Dosing and Switching Strategies for Paliperidone Palmitate 3-Month Formulation in Patients with Schizophrenia Based on Population Pharmacokinetic Modeling and Simulation, and Clinical Trial Data

Factors Associated with Symptom Stabilization that Allow for Successful Transition from Once-Monthly Paliperidone Palmitate to Three-Monthly Paliperidone Palmitate: A Post Hoc Analysis Examined Clinical Characteristics in Chinese Patients with Schizophrenia

BACKGROUND AND OBJECTIVES

Identifying key factors for a successful transition from once-monthly paliperidone palmitate (PP1M) to three-monthly paliperidone palmitate (PP3M) is crucial for improving treatment outcomes, enhancing patient adherence, and reducing relapse risk in patients with schizophrenia. Providing region-specific insights for evidence-based clinical decisions can aid clinicians in optimizing transition strategies for Chinese patients with schizophrenia. Therefore, the objective of this post hoc analysis of a double-blind parallel-group multicenter phase 3 study (NCT01515423) was to identify factors related to the disease stabilization that may allow for a successful transition from PP1M to PP3M in the treatment of Chinese patients with schizophrenia.

METHODS

Adults (18-70 years) diagnosed with schizophrenia using the Diagnostic and Statistical Manual of Mental Disorders, fourth edition text revision, for over 1 year and with a baseline Positive and Negative Syndrome Scale (PANSS) total score between 70 and 120 were entered into an open-label (OL) phase receiving PP1M for 17 weeks. After the 17-week OL phase, patients who met the criteria necessary for stabilization were randomized (1:1) to PP1M (fixed-dose, 50, 75, 100, or 150 mg eq.) or PP3M (fixed-dose, 175, 263, 350, or 525 mg eq.) in a 48-week double-blind phase. Stabilization was defined as a PANSS total score < 70, PANSS item (P1, P2, P3, P6, P7, G8, G14) scores ≤ 4, and a reduction in Clinical Global Impression Severity (CGI-S) score of ≥ 1 from OL baseline. This post hoc analysis evaluated changes and trends in symptom severity using PANSS, changes in mental states using CGI-S, and changes in personal and social functioning using Personal and Social Performance (PSP) scores from baseline to the endpoint of the OL phase in patients who either met or did not meet the stabilization criteria (stabilized versus non-stabilized group). Comparison of changes and trends in the clinical scores between the stabilized group and non-stabilized group were conducted using linear mixed model and Mann-Kendall trend analysis, respectively. Univariate and multivariate logistic regression analyses were conducted to explore factors associated with stabilization status for transition.

RESULTS

Of 296 patients enrolled, 210 achieved disease stabilization (106 patients and 104 patients were randomized to PP1M and PP3M, respectively). Significant downward trends in the PANSS and CGI-S scores were detected in the stabilized patients (n = 210, ZPANSS = -2.21, p = 0.028; ZCGI-S = -2.21, p = 0.028) but not in the non-stabilized patients (n = 86). No significant trends in the PSP scores were observed in either group. The factors significantly associated with disease stabilization were the CGI-S score at baseline [odds ratio (OR) = 0.22, 95% confidence interval (CI): 0.09, 0.5), reduction of the PANSS score at week 13 (OR = 1.11, 95% CI: 1.06, 1.17), and reduction of CGI-S score at week 13 (OR = 2.27, 95% CI: 1.03, 5.02).

CONCLUSION

A lower CGI-S total score at baseline and greater reductions in PANSS and CGI-S scores at week 13 were associated with patients achieving disease stabilization, that may allow for a successful transition. Evidence from this study indicates that better disease condition at baseline, early functional improvement and symptomatic relief were the key factors associated with disease stabilization. The findings may guide clinicians to identify suitable patients for transition from PP1M to PP3M and further optimize the use of PP3M in China.

CLINICAL TRIALS REGISTRATION

EudraCT number: 2011-004889-15 and ClinicalTrials.gov (identifier: NCT01515423) for the original double-blind randomized study.

