Long-term mood/antidepressant effects of quetiapine extended-release formulation: an open-label, non-controlled extension study in Japanese patients with bipolar depression

BACKGROUND: In an 8-week, randomized, placebo-controlled, double-blind study, an extended-release formulation of quetiapine, quetiapine XR, demonstrated efficacy and safety in Japanese patients with bipolar depression. Bipolar disorder is a chronic disease requiring continuous treatment. METHODS: This was a long-term (52-week), open-label, non-controlled extension study to evaluate the long-term safety and efficacy of quetiapine XR in Japanese patients with bipolar depression who had previously completed the initial 8-week double-blind study. Efficacy was determined by the Montgomery–Åsberg Depression Rating Scale (MADRS), Hamilton Depression Scale 17-item (HAM-D(17)), and Clinical Global Impressions-Bipolar scale (CGI-BP). Safety evaluations included analysis of adverse events, clinical laboratory measures, vital signs, Drug-induced Extrapyramidal Symptoms Scale, Young Mania Rating Scale, and the Columbia Suicide Severity Rating Scale. RESULTS: The mean (SD) MADRS total score decreased from 30.9 (6.9) at baseline to 16.1 (10.6) at week 8, and eventually to 9.1 (8.7) at week 52. The sustained efficacy of quetiapine XR treatment was also shown using HAM-D(17) total scores, CGI-BP-Severity and Change evaluations. The most common adverse events were somnolence, nasopharyngitis, and thirst. Long-term treatment with quetiapine XR caused no substantial changes in the safety profiles, including clinical laboratory parameters, and no new safety concerns were identified. CONCLUSIONS: The efficacy of quetiapine XR was sustained long-term and no new safety concerns were identified in Japanese patients with bipolar depression. TRIAL REGISTRATION: ClinicalTrials.gov Registration: NCT01725308. Date of registration; 12th November 2012 (retrospectively registered). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12888-019-2181-9) contains supplementary material, which is available to authorized users.