ABSTRACT
UNLABELLED: This randomised 12-month open study analysed the effectiveness of quetiapine XR (400-800 mg) versus risperidone (2-6 mg) on subjective well-being in schizophrenia (NCT00600756). Primary objective was to demonstrate non-inferiority of quetiapine XR to risperidone in 6-month responder rate using the Subjective Well-Being under Neuroleptics scale (SWN-K) (per-protocol at Month 6 [PP 6] population). Non-inferiority was defined as the lower limit of the 95% confidence interval (CI) greater than -9.7% for the adjusted difference between quetiapine XR and risperidone. Secondary objectives included non-inferiority of quetiapine XR versus risperidone (lower limit of 95% CI greater than -7.5 points) for SWN-K change from baseline to Month 12 (PP 12). 798 patients were randomised (quetiapine XR, n=395; risperidone, n=403); at Month 12, 212 (54%) and 227 (56%) patients, respectively, completed the study. At Month 6, SWN-K responder rate in the PP 6 population was 65% (136/210) with quetiapine XR and 68% (158/232) with risperidone (adjusted treatment difference: -5.7%; 95% CI: -15.1, 3.7); thus, non-inferiority could not be established. SWN-K change from baseline to Month 12 was 23.2 points for quetiapine XR and 21.1 points for the risperidone group; treatment difference was 2.1 (95% CI: -0.8; 5.0); non-inferiority was established (PP 12). CONCLUSION: SWN-K response at 6 months was comparable between the two antipsychotics. However, with a lower than expected responder rate and a lower than expected number of evaluable patients in the PP 6 population, non-inferiority was not demonstrated. A secondary objective (SWN-K total score) established non-inferiority of quetiapine XR to risperidone at Month 12.
