Pharmacokinetics, safety, and tolerability of paliperidone palmitate 3-month formulation in patients with schizophrenia: A phase-1, single-dose, randomized, open-label study

Model-Informed Clinical Development of 6-Monthly Injection of Paliperidone Palmitate in Patients with Schizophrenia: Dosing Strategies Guided by Population Pharmacokinetic Modeling and Simulation (Part II)

BACKGROUND AND OBJECTIVE

Paliperidone palmitate 6-month (PP6M) intramuscular (IM) injection is the longest-acting treatment available for patients with schizophrenia. A population pharmacokinetic (popPK) modeling and simulation approach was deployed to inform dosing strategies for PP6M.

METHODS

The extensive analysis database included 15,932 paliperidone samples from 700 patients receiving gluteal paliperidone palmitate 3-month (PP3M) or PP6M injections in the double-blind phase of a phase-3 noninferiority study (NCT03345342). Exposure parameters for paliperidone appeared to increase dose-proportionally within each dosing schedule (PP3M/PP6M). The range of paliperidone exposures after IM administration of PP6M overlaps with that of corresponding doses of oral paliperidone extended release, PP 1-month (PP1M), and PP3M. Model-based simulations were performed to investigate paliperidone exposures in different PP6M dosing scenarios and relevant subpopulations.

RESULTS

A dosing window of ≤ 2 weeks earlier and ≤ 3 weeks later than the target 6-month interval for maintenance treatment with PP6M dosing maintains paliperidone exposures at levels that are not expected to substantially impact its safety and efficacy. For missed-dose scenarios, tailored re-initiation regimens are proposed that should be applied before resuming PP6M maintenance dosing. Regarding subpopulations, PP6M 700 mg eq. is the highest dose recommended in mild renal-impairment patients; the paliperidone pharmacokinetics after PP6M administration is not affected by sex, body mass index, or age in a clinically meaningful way.

CONCLUSION

Paliperidone concentration-time profiles after PP6M and PP3M dosing were adequately described by the popPK model. Model-based simulation results provide guidance for clinicians on initiating PP6M therapy, transitioning between paliperidone formulations, the dosing windows to use for maintenance dosing, and managing missed PP6M doses.

Evaluating the 6-month formulation of paliperidone palmitate: a twice-yearly injectable treatment for schizophrenia in adults

INTRODUCTION

Paliperidone Palmitate is the only antipsychotic that has been developed in three different intramuscular long-acting injectable (LAI) dosing regimen: monthly (PP1M), quarterly (PP3M), and from 2020 also twice-yearly (PP6M). The latter was approved for the maintenance treatment of adults with schizophrenia and clinically stabilized with PP1M or PP3M.

AREAS COVERED

Data from studies evaluating efficacy in the maintenance treatment of schizophrenia with PP6M are reviewed. Since no post-marketing safety studies are currently available, data from spontaneous reporting system databases, FAERS and Eudravigilance, are analyzed and the reported treatment-emergent adverse events of PP6M are discussed.

EXPERT OPINION

The efficacy of PP6M is comparable to that of PP3M in terms of relapses prevention in patients with schizophrenia previously stabilized on PP3M or PP1M. Also, the maintenance of clinical efficacy in the long term has been demonstrated. Data from pharmacovigilance analyses, as well as from phase 3 studies, show that PP6M is generally well tolerated, consistently with PP3M safety data. PP6M allows a longer dosing interval than any other LAI antipsychotics, potentially reducing nonadherence and disease relapses. In future, an increase in the prescription rates of PP6M is expected and real-world efficacy and tolerability studies will be conducted.

Prodrugs as empowering tools in drug discovery and development: recent strategic applications of drug delivery solutions to mitigate challenges associated with lead compounds and drug candidates

The delivery of a drug to a specific organ or tissue at an efficacious concentration is the pharmacokinetic (PK) hallmark of promoting effective pharmacological action at a target site with an acceptable safety profile. Sub-optimal pharmaceutical or ADME profiles of drug candidates, which can often be a function of inherently poor physicochemical properties, pose significant challenges to drug discovery and development teams and may contribute to high compound attrition rates. Medicinal chemists have exploited prodrugs as an informed strategy to productively enhance the profiles of new chemical entities by optimizing the physicochemical, biopharmaceutical, and pharmacokinetic properties as well as selectively delivering a molecule to the site of action as a means of addressing a range of limitations. While discovery scientists have traditionally employed prodrugs to improve solubility and membrane permeability, the growing sophistication of prodrug technologies has enabled a significant expansion of their scope and applications as an empowering tool to mitigate a broad range of drug delivery challenges. Prodrugs have emerged as successful solutions to resolve non-linear exposure, inadequate exposure to support toxicological studies, pH-dependent absorption, high pill burden, formulation challenges, lack of feasibility of developing solid and liquid dosage forms, first-pass metabolism, high dosing frequency translating to reduced patient compliance and poor site-specific drug delivery. During the period 2012-2022, the US Food and Drug Administration (FDA) approved 50 prodrugs, which amounts to 13% of approved small molecule drugs, reflecting both the importance and success of implementing prodrug approaches in the pursuit of developing safe and effective drugs to address unmet medical needs.

Long-Acting Injectable Antipsychotic Treatment for Schizophrenia in Asian Population: A Scoping Review

Evidence of comparative benefits of long-acting injectable (LAI) antipsychotics in Asian patients with schizophrenia has been inconsistent. This scoping review aimed to synthesize the current evidence in the past ten years and provide an overview of efficacy, safety, treatment adherence, patient attitudes, and healthcare resource utilization of LAI in this population. A systematic search was conducted with a pre-defined search strategy in six electronic databases including Chinese National Knowledge Infrastructure (CNKI), Wanfang, PubMed, Embase, CINAHL, and PsycArticles. A total of 46 studies were included, including 15 cohort studies, 13 single-arm trials, 10 randomized controlled trials, four mirror-image studies, three cross-sectional studies, and one controlled clinical trial. Paliperidone palmitate once-monthly injection (27/46) and risperidone LAI (14/46) were the most frequently investigated LAIs. Compared with oral antipsychotic medications (OAMs), LAIs demonstrated a lower rate of relapse/hospitalization and comparable improvement in efficacy. Adverse events (AEs) were similar between LAIs and OAMs, although types and incidence varied. Significant reduction in the length of hospitalization and number of outpatient visits/inpatient admission was observed after initiation of LAIs. These findings suggest that LAI demonstrated comparable efficacy and safety among Asian populations with schizophrenia in comparison to OAMs. Better adherence and lower relapse were observed in patients receiving LAIs from published evidence. Future research is warranted to better understand the comprehensive performance of LAI in specific population or context.

