Table 1.
Summary of published efficacy and tolerability studies of quetiapine XR in adult patients with schizophrenia
| Study identifier | Study design | Study efficacy outcomes | Reference |
|---|---|---|---|
| D1444C00132 | 6-week, randomized, double-blind, placebo-controlled study. Patients were randomized to receive quetiapine XR 400, 600, or 800 mg/d, quetiapine IR 400 mg/d, or placebo. |
Significant improvements in PANSS total score, PANSS, and CGI-I response rates with all active treatments versus placebo. | Kahn et al64 |
| D1444C00133 | 6-week, randomized, double-blind, placebo-controlled study. Patients were randomized to receive quetiapine XR 400, 600, or 800 mg/d, quetiapine IR 800 mg/d, or placebo. |
Greater numeric improvements in PANSS total score were seen for quetiapine XR (all doses) and quetiapine IR versus placebo at week 6; the differences were not statistically significant. Secondary efficacy endpoint results did not significantly separate from placebo. A post-hoc analysis of the primary efficacy variable (change in PANSS total score at week 6) revealed that there was a significant separation from placebo in patients who were markedly ill at baseline (CGI-S ≥ 5) for the quetiapine XR 600 and 800 mg/d groups. |
Cutler et al67 |
| 5077IL/0041 | 6-week, randomized, double-blind, placebo-controlled study. Patients were randomized to receive quetiapine XR 400, 600, or 800 mg/d, quetiapine IR 300 or 600 mg/d, or placebo. |
Statistically significant improvement in PANSS total score versus placebo recorded only for quetiapine XR 600 mg/d. Numerical, but not significant, improvements in other efficacy measures. |
Lindenmayer et al65 |
| D1444C00004 | Long-term, randomized, double-blind, placebo-controlled study. Patients received quetiapine XR 400–800 mg/d (flexible dosing) for 16 weeks; clinically stable patients were randomized to quetiapine XR 400–800 mg/d (flexible dosing) or placebo. |
Study terminated early because first interim analysis showed significant difference between treatment groups. Quetiapine XR significantly prolonged time to relapse versus placebo. |
Peuskens et al31 |
| D1444C00146 | 6-week, double-blind, randomized, parallel group, fixed-dose study with a 4-week run-in period. Patients received quetiapine IR 400, 600, or 800 mg/d during the run-in period; clinically stable patients were randomized to receive quetiapine XR or quetiapine IR at the same daily dose received during run-in. |
Efficacy maintained. For the per-protocol population, quetiapine XR was noninferior to quetiapine IR in an analysis of the proportion of patients who discontinued due to lack of efficacy, or whose PANSS total score increased by ≥ 20% from randomization. |
Moller et al66 |
| D1444C00147 | 12-week, open-label study in patients with schizophrenia who were experiencing inadequate efficacy or tolerability with their ongoing antipsychotic medication. Patients were switched to quetiapine XR 400–800 mg/d (flexible-dosing) during a 4-day cross-titration period. |
Patients switched to quetiapine XR experienced a significant clinical benefit (improvements in CGI-I and PANSS total scores; P < 0.0001). | Ganesan et al63 |
Abbreviations: CGI-I, Clinical Global Impression-Improvement; IR, immediate release; PANSS, Positive and Negative Syndrome Scale; XR, extended release.