Switching from Monthly to Three-Monthly Long-Acting Injectable Paliperidone: A Survey on Subjective Satisfaction and Safety

Introduction

Poor adherence to antipsychotic medication is common in the treatment of schizophrenia and other psychotic disorders. Paliperidone palmitate 3-monthly (PP3M) is the first long-acting injectable (LAI) antipsychotic to allow for only four medication administrations per year, and although there is sufficient information available about the clinical effects, there is relatively limited insight into the subjective experience of people with lived experience.

Methods

This descriptive, cross-sectional survey explored patient's satisfaction and perspectives on the advantages and disadvantages of switching from monthly to 3-monthly paliperidone while also reporting on perceived levels of safety with regard to the reducing dose regimen during the Covid-19 pandemic. Information on discontinuation and hospitalisation rates at one year was also collected from the electronic records.

Results

Of the 46 patients included in the study, the vast majority reported feeling satisfied (89.2%) and safer (93.5%) after switching to the three-monthly formulation. Participants highlighted several advantages of changing to PP3M, most notably convenience (93.5%), improved quality of life (58.7%), decreased stigma (39.1%) and better adherence (28.3%). Furthermore, 93.5% of respondents experienced no disadvantages, while 6.5% described worsening side effects or symptoms. In fact, only one patient discontinued PP3M at one year with the overall number of hospitalisations also reducing in the same period compared to the year before switching.

Discussion

Our findings add to the small, but growing, body of evidence supporting patient satisfaction and acceptance with the use of PP3M and may reinforce the use of less frequent LAIs in clinical practice to enhance individual experience and treatment persistence and decrease levels of stigmatisation.

In silico cancer immunotherapy trials uncover the consequences of therapy-specific response patterns for clinical trial design and outcome

Late-stage cancer immunotherapy trials often lead to unusual survival curve shapes, like delayed curve separation or a plateauing curve in the treatment arm. It is critical for trial success to anticipate such effects in advance and adjust the design accordingly. Here, we use in silico cancer immunotherapy trials - simulated trials based on three different mathematical models - to assemble virtual patient cohorts undergoing late-stage immunotherapy, chemotherapy, or combination therapies. We find that all three simulation models predict the distinctive survival curve shapes commonly associated with immunotherapies. Considering four aspects of clinical trial design - sample size, endpoint, randomization rate, and interim analyses - we demonstrate how, by simulating various possible scenarios, the robustness of trial design choices can be scrutinized, and possible pitfalls can be identified in advance. We provide readily usable, web-based implementations of our three trial simulation models to facilitate their use by biomedical researchers, doctors, and trialists.

Prospective analysis of serum prolactin levels, clinical symptomatology and sexual functions in patients with schizophrenia switched to paliperidone palmitate 3-monthly from paliperidone palmitate 1-monthly: Preliminary findings of the first 3 months

OBJECTIVE

Long-acting injectable (LAI) antipsychotics were developed to improve adherence to schizophrenia treatment. Paliperidone palmitate (PP) has two LAI forms: Monthly (PP1M) and three-monthly (PP3M). PP3M shows less difference in Peak-to-Trough drug concentration levels. This could be related to a lower incidence of hyperprolactinemia, which may negatively affect adherence. We aimed to compare prolactin levels and investigate relationships between prolactin levels, symptomatology and sexual function in patients with schizophrenia after switching from PP1M to PP3M.

METHODS

Twenty-five patients were enrolled. The sociodemographic data form, the Positive and Negative Syndromes Scale (PANSS) and the Arizona Sexual Experience Scale (ASEX) were used. Morning blood samples were drawn to determine prolactin levels.

RESULTS

Prolactin level (p < 0.001), the total score and arousal sub-score of ASEX (respectively; p = 0.015, p = 0.020) and the total score and positive scale of PANSS (respectively; p = 0.017, p = 0.021) were decreased on the 90th day (±15 days).

CONCLUSIONS

After switching to PP3M, the decreases in prolactin levels and potentially related sexual side effects was statistically significant. There may be a difference between two formulations of the same drug in terms of side effects, and there is a need for prospective follow-up studies with larger samples.

How to handle the delayed or missed dose of rivaroxaban in patients with non-valvular atrial fibrillation: model-informed remedial dosing

BACKGROUND

Rivaroxaban is an oral anticoagulant widely used for stroke prevention in patients with non-valvular atrial fibrillation (NVAF). During long-term anticoagulant therapy, delayed or missed doses are common. This study aimed to explore appropriate remedial dosing regimens for non-adherent rivaroxaban-treated patients.

