Abstract
BackgroundIn patients with schizophrenia, early non-response to oral antipsychotic therapy robustly predicts subsequent non-response to continued treatment with the same medication. This study assessed whether early response predicted later response when using a long-acting injection (LAI) antipsychotic.MethodsData were taken from an 8-week, randomized, double-blind, placebo-controlled study of olanzapine LAI in acutely ill patients with schizophrenia (n = 233). Early response was defined as ≥30% improvement from baseline to Week 4 in Positive and Negative Syndrome Scale (PANSS0-6) Total score. Subsequent response was defined as ≥40% baseline-to-endpoint improvement in PANSS0-6 Total score. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and predictive accuracy were calculated. Clinical and functional outcomes were compared between Early Responders and Early Non-responders.ResultsEarly response/non-response to olanzapine LAI predicted later response/non-response with high sensitivity (85%), specificity (72%), PPV (78%), NPV (80%), and overall accuracy (79%). Compared to Early Non-responders, Early Responders had significantly greater improvement in PANSS0-6 Total scores at all time points and greater baseline-to-endpoint improvement in PANSS subscale scores, Quality of Life Scale scores, and Short Form-36 Health Survey scores (all p ≤ .01). Among Early Non-responders, 20% demonstrated response by Week 8. Patients who lacked early improvement (at Week 4) in Negative Symptoms and Disorganized Thoughts were more likely to continue being non-responders at Week 8.ConclusionsAmong acutely ill patients with schizophrenia, early response predicted subsequent response to olanzapine LAI. Early Responders experienced significantly better clinical and functional outcomes than Early Non-responders. Findings are consistent with previous research on oral antipsychotics.Clinical Trials RegistryF1D-MC-HGJZ: Comparison of Intramuscular Olanzapine Depot With Placebo in the Treatment of Patients With Schizophrenia http://clinicaltrials.gov/ct2/show/NCT00088478?term=olanzapine+depot&rank=3Registry identifier - NCT00088478
Highlights
In patients with schizophrenia, early non-response to oral antipsychotic therapy robustly predicts subsequent non-response to continued treatment with the same medication
The total accuracy of predicting later response to olanzapine long-acting injection (LAI) based on early response exceeded that seen in studies of oral antipsychotics, including analyses of patients with chronic schizophrenia,[7]. of patients with first-episode psychosis,[9]. of a prospective study of patients with chronic schizophrenia,[7]. and of 5 pooled studies of patients with chronic schizophrenia [6]. (79% for olanzapine LAI versus 72%, 70%, and 74%, respectively)
Another possible explanation for why the predictive accuracy seen in this study of olanzapine LAI was better than that seen in studies of oral antipsychotics is that with depot formulations, adherence is guaranteed at least through the injection interval
Summary
Early non-response to oral antipsychotic therapy robustly predicts subsequent non-response to continued treatment with the same medication. Most of the symptomatic improvement seen in response to atypical antipsychotic therapy occurs in the first 2 to 4 weeks, with effects seen in some patients in as early as 24 hours [1,2,3]. This finding has important implications for the medical management of acutely ill patients with schizophrenia who, individually, have an unpredictable response to any given antipsychotic. Constant has been the use of oral antipsychotic agents; the predictive strength of early response to depot (injectable) formulations has not yet been evaluated
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