Objective: To evaluate the clinical benefit, efficacy and tolerability of switching patients experiencing suboptimal efficacy or tolerability with their current antipsychotic to once-daily extended release quetiapine fumarate (quetiapine XR).
Research design and methods: 12-week, multicenter, open-label study in adult, in- or outpatients with schizophrenia. Quetiapine XR (mg/day) was initiated during a 4-day cross-titration phase (day 1: 300; day 2: 600; days 4-84: 400-800 [flexible-dosing]). The primary endpoint was the percentage of patients achieving clinical benefit (improvement on the Clinical Global Impression-Clinical Benefit [CGI-CB] scale). Secondary endpoints included CGI-Improvement (CGI-I) and Positive and Negative Syndrome Scale (PANSS) total scores. Tolerability was assessed by adverse events (AEs), Simpson-Angus Scale (SAS) and Barnes Akathisia Rating Scale (BARS) scores. Changes in rating scale scores were analyzed using analysis of covariance and are presented as least squares mean (LSM) changes using the baseline level as a covariate.
Results: Of 477 patients switched to quetiapine XR, 77.6% completed treatment. Following switching, 295 of 470 patients adequate for evaluation (62.8%) achieved a clinical benefit (95% confidence interval [CI] 58.4, 67.1; p < 0.0001). Significant improvements in LSM (95% CI) CGI-I of 2.88 (2.67, 3.08) and the LSM change in PANSS total scores of -12.3 (-14.95, -9.58) were observed (both p < 0.001). Common AEs included somnolence (17.8%), sedation (15.1%), dizziness and dry mouth (14.0% each). The incidence of extrapyramidal symptoms (EPS) was 8.0%. Mean improvements from baseline in SAS and BARS scores were -2.1 and -0.4, respectively (both p < 0.001).
Conclusions: Switching to quetiapine XR was associated with clinical benefit and good efficacy and tolerability.
Trial registration: ClinicalTrials.gov NCT00234377.