Optimal thresholds of early response to atypical antipsychotics: application of signal detection methods.
ABSTRACT Identify the optimal magnitude of response to antipsychotic medication at various early time points that best predicts subsequent non-response at 8 weeks.
Data were pooled from 5 randomized, double-blind clinical trials of atypical antipsychotics in the treatment of schizophrenia and related disorders (n=1137 moderately-to-severely ill; n=300 less than moderately ill). Signal detection methods (receiver-operating characteristic curves) were used to identify the optimal response threshold based on percent change from baseline on the PANSS total score at different early time points (Weeks 1-4) to predict subsequent 'non-response' at 8 weeks (i.e., not 'minimally improved', 'much improved' or 'remitted') while holding the false positive rate to a level of 30% or less. Analyses were implemented separately for patients with schizophrenia who differed on baseline illness severity.
Using Area Under the Curve (AUC) >or=0.8 to define optimal discriminative ability at the earliest time point, the early response threshold in moderately-to-severely ill patients for predicting not 'minimally improved' was <15% reduction in PANSS total at Week 2, not 'much improved' was <23% at Week 2, and not 'remitted' was <26% at Week 4. Similarly, in less than moderately ill patients, the optimal early response threshold for predicting not 'minimally improved' was <12% reduction in PANSS total at Week 2, and not 'much improved' was <14% at Week 1.
Specific thresholds of response were identified at early time points for predicting subsequent non-response. Not attaining these early response thresholds may serve as important clinical markers of subsequent non-response to antipsychotic therapy.
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ABSTRACT: The Paliperidone ER Treatment in Acute Intervention (PERTAIN) study was designed to explore treatment response, tolerability, and safety of flexible doses of paliperidone ER in patients with schizophrenia admitted for an acute exacerbation. This paper addresses a secondary analysis of PERTAIN data designed to explore predictors for treatment response, flexible dosing, and concomitant benzodiazepine use. This prospective, multicenter, phase 3b, open-label, single-arm, 6-week study used flexible doses of paliperidone ER (3 to 12mg once daily) to treat patients hospitalized for an acute exacerbation of schizophrenia, reflecting more closely daily clinical practice. Predictive models were evaluated for paliperidone ER flexible dosing, treatment response, and concomitant treatment with benzodiazepines as distinct independent variables. For the analysis of explanatory variables, a stepwise logistic regression was used, taking into account patient age, gender, body mass index, diagnosis and duration of schizophrenia, number of prior hospitalizations, psychotic symptoms (PANSS), disease severity (CGI-S), and patient functioning (PSP) at baseline. Early response (defined as response within 2weeks of treatment initiation) was also used as a predictor. Clinical response (defined as ≥30% decrease in PANSS total score and ≥1 point decrease in CGI-S from baseline to endpoint) was predicted by early clinical response (p<0.001) and there was a trend for the diagnosis of paranoid schizophrenia vs. other types of schizophrenia to predict clinical response (p=0.0525). High response (defined as ≥50% decrease in PANSS total score and ≥2 points decrease in CGI-S from baseline to endpoint) was predicted by early high response, higher baseline CGI-S, or female gender. More severely ill patients with a higher baseline CGI-S were twice likely to be treated concomitantly with a benzodiazepine.Progress in Neuro-Psychopharmacology and Biological Psychiatry 10/2013; · 3.55 Impact Factor
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ABSTRACT: Literature suggests that disease severity and neurotransmitter signaling pathway genes can accurately identify antipsychotic response in schizophrenia patients. However, putative role of signaling molecules has not been tested in schizophrenia patients based on severity of illness, despite its biological plausibility. In the present study we investigated the possible association of polymorphisms from five candidate genes RGS4, SLC6A3, PIP4K2A, BDNF, PI4KA with response to antipsychotic in variably ill schizophrenia patients. Thus in present study, a total 53 SNPs on the basis of previous reports and functional grounds were examined for their association with antipsychotic response in 423 schizophrenia patients segregated into low and high severity groups. Additionally, haplotype, diplotype, multivariate logistic regression and multifactor-dimensionality reduction (MDR) analyses were performed. Furthermore, observed associations were investigated in atypical monotherapy (n = 355) and risperidone (n = 260) treated subgroups. All associations were estimated as odds ratio (OR) and 95% confidence interval (CI) and test for multiple corrections was applied. Single locus analysis showed significant association of nine variants from SLC6A3, PIP4K2A and BDNF genes with incomplete antipsychotic response in schizophrenia patients with high severity. We identified significant association of six marker diplotype ATTGCT/ATTGCT (rs746203-rs10828317-rs7094131-rs2296624-rs11013052-rs1409396) of PIP4K2A gene in incomplete responders (corrected p-value = 0.001; adjusted-OR = 3.19, 95%-CI = 1.46-6.98) with high severity. These associations were further observed in atypical monotherapy and risperidone sub-groups. MDR approach identified gene-gene interaction among BDNF_rs7103411-BDNF_rs1491851-SLC6A3_rs40184 in severely ill incomplete responders (OR = 7.91, 95%-CI = 4.08-15.36). While RGS4_rs2842026-SLC6A3_rs2975226 interacted synergistically in incomplete responders with low severity (OR = 4.09, 95%-CI = 2.09-8.02). Our findings provide strong evidence that diplotype ATTGCT/ATTGCT of PIP4K2A gene conferred approximately three-times higher incomplete responsiveness towards antipsychotics in severely ill patients. These results are consistent with the known role of phosphatidyl-inositol-signaling elements in antipsychotic action and outcome. Findings have implication for future molecular genetic studies as well as personalized medicine. However more work is warranted to elucidate underlying causal biological pathway.PLoS ONE 01/2014; 9(7):e102556. · 3.53 Impact Factor
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ABSTRACT: The present study explores whether ankyrin repeat and kinase domain containing 1 (ANKK1) and dopamine receptor D2 (DRD2) variants could predict efficacy and tolerability of haloperidol in the treatment of psychotic patients. We also attempted to replicate findings in a group of schizophrenic patients from the Clinical Antipsychotic Trials in Intervention Effectiveness (CATIE) study. Eighty-eight acutely psychotic patients were genotyped for 9 ANKK1 and 27 DRD2 SNPs. Treatment efficacy and tolerability were assessed using the Positive and Negative Symptoms Scale and the Udvalg for Kliniske Undersogelser side effects rating scales, respectively. Multivariate analyses were employed to test possible influences of single-nucleotide polymorphisms on clinical and safety variables. Analysis of haplotypes was also performed. Outcomes in the replication sample were response versus nonresponse and the presence versus absence of motor side effects at 1 month of treatment. rs2242592 within ANKK1 gene and rs1124493 within DRD2 gene were associated with clinical improvement (p = 0.008 and p = 0.001, respectively). Results were confirmed in the allelic analysis. Three haplotype blocks, one among ANKK1 and two among DRD2 gene were associated with better clinical improvement. Our results were not replicated in the CATIE sample, although rs11604671, which is in strong linkage disequilibrium with rs2242592, was associated with response in the replication sample. Our findings support a possible role of ANKK1 and DRD2 variability on haloperidol efficacy. However, due to the discrepancies between the results in the two samples, our results need further validation.European Archives of Psychiatry and Clinical Neuroscience 08/2012; · 3.36 Impact Factor