Indirect comparisons of relative efficacy estimates of zuranolone and selective serotonin reuptake inhibitors for postpartum depression

Abstract

Aims: Estimate relative efficacy of zuranolone, a novel oral, Food and Drug Administration-approved treatment for postpartum depression (PPD) in adults vs. selective serotonin reuptake inhibitors (SSRIs) and combination therapies used for PPD in the United States.

Materials and methods: Randomized controlled trials (RCTs) for zuranolone and SSRIs, identified from systematic review, were used to construct evidence networks, linking via common comparator arms. Due to heterogeneity in placebo responses, matching-adjusted indirect comparison (MAIC) was applied, statistically weighting the zuranolone treatment arm of Phase 3 SKYLARK Study (NCT04442503) to the placebo arm of RCTs investigating SSRIs for PPD. MAIC outputs were applied in Bucher indirect treatment comparisons (ITCs) and network meta-analysis (NMA), using Edinburgh Postnatal Depression Scale (EPDS) and 17-item Hamilton Rating Scale for Depression (HAMD-17) change from baseline (CFB) on Days 3, 15, 28 (Month 1), 45, and last observation (Day 45, Week 12/18).

Results: Larger EPDS CFB was observed among zuranolone-treated vs. SSRI-treated patients from Day 15 onward. Zuranolone-treated (vs. SSRI-treated) patients exhibited 4.22-point larger reduction in EPDS by Day 15 (95% confidence interval: -6.16, -2.28) and 7.43-point larger reduction at Day 45 (-9.84, -5.02) with Bucher ITC. NMA showed EPDS reduction for zuranolone was 4.52 (-6.40, -2.65) points larger than SSRIs by Day 15 and 7.16 (-9.47, -4.85) larger at Day 45. Lack of overlap between study populations substantially reduced effective sample size post-matching, making HAMD-17 CFB analysis infeasible.

Limitations: Limited population overlap between SKYLARK Study and RCTs reduced feasibility of undertaking HAMD-17 CFB ITCs and may introduce uncertainty to EPDS CFB ITC results.

Conclusions: Analysis showed zuranolone-treated patients with PPD experienced greater symptom improvement than SSRI-treated patients from Day 15 onward, with largest mean difference at Day 45. Adjusting for differences between placebo arms, zuranolone may be associated with greater PPD symptom improvement (measured by EPDS) vs. SSRIs.

Keywords: Bucher ITC; I; I1; I10; I11; I19; Indirect treatment comparison (ITC); L; L6; L65; MAIC; SSRIs; network meta-analysis; postpartum depression (PPD); zuranolone.