A Study to Assess the Safety, Tolerability and Pharmacokinetics of Multiple Doses of ASP8062 With a Single Dose of Morphine in Recreational Opioid Using Participants

Inclusion Criteria

• Participant is a recreational opioid user who has used opioids for nontherapeutic (recreational) purposes on at least 10 occasions within their lifetime, with at least 1 opioid use in the last 90 days.
• Participant has a body mass index (BMI) range of 18 to 36 kg/m^2, inclusive and weighs at least 50 kg at screening.
• Female participant 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 28 days after final investigational product (IP) administration.
• Female participant must agree not to breastfeed starting at screening and throughout the study period and for 28 days after final IP administration.
• Female participant must not donate ova starting at first dose of IP and throughout the study period and for 28 days after final IP administration.
• Male participant with female partner(s) of childbearing potential (including breastfeeding partner[s]) must agree to use contraception throughout the treatment period and for 90 days after final IP administration.
• Male participant must not donate sperm during the treatment period and for 90 days after final IP administration.
• Male participant with a pregnant partner(s) must agree to remain abstinent or use a condom with spermicide for the duration of the pregnancy throughout the study period and for 90 days after final IP administration.
• Participant agrees to not participate in another interventional study while participating in the present study.

Exclusion Criteria

• Participant has received any investigational therapy within 28 days or 5 half-lives, whichever is longer, prior to screening.
• Participant has any condition which makes the participant unsuitable for study participation.
• Female participant who has been pregnant within 6 months prior to screening or breastfeeding within 3 months prior to screening.
• Participant has a known or suspected hypersensitivity to ASP8062 or morphine and/or other opioids, or any components of the formulations used.
• Participant has had previous exposure with ASP8062.
• Participant has any of the liver function tests (alkaline phosphatase [ALP], alanine aminotransferase [ALT], aspartate aminotransferase [AST], gamma-glutamyl transferase and total bilirubin [TBL]) ≥ 1.5 × upper limit of normal (ULN) on day -1. In such a case, the assessment may be repeated once.
• Participant 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.
• Participant 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.
• Participant has a history of moderate or severe use disorder for any substance other than caffeine or tobacco (based on the Diagnostic and Statistical Manual of Mental Disorders, edition 5 (DSM-5) criteria).
• Participant has a history or presence of any clinically significant psychiatric disorders such as, bipolar 1, schizophrenia, schizoaffective disorder or major depressive disorders.
• Participant has had recent suicidal ideation within the last 12 months or participant who is at significant risk to commit suicide using the Baseline/Screening Columbia-suicide severity rating scale (C-SSRS) at screening and the Since Last Visit C-SSRS on day -1.
• Participant has/had febrile illness or symptomatic, viral, bacterial (including upper respiratory infection) or fungal (noncutaneous) infection within 1 week prior to day -1.
• Participant has any clinically significant abnormality following an investigator's review of the physical examination, ECG and protoco