Calibrated meta-analysis to estimate the efficacy of mental health treatments in target populations: an application to paliperidone trials for treatment of schizophrenia

BACKGROUNDS

Meta-analyses can be a powerful tool but need to calibrate potential unrepresentativeness of the included trials to a target population. Estimating target population average treatment effects (TATE) in meta-analyses is important to understand how treatments perform in well-defined target populations. This study estimated TATE of paliperidone palmitate in patients with schizophrenia using meta-analysis with individual patient trial data and target population data.

METHODS

We conducted a meta-analysis with data from four randomized clinical trials and target population data from the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) study. Efficacy was measured using the Positive and Negative Syndrome Scale (PANSS). Weights to equate the trial participants and target population were calculated by comparing baseline characteristics between the trials and CATIE. A calibrated weighted meta-analysis with random effects was performed to estimate the TATE of paliperidone compared to placebo.

RESULTS

A total of 1,738 patients were included in the meta-analysis along with 1,458 patients in CATIE. After weighting, the covariate distributions of the trial participants and target population were similar. Compared to placebo, paliperidone palmitate was associated with a significant reduction of the PANSS total score under both unweighted (mean difference 9.07 [4.43, 13.71]) and calibrated weighted (mean difference 6.15 [2.22, 10.08]) meta-analysis.

CONCLUSIONS

The effect of paliperidone palmitate compared with placebo is slightly smaller in the target population than that estimated directly from the unweighted meta-analysis. Representativeness of samples of trials included in a meta-analysis to a target population should be assessed and incorporated properly to obtain the most reliable evidence of treatment effects in target populations.

Paliperidone palmitate as model of heat-sensitive drug for long-acting 3D printing application

In this work, two technologies were used to prepare long-acting implantable dosage forms in the treatment of schizophrenia. Hot-melt extrusion (HME) as well as fused deposition modelling (FDM) were used concomitantly to create personalized 3D printed implants. Different formulations were prepared using an amorphous PLA as matrix polymer and different solid-state plasticizers. Paliperidone palmitate (PP), a heat sensitive drug prescribed in the treatment of schizophrenia was chosen as model drug. After extrusion, different formulations were characterized using DSC and XRD. Then, an in vitro dissolution test was carried out to discriminate the formulation allowing a sustained drug release of PP. The formulation showing a sustained drug release of the drug was 3D printed as an implantable dosage form. By modulating the infill, the release profile was related to the proper design of tailored dosage form and not solely to the solubility of the drug. Indeed, different release profiles were achieved over 90 days using only one formulation. In addition, a stability test was performed on the 3D printed implants for 3 months. The results showed the stability of the amorphous state of PP, independently of the temperature as well as the integrity of the matrix and the drug.

Paliperidone Palmitate-Induced Delirium in an Adolescent with Schizophrenia: Case report

Schizophrenia is a serious long-term mental disorder which usually presents in adolescence or early adulthood. However, poor adherence to oral antipsychotics can lead to relapse and rehospitalisation. We report an adolescent male with schizophrenia who was referred to the South London & Maudsley National Health Service Foundation Trust, London, UK, in 2015 due to worsening psychotic symptoms. Following poor compliance with oral medications, a four-week regimen of paliperidone palmitate long-acting injections was initiated, with an initial positive response. However, 10 days after the second dose, the patient developed severe acute-onset delirium with fluctuating levels of consciousness. Paliperidone palmitate was discontinued and the patient instead underwent a course of zuclopenthixol decanoate long-acting injections with a favourable outcome.

An open-treatment six-week study of the clinical effectiveness of Paliperidone Palmitate in schizophrenia: data from acute units in Spain (SHADOW study)

OBJECTIVES

To evaluate clinical evolution of patients with schizophrenia admitted in acute units because of a relapse and treated with once-monthly Paliperidone Palmitate (PP1M).

METHODS

This multicentre, open-label, prospective observational study followed patients with schizophrenia treated with PP1M in acute psychiatric units for up to 6 weeks.

RESULTS

Out of the 280 enrolled patients, 61 received PP1M as antipsychotic monotherapy, and 219 in combination with other antipsychotics. The average Clinical Global Impression-Schizophrenia (CGI-SCH) score decreased from 4.7 at baseline to 3.3 at final visit (p < .0001); the change was clinically and statistically significant both in patients treated with PP1M in monotherapy and in combination with other antipsychotics. Clear improvements in functioning and high patient satisfaction with the treatment were observed. Time from admission to PP1M therapy initiation correlated with the length of hospital stay (p < .0001); earlier start of PP1M treatment was associated with shorter hospital stay. Adverse events were reported in 7.1% of patients (all non-serious).

CONCLUSIONS

PP1M was effective and well tolerated in treatment of acute episodes of schizophrenia both in monotherapy and in combination with other antipsychotics in clinical setting. Early start of PP1M therapy in acute schizophrenia episodes might help to shorten hospital stay.

Paliperidone palmitate versus risperidone long-acting injection in markedly-to-severely ill schizophrenia subjects: onset of efficacy with recommended initiation regimens

OBJECTIVE

To examine onset of efficacy of two long-acting injectable atypical antipsychotics in markedly-to-severely ill schizophrenia subjects.

METHODS

This subgroup analysis included 292 subjects with baseline Clinical Global Impressions-Severity scores of markedly ill or worse from a 13-week, randomized, double-dummy noninferiority study (NCT00589914). Subjects received either: 1) paliperidone palmitate (PP; 234 mg day 1 and 156 mg day 8 [corresponding to 150 and 100 milligram equivalents of paliperidone, respectively], both administered in deltoid muscle, followed by once-monthly flexible dosing in deltoid or gluteal muscle) and risperidone long-acting injection (RLAI)-matched placebo injections; or, 2) RLAI (25 mg, days 8 and 22; followed by biweekly flexible dosing) and PP-matched placebo injections. RLAI subjects received oral risperidone days 1-28; PP subjects received oral placebo. Because of RLAI's release profile, data through day 22 correspond to oral risperidone. Assessments included Positive and Negative Syndrome Scale (PANSS) and adverse event (AE) reports. Paired t-tests assessed within-group changes.

RESULTS

LS mean (SE) PANSS total scores improved significantly (both p<.001) with PP and oral risperidone by day 4 (-5.0 [0.6] and -3.4 [0.6], respectively) through day 22; and with PP and RLAI through end point (-21.5 [1.9] and -18.6 [1.9], respectively). The between-group difference was significant only at day 4 (p=.006). Proportion of subjects with a .30% reduction in PANSS total score was not significantly different between the two groups at day 4 and was significantly greater with paliperidone palmitate than oral risperidone at days 15 and 22 (26.1% versus 12.7%, p=.013; 41.6% versus 32.0%, p=.048, respectively). Most common AEs (.5% in either treatment group): headache (PP 6.3% and RLAI 14.0%), insomnia (10.6% and 10.7%), somnolence (7.8% and 1.3%), akathisia (7.0% and 5.3%), schizophrenia (8.5% and 5.3%), agitation (5.6% and 2.0%), and injection site pain (5.6% and 1.3%).

CONCLUSIONS

Using the recommended dosing regimens for PP and RLAI, both PP and oral risperidone (used during RLAI initiation) improved symptoms of schizophrenia in markedly-to-severely ill subjects at days 4-22.