Study Assessing the Safety, Tolerability, and Pharmacokinetics of SEP-363856 in Male and Female Subjects With Schizophrenia

This multicenter study will be conducted in 2 parts (Part 1 and 2). Part 1 of the study is a multicenter, randomized, single-blind, placebo-controlled portion, ascending multiple oral dose study designed to evaluate the safety, tolerability, and PK of ascending multiple oral doses of SEP-363856 and its metabolite SEP-363854 in male and female subjects with schizophrenia. Part 1 This study will determine the MTD for once-daily multiple oral administration of SEP-363856, and characterize the plasma and urine PK profiles of SEP-363856 and its metabolite SEP-363854 in male and female subjects with schizophrenia. The effect of SEP-363856 on the PANSS, CGI-S, and CDSS scales will also be assessed. For each of the dose-escalation cohorts, 12 subjects (9 active subjects and 3 placebo subjects) will be dosed for 7 consecutive days with serial collection of PK blood samples after the first and last doses, and daily collection of trough PK blood samples. An attempt will be made to have at least one-third of subjects in each cohort be female. Part 2 of the study is an open-label safety and tolerability study designed to gain longer-term safety and tolerability data for 75 mg SEP-363856 given once-daily for 28 days in male and female subjects with schizophrenia. The effect of SEP-363856 on the PANSS, CGI-S, and CDSS scales will also be assessed. In Part 2, 16 subjects will be dosed.