The subject who meets the inclusion criteria and does not meet the exclusion criteria at the baseline visit will be allocated to the 1% formulation of OPA-15406 or the comparator (vehicle [placebo]). The allocated IMP will be administered to the treatment area from the day of baseline visit twice-daily for 4 weeks. After the baseline visit, the examinations will be performed at Weeks 1, 2, and 4. If a subject discontinues the IMP administration between the day of baseline visit and the day of Week 4 visit, a withdrawal visit will be performed for that subject.~Trial period The trial period for individual subject is the period from the day of obtaining the subject's written informed consent to the day of the Week 4 visit or withdrawal visit. For subjects who missed the Week 4 visit or withdrawal visit, the day of discontinuation will be the day when the investigator determined that the subject was to be withdrawn from the trial. It does not include the follow-up period for AE.To evaluate the efficacy (secondary endpoint) and safety of IMP (1% OPA-15406 ointment) when administered twice-daily for 4 weeks in adult patients with AD.
This is a multinational (China and Korea), multicenter, randomized, double-blind, vehicle-controlled, parallel-group, comparison trial to demonstrate the superiority of 1% OPA-15406 ointment to the vehicle in adult AD subjects.