Dong-Jing Fu

Onset of efficacy and tolerability following the initiation dosing of long-acting paliperidone palmitate: post-hoc analyses of a randomized, double-blind clinical trial.

BackgroundPaliperidone palmitate is a long-acting injectable atypical antipsychotic for the acute and maintenance treatment of adults with schizophrenia. The recommended initiation dosing regimen is 234 mg on Day 1 and 156 mg on Day 8 via intramuscular (deltoid) injection; followed by 39 to 234 mg once-monthly thereafter (deltoid or gluteal). These post-hoc analyses addressed two commonly encountered clinical issues regarding the initiation dosing: the time to onset of efficacy and the associated tolerability.MethodsIn a 13-week double-blind trial, 652 subjects with schizophrenia were randomized to paliperidone palmitate 39, 156, or 234 mg (corresponding to 25, 100, or 150 mg equivalents of paliperidone, respectively) or placebo (NCT#00590577). Subjects randomized to paliperidone palmitate received 234 mg on Day 1, followed by their randomized fixed dose on Day 8, and monthly thereafter, with no oral antipsychotic supplementation. The onset of efficacy was defined as the first timepoint where the paliperidone palmitate group showed significant improvement in the Positive and Negative Syndrome Scale (PANSS) score compared to placebo (Analysis of Covariance [ANCOVA] models and Last Observation Carried Forward [LOCF] methodology without adjusting for multiplicity) using data from the Days 4, 8, 22, and 36 assessments. Adverse event (AE) rates and relative risks (RR) with 95% confidence intervals (CI) versus placebo were determined.ResultsPaliperidone palmitate 234 mg on Day 1 was associated with greater improvement than placebo on Least Squares (LS) mean PANSS total score at Day 8 (p = 0.037). After the Day 8 injection of 156 mg, there was continued PANSS improvement at Day 22 (p ≤ 0.007 vs. placebo) and Day 36 (p < 0.001). Taken together with results in the 39 mg and 234 mg Day 8 arms, these findings suggest a trend towards a dose-dependent response. During Days 1 to 7, AEs reported in ≥2% of paliperidone palmitate subjects (234 mg) and a greater proportion of paliperidone palmitate than placebo subjects were: agitation (3.2% vs. 1.3%; RR 2.52 [95% CI 0.583, 10.904]), headache (4.0% vs. 3.8%; RR 1.06 [95% CI 0.433, 2.619]), and injection site pain (6.7% vs. 3.8%; RR 1.79 [95% CI 0.764, 4.208]). Days 8 to 36 AEs meeting the same criteria in the 156 mg Day 8 arm were: anxiety (3.1% vs. 2.5%; RR 1.24 [95% CI 0.340, 4.542]), psychotic disorder (2.5% vs. 1.3%; RR 1.99 [95% CI 0.369, 10.699]), dizziness (2.5% vs. 1.3%; RR 1.99 [95% CI 0.369, 10.699]), and injection site pain (2.5% vs. 1.3%; RR 1.99 [95% CI 0.369, 10.699]). Corresponding Days 8 to 36 AEs in the 39 mg Day 8 group were: agitation (4.5% vs. 4.4%; RR 1.03 [95% CI 0.371, 2.874]), anxiety (3.9% vs. 2.5%; RR 1.55 [95% CI 0.446, 5.381]), and psychotic disorder (2.6% vs. 1.3%; RR 2.07 [95% CI 0.384, 11.110]) while in the 234 mg Day 8 group it was anxiety (3.1% vs. 2.5%, RR 1.25 [95% CI 0.342, 4.570]).ConclusionsSignificantly greater symptom improvement was observed by Day 8 with paliperidone palmitate (234 mg on Day 1) compared to placebo; this effect was maintained after the 156 mg Day 8 injection, with a trend towards a dose-dependent response. No unexpected tolerability findings were noted in the first week or month after the initiation dosing.Trial registrationClinicalTrials.gov: NCT#00590577

