Background: Brexanolone (BRX) injection was approved by the United States Food and Drug Administration in 2019 for the treatment of adults with postpartum depression (PPD) based on two Phase 3 clinical trials. Materials and Methods: Data from the three trials were combined. PPD-specific 17-item Hamilton Rating Scale for Depression (HAMD-17) group-level minimal important difference (MID) and patient-level meaningful change (meaningful change threshold [MCT]) were estimated and applied to differences in BRX versus placebo (PBO) at hour 60 (primary endpoint) and day 30 (end of trial follow-up). Likelihood of HAMD-17 response and remission and Clinical Global Impression of Improvement (CGI-I) response for BRX versus PBO were assessed at hour 60 and as sustained through day 30 using relative risk. Associated number needed to treat (NNT) and number needed to harm (NNH) values were also estimated. Results: Two-hundred nine patients were included. The average HAMD-17 MID estimate was -2.1; the least-squared mean difference between BRX and PBO exceeded this at hour 60 and day 30. Minimal, moderate, and large MCTs were estimated to be -9, -15, and -20 points, respectively. Significantly more BRX-treated than PBO-treated patients achieved minimal, moderate, and large change (all ps < 0.05) at hour 60 and large meaningful response at day 30 (p < 0.05). BRX-treated patients were more likely to sustain HAMD-17 remission and CGI-I response through day 30 versus PBO. NNTs ranged from 4 to 8, with NNH of 97. Conclusions: BRX provided meaningful changes relative to PBO, rapid (hour 60), and sustained improvements (day 30) in PPD symptoms, low NNT, and large NNH. These results may help inform treatment decision-making. Clinicaltrials.gov registration numbers: NCT02614547, NCT02942004, and NCT02942017.
Keywords: brexanolone; meaningful change; number needed to harm; number needed to treat; postpartum depression.