PMH2 EARLY RESPONSE PREDICTS SUBSEQUENT RESPONSE TO OLANZAPINE LONG-ACTING INJECTIONS IN THE TREATMENT OF SCHIZOPHRENIA

Abstract

Objective: Early non-response to oral antipsychotics was previously shown to be a robust predictor of subsequent non-response to continued treatment with the same oral antipsychotic medication in the treatment of schizophrenia. This study assessed whether early response or early non-response to treatment can serve as a clinical marker in the treatment of schizophrenia with an atypical antipsychotic in long-acting injection formulation (depot). Methods: This post-hoc analysis used data (n=233) from an 8-week randomized, double-blind, placebocontrolled study of olanzapine long-acting injection (olanzapine LAI) in the treatment of inpatients with schizophrenia. Early response to olanzapine LAI was defined as a ≥30% improvement on the PANSS total score (items scored 0-6) from baseline to 4 weeks of treatment. Subsequent response was defined as a ≥40% improvement on the PANSS total score from baseline to endpoint. Predictive accuracy was assessed by calculating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall predictive accuracy. Early responders and early nonresponders to olanzapine LAI were also compared on change in clinical and functional outcome measures. Results: Early response/non-response to olanzapine LAI, assessed following 4 weeks of treatment, predicted subsequent response/nonresponse with a high level of overall accuracy (79%), sensitivity (85%), specificity (72%), PPV (78%), and NPV (80%). Compared to early nonresponders, early responders had significantly longer time to all-cause treatment discontinuation, greater symptom improvement at all time points (per PANSS total and subscale scores), and greater improvement in quality of life and level of social functioning (all at p≤.01). Conclusions: In this study of inpatients with schizophrenia, early response to olanzapine LAI was found to be a robust predictor of subsequent response to the medication. Early responders experienced significantly better clinical and functional outcomes compared to early nonresponders and had longer treatment duration. Current findings are consistent with previous research on oral antipsychotics and will require replication in future studies.