Long-acting injectable paliperidone palmitate versus oral paliperidone extended release: a comparative analysis from two placebo-controlled relapse prevention studies

BackgroundIncreasing availability and use of long-acting injectable antipsychotics have generated a need to compare these formulations with their oral equivalents; however, a paucity of relevant data is available.MethodsThis post hoc comparison of the long-term efficacy, safety and tolerability of maintenance treatment with paliperidone palmitate (PP) versus oral paliperidone extended release (ER) used data from two similarly designed, randomised, double-blind (DB), placebo-controlled schizophrenia relapse prevention trials. Assessments included measures of time to relapse, symptom changes/functioning and treatment-emergent adverse events (TEAEs). Time to relapse between treatment groups was evaluated using a Cox proportional hazards model. Between-group differences for continuous variables for change scores during the DB phase were assessed using analysis of co-variance models. Categorical variables were evaluated using Chi-square and Fishers exact tests. No adjustment was made for multiplicity.ResultsApproximately 45% of enrolled subjects in both trials were stabilised and randomised to the DB relapse prevention phase. Risk of relapse was higher in subjects treated with paliperidone ER than in those treated with PP [paliperidone ER/PP hazard ratio (HR), 2.52; 95% confidence interval (CI), 1.46–4.35; p < 0.001]. Similarly, risk of relapse after withdrawal of paliperidone ER treatment (placebo group of the paliperidone ER study) was higher than after withdrawal of PP (paliperidone ER placebo/PP placebo HR, 2.25; 95% CI, 1.59–3.18; p < 0.001). Stabilised schizophrenic subjects treated with PP maintained functioning demonstrated by the same proportions of subjects with mild to no difficulties in functioning at DB baseline and end point [Personal and Social Performance (PSP) scale total score >70, both approximately 58.5%; p = 1.000] compared with a 10.9% decrease for paliperidone ER (58.5% vs 47.6%, respectively; p = 0.048). The least squares mean change for Positive and Negative Syndrome Scale (PANSS) total score at DB end point in these previously stabilised subjects was 3.5 points in favour of PP (6.0 vs 2.5; p = 0.025). The rates of TEAEs and AEs of interest appeared similar.ConclusionsThis analysis supports maintenance of effect with the injectable compared with the oral formulation of paliperidone in patients with schizophrenia. The safety profile of PP was similar to that of paliperidone ER. Future studies are needed to confirm these findings.

Paliperidone palmitate and risperidone long-acting injectable in subjects with schizophrenia recently treated with oral risperidone or other oral antipsychotics.

Video abstract Video

Paliperidone palmitate versus oral risperidone and risperidone long-acting injection in patients with recently diagnosed schizophrenia: a tolerability and efficacy comparison.

Early in the course of illness, patients with schizophrenia may be particularly susceptible to adverse events (AEs). In this post-hoc, subgroup analysis of a 13-week, double-blind, double-dummy, multicenter study, patients recently diagnosed with schizophrenia (⩽5 years) were administered once-monthly flexible-dose paliperidone palmitate (PP) (n=161; initiation doses, 150 mg eq day 1 and 100 mg eq day 8) [PP doses can be expressed as milligram equivalents (mg eq) of paliperidone or as milligrams (mg) of PP. 150 mg eq paliperidone=234 mg PP; 100 mg eq paliperidone=156 mg PP. In the USA, dosing tends to be expressed in mg] or oral risperidone [during initiation of risperidone long-acting injection (RLAI) days 1–28] and biweekly flexible-dose RLAI (n=173; initial injection day 8). Assessments were performed at baseline and days 4, 15, 22, 36, 64, and 92. Because of RLAI’s release profile, data through day 22 correspond to oral risperidone in the RLAI arm. During this period, the AE profile and onset of efficacy of PP and oral risperidone were similar. The overall AE rates at week 13 for PP and RLAI were 54.7 and 50.3%, respectively, for any AE; 11.2 and 8.1% for extrapyramidal symptom–related AEs; and 2.5 and 2.3% for prolactin-related AEs. No significant differences in the mean weight change, most metabolic parameters, or mean efficacy measures were observed at end point. In patients with recently diagnosed schizophrenia, the tolerability and efficacy of PP and RLAI were generally similar over 13 weeks.

