Long-Term Safety and Efficacy of Initial and Repeat Treatment Courses With Zuranolone in Adult Patients With Major Depressive Disorder: Interim Results From the Open-Label, Phase 3 SHORELINE Study.

Objective: Zuranolone is a positive allosteric modulator of both synaptic and extrasynaptic γ-aminobutyric acid (GABA) type A receptors and a neuroactive steroid approved in the United States as an oral, once-daily, 14-day treatment course for adults with postpartum depression and under investigation for adults with major depressive disorder (MDD). Interim results from the open-label, longitudinal, phase 3 SHORELINE Study (NCT03864614) that evaluated the long-term safety and efficacy of zuranolone in adults with MDD are reported.

Methods: This interim report includes patients who were enrolled and had the opportunity to be on study for up to 1 year between February 2019 and September 2021. Adults aged 18-75 years with MDD diagnosed per DSM-5 criteria and a 17-item Hamilton Rating Scale for Depression (HAMD-17) total score ≥ 20 received an initial 30-mg or 50-mg 14-day zuranolone course. HAMD-17 responders (≥ 50% reduction from baseline) at Day (D)15 of the initial treatment period were allowed to continue in the study beyond D28 and were followed up for ≤ 1 year, during which repeat treatment courses were permitted. The primary endpoint was safety and tolerability of the initial and repeat treatment courses through 1 year. Secondary endpoints included change from baseline (CFB) in HAMD-17 total score and need for repeat treatment course(s).

Results: As of September 2021, among patients in the 30-mg (n = 725) and 50-mg (n = 199) Cohorts who received a zuranolone dose, 493 (68.0%) and 137 (68.8%), respectively, reported a treatment-emergent adverse event (TEAE); most patients who experienced TEAEs reported mild/moderate events (30-mg Cohort, 90.9% [448/493]; 50-mg Cohort, 85.4% [117/137]). Mean (standard deviation) CFB HAMD-17 total score at D15 of the initial treatment period was -15.2 (7.1) and -16.0 (6.0) for the 30-mg and 50-mg Cohorts, respectively; similar improvements were observed after repeat treatment courses. The proportion of patients who received only 1 treatment course during their time on study was 42.9% (210/489) in the 30-mg Cohort and 54.8% (80/146) in the 50-mg Cohort; 57.1% (279/489) and 45.2% (66/146) patients, respectively, received 2-5 total treatment courses. The majority of patients who initially responded to zuranolone received ≤ 2 total treatment courses (30-mg Cohort, 68.5% [335/489]; 50-mg Cohort, 79.5% [116/146]).

Conclusions: Of patients who experienced TEAEs, most reported mild or moderately severe events, and responders to zuranolone experienced improvements in depressive symptoms with initial and repeat treatment courses.

Trial Registration: ClinicalTrials.gov identifier: NCT03864614.