Implementing gradual, hyperbolic tapering of long-acting injectable antipsychotics by prolonging the inter-dose interval: an in silico modelling study

Gradual, hyperbolic tapering has been proposed as a method to reduce the risk of withdrawal effects and potential relapse of an underlying condition by minimising disruption of existing equilibria. We applied hyperbolic tapering principles in silico to long-acting aripiprazole to generate regimens for withdrawal in clinical practice. We derived thresholds for taper rates using existing studies and consensus. Using pharmacokinetic data for aripiprazole long-acting injectable antipsychotic (ALAI), we conducted in silico modelling to examine the impact of abrupt cessation of long-acting injectable antipsychotic (LAI) medication and the effect of prolonging inter-dose interval on plasma aripiprazole levels and consequent D2 occupancy. We also modelled transitions from LAI medication to oral medication. Regimens were designed to afford a rate of reduction between 5 and 12.5 percentage points of D2 occupancy per month. Abrupt discontinuation of ALAI was shown to lead to a maximal D2 occupancy reduction of 16.8 percentage points per month; prolongation of the inter-dose interval of ALAI produced a slower reduction. Specifically, hyperbolic tapering was afforded by prolongation of a 400 mg ALAI inter-dose interval from 4 to 7 weeks, before reducing the dose to 300 mg ALAI. This could then be administered at up to 4-week (for 6% maximal D2 occupancy change), 6-week (9% change) or 7-week (11% change) intervals. Switching to oral medication - 5, 2.5 and 1.25 mg for the three regimens, respectively - is required for ALAI to complete full cessation to prevent too rapid a reduction in D2 occupancy. Oral medication should probably be maintained at a consistent dose for 3-6 months before further reductions to account for residual LAI being concurrently eliminated. Hyperbolic dose tapering is possible with ALAI through prolongation of the inter-dose interval and may reduce the risk of relapse compared to abrupt discontinuation of LAI medication.

Cumulative Clinical Experience of the Use of Paliperidone Palmitate 3-Monthly Long-Acting Injection in the Treatment of Schizophrenia: A Critical Appraisal

Paliperidone palmitate 3-monthly (PP3M), an approved maintenance treatment for patients with schizophrenia, was the first long-acting antipsychotic injectable (LAI) to require only four administrations per year. Here, we aimed to review the available evidence about its use in the management of schizophrenia to date and highlight key study findings in order to provide a balanced overview of current experience in clinical practice. For that purpose, an extensive search of available literature from PubMed, Embase, and Web of Science was conducted in March 2023. Emerging data from real-world studies appear to signal that the benefits of the use of PP3M may well extent beyond the obvious convenience for patients and resource efficiency for services and may be actually associated with improved effectiveness and patient satisfaction. Large naturalistic studies from Australia, Europe and the US comparing treatment continuation between newer LAIs and/or oral antipsychotics showed that patients treated with PP3M had higher compliance rates and a longer period of continuous use. The risk of relapse, re-hospitalization and number of bed days was also lower with PP3M compared to PP1M and other LAIs as demonstrated by several cohort studies. Furthermore, patients treated with PP3M were using lower doses of benzodiazepines and concomitant oral antipsychotics compared with other LAIs. What is more, PP3M appears to positively impact patients' satisfaction and quality of life, facilitating long-term goals. In fact, recent studies recorded better quality-adjusted life years and decreased stigma, with improved social acceptability and promotion of rehabilitation for patients transitioning to PP3M. The rates of general satisfaction rates with PP3M were also higher among psychiatrists and caregivers who reported overall less concerns. In conclusion, clinical exposure and a growing body of evidence thus far, reinforce the use of PP3M in an effort to enhance patient outcomes alongside individual experience and treatment persistence.

Long-Term Efficacy and Safety of Paliperidone 6-Month Formulation: An Open-Label 2-Year Extension of a 1-Year Double-Blind Study in Adult Participants With Schizophrenia

BACKGROUND

Paliperidone palmitate 6-month (PP6M) demonstrated noninferiority to paliperidone palmitate 3-month in preventing relapse in patients with schizophrenia in a phase 3 double-blind (DB) study (NCT03345342). Here, we report long-term efficacy and safety results from a 2-year single-arm, open-label extension (OLE; NCT04072575) of this DB study.

METHODS

Participants who completed the DB study without relapse were enrolled and followed-up every 3 months up to 2 years. Participants received 4 PP6M gluteal injections (700/1000 mg eq.) at baseline, 6-month, 12-month, and 18-month visits. Efficacy endpoints included assessment of relapse, Positive and Negative Syndrome Scale total score, Personal and Social Performance score, and Clinical Global Impression-Severity scale change from baseline. Safety was assessed by treatment-emergent adverse events (TEAEs), physical examinations, and laboratory tests.

RESULTS

Of 178 participants enrolled, 154 (86.5%) completed the OLE (mean age: 40.4 years, men: 70.8%; mean duration of PP6M exposure during OLE: 682.1 days). Overall, 7/178 (3.9%) participants relapsed between 20 and 703 days after enrolment. Mean (SD) changes from baseline to endpoint were as follows: Positive and Negative Syndrome Scale total score, 0.7 (8.22); Clinical Global Impression-Severity, 0.0 (0.51); and Personal and Social Performance Scale, 0.5 (7.47). Overall, 111/178 participants (62.4%) reported ≥1 TEAE; most common (>5%) TEAEs were headache (13.5%) and increased blood prolactin/hyperprolactinemia (18.0%); 8/178 (4.5%) participants experienced serious TEAEs, and 6/178 (3.4%) participants withdrew due to TEAEs. No deaths were reported.

CONCLUSIONS

The relapse rate observed with PP6M during the 2-year OLE was low (3.9%). Clinical and functional improvements demonstrated in the DB study were maintained during OLE, and no new safety concerns were identified.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04072575; EudraCT number: 2018-004532-30.

A Retrospective Analysis of Preclinical and Clinical Pharmacokinetics from Administration of Long-Acting Aqueous Suspensions

Administration of long-acting injectable suspensions is an increasingly common approach to increasing patient compliance and improving therapeutic efficacy through less frequent dosing. While several long-acting suspensions have recently been marketed, parameters modulating drug absorption from suspension-based formulations are not well understood. Further, methods for predicting clinical pharmacokinetic data from preclinical studies are not well established. Together, these limitations hamper compound selection, formulation design and formulation selection through heavy reliance on iterative optimization in preclinical and clinical studies. This article identifies key parameters influencing absorption from suspension-based formulations through compilation and analysis of preclinical and clinical pharmacokinetic data of seven compounds marketed as suspensions; achievable margins for predicting the clinical dose and input rate from preclinical studies as a function of the preclinical species, the clinical injection location and the intended therapeutic duration were also established.

Long-acting antipsychotics in the treatment of schizophrenia: opportunities and challenges

INTRODUCTION

Maintenance antipsychotic treatment improves multiple outcomes in people with schizophrenia. These benefits are challenged by medication nonadherence, which is a common occurrence. Long-acting injectable antipsychotic (LAI) formulations were developed to reduce nonadherence and thereby improve outcomes. This narrative review is based on a PubMed search (January 2000 - August 2022) for studies on LAI antipsychotics.

AREAS COVERED

Opportunities and challenges associated with LAIs are reviewed. Advantages, compared to oral antipsychotics (OAs), include improved adherence, reduced relapse and hospitalization risk, delayed and lower relapse risk after stopping treatment, and the ability to differentiate true treatment resistance from 'pseudo'-resistance. Additionally, LAIs are associated with lower all-cause mortality than OAs. LAIs are under-used in many services, partly reflecting negative attitudes, misconceptions, and lack of knowledge among clinicians, patients, and carers. Practical barriers to LAI use include acquisition costs and inadequate service structures to administer/monitor LAI treatment.

