How do clinical trial participants compare to other patients with schizophrenia?

Can multisite clinical trial results change clinical practice? Use of long-acting injectable risperidone nationally in the Veterans Health Administration

BACKGROUND

Multisite practical clinical trials evaluate treatments in real-world practice. A multisite randomized Veterans Health Administration (VHA) cooperative study (CSP#555) published in 2011 compared the first long-acting injectable (LAI) second-generation antipsychotic (SGA), Risperidone Consta®, in veterans with a diagnosis of schizophrenia or schizoaffective disorder, to oral antipsychotics, with unexpected null results for effectiveness and cost-effectiveness. Whether null results of this type could change VHA practice has not been studied.

METHODS

A longitudinal observational analysis was used to evaluate the impact of the trial findings on VHA clinical practices. National administrative data compared new starts on LAI risperidone during the 4 years before the publication of CSP#555 in 2011 to new starts on LAI risperidone during the 4 years after.

RESULTS

Among 119,565 Veterans with the indicated diagnoses treated with antipsychotics from 2007 to 2015, the number and proportion of new starts on LAI risperidone declined significantly following the study publication, as did the total number of annual users and drug expenditures. However, data from 2007 to 2010 showed the decline in new starts actually preceded the publication of CSP#555. This change was likely explained by the increase in new starts, total use, and expenditures on a newer medicine, LAI paliperidone, a 4-week LAI treatment, in the 2 years prior to the publication of CSP#555.

CONCLUSIONS

The declining use of LAI risperidone likely primarily reflects the substitution of a longer-acting LAI SGA, paliperidone, that came to market 2 years before the study publication, a substitution that may have been reinforced by null CSP#555 study results for LAI risperidone.

Representativeness of clinical PET study participants with schizophrenia: A systematic review

While positron emission tomography (PET) studies have provided invaluable data on antipsychotic effects, selection bias remains a serious concern. A systematic review of PET studies that measured dopamine D₂ receptor blockade with antipsychotics was conducted to examine their inclusion/exclusion criteria, using PubMed, EMBASE, and ClinicalTrials.gov (last search, September 2016). PET studies were included if they measured D₂ receptor occupancy in patients with schizophrenia and included introduction of antipsychotic treatment or antipsychotic regimen change in a systematic manner. Twenty-six studies were identified. Age limit was included in 13 studies; one study solely included geriatric patients while others targeted younger adults. Eleven, 6, and 3 studies specifically targeted clinically stable patients, patients with severe psychopathology, and antipsychotic-free patients, respectively. Nineteen and 18 studies excluded patients with physical comorbidity and substance abuse, respectively. As a result, the mean age of subjects ranged from 23 to 42 years when one study that targeted geriatric patients was excluded. Mean Positive and Negative Syndrome Scale total scores ranged from 54 to 95. No comparison active-drug or placebo arm was employed in 24 studies. Blind assessment of symptomatology was performed in 5 studies. In general, subjects participating in clinical PET studies were relatively young, presented with mild symptomatology, and were free from substance abuse or physical comorbidities. These characteristics need to be taken into account when clinical PET data are interpreted. On the other hand, it should also be noted that this study was only qualitative and conservative interpretation is necessary for possibility of subjective bias.

Comparison of clinical outcomes with orodispersible versus standard oral olanzapine tablets in nonadherent patients with schizophrenia or bipolar disorder

PURPOSE

Medication nonadherence is common in the treatment of patients with severe mental illness and is a frequent cause of relapse. Different formulations have been developed in an effort to improve medication adherence. The aim of this study was to explore whether there are differential clinical outcomes between two different formulations of olanzapine (orodispersible tablets [ODTs] vs standard oral tablets [SOT]) for the treatment of nonadherent patients with schizophrenia or bipolar disorder.

METHODS

Data for this analysis were from an observational study conducted in Europe (N=903). Adult schizophrenia and bipolar disorder patients in outpatient settings who initiated or changed to either olanzapine ODT or SOT according to physician decision within the last 45 days were eligible for enrollment. The follow-up period was 1 year. Of the 903 participants, 266 nonadherent patients (Medication Adherence Rating Scale score 0-4 at baseline) were included in the analysis. Clinical outcomes of interest were: 1) hospitalization and 2) relapse identified by the participating psychiatrist or hospitalization. An adjusted logistic regression model was fitted.

RESULTS

Patients taking ODT had more severe illness at baseline (P<0.001) as assessed with the Clinical Global Impression with mean (standard deviation [SD]) scores of ODT 4.63 (1.03) and SOT 4 (1.16). In the regression models adjusted for potential confounders, patients taking ODT had significantly lower odds for hospitalization (odds ratio =0.355; 95% confidence interval =0.13-0.974) and relapse or hospitalization (odds ratio =0.368; 95% confidence interval =0.183-0.739), respectively.

CONCLUSION

Nonadherent patients with schizophrenia or bipolar disorder treated with the orodispersible formulation were less likely to be hospitalized or suffer relapse compared to those patients taking the standard oral coated tablets.

Validation of an economic model of paliperidone palmitate for chronic schizophrenia

OBJECTIVE

Model validation is important, but seldom applied in chronic schizophrenia. Validation consists of verifying the model itself for face validity (i.e., structure and inputs), cross-validation with other models assessing the same issue, and comparison with real-life outcomes. The primary purpose was to cross-validate a recent pharmacoeconomic model comparing long-acting injectable (LAI) antipsychotics for treating chronic schizophrenia in Sweden. The secondary purpose was to provide external validation.

