Extrapyramidal adverse events and anticholinergics use after the long-term treatment of patients with schizophrenia with the new long-acting antipsychotic Risperidone ISM®: results from matching-adjusted indirect comparisons versus once-monthly formulations of Paliperidone palmitate and Aripiprazole monohydrate in 52-week studies.

Background: Risperidone ISM^® is a newly developed long-acting injectable (LAI) treatment for schizophrenia in adults. In the absence of head-to-head comparisons with other similar antipsychotics, the objective of this study was to generate indirect evidence of some aspects of the safety and tolerability of Risperidone ISM compared to other LAI antipsychotics for treatment of patients with schizophrenia in the maintenance treatment setting.

Methods: A literature review was conducted systematically to identify maintenance treatment studies reporting safety and tolerability outcomes for LAI antipsychotic therapies. Following an assessment of between-trial heterogeneity, a matching-adjusted indirect comparison (MAIC) was performed to account for between-trial imbalances in patient characteristics and to generate comparative evidence for safety and tolerability endpoints.

Results: The analysis showed that incidence of extrapyramidal symptoms (EPS) was found to be numerically, but not statistically significantly, lower in patients receiving Risperidone ISM than in those receiving Paliperidone palmitate (PP) (OR [95% CI] 0.63 [0.29, 1.38], p = 0.253) and statistically significantly lower than with Aripiprazole monohydrate once-monthly (AOM) (OR [95% CI] 0.25 [0.12, 0.53], p < 0.001). Use of anticholinergic agents for the alleviation of EPS was also shown to be significantly lower in Risperidone ISM patients than in those receiving PP (OR [95% CI] 0.29 [0.10, 0.83], p = 0.021) or AOM (OR [95% CI] 0.01 [0.003, 0.06], p < 0.001), suggesting a superior tolerability profile for clinically relevant EPS. Results from the sensitivity analyses comparing stabilized and stable patients receiving Risperidone ISM to those receiving AOM yielded similarly favorable conclusions in line with the base case analyses.

Conclusions: This MAIC is consistent with the safety and tolerability results obtained during the PRISMA-3 clinical trial in the long-term treatment of schizophrenia and suggests a favorable safety and tolerability profile in terms of EPS incidence and anticholinergic agent use, relative to other antipsychotic therapies used for treatment of patients with schizophrenia in the maintenance setting.