A Study of CLE-100 (Oral Esketamine) as an Adjunctive Treatment to Standard Antidepressants for Major Depressive Disorder

This is a Phase 2 study in subjects with MDD currently treated with an oral antidepressant medication with an inadequate response to at least 2 antidepressants. SOLEO will be an outpatient study to assess the safety, efficacy, and tolerability of CLE-100 as compared to placebo. Eligible subjects will be randomized to receive either placebo or CLE-100 (oral esketamine) once daily in addition to their current oral antidepressant monotherapy for 4 weeks. All subjects who adequately completed the 4-week Double-Blind Treatment Period and who meet the eligibility criteria will be offered the option to roll-over to a 6-month Open-label Extension (OLE) Treatment Period with CLE-100.