EXPERT OPINION

The education and engagement of clinicians, patients and caregivers can assist more informed decision-making regarding LAIs. Future research regarding LAIs should encompass multiple complementary designs, focus on functionality and recovery outcomes, and include groups at high risk of relapse, including those with comorbid substance use disorders and early in the course of schizophrenia.

Tolerability profile of paliperidone palmitate formulations: A pharmacovigilance analysis of the EUDRAVigilance database

Introduction

Long-acting injectable antipsychotics (LAIs) have proven to be effective in the maintenance treatment of patients suffering from schizophrenia, and their safety and tolerability profiles represent a key factor in their long-term use and choice in clinical practice. Paliperidone palmitate (PP) is the only second-generation LAI (SGA-LAI), available in both one- (PP1M) and 3-month (PP3M) formulations. However, real-world prospective studies on PP1M and PP3M are still few and mostly conducted on small samples. In this context, we aimed to better define the safety and tolerability profile of PP using real world pharmacovigilance data.

Methods

We retrospectively analyzed the publicly available data regarding Individual Case Safety Reports (ICSRs), presenting PP1M and/or PP3M as suspected drugs, reported on EUDRAVigilance between 2011 and June 30th, 2022. ICSRs relative to at least one SGA-LAI other than PP, reported between 2003 and June 30th, 2022, were also examined as reference group. Data were evaluated with a descriptive analysis, and then, as disproportionality measures, crude reporting odds ratio (ROR) and 95% confidence interval (CI) were calculated.

Results

A total of 8,152 ICSRs met the inclusion criteria, of those 77.7% (n = 6,332) presented as suspected drug PP1M, 21.2% (n = 1,731) PP3M, while 89 cases indicated both PP1M and PP3M. Significantly higher probabilities of reporting in PP-related reports were observed for the primary Standardized MedDRA Queries "Sexual Dysfunctions" (ROR = 1.45; 95% CI 1.23-1.70), "Haemodynamic oedema, effusions and fluid overload" (ROR = 1.42; 1.18-1.70), as well as "Fertility disorders" (ROR = 2.69; 1.51-4.80).

Discussion

Our analysis indicates that the tolerability and safety profiles of PP are in line with what is known for the other SGA-LAIs. However, differences regarding endocrine system ADRs have been noticed. The results presented in this work do not discourage the prescription of SGA-LAI formulations but aim to enhance their safety.

Convolution-based approach for modeling the paliperidone extended release and Long-Acting Injectable (LAI) PK of once-, and three-monthly products administration and for optimizing the development of new LAI products

The aim of this paper was to develop a convolution-based modeling approach for describing the paliperidone PK resulting from the administration of extended-release once-a-day oral dose, and once- and three monthly long-acting injectable products and to compare the performances of this approach to the traditional modeling strategy. The results of the analyses indicated that the traditional and convolution-based models showed comparable performances in the characterization of the paliperidone PK. However, the convolution-based approach showed several appealing features that justify the choice of this modeling as a preferred tool for modeling Long Acting Injectable (LAI) products and for deploying an effective model-informed drug development process. In particular, the convolution-based modeling can (a) facilitate the development of in vitro/in vivo correlation, (b) be used to identify formulations with optimal in vivo release properties, and (c) be used for optimizing the clinical benefit of a treatment by supporting the implementation of integrated models connecting in vitro and in vivo drug release, in vivo drug release to PK, and PK to PD and biomarker endpoints. A case study was presented to illustrate the benefits and the flexibility of the convolution-based modeling outcomes. The model was used to evaluate the in vivo drug release properties associated with a hypothetical once-a-year administration of a LAI product with the assumption that the expected paliperidone exposure during a 3-year treatment overlays the exposure expected after repeated administrations of a 3-month LAI product.

Pharmacokinetics of Long-Acting Aqueous Nano-/Microsuspensions After Intramuscular Administration in Different Animal Species and Humans-a Review

Formulating aqueous suspensions is an attractive strategy to incorporate poorly water-soluble drugs, where the drug release can be tailored to maintain desired release profiles of several weeks to months after parenteral (i.e., intramuscular or subcutaneous) administration. A sustained drug release can be desirable to combat chronic diseases by overcoming pill fatigue of a daily oral intake, hence, improving patient compliance. Although the marketed aqueous suspensions for intramuscular injection efficiently relieve the daily pill burden in chronic diseases, the exact drug release mechanisms remain to be fully unraveled. The in vivo drug release and subsequent absorption to the systemic circulation are influenced by a plethora of variables, resulting in a complex in vivo behavior of aqueous suspensions after intramuscular administration. A better understanding of the factors influencing the in vivo performance of aqueous suspensions could advance their drug development. An overview of the potential influential variables on the drug release after intramuscular injection of aqueous suspensions is provided with, where possible, available pharmacokinetic parameters in humans or other species derived from literature, patents, and clinical trials. These variables can be categorized into drug substance and formulation properties, administration site properties, and the host response towards drug particles. Based on the findings, the most critical factors are particle size, dose level, stabilizing excipient, drug lipophilicity, gender, body mass index, and host response.

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.

Predictors of Lack of Relapse After Random Discontinuation of Oral and Long-acting Injectable Antipsychotics in Clinically Stabilized Patients with Schizophrenia: A Re-analysis of Individual Participant Data

OBJECTIVE

To quantify the risk and predictors of relapse among individuals with schizophrenia randomly withdrawn from antipsychotic maintenance treatment.

METHODS

We re-analyzed time-to-event and baseline predictors from placebo arms in five placebo-controlled randomized trials of antipsychotics (n = 688 individuals; 173 stabilized on oral antipsychotic [OAP] and 515 on long-acting injectables [LAI]) for relapse-prevention available in the Yale Open Data Access repository. Using a survival and Cox-proportional hazards regression analyses, we estimated survival rates of "relapse-free" individuals by the end of follow-up (median = 118 days, IQR = 52.0-208.0), the rate of study-confirmed relapse, and adjusted hazard ratios (aHR, 95% confidence intervals [CI]) associated with baseline predictors. We also estimated these parameters for individuals followed for >5 half-lives of the stabilizing antipsychotic, and studied predictors of "rebound psychosis" in OAP-stabilized participants, defined as occurring within 30 days of antipsychotic withdrawal.

RESULTS

29.9% (95%CI = 23.2-38.5) remained relapse-free by the end of follow-up, 11.1% (95%CI = 5.65-21.9) among those OAP-stabilized, 36.4% (95%CI = 28.4-46.7) among those LAI-stabilized. The study-confirmed relapse rate was 45.2%, 62.4% among those OAP-stabilized and 39.4% among those LAI-stabilized. Predictors of relapse included smoking (aHR = 1.54, 95%CI = 1.19-2.00), female sex (aHR = 1.37, 95%CI = 1.08-1.79), and having been stabilized on OAPs vs LAIs (aHR = 3.56, 95%CI = 2.68-4.72). Greater risk of relapse on OAP persisted even after sufficient time had elapsed to clear antipsychotic plasma level among LAI-stabilized (aHR = 5.0, 95%CI = 3.5-7.1). "Rebound psychosis" did not show predictors.

