The study will consist of the following periods: Screening Period (up to 56 days); Double-blind treatment period (12 weeks/ 85 days); a Buprenorphine/naloxone down-titration period (as determined by the participant in collaboration with the investigator) (14 days); and a Follow-up period (30 days post last dose ASP8062 or placebo ASP8062 for ASP8062 End of Treatment [EOT]).
The purpose of this study is to evaluate the efficacy; safety and tolerability of ASP8062 compared with placebo ASP8062 as add-on therapy to buprenorphine/naloxone.