Long-Term Study to Assess the Safety and Tolerability of NBI-1065845 as an Adjunctive Treatment in Participants With Major Depressive Disorder (MDD)

Key Inclusion Criteria: * Participant has a primary diagnosis of recurrent MDD (moderate or severe) or persistent depressive disorder. * Participant has had an inadequate response to oral antidepressant treatments in the current episode of depression. * Participant must have been taking oral antidepressants for at least 8 weeks prior to screening. * Willing and able to comply with all study procedures and restrictions in the opinion of the investigator. Key Exclusion Criteria: * A current or prior psychiatric disorder diagnosis in the last 1 year that was the primary focus of treatment other than MDD. * Are considered by the investigator to be at imminent risk of suicide or injury to self or others. Other protocol defined inclusion and exclusion criteria apply.