BTRX-246040 Administered Once Daily to Patients With Major Depressive Disorder

Inclusion Criteria: * Patients with a diagnosis of MDD as defined by DSM-5 criteria and have had at least 1 prior major depressive episode in the past 10 years * Patients must present with a new current episode of MDD and the duration of the current episode must be at least 4 weeks but not longer than 18 months. * At Visit 1 (screening) and Visit 2 (baseline), patients must have clinically significant depressive symptoms defined by tandem (investigator- and computer-administered) Montgomery-Asberg Depression Rating Scale (MADRS) total scores ≥ 26 with a difference of ≤ 7 points between the Investigator- and computer-administered MADRS total scores * Patients must have a CGI-S score ≥ 4 at Visit 2 (baseline). Exclusion Criteria: * Patients who present with any current DSM-5 disorder other than MDD which is the focus of treatment. * Patients who are homicidal in the opinion of the Investigator or are at suicidal risk (any suicide attempts within 12 months prior to Visit 1 \[screening\] or any suicidal intent, including a plan, within 3 months prior to Visit 1 \[screening\]; C-SSRS answer of "YES" on item 4 or 5 \[suicidal ideation\]; Investigator- or computer-administered MADRS score of ≥ 5 on item 10 \[suicidal thoughts\]; by Investigator clinical evaluation). * Patients cannot have any history of substance or alcohol use disorder within 12 months prior to Visit 1 (screening) per DSM-5 criteria * Patients must not have a clinically significant comorbid disease.