METHODS

Monte Carlo simulation based on a previously established rivaroxaban population pharmacokinetic/pharmacodynamic (PK/PD) model for patients with NVAF was employed to design remedial dosing regimens. The proposed regimens were compared with remedial strategies in the European Heart Rhythm Association (EHRA) guide by assessing deviation time in terms of drug concentration, factor Xa activity, and prothrombin time.

RESULTS

The proposed remedial dosing regimens were dependent on delay duration. The missed dose should be taken immediately when the delay does not exceed 6 h; a half dose is advisable when the delay is between 6 and 20 h. A missed dose should be skipped if less than 4 h remains before the next dose. The proposed regimens resulted in shorter deviation time than that of the EHRA guide.

CONCLUSION

PK/PD modeling and simulation provide valid evidence on the remedial dosing regimen of rivaroxaban, which could help to minimize the risk of bleeding and thromboembolism.

Defining "Adequately Treated": A Post Hoc Analysis Examining Characteristics of Patients with Schizophrenia Successfully Transitioned from Once-Monthly Paliperidone Palmitate to Once-Every-3-Months Paliperidone Palmitate

PURPOSE

Paliperidone palmitate once every 3 months (PP3M) is indicated in adults with schizophrenia adequately treated with once-monthly paliperidone palmitate (PP1M) for at least 4 months, in whom the last two consecutive doses are the same. The decision of when to transition to PP3M is based on the patient's symptom status while receiving PP1M.

PATIENTS AND METHODS

In a double-blind relapse-prevention study (NCT01529515), patients who met Positive and Negative Syndrome Scale (PANSS) score stabilization criteria after 4 months of PP1M were eligible for transition to PP3M; those who continued to meet stabilization criteria after 12 weeks following an open-label PP3M dose were randomized to receive PP3M or placebo. We compared (post hoc) PANSS, Clinical Global Impression-Severity (CGI-S), and Personal and Social Performance (PSP) scores during the pre-randomization, open-label phase in patients in randomized versus non-randomized groups using analysis of variance or chi-square tests.

RESULTS

Of 506 patients enrolled, 305 were randomized. After 4 months' PP1M treatment, PANSS and CGI-S scores were significantly lower and PSP scores significantly higher in randomized patients versus non-randomized patients (least squares means [95% CI]: 57.1 [55.7, 58.6] vs 62.2 [60.0, 64.3], 2.9 [2.8, 3.1] vs 3.3 [3.1, 3.4], and 67.0 [65.7, 68.3] vs 64.5 [62.6, 66.4], respectively); changes from baseline between groups differed significantly (all P ≤0.009).

CONCLUSION

Confirming adequate stabilization with PP1M prior to transitioning to PP3M is critical in maximizing treatment response; clinicians should consider transitioning patients to PP3M only if patients respond well to PP1M for at least 4 months and their last two consecutive doses are the same.

Pharmacokinetic-Pharmacodynamic Characterization of Relapse Risk for Paliperidone Palmitate 1-Month and 3-Month Formulations

BACKGROUND

Pharmacokinetic-pharmacodynamic (PK/PD) models were developed to describe the relationship between the time course of paliperidone plasma concentrations and the risk of relapse of schizophrenia symptoms following administration of paliperidone palmitate 1-month (PP1M) and 3-month (PP3M) long-acting injectables, and to identify relevant covariates for relapse and dropout events.

METHODS

Patient data from two global phase 3, relapse prevention studies comparing PP3M to placebo (study A) and PP3M to PP1M (study B) were analyzed. Dropout and relapse data were assessed using survival analysis as two separate single time-to-event models. Baseline covariates included age, sex, race/country, duration of illness, previous hospitalizations, prior use of long-acting injectables and use of multiple (≥2) antipsychotics at screening.