CONCLUSIONS AND RELEVANCE

Our results corroborate the high relapse risk following antipsychotic withdrawal after symptom stabilization with limited patient-related predictors of safe treatment discontinuation. Stabilization with LAIs reduces the short-/medium-term relapse risk.

The Switch From Paliperidone Long-Acting Injectable 1- to 3-Monthly: Clinical Pharmacokinetic Evaluation in Patients With Schizophrenia (Preliminary Data)

PURPOSE/BACKGROUND

The aim of the study was a preliminary evaluation of the maintenance of clinical efficacy and tolerability of paliperidone palmitate in patients with schizophrenia during the transition phase from 1-monthly paliperidone palmitate formulation (PP1M) to PP3M, with the evaluation of plasma levels of the drug.

METHODS/PROCEDURES

A prospective observational study was conducted for 13 months involving 22 outpatients, aged 18 to 66 years and clinically stabilized. Patients were affected by schizophrenia according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, criteria. For each patient, clinical assessment, safety and tolerability, and drug plasma level determination were performed. Clinical efficacy was assessed by Brief Psychiatric Rating Scale, Positive and Negative Symptom Scale, and Hamilton Rating Scale for Depression. During the first 4 months of the study, once-monthly paliperidone palmitate was administered, and then during the following 9 months, the 3-monthly formulation was administered.

FINDINGS/RESULTS

The time course of the Brief Psychiatric Rating Scale total scores showed a statistically significant (P = 0.006) improvement from T0 to T8; Positive and Negative Symptom Scale scores showed a similar time course, with a statistically significant (P = 0.0016) reduction of the mean total score; Hamilton Rating Scale for Depression mean scores showed a statistically significant (P = 0.003) reduction with substantial maintenance of clinical stabilization of the patients. Only 1 patient dropped out after the first PP3M injection.

IMPLICATIONS/CONCLUSIONS

Our preliminary data currently confirm the maintenance of clinical stability shifting from PP1M to PP3M.

Review of Pharmacokinetics and Pharmacogenetics in Atypical Long-Acting Injectable Antipsychotics

Over the last two decades, pharmacogenetics and pharmacokinetics have been increasingly used in clinical practice in Psychiatry due to the high variability regarding response and side effects of antipsychotic drugs. Specifically, long-acting injectable (LAI) antipsychotics have different pharmacokinetic profile than oral formulations due to their sustained release characteristics. In addition, most of these drugs are metabolized by CYP2D6, whose interindividual genetic variability results in different metabolizer status and, consequently, into different plasma concentrations of the drugs. In this context, there is consistent evidence which supports the use of therapeutic drug monitoring (TDM) along with pharmacogenetic tests to improve safety and efficacy of antipsychotic pharmacotherapy. This comprehensive review aims to compile all the available pharmacokinetic and pharmacogenetic data regarding the three major LAI atypical antipsychotics: risperidone, paliperidone and aripiprazole. On the one hand, CYP2D6 metabolizer status influences the pharmacokinetics of LAI aripiprazole, but this relation remains a matter of debate for LAI risperidone and LAI paliperidone. On the other hand, developed population pharmacokinetic (popPK) models showed the influence of body weight or administration site on the pharmacokinetics of these LAI antipsychotics. The combination of pharmacogenetics and pharmacokinetics (including popPK models) leads to a personalized antipsychotic therapy. In this sense, the optimization of these treatments improves the benefit–risk balance and, consequently, patients’ quality of life.

Pharmacokinetic Correlates of Once-Monthly Paliperidone Palmitate-Related Adverse Drug Reactions

OBJECTIVE

The objective of this study was to investigate associations between pharmacokinetic correlates and once-monthly paliperidone palmitate (PP1M)-related adverse drug reactions (ADRs).

METHODS

Plasma concentrations and dose-adjusted plasma concentrations ('concentration-by-dose' [C/D]) of paliperidone from a naturalistic therapeutic drug monitoring database of PP1M-treated patients were compared between patients with ADRs, classified according to the Udvalg for Kliniske Undersogelser side-effect rating scales categories, and patients without ADRs. Analyses included non-parametric tests and a logistic regression model with a significance level set at 0.05.

RESULTS

In 172 patients, we found no differences in sex, age, smoking, body mass index, PP1M dose, paliperidone plasma concentrations, and C/D values (p > 0.05) between 44 patients with and 128 patients without PP1M-related ADRs. We did not detect differences when specifying for different types of ADRs (p > 0.05). Injection intervals were shorter in patients with vs patients without ADRs (p = 0.03). The logistic regression did not report effects for sex, plasma concentrations, or C/D values (p > 0.05). Post hoc analyses in male patients receiving PP1M every 28 weeks reported higher paliperidone concentrations and C/D values in patients with vs without ADRs (p = 0.049 and p = 0.022). Within the group of male patients, we found an odds ratio of 3.07 for PP1M-associated ADRs in patients with C/D values above 7.7 (ng/mL)/(mg/day).

CONCLUSIONS

Our findings did not reveal distinct patterns of paliperidone concentrations in patients with PP1M-related ADRs. However, male patients receiving PP1M every 28 days with C/D values higher than 7.7 (ng/mL)/(mg/day) showed a higher risk for ADRs, implying that therapeutic drug monitoring may be useful in assessing the risk of PP1M-related ADRs.

Paliperidone Palmitate Every Three Months (PP3M) 2-Year Treatment Compliance, Effectiveness and Satisfaction Compared with Paliperidone Palmitate-Monthly (PP1M) in People with Severe Schizophrenia

Paliperidone palmitate every three months (PP3M) is expected to facilitate patient's treatment compliance and satisfaction. The objective here was to compare PP3M treatment compliance and satisfaction, effectiveness and tolerability, with paliperidone palmitate-monthly (PP1M) in patients with severe schizophrenia. A 24-month prospective, open-label study of patients with severe schizophrenia treated with PP3M after at least 2 years of stabilization with PP1M (n = 84) was carried out. Treatment satisfaction was assessed with the Treatment Satisfaction Questionnaire for Medication (TSQM) and with a Visual Analogue Scale (VAS). Effectiveness was measured with psychiatric hospital admissions and the Clinical Global Impression-Severity (CGI-S) scale. Tolerability assessments included laboratory tests, weight and adverse effects. Reasons for treatment discontinuation were recorded. CGI-S significantly improved after 24 months. Three patients changed back to PP1M due to adverse effects, and four were hospitalized. There were neither abandoning nor significant changes in weight or biological parameters, and lower incidence of side effects, with PP3M treatment. TSQM and VAS scales increased. No differences were found related to doses. Apart from somewhat improvement in treatment adherence, effectiveness, and tolerability, patients with severe schizophrenia lengthy treated with PP1M showed more satisfaction with PP3M, even those who needed high doses to get clinical stabilization.

