Clinical Trial Response and Dropout Rates with Olanzapine versus Risperidone

Abstract

BACKGROUND: In schizophrenia, comparing treatment dropouts between olanzapine and risperidone can be useful to better understand their relative effectiveness. OBJECTIVE: To analyze the differences in the rates of dropout from clinical trials and response between these 2 antipsychotics. METHODS: Literature search was based on MEDLINE (1966–May 2002). Analysis 1 included 4 randomized studies (838 patients), analysis 2 included 2 randomized studies (n = 716), and analysis 3 assessed 5 clinical studies for olanzapine (n = 928) and 3 for risperidone (n = 290). Odds ratios were estimated by the fixed-effect model. RESULTS: The risk of treatment discontinuation (analysis 1) was significantly greater for risperidone than for olanzapine (42% vs. 33%, respectively). The response rates were identical for the 2 drugs (analysis 2). A slightly better pattern of maintenance of response was found for olanzapine (analysis 3). CONCLUSIONS: The pattern of dropout and maintenance of remission seems to be better controlled for olanzapine than for risperidone.