Switching patients with stable schizophrenia or schizoaffective disorder from olanzapine to risperidone long-acting injectable.

BACKGROUND: Patients with schizophrenia or related disorders often switch antipsychotic therapy, most commonly due to lack of efficacy and side effects. The differences in anticipated efficacy and tolerability among atypical antipsychotics may drive switching behaviours. Switching to long-acting antipsychotics may improve adherence. Improving adherence is essential as relatively short medication gaps significantly increase the risk of schizophrenia hospitalizations. Long-term treatment with risperidone long-acting injectable (RLAI), the first available long-acting atypical antipsychotic, versus oral atypical antipsychotics showed better adherence with RLAI. Stable patients with schizophrenia or related disorders treated with a stable dose of antipsychotic showed improved efficacy when switched to flexible doses of RLAI. The most common reason for patients to switch from olanzapine to another antipsychotic is excessive weight gain. Metabolic dysfunction also occurs more commonly with olanzapine than with risperidone. Patients switching from olanzapine to risperidone experienced significant decreases in body weight, body mass index and triglyceride levels, whereas patients switching from risperidone to olanzapine experienced significant increases in body weight and triglyceride levels. The efficacy, tolerability and safety of RLAI in non-acute patients with schizophrenia or schizoaffective disorder previously treated with oral olanzapine needs to be explored.

OBJECTIVE: The objective of this study was to evaluate the efficacy, tolerability and safety of switching from oral olanzapine to RLAI.

METHODS: This was a six-month, prospective, multicentre, non-randomized, single-arm, open-label trial. The trial evaluated non-acute adult patients with psychotic disorders treated with a stable olanzapine dose who required a treatment change. Three weeks after RLAI initiation, olanzapine was tapered off over 1 week or 3 weeks. Efficacy and safety measures included the Positive and Negative Syndrome Scale (PANSS), the Clinical Global Impression-Severity (CGI-S), Global Assessment of Functioning (GAF) and treatment-emergent adverse events (TEAEs).

RESULTS: Among 96 patients analysed, significant endpoint efficacy changes versus baseline were observed for PANSS, CGI-S and GAF (all p<0.0001). PANSS total score improvement was ≥20% for 65.6% of patients and ≥50% for 31.3%. TEAEs were similar in the 1- and 3-week taper groups (40.0% and 46.5%, respectively). TEAEs were generally mild (34.5%) or moderate (49.0%) in intensity.

CONCLUSION: Switching non-acute patients with schizophrenia or schizoaffective disorder requiring a treatment change from a stable dose of oral olanzapine to RLAI improved psychiatric symptom control, functioning and patient treatment satisfaction. RLAI was generally well tolerated.

CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT00216632.