Long-acting injectable antipsychotics: what, when, and how

Current guidelines for the treatment of patients with schizophrenia advocate that patients receive treatment with a long-acting injectable (LAI) antipsychotic medication if they prefer such treatment or if they have a history of poor or uncertain adherence. Available LAI formulations in the United States include first-generation antipsychotics (fluphenazine decanoate and haloperidol decanoate), risperidone/paliperidone containing products (risperidone microspheres, paliperidone palmitate, and risperidone subcutaneous), aripiprazole containing products (aripiprazole monohydrate and aripiprazole lauroxil), and olanzapine pamoate. LAI antipsychotics can address the guesswork about adherence status and patients may prefer them if they are offered this as a choice, including individuals early in their disease course. Additional approved indications in the United States for LAI antipsychotics include bipolar I disorder maintenance treatment for risperidone microspheres and aripiprazole monohydrate, and schizoaffective disorder for paliperidone palmitate once monthly. Differences and similarities among the different products are discussed, including guidance regarding optimal treatment selection. Tips are provided to enhance effective patient communication to maximize the likelihood of acceptance of this treatment modality.

Impact of Formulation Parameters on In Vitro Release from Long-Acting Injectable Suspensions

The development of long-acting injectable (LAI) suspension products has increased in recent years. A better understanding of the relationship between the physicochemical properties of these products and their in vitro as well as in vivo performance is expected to further facilitate their development and regulatory review. Using Depo-SubQ Provera 104® as the reference listed drug (RLD), four qualitatively and quantitatively (Q1/Q2) equivalent LAI suspensions with different formulation properties were prepared. Two recrystallization methods (solvent evaporation and antisolvent) were utilized to obtain active pharmaceutical ingredient (API) with different properties and solid-state characterization was performed. In addition, two different sources of the major excipient were used to prepare the Q1/Q2 equivalent suspensions. Physiochemical characterization and in vitro release testing of the prepared Q1/Q2 equivalent suspension formulations and the RLD were conducted. In vitro drug release was dependent not only on the particle size, the morphology, and the crystallinity of the API but also on the residual solvent in the API. The excipient source also affected the drug release rates.

Fatal and life-threatening ADRs associated with paliperidone palmitate: an observational study in the French pharmacovigilance database

INTRODUCTION

Paliperidone palmitate (PP), a long-acting intramuscular formulation of paliperidone, has been marketed in Europe within the last 10 years and provides an important treatment option for patients with schizophrenia.Our aim was to describe PP-related adverse drug reactions (ADRs) leading to death or life-threatening events, specifying their main clinical and pharmacological characteristics.

METHODS

This observational study was a retrospective review of PP-related ADRs in the French pharmacovigilance database between January 1, 2013, and December 31, 2019.

RESULTS

Out of 473 PP-related ADRs, we identified 13 deaths and 14 life-threatening events. ADRs were primarily cardiorespiratory (n = 17; 63%). Other symptoms observed were mainly metabolic (n = 4), digestive (n = 4), and neurological (n = 4). Cardiorespiratory symptoms were generally observed within first 6 months after initiation of treatment (11 out of 17 cases), unlike metabolic disorders (all 4 cases 12-21 months after initiation). Cardiac arrests and sudden unexpected deaths occurred 10-14 days after the last PP once-monthly injection (23 cases) or 11-24 days after the last PP three-monthly injection (remaining 4 cases). No PP blood concentration assays were performed for these patients.

DISCUSSION

In this study, PP-related ADRs leading to death or life-threatening events mainly presented with cardiorespiratory symptoms and tended to occur in the first 6 months after the initiation of treatment and within postadministration periods aligned with peak plasma PP concentrations. The hypothesis of supratherapeutic drug concentrations following intramuscular PP injection must be raised.

CONCLUSION

PP-related ADRs leading to death or life-threatening events mainly presented with cardiorespiratory symptoms. Cardiac arrests and sudden unexpected deaths following initiation of PP treatment could be due to supratherapeutic drug concentrations. This study highlights the need to monitor blood concentrations of PP.Key pointsAdverse reactions to paliperidone palmitate can lead to death or life-threatening events.It is hypothesized that cardiac arrests and sudden unexpected deaths following initiation of paliperidone palmitate treatment could be due to supratherapeutic drug concentrations.This paper proposes the need to monitor blood concentrations of paliperidone palmitate in future studies.

Paliperidone 3-Month Injection for Treatment of Schizophrenia: A Narrative Review

Given the typical age onset of schizophrenia, there are tremendous economic and social impacts that extend beyond the person and their families. One critical determinant of the diseases' impact is the patient's adherence to antipsychotic drug treatment. Approved in 2015 for the treatment of schizophrenia, paliperidone palmitate (Invega Trinza, a 3-month injection, noted as PP3M) is a second-generation long-acting injectable antipsychotic medication. Among the different formulations offered for palmitate paliperidone, including the 1 and 3-month formulations, the longer duration 3-month formulation was better at preventing relapse in schizophrenic patients. To date, different formulations of palmitate paliperidone that have been studied on relapse episodes of schizophrenia include once-daily extended-release oral paliperidone (ORAL paliperidone), once-monthly paliperidone palmitate (PP1M), and once-every-3-months paliperidone palmitate (PP3M). Post-hoc analyses show that patients who were withdrawn from PP1M paliperidone had the least risk of relapse, followed by patients withdrawn from PP3M and patients withdrawn from ORAL paliperidone. PP3M was better at preventing relapse compared to ORAL paliperidone. The results demonstrated that 50% of patients who were withdrawn from ORAL paliperidone, PP1M, or PP3M remained relapse-free for ~2, 6, and 13 months, respectively. Compared to PP1M, PP3M is just as safe and effective and has the added advantage of increased adherence related to a longer dose interval, decreasing the risk of relapse.

Pharmacokinetic Characteristics of Long-Acting Injectable Antipsychotics for Schizophrenia: An Overview

The availability of long-acting injectable (LAI) antipsychotics for the treatment of schizophrenia provides clinicians with options that deliver continuous drug exposure and may improve adherence compared with daily oral antipsychotics. However, all LAI antipsychotics have unique formulations and pharmacokinetic characteristics that have implications for medication selection, administration interval, and injection site. This review outlines key differences in drug formulations and pharmacokinetics among LAI antipsychotics. A systematic search of the PubMed database was conducted to identify physical and formulation properties and pharmacokinetic data of commercially available LAI antipsychotics, including flupentixol decanoate, fluphenazine decanoate, haloperidol decanoate, zuclopenthixol decanoate, aripiprazole monohydrate, aripiprazole lauroxil, olanzapine pamoate, paliperidone palmitate, risperidone microspheres, and risperidone polymeric microspheres. Additional information was obtained from package inserts and product monographs. Relevant data on drug properties, administration details, pharmacokinetic parameters, and oral dose equivalencies of LAI antipsychotics are summarized. Based on our analysis, formulation characteristics (e.g., vehicle medium) and administration characteristics (e.g., injection site) can affect rate of absorption and adverse effects and may factor into whether oral supplementation or an additional injection is needed. Dose adjustments may be necessary based on potential drug-drug interactions, and approximate dose equivalence with oral formulations can help inform titration when switching from oral to LAI formulations. Clinicians administering LAI antipsychotics should consider these formulation and pharmacokinetic factors to maximize clinical impact and to adjust to an individual patient's needs and treatment goals.

