Treatment Effects of Olanzapine/Samidorphan on Negative Symptoms in Patients With Schizophrenia: A Post Hoc Analysis

INTRODUCTION: Addressing negative symptoms of schizophrenia can be a treatment challenge. This post hoc analysis examined the long-term effect of the combination of olanzapine and samidorphan (OLZ/SAM) on negative symptoms.
METHODS: All adults who completed a 4-week OLZ/SAM study (olanzapine- and placebo-controlled) for the treatment of acute schizophrenia and who had ≥1 postbaseline visit in a 52-week open-label extension study were analyzed. The 4-week study OLZ/SAM, olanzapine, and placebo arms were combined for this analysis, and all patients received OLZ/SAM during the extension. Negative symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS) Marder Negative Symptoms Factor score (Marder, 1997). Changes from the 4-week study baseline were evaluated overall, in a high baseline negative symptoms (Marder Negative Symptoms Factor score ≥24) subgroup, and in a high negative/low positive symptoms subgroup.
RESULTS: Patients (n=281) had a mean (SD) PANSS Total score of 101.7 (11.1) and Marder Negative Symptoms Factor score of 25.2 (4.6) at baseline. Mean (SE) change from baseline in Marder Negative Symptoms Factor score at week 56 was (–8.5 [0.41], n=183). Among patients with a Marder Negative Symptoms Factor score ≥24 at baseline (mean, 27.7), mean (SE) change in Marder Negative Symptoms Factor Score was –9.8 (0.50) at week 56 (n=124). A similar pattern of change was observed for the high negative symptoms/low positive symptoms subgroup (change at week 56: –8.9 [0.90], n=37).
CONCLUSIONS: This post hoc analysis suggests that OLZ/SAM provides a treatment benefit for negative symptoms of schizophrenia that is observable over long-term therapy.