A Study to Assess the Effect of a Single Dose of ASP8062 on the Multiple Dose Safety, Tolerability and Pharmacokinetics of Buprenorphine/Naloxone in Participants With Opioid Use Disorder

Inclusion Criteria

• Subject has a body mass index range of 18 to 36 kg/m^2, inclusive and weighs at least 50 kg at screening.
• Subject has a diagnosis of moderate or severe opioid use disorder (OUD) according to the Diagnostic and Statistical Manual of Mental Disorders, edition 5 (DSM-5) at screening.
• Subject tests positive for opioids at screening and/or on day -1 or subject shows signs of opioid withdrawal on day -1.
• Subject is willing to take buprenorphine/naloxone and is not taking buprenorphine or buprenorphine/naloxone at screening.
• Female subject is not pregnant and at least 1 of the following conditions apply:
• Not a woman of childbearing potential (WOCBP)
• WOCBP who agrees to follow the contraceptive guidance from the time of informed consent through at least 30 days after final investigational product (IP) administration.
• Female subject must agree not to breastfeed starting at screening and throughout the study period and for 30 days after final IP administration.
• Female subject must not donate ova starting at first dose of IP and throughout the study period and for 30 days after final IP administration.
• Male subject with female partner(s) of childbearing potential (including breastfeeding partner) must agree to use contraception throughout the study period and for 90 days after final IP administration.
• Male subject must not donate sperm during the treatment period and for 90 days after final IP administration.
• Male subject with pregnant partner(s) must agree to remain abstinent or use a condom and spermicide for the duration of the pregnancy throughout the study period and for 90 days after final IP administration.
• Subject agrees not to participate in another interventional study while participating in the present study.
• Subject must be willing to abstain from smoking (including use of tobacco containing products and nicotine or nicotine-containing products [e.g., electronic vapes] from at least 1 hour predose through at least 8 hours postdose on days 11 and 12.

Exclusion Criteria

• Subject has received any investigational therapy within 28 days or 5 half-lives, whichever is longer, prior to screening.
• Subject has any condition which makes the subject unsuitable for study participation.
• Female subject who has been pregnant within 6 months prior to screening or breastfeeding within 3 months prior to screening.
• Subject has a known or suspected hypersensitivity to ASP8062, buprenorphine, naloxone or any components of the formulations used.
• Subject has had previous exposure with ASP8062.
• Subject has any of the liver function tests (alkaline phosphatase [ALP], alanine aminotransferase [ALT], aspartate aminotransferase [AST], gamma-glutamyl transferase and total bilirubin [TBL]) > 2 × upper limit of normal (ULN) on day -1. In such a case, the assessment may be repeated once.
• Subject has any clinically significant history of allergic conditions (including drug allergies, asthma or anaphylactic reactions, but excluding untreated, asymptomatic, seasonal allergies) prior to first IP administration.
• Subject has any history or evidence of any clinically significant cardiovascular, gastrointestinal, endocrinologic, hematologic, hepatic, immunologic, metabolic, urologic, pulmonary, neurologic, dermatologic, renal and/or other major disease or malignancy with exception of history of cholecystectomy.
• Subject has current or recent diagnosis (within the last 12 months) of moderate or severe alcohol, sedative, hypnotic, anxiolytic, cocaine or any other substance use disorder (except for opioids, caffeine, tobacco or nicotine) according to the DSM-5 at screening.
• Subject has a history or presence of any clinically significant psychiatric disorders such as, bipolar 1, schizophrenia, schizoaffective disorder or major depressive disorders.
• Subject tests positive for alcohol, benzodiazepine or methadone on day -1. Subject tests positive for buprenorphine on day -1.
• Subject has had recent