RESULTS

The PK/PD analysis data set included 305 patients who were randomized to receive PP3M or placebo in the double-blind phase of study A and 1002 patients randomized to receive PP3M or PP1M in the double-blind phase of study B. Risk of relapse decreased with increasing paliperidone concentrations for both PP1M and PP3M, while it appeared to increase in patients with higher number of previous hospitalizations and/or with higher prerandomization (trough) paliperidone concentration (study A), and in patients on concomitant benzodiazepine medication and/or at Japan centers (study B). These findings are reflective of different illness severity in the population and of differences in medical practice for Japanese patients. In model-based simulations, PP3M and PP1M displayed similar relapse rates over time.

CONCLUSIONS

This PK/PD analysis confirmed that PP1M and PP3M provide comparable efficacy in terms of relapse prevention, and that PP3M is superior to placebo. The PK/PD models presented here may as well be applied to studies with similar designs as either study A or B.

The current data on the 3-month paliperidone palmitate formulation for the treatment of schizophrenia

INTRODUCTION

A three-month injection of paliperidone palmitate (PP3M) has been gradually introduced in the market since 2015. Recently, and due to different reasons, there is an increase in the LAIAs prescription rates, including patients in early phases of psychotic disorders. Areas covered: The following article provides an overview of the antipsychotic market before providing the reader with an overview of the efficacy and tolerability data of the 3-month paliperidone palmitate formulation for the treatment of schizophrenia. The authors take into account the current state of knowledge, as well as the needs not covered by other therapeutic tools at our disposal at this time. Expert opinion: PP3M offers a substantially longer dosing interval than other options, which may be a potential advancement to reduce nonadherence in some patients. Future research, both from randomized controlled trials and large pragmatic studies in real-world settings, will identify which subpopulation and disease stages may obtain greater benefit from this new formulation.

Maintenance dose conversion between oral risperidone and paliperidone palmitate 1 month: Practical guidance based on pharmacokinetic simulations

AIM

We assessed the dosage strengths of paliperidone palmitate 1-month (PP1M) long-acting injectable resulting in similar steady-state (SS) exposures to the dosage strengths of oral risperidone using pharmacokinetic (PK) simulations.

METHODS

Population PK simulations of SS PK were performed using the PK models of oral risperidone and PP1M. The concentrations of active moiety (risperidone + paliperidone) from risperidone were compared to paliperidone concentrations resulting from PP1M administration. Similarity was assessed via graphical evaluation of median and 90% prediction intervals of SS PK profiles over 28 days.

RESULTS

Oral risperidone doses of 1, 2, 3, 4, and 6 mg/d are expected to result in similar SS PK as PP1M doses of 25, 50, 75, 100, and 150 mg eq. (which correspond to 39, 78, 117, 156, and 234 mg of paliperidone palmitate) respectively (ie 25-fold dose conversion factor from oral risperidone to PP1M).

CONCLUSIONS

This study provides clinicians with a practical guidance to establish suitable maintenance dose levels of PP1M and oral risperidone when transitioning patients from one formulation to another.

Long-Acting Injectable Second-Generation Antipsychotics: An Update and Comparison Between Agents

Schizophrenia is a chronic medical condition with periods of remission and relapses over a patient's lifetime. Antipsychotic medications represent the mainstay of treatment for this disease. Long-acting injectable (LAI) formulations of antipsychotics are an attractive alternative to their oral counterparts, as they enhance patient adherence. A number of second-generation antipsychotics (SGAs) are available in LAI formulations. These include paliperidone, aripiprazole, olanzapine, and risperidone. This article reviews the most recently developed and approved of these formulations-aripiprazole monohydrate, aripiprazole lauroxil, and paliperidone palmitate. While all were initially available as once-monthly formulations, a paliperidone palmitate 3-monthly injection formulation has been approved and is the first LAI agent to extend the dosing administration beyond the typical monthly time period. In addition, aripiprazole lauroxil every 6-week and 8-week administration preparations have been developed. LAI preparations of the SGAs have all demonstrated superiority over placebo and are comparable to their oral counterparts in terms of safety and tolerability, if injection site reactions are not taken into account. First-generation antipsychotic LAI preparations (e.g., haloperidol decanoate) have recently been compared with SGA LAI agents, and both formulations demonstrated comparable efficacy with the expected adverse events seen with each drug. Despite their availability, barriers to the use of LAIs remain. Education of both patients and clinicians on the use of LAI formulations and the continued development of these agents are important steps in ensuring these medications are available to the patients they would be most likely to benefit.