Shionogi’s Zazbei antidepressant wins Japan approval

Shionogi & Co., Ltd. has received manufacturing and marketing approval in Japan for Zazbei® Capsule 30mg (zuranolone) for the treatment of depression and depressive states, effective December 22, 2025. This novel antidepressant demonstrated efficacy and safety in a Phase 3 validation study, showing early improvement in symptoms with once-daily 30mg administration over 14 days.

The study's primary endpoint, the change from baseline in HAM-D17 total score at the end of 14-day treatment, showed a statistically significant difference. The treatment group had an average change of -7.43, compared to -6.23 for the placebo group, with a group difference of -1.20 (95% CI: -2.32, -0.08; p<0.0365). Re-administration after a break of six weeks or more also confirmed effectiveness and safety.

This approval addresses an unmet need for rapid-acting antidepressants in Japan, where approximately 5m people are estimated to suffer from depression. Shionogi aims to make Zazbei available quickly to patients, contributing to its commitment to enabling longer, healthier, and more fulfilling lives.