Phase 1 Study to Assess the Safety/Tolerability of Brexpiprazole as Adjunctive Therapy in Elderly Subjects With Major Depressive Disorder

This is a phase 1, multicenter, randomized, double-blind, placebo-controlled, multiple ascending dose trial in 3 sequential cohorts of elderly subjects (age 70 to 85 years old) with MDD. Brexpiprazole will be administered as an adjunct treatment to the current antidepressant therapy that the subject is receiving. Total individual subject duration is expected to be no more than 119 days (a 30-day screening period, a 14-day washout period, up to 45-day in-clinic treatment period, and a 30-day follow-up after the last dose of trial medication).