Participants were screened for up to 28 days prior to first investigational product administration. Eligible participants were admitted to the clinical unit on day -1 and were residential for a single period of 17 days/16 nights.~Participants were discharged from the clinical unit on day 16 on the condition that all required assessments had been performed and that there were no medical reasons for a longer stay in the clinical unit.
The primary purpose of this study was to assess the safety and tolerability of multiple doses of ASP8062 or placebo alone and in combination with a single dose of morphine.~This study also assessed the potential for pharmacokinetic interaction between ASP8062 and morphine.