title: Evaluation of the feasibility of switching from immediate release quetiapine to extended release quetiapine fumarate in stable outpatients with schizophrenia.
abstract: This double-blind, double-dummy study (D1444C00146) evaluated the efficacy and safety of switching patients with clinically stable schizophrenia from quetiapine immediate release (IR) to the same dose of once-daily extended release quetiapine fumarate (quetiapine XR). Patients received quetiapine IR 400-800 mg/day twice daily for 4 weeks, and were then randomized (2 : 1) to a once-daily equivalent dose of quetiapine XR or maintained on IR for 6 weeks. The primary variable was the proportion of patients who discontinued treatment owing to lack of efficacy or whose Positive and Negative Syndrome Scale scores increased by at least 20% from randomization to any visit. In total, 497 patients were randomized to quetiapine XR (n=331) or IR (n=166). Noninferiority (6% margin; one-sided test, 2.5% significance level) was narrowly missed for the primary efficacy variable for the modified intention-to-treat population (9.1%, quetiapine XR; 7.2%, quetiapine IR; difference 1.86%; 95% confidence interval: -3.78, 6.57; P=0.0431), but was shown for the per-protocol population (5.3%, quetiapine XR; 6.2%, quetiapine IR; difference: -0.83%; 95% confidence interval: -6.75, 3.71; P=0.0017). Serious adverse event incidence was low for quetiapine XR and IR; there were no unexpected adverse events. In conclusion, efficacy was maintained without compromising safety/tolerability when switching patients with stable schizophrenia from twice-daily quetiapine IR to once-daily quetiapine XR (400-800 mg/day).
authors.affiliation: Psychiatric Hospital of the University of Munich, Munich, Germany. hans-juergen.moeller@med.uni-muenchen.de
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Möller
authors.forename: Sunny
authors.initials: S
authors.lastname: Johnson
authors.forename: Temenuzhka
authors.initials: T
authors.lastname: Mateva
authors.forename: Martin
authors.initials: M
authors.lastname: Brecher
authors.forename: Ola
authors.initials: O
authors.lastname: Svensson
authors.forename: Frank
authors.initials: F
authors.lastname: Miller
authors.forename: Didier
authors.initials: D
authors.lastname: Meulien
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D003692:Delayed-Action Preparations; D003987:Dibenzothiazepines / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000069348:Quetiapine Fumarate; D012559:Schizophrenia / Q000188:drug therapy*
chemical_list: D014150:Antipsychotic Agents; D003692:Delayed-Action Preparations; D003987:Dibenzothiazepines; D000069348:Quetiapine Fumarate