Tolerability of initiation doses of once-monthly paliperidone palmitate in patients with recently diagnosed schizophrenia in an acute treatment trial.

Objective: To examine the tolerability of the recommended initiation doses for once-monthly injectable paliperidone palmitate in patients who have recently been diagnosed with schizophrenia and for whom high doses may pose tolerability concerns. Methods: A post hoc analysis from a 13-week double-blind study of patients with schizophrenia randomized 1:1:1:1 to placebo or paliperidone palmitate at 25, 100, or 150 mg equivalents (mg eq) of paliperidone (corresponding to 39, 156, or 234 mg respectively). This analysis focused on the recently diagnosed subgroup (≤5 years; N = 146) who received the recommended initiation dosage of paliperidone palmitate [150 mg eq on day 1 (n = 109) followed by 100 mg eq on day 8 (n = 39)] or placebo (n = 37). Adverse events (AEs), reported in ≥2% of patients receiving paliperidone palmitate during days 1–7 or ≥5% during days 8–36, and in a higher percentage of patients receiving paliperidone palmitate than placebo, were identified. AE relative risks (RRs) and 95% confidence intervals (CIs) were determined. A RR was considered potentially significant when its 95% CI did not include 1. Results: Overall, day 1–7 AE rates were 37.6% (41 of 109) and 29.7% (11 of 37) with paliperidone palmitate and placebo respectively; injection site pain (5.5% versus 2.7%, RR 2.0; 95% CI 0.25 to 16.37), agitation (4.6% versus 2.7%; RR 1.7; 95% CI 0.21 to 14.06), and headache (3.7% versus 0.0%; RR 3.1; 95% CI 0.17 to 56.41) met the ≥2% criteria. Day 8–36 AE rates were 41.0% (16 of 39) and 37.8% (14 of 37) with paliperidone palmitate and placebo respectively; anxiety (5.1% versus 0.0%; RR 4.8; 95% CI 0.24 to 95.76) met the ≥5% criteria. Key limitations were that some patients may have been ill for a significant time before formal diagnosis and that the number of patients is low in this subgroup, limiting the ability to detect statistical significance for AE RRs. Conclusions: Paliperidone palmitate initiation doses (150 mg eq day 1, 100 mg eq day 8) were tolerated in this subgroup of patients who were recently diagnosed with schizophrenia, with no unexpected findings. Although the same size was small, these data identified AEs that may be encountered during the week and month after initiation dosing. These findings may assist clinicians when paliperidone palmitate is considered an appropriate treatment choice for these patients.

Incidence of tardive dyskinesia: a comparison of long-acting injectable and oral paliperidone clinical trial databases.

To assess the tardive dyskinesia (TD) rate in studies of once‐monthly long‐acting injectable (LAI) paliperidone palmitate (PP) and once‐daily oral paliperidone extended release (Pali ER).

Long-term tolerability of once-monthly injectable paliperidone palmitate in subjects with recently diagnosed schizophrenia

Video abstract Video

Management of antipsychotic treatment discontinuation and interruptions using model-based simulations.