Attitudes of European physicians towards the use of long-acting injectable antipsychotics

BACKGROUND

Prescription rates for long-acting injectable (LAI) antipsychotic formulations remain relatively low in Europe despite improved adherence over alternative oral antipsychotic treatments. This apparent under-prescription of LAI antipsychotics may have multiple contributing factors, including negative mental health practitioner attitudes towards the use of LAIs.

METHODS

The Antipsychotic Long acTing injection in schizOphrenia (ALTO) non-interventional study (NIS), conducted across several European countries, utilised a questionnaire that was specifically designed to address physicians' attitudes and beliefs towards the treatment of schizophrenia with LAI antipsychotics. Exploratory principal component analysis (PCA) of feedback from the questionnaire aimed to identify and characterize the factors that best explained the physicians' attitudes towards prescription of LAIs.

RESULTS

Overall, 136/234 solicited physicians returned fully completed questionnaires. Physicians' mean age was 48.5 years, with mean psychiatric experience of 20.0 years; 69.9% were male, 84.6% held a consultant position, and 91.9% had a clinical specialty in general adult care. Most physicians considered themselves to have a high level of clinical experience with LAI antipsychotics (77.2%), with an increased rate of LAI antipsychotics prescription over the last 5 years (59.6%). Although the majority of physicians (69.9%) declared feeling no difference in stress levels when offering LAI compared to oral antipsychotics, feelings of 'no/more stress' versus 'less stress' was found to influence prescription patterns. PCA identified six factors which collectively explained 66.1% of the variance in physician feedback. Multivariate analysis identified a positive correlation between physicians willing to accept usage of LAI antipsychotics and the positive attitude of colleagues (co-efficient 3.67; p = 0.016).

CONCLUSIONS

The physician questionnaire in the ALTO study is the first to evaluate the attitudes around LAI antipsychotics across several European countries, on a larger scale. Findings from this study offer an important insight into how physician attitudes can influence the acceptance and usage of LAI antipsychotics to treat patients with schizophrenia.

Efficacy and safety of paliperidone palmitate 3-month formulation in Latin American patients with schizophrenia: A subgroup analysis of data from two large phase 3 randomized, double-blind studies

Objective:

To analyze the efficacy and safety of paliperidone palmitate 3-monthly (PP3M) in Latin American patients with schizophrenia vs. rest-of-world (ROW).

Methods:

We analyzed data from two multinational, double-blind (DB), randomized, controlled phase 3 studies including patients with schizophrenia (DSM-IV-TR) previously stabilized on PP1M/PP3M (open-label [OL] phase). Patients were randomized to PP3M or PP1M (noninferiority study A) and PP3M or placebo (study B) in DB phase. The subgroup analysis included Latin American (Argentina, Brazil, Colombia, Mexico) patients. Primary efficacy endpoints were relapse-free rates (study A) and time-to-relapse (study B).

Results:

In study A, 63/71 (88.7%) and in study B 38/43 (88.4%) Latin American patients completed the DB phase. In study A, relapse-free percentage was similar in Latin America (PP3M: 97%, PP1M: 100%) and ROW (PP3M: 91%, PP1M: 89%). In study B, median time-to-relapse was not estimable in the Latin American subgroup for either placebo or PP3M groups, nor for the ROW PP3M group; the median time-to-relapse in the ROW placebo group was 395 days. Caregiver burden improved in patients switching from oral antipsychotics (OL baseline) to PP3M/PP1M in DB phase (Involvement Evaluation Questionnaire score mean ± SD change, -9.4±15.16; p < 0.001). Treatment emergent adverse events with PP3M during DB phase were similar in Latin America (study A: 24/34 [70.6%]; study B: 15/21 [71.4%]) and ROW (study A: 318/470 [67.7%]; study B: 84/139 [60.4%]) subgroups.

Conclusion:

PP3M was efficacious and showed no new safety concerns in patients with schizophrenia from Latin America, corroborating ROW findings.

Clinical trial registration:

NCT01515423, NCT01529515

Systematic Review of Gender Bias in the Clinical Trials of New Long-Acting Antipsychotic Drugs

PURPOSE/BACKGROUND

This article evaluates gender bias in the published clinical trials of new long-acting antipsychotics.

METHODS/PROCEDURES

We conducted a review of controlled clinical trials of the new prolonged-release antipsychotics (aripiprazole, risperidone, or paliperidone) for the treatment of schizophrenia published in MEDLINE over the last 10 years and available in full text in English. The study followed the corresponding international recommendations.

RESULTS

We identified 132 trials, and of these, 40 met the inclusion and exclusion criteria. We found that only 36.41% of the total patients were women. The separate analysis of the main variable between the subpopulations of men and women was carried out in only 6 of the 40 works included. In contrast, in 15 trials, this analysis was performed on secondary variables, generally related to safety. Only 3 of the 40 trials discussed the results separately according to sex.

CONCLUSIONS

The clinical trials of long-acting atypical antipsychotic drugs show a far-from-negligible gender bias. Women are underrepresented, and the main and secondary variables are not analyzed separately according to gender. This is despite international recommendations establishing these criteria as part of a package of minimum requirements for meeting scientific validity and making results apt to extrapolate to the general population of patients.

Synthesis and characterization of a long-acting emtricitabine prodrug nanoformulation

Purpose

A palmitoylated prodrug of emtricitabine (FTC) was synthesized to extend the drug’s half-life, antiretroviral activities and biodistribution.

Methods

A modified FTC prodrug (MFTC) was synthesized by palmitoyl chloride esterification. MFTC’s chemical structure was evaluated by nuclear magnetic resonance. The created hydrophobic prodrug nanocrystals were encased into a poloxamer surfactant and the pharmacokinetics (PK), biodistribution and antiretroviral activities of the nanoformulation (NMFTC) were assessed. The conversion of MFTC to FTC triphosphates was evaluated.

Results

MFTC coated with poloxamer formed stable nanocrystals (NMFTC). NMFTC demonstrated an average particle size, polydispersity index and zeta potential of 350 nm, 0.24 and −20 mV, respectively. Drug encapsulation efficiency was 90%. NMFTC was readily taken up by human monocyte-derived macrophages yielding readily detected intracellular FTC triphosphates and an extended PK profile.

Conclusion

NMFTC shows improved antiretroviral activities over native FTC. This is coordinate with its extended apparent half-life. The work represents an incremental advance in the development of a long-acting FTC formulation.

Human health benefit and burden of the schizophrenia health care pathway in Belgium: paliperidone palmitate long-acting injections

Background

Environmental impact assessments of pharmaceuticals typically consider only a part of the pharmaceutical supply chain, e.g. tablet formulation. While the environmental impact can be expressed in environmental Human Health burden due to resource use and emissions, the Human Health benefit of the pharmaceutical treatment of patients is currently not simultaneously taken into account. The study aims include a cradle-to-grave assessment of all Human Health impacts of the production, administration and disposal of two antipsychotics for the treatment of schizophrenia. This is complemented with the environmental impact of health care providers such as hospitals. The aim is to holistically quantify to what extent the environmental Human Health burden compares to the Human Health benefit associated with the treatment.