METHODS

The model of interest was a decision tree analysis with a 1-year time horizon with costs in 2011 Swedish kroner. Drugs analyzed included paliperidone palmitate (PP-LAI), olanzapine pamoate (OLZ-LAI), risperidone (RIS-LAI), haloperidol (HAL-LAI), and oral olanzapine (oral-OLZ). Embase and Medline were searched from 1990-2012 for models examining LAIs. Articles were retrieved, with data extracted for all drugs compared including: expected costs, rates of hospitalization, proportion of time not in relapse, and associated QALYs. Outcomes from the model of interest were compared with those from other articles; costs were projected to 2012 using the consumer price index.

RESULTS

Twenty-six studies were used for validation; 14 of them provided evidence for cross-validation, 13 for external validation, and four for cost. In cross-validation, cost estimates varied -1.8% (range: -12.4-20.1%), hospitalizations 5.2% (-12.1-3.1%), stable disease 2.5% (-5.6-1.5%), QALYs 9.0% (4.3% after removing outliers). All estimates of clinical outcomes were within 15%. In external validation, hospitalization rates varied by 6.3% (-0.7-11.3%). The research was limited by data availability and validity of the original results.

CONCLUSION

Other models validated the outputs of our model very well.

Veteran subjects willingness to participate in schizophrenia clinical trials

Predictive characteristics of subjects agreeing to be randomized into clinical trials for the treatment of schizophrenia and schizoaffective disorder have been little studied. In this study, we used data from the recruitment phase of a randomized trial that compared long acting injectable (LAI) risperidone to oral antipsychotic medications. Basic socio-demographic and clinical data were gathered from eligible patients and clinicians at the time of screening for trial entry. Bivariate comparisons and multivariate logistic regression were used to compare those who agreed to participate and those who refused. Altogether 446 veterans were eligible on preliminary screening, of these 382 (86 %) agreed to participate and 64 (14 %) declined. Eligible patients who agreed to be randomized were more willing to change medications without regard to their level of satisfaction with their current medication. Subjects reported as currently taking LAI medication and taking risperidone, in particular, were more likely to agree to participate. Factors that did not significantly predict participation included age, years on current medication, reported medication compliance, race, and gender. Veterans with schizophrenia or schizoaffective disorder who were actually more satisfied with their current medications and who were currently taking the experimental agent were more likely to agree to participate in this randomized clinical trial in contrast to expectations that individuals who are unsatisfied with their current treatment would be more likely to enroll in such studies.

The cost effectiveness of long-acting/extended-release antipsychotics for the treatment of schizophrenia: a systematic review of economic evaluations

BACKGROUND

Antipsychotic medication is the mainstay of treatment in schizophrenia. Long-acting medication has potential advantages over daily medication in improving compliance and thus reducing hospitalization and relapse rates. The high acquisition and administration costs of such formulations raise the need for pharmacoeconomic evaluation.

OBJECTIVE

The aim of this article is to provide a comprehensive review of the available evidence on the cost effectiveness of long-acting/extended-release antipsychotic medication and critically appraise the strength of evidence reported in the studies from a methodological viewpoint.

METHODS

Relevant studies were identified by searching five electronic databases: PsycINFO, MEDLINE, EMBASE, the NHS Economic Evaluation Database and the Health Technology Assessment database (HTA). Search terms included, but were not limited to, 'long-acting injection', 'economic evaluation', 'cost-effectiveness' and 'cost-utility'. No limits were applied for publication dates and language. Full economic evaluations on long-acting/extended-release antipsychotics were eligible for inclusion. Observational studies and clinical trials were also checked for cost-effectiveness information. Conference abstracts and poster presentations on the cost effectiveness of long-acting antipsychotics were excluded. Thirty-two percent of identified studies met the selection criteria. Pertinent abstracts were reviewed independently by two reviewers. Relevant studies underwent data extraction by one reviewer and were checked by a second, with any discrepancies being clarified during consensus meetings. Eligible studies were assessed for methodological quality using the quality checklist for economic studies recommended by the NICE guideline on interventions in the treatment and management of schizophrenia.

RESULTS

After applying the selection criteria, the final sample consisted of 28 studies. The majority of studies demonstrated that risperidone long-acting injection, relative to oral or other long-acting injectable drugs, was associated with cost savings and additional clinical benefits and was the dominant strategy in terms of cost effectiveness. However, olanzapine in either oral or long-acting injectable formulation dominated risperidone long-acting injection in a Slovenian and a US study. Furthermore, in two UK studies, the use of long-acting risperidone increased the hospitalization days and overall healthcare costs, relative to other atypical or typical long-acting antipsychotics. Finally, paliperidone extended-release was the most cost-effective treatment compared with atypical oral or typical long-acting formulations. From a methodological viewpoint, most studies employed decision analytic models, presented results using average cost-effectiveness ratios and conducted comprehensive sensitivity analyses to test the robustness of the results.

LIMITATIONS

Variations in study methodologies restrict consistent and direct comparisons across countries. The exclusion of a large body of potentially relevant conference abstracts as well as some papers being unobtainable may have increased the likelihood of misrepresenting the overall cost effectiveness of long-acting antipsychotics. Finally, the review process was restricted to qualitative assessment rather than a quantitative synthesis of results, which could provide more robust conclusions.

CONCLUSIONS

Atypical long-acting (especially risperidone)/extended-release antipsychotic medication is likely to be a cost-effective, first-line strategy for managing schizophrenia, compared with long-acting haloperidol and other oral or depot formulations, irrespective of country-specific differences. However, inconsistencies in study methodologies and in the reporting of study findings suggest caution needs to be applied in interpreting these findings.