Endoxifen: A new, protein kinase C inhibitor to treat acute and mixed mania associated with bipolar I disorder.

OBJECTIVES: Endoxifen is a protein kinase C inhibitor. The objective of the present phase III study was to demonstrate the safety and efficacy of endoxifen in treating bipolar I disorder (BPD I) patients. METHODS: A multicenter, double-blind, active-controlled study was conducted using a daily dose of 8 mg endoxifen compared to 1000 mg divalproex, the current standard treatment, in patients with BPD I acute manic episodes with/without mixed features. The primary endpoint of our study was the mean change in total Young Mania Rating Scale (YMRS) score at day 21. RESULTS: Endoxifen (n = 116) significantly (p < 0.0001) reduced total YMRS score (from 33.1 to 17.8. A significant (p < 0.001) improvement in Montgomery-Åsberg Depression Rating Scale (MADRS) score was observed for endoxifen (4.8 to 2.5). Early time to remission of the disease was observed with endoxifen compared to divalproex. None of the patients required rescue medication and there was no drug-associated withdrawals. Changes in Clinical Global Impressions-Bipolar Disorder and Clinical Global Impression-Severity of Illness scores showed that treatment with endoxifen was well-tolerated. CONCLUSIONS: Endoxifen at a low daily dose of 8 mg was as efficacious and safe in patients with BPD I acute manic episodes with/without mixed features.