Methods

We applied an overall framework which included Life Cycle Assessment to model the environmental Human Health impacts of the pharmaceutical supply chain, administration and disposal of the drug and health care providers. To model the patient benefit, this was complemented with a Markov model with a 1-year time horizon. Three patient groups were modeled: medicine coverage of paliperidone palmitate for either one month (PP1M) or three months (PP3M) at a time, and compared to Treatment Interruption (TI) as a control group. Outcomes were quantified using Years of Life Lost (YLL), Years Lived with Disability (YLD) and Disability-Adjusted Life Years (DALY).

Results

The main environmental impacts were visits to the psychiatrist and psychiatric hospitals. The pharmaceutical supply chain had a limited impact. For 1000 patients for 1 year, PP1M and PP3M respectively avoided 0.38 and 0.49 environmental DALYs compared to TI. PP1M and PP3M further avoided 45.60 and 57.87 YLL and 23.31 and 29.91 YLD compared to TI. The main outcome was the sum of environmental DALYs, YLL and YLD, in which PP1M and PP3M respectively avoided 69.29 and 88.26 DALYs. Alternative analysis of Quality-Adjusted Life Years confirmed the results.

Conclusions

The overall environmental burden was lower for PP1M and PP3M treatment than Treatment Interruption because patients are kept more stable, which reduces the environmental burden due to hospitals. Moreover, the Human Health burden was outweighed by the Human Health benefit.

Electronic supplementary material

The online version of this article (10.1186/s12913-019-4247-2) contains supplementary material, which is available to authorized users.

Role of paliperidone palmitate 3-monthly in the management of schizophrenia: insights from clinical practice

Schizophrenia is a complex, chronic psychiatric disorder associated with reduced quality of life and shortened life span. The majority of patients with schizophrenia will relapse within 1 year following an acute episode. The ultimate goals of treatment are to improve functional capabilities, minimize residual symptoms during periods of remission, and decrease relapse frequency and duration, as each relapse brings with it the possibility of a worsening prognosis. Maintaining therapeutic continuity is essential for long-term, positive patient outcomes in schizophrenia. Medication nonadherence and symptomatic relapses magnify the disease burden associated with this disorder. Medication adherence in chronic disease states generally improves with a decrease in dosing frequency. Long-acting injectable (LAI) antipsychotics were developed to improve patient outcomes secondarily to improving medication adherence. Paliperidone palmitate 3-monthly injection (PP3M) is the only LAI available with a quarterly dosing interval. PP3M has been US Food and Drug Administration-approved for use in the long-term maintenance treatment of schizophrenia in patients already controlled on once-monthly PP LAI (paliperidone palmitate once-monthly injection [PP1M]) for a minimum of 4 months. As current evidence supports the efficacy and tolerability of PP3M compared to PP1M and placebo, PP3M appears to be a viable treatment option for patients previously maintained on PP1M. However, to truly establish the place of PP3M in therapy relative to other oral antipsychotics and LAIs, more research is needed. This narrative review aims briefly to describe the pharmacotherapeutic characteristics of PP3M and summarize current literature pertaining to the use of PP3M in the management of schizophrenia.

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.

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.

Time to onset and time to resolution of extrapyramidal symptoms in patients with exacerbated schizophrenia treated with 3-monthly vs once-monthly paliperidone palmitate

OBJECTIVE

The aim of this study was to evaluate the safety of 3-monthly paliperidone palmitate (PP3M) vs once-monthly paliperidone palmitate (PP1M) treatment with regard to extrapyramidal symptom (EPS)-related treatment-emergent adverse events (TEAEs) in patients with schizophrenia, previously stabilized on PP1M treatment.

PATIENTS AND METHODS

Data on overall incidence, time to onset (TTO), and time to resolution (TTR) of EPS-related TEAEs (overall, subclasses such as dyskinesia, dystonia, hyperkinesia, parkinsonism, and tremor) from a randomized double-blind (DB) non-inferiority study were compared between PP3M and PP1M. Subgroup analysis was performed by age (18-25, 26-50, and 50+ years) and final open-label (OL) dose (50/75, 100, and 150 mg eq.).

RESULTS

Overall incidence of spontaneously reported EPS-related TEAEs decreased from 12.6% (PP1M) in OL phase to 8.3% (PP3M) and 7.4% (PP1M) in the DB phase; overall median TTO and TTR values were comparable between both groups. Among patients with reported EPS-related TEAEs, the median TTO for all EPS-related TEAEs was 17 days (PP1M) in OL phase and 115 days (PP3M) and 98.5 days (PP1M) in DB phase; median TTR was 36.5 days (PP1M) in OL phase and 91 days (PP3M) and 85.5 days (PP1M) in DB phase. No clear dose- or age-related differences in TTO and TTR of EPS-related TEAEs were noted.

CONCLUSION

Despite differences in apparent half-life and pharmacokinetic profiles (peak plasma exposure of PP3M formulation is 70% higher than that of PP1M formulation), both PP3M and PP1M formulations exhibited comparable incidence of EPS-related TEAEs, TTO, and TTR in patients with schizophrenia.

Population Pharmacokinetics of a Novel Once-Every 3 Months Intramuscular Formulation of Paliperidone Palmitate in Patients with Schizophrenia

OBJECTIVES

Our objective was to characterize the population pharmacokinetics of paliperidone after intramuscular administration of its long-acting 3-month formulation palmitate ester at various doses and at different injection sites (deltoid and gluteal muscles).

METHODS

This retrospective analysis included pooled data from 651 subjects from one phase I study (single injection of the 3-month formulation) and one phase III study (multiple injections of both 1- and 3-month formulations). A total of 8990 pharmacokinetic samples with valid concentration time points were available for this analysis. Nonlinear mixed-effects modelling of the pooled data was conducted using NONMEM software. Knowledge from a previously developed 1-month formulation model was used as a starting point to build the 3-month formulation model.

RESULTS

The final model describing the plasma concentrations after administration of the 3-month formulation was a one-compartment model with first-order elimination and two saturable absorption processes (rapid and slow). The apparent volume of distribution estimated for the 3-month formulation was not the same as for the previously modelled 1-month formulation. Apparent clearance (CL), apparent volume of distribution (V), and fraction of the absorbed dose (F₃) were estimated to be 3.84 l/h, 1960 L, and 20.9 %. For slow absorption, the maximum absorption rate constant (k _{a1 max}), amount of paliperidone at the absorption site when half of the maximum absorption rate was achieved (k _{amt1 50}), and Hill factor (γ) were estimated to be 90.4 µg/h, 120 mg, and 1.44, respectively. For rapid absorption, the maximum absorption rate constant (k _{a3 max}) and amount of paliperidone at the absorption site when half of the maximum absorption rate was achieved (k _{amt3 50}) were estimated to be 164 µg/h and 21.4 mg, respectively.

CONCLUSION

The final model with two saturable absorption processes provided a good description of the pharmacokinetic characteristics of paliperidone after intramuscular administration of its long-acting 3-month formulation palmitate ester. In addition to the structural covariates (creatinine clearance on CL, body mass index on V, and injection volume on both absorption rates), injection site and sex were identified as covariates on k _{a max} of the slow absorption process (k _{a1 max}). Clinical trial registration numbers: NCT01559272, NCT01529515, and NCT01515423.