Background Medication nonadherence is a well described and prevalent clinical occurrence in schizophrenia. These pharmacokinetic model-based simulations analyze predicted antipsychotic plasma concentrations in nonadherence and treatment interruption scenarios and with treatment reinitiation. Methods Starting from steady state, pharmacokinetic model-based simulations of active moiety plasma concentrations of oral, immediate-release risperidone 3 mg/day, risperidone long-acting injection 37.5 mg/14 days, oral paliperidone extended-release 6 mg/day, and paliperidone palmitate 117 mg (75 mg equivalents)/28 days were assessed under three treatment discontinuation/interruption scenarios, ie, complete discontinuation, one week of interruption, and four weeks of interruption. In the treatment interruption scenarios, pharmacokinetic simulations were performed using medication-specific reinitiation strategies. Results Following complete treatment discontinuation, plasma concentrations persisted longest with paliperidone palmitate, followed by risperidone long-acting injection, while oral formulations exhibited the most rapid decrease. One week of oral paliperidone or risperidone interruption resulted in near complete elimination from the systemic circulation within that timeframe, reflecting the rapid elimination rate of the active moiety. After 1 and 4 weeks of interruption, minimum plasma concentrations were higher with paliperidone palmitate than risperidone long-acting injection over the simulated period. Four weeks of treatment interruption followed by reinitiation resulted in plasma levels returning to predicted therapeutic levels within 1 week. Conclusion Due to the long half-life of paliperidone palmitate (25–49 days), putative therapeutic plasma concentrations persisted longest in simulated cases of complete discontinuation or treatment interruption. These simulations may help clinicians better conceptualize the impact of antipsychotic nonadherence on plasma concentrations, and the impact of medication-specific reinitiation strategies after intermittent nonadherence.

Relationship between the clinical global impression of severity for schizoaffective disorder scale and established mood scales for mania and depression

BACKGROUND This analysis explored the relationship between ratings on HAM-D-17 or YMRS and those on the depressive or manic subscale of CGI-S for schizoaffective disorder (CGI-S-SCA). METHODS This post hoc analysis used the database (N=614) from two 6-week, randomized, placebo-controlled studies of paliperidone ER versus placebo in symptomatic subjects with schizoaffective disorder assessed using HAM-D-17, YMRS, and CGI-S-SCA scales. Parametric and nonparametric regression models explored the relationships between ratings on YMRS and HAM-D-17 and on depressive and manic domains of the CGI-S-SCA from baseline to the 6-week end point. A clinically meaningful improvement was defined as a change of 1 point in the CGI-S-SCA score. No adjustment was made for multiplicity. RESULTS Multiple linear regression models suggested that a 1-point change in the depressive domain of CGI-S-SCA corresponded to an average 3.6-point (SE=0.2) change in HAM-D-17 score. Similarly, a 1-point change in the manic domain of CGI-S-SCA corresponded to an average 5.8-point (SE=0.2) change in YMRS score. Results were confirmed using local and cumulative logistic regression models in addition to equipercentile linking. LIMITATIONS Lack of subjects scoring over the complete range of possible scores may limit broad application of the analyses. CONCLUSION Clinically meaningful score changes in depressive and manic domains of CGI-S-SCA corresponded to approximately 4- and 6-point score changes on HAM-D-17 and YMRS, respectively, in symptomatic subjects with schizoaffective disorder.

Large-scale candidate gene study to identify genetic risk factors predictive of paliperidone treatment response in patients with schizophrenia.

Objective Clinical response to antipsychotic medications can vary markedly in patients with schizophrenia. Identifying genetic variants associated with treatment response could help optimize patient care and outcome. To this end, we carried out a large-scale candidate gene study to identify genetic risk factors predictive of paliperidone efficacy. Patients and methods A central nervous system custom chip containing single nucleotide polymorphisms from 1204 candidate genes was utilized to genotype a discovery cohort of 684 schizophrenia patients from four clinical studies of paliperidone extended-release and paliperidone palmitate. Variants predictive of paliperidone efficacy were identified and further tested in four independent replication cohorts of schizophrenic patients (N=2856). Results We identified an SNP in ERBB4 that may contribute toward differential treatment response to paliperidone. The association trended in the same direction as the discovery cohort in two of the four replication cohorts, but ultimately did not survive multiple testing corrections. The association was not replicated in the other two independent cohorts. We also report several SNPs in well-known schizophrenia candidate genes that show suggestive associations with paliperidone efficacy. Conclusion These preliminary findings suggest that genetic variation in the ERBB4 gene may differentially affect treatment response to paliperidone in individuals with schizophrenia. They implicate the neuregulin 1 (NRG1)–ErbB4 pathway for modulating antipsychotic response. However, these findings were not robustly reproduced in replication cohorts.