Cost-effectiveness of 3-month paliperidone therapy for chronic schizophrenia in the Netherlands

BACKGROUND

A new depot formulation of paliperidone has been developed that provides effective treatment for schizophrenia for 3 months (PP3M). It has been tested in phase-3 trials, but no data on its cost-effectiveness have been published.

PURPOSE

To determine the cost-effectiveness of PP3M compared with once-monthly paliperidone (PP1M), haloperidol long-acting therapy (HAL-LAT), risperidone microspheres (RIS-LAT), and oral olanzapine (oral-OLZ) for treating chronic schizophrenia in The Netherlands.

METHODS

A previous 1-year decision tree was adapted, based on local inputs supplemented with data from published literature. The primary analysis used DRG costs in 2016 euros from the insurer perspective, as derived from official lists. A micro-costing analysis was also conducted. For the costing scenario, official list prices were used. Clinical outcomes included relapses (treated as outpatients, requiring hospitalization, total), and quality-adjusted life-years (QALYs). Rates and utility scores were derived from the literature. Economic outcomes were the incremental cost/QALY-gained or relapse-avoided. Model robustness was examined in scenario, 1-way, and probability sensitivity analyses.

RESULTS

The expected cost was lowest with PP3M (8,781€), followed by PP1M (10,325€), HAL-LAT (11,278€), RIS-LAT (11,307€), and oral-OLZ (13,556€). PP3M had the fewest total relapses/patient (0.36, 0.94, 1.39, 1.21, and 1.70, respectively), hospitalizations (0.11, 0.46, 0.40, 0.56, and 0.57, respectively), emergency room visits (0.25, 0.48. 0.99, 0.65, and 1.14, respectively) and the most QALYs (0.847, 0.735, 0.709, 0.719, and 0.656, respectively). In both cost-effectiveness and cost-utility analyses, PP3M dominated all other drugs. Sensitivity analyses confirmed base case findings. In the costing analysis, total costs were, on average, 31.9% higher than DRGs.

CONCLUSIONS

PP3M dominated all commonly used drugs. It is cost-effective for treating chronic schizophrenia in the Netherlands. Results were robust over a wide range of sensitivity analyses. For patients requiring a depot medication, such as those with adherence problems, PP3M appears to be a good alternative anti-psychotic treatment.

Cost-effectiveness of 3-month paliperidone treatment for chronic schizophrenia in Spain

BACKGROUND

A 3-month long treatment of paliperidone palmitate (PP3M) has been introduced as an option for treating schizophrenia. Its cost-effectiveness in Spain has not been established.

AIMS

To compare the costs and effects of PP3M compared with once-monthly paliperidone (PP1M) from the payer perspective in Spain.

METHODS

This study used the recently published trial by Savitz et al. as a core model over 1 year. Additional data were derived from the literature. Costs in 2016 Euros were obtained from official lists and utilities from Osborne et al. The authors conducted both cost-utility and cost-effectiveness analyses. For the former, the incremental cost per quality-adjusted life-year (QALY) gained was calculated. For the latter, the outcomes were relapses and hospitalizations avoided. To assure the robustness of the analyses, a series of 1-way and probability sensitivity analyses were conducted.

RESULTS

The expected cost was lower with PP3M (4,780€) compared with PP1M (5,244€). PP3M had the fewest relapses (0.080 vs 0.161), hospitalizations (0.034 v.s 0.065), and emergency room visits (0.045 v.s 0.096) and the most QALYs (0.677 v.s 0.625). In both cost-effectiveness and cost-utility analyses, PP3M dominated PP1M. Sensitivity analyses confirmed base case findings. For the primary analysis (cost-utility), PP3M dominated PP1M in 46.9% of 10,000 simulations and was cost-effective at a threshold of 30,000€/QALY gained.

CONCLUSIONS

PP3M dominated PP1M in all analyses and was, therefore, cost-effective for treating chronic relapsing schizophrenia in Spain. For patients who require long-acting therapy, PP3M appears to be a good alternative anti-psychotic treatment.

Five Month-Persistent Extrapyramidal Symptoms following a Single Injection of Paliperidone Palmitate: A Case Report

Long-acting injectable (LAI) antipsychotics are useful in the treatments for schizophrenic patients with poor adherence due to their maintaining feature of therapeutic plasma level without daily administrations. However, their long-lasting property can cause complicated problems such as a long-lasting side effect. We report a patient who experienced LAI-induced extrapyramidal symptoms (EPSs) for 5 months after a single injection. During that period, every trial to ameliorate this condition turned out to be a failure. The 3-month formulation of paliperidone palmitate is now close at hand. We have to be aware of possible long-lasting adverse events and confirm the tolerability to LAI before use.

Safety concerns associated with second-generation antipsychotic long-acting injection treatment. A systematic update

Background It has been recently suggested that second-generation antipsychotic long-acting injection (SGA-LAIs) are underutilized in clinical practice, despite that their costs significantly impact on national health system budgets. Hence, an updated analysis of safety data shown by SGA-LAIs may contribute to clarify their role in clinical practice. Materials and methods English-language, peer-reviewed articles reporting updated, primary findings on the SGA-LAI safety were identified (updated through an electronic search of five databases - PubMed, EMBASE, PsycInfo, DARE and the Cochrane Library). Results The articles reviewed suggest that the most frequent treatment emergent adverse events (TEAEs) associated with aripiprazole long-acting injection (ARI-LAI) are psychotic symptoms, extrapyramidal symptoms (EPS) and weight gain. Data on olanzapine long-acting injection (OLA-LAI)-associated TEAEs highlight the risk of psychosis, metabolic disturbances and hyperprolactinemia. Four-hundred and forty cases of post-injection delirium/sedation syndrome (PDSS) have also been recorded. Although not reported in reviewed studies, the risk of impulse-control problem and drug reaction with eosinophilia and systemic symptoms (DRESS) ARI- and OLA-associated, respectively, must not be underestimated. With regards paliperidone palmitate 1-month formulation (PP1), the high incidence of clinically relevant weight gain and hyperprolactinemia are both findings of concern. Reviewed data also confirm that the leading cause of death in risperidone long-acting injection (RIS-LAI) clinical trials is suicide. The new 3-month paliperidone palmitate formulation, risperidone sustained release 1-month formulation (RIS-SR1), aripiprazole lauroxil (ARI-LXL) are still lacking exhaustive safety data. Conclusion The risk of specific TEAEs associated with all SGA-LAIs confirms SGA-LAIs do not offer advantages in safety compared with FGA-LAIs or oral antipsychotics and, especially, in early-phase schizophrenia patients. Implementing non pharmacological intervention and strategies can be effective for people with schizophrenia and bipolar disorder who adhere poorly to medication regimens.

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

Paliperidone palmitate 3-month formulation (PP3M), a long-acting injectable atypical antipsychotic, was recently approved in the US and Europe for the treatment of schizophrenia in adult patients who have already been treated with paliperidone palmitate 1-month formulation (PP1M) for ≥4 months. This article reviews the pharmacokinetic rationale for the approved dosing regimens for PP3M, dosing windows, management of missed doses and treatment discontinuation, switching to other formulations, and dosing in special populations. Approved PP3M dosing regimens are based on the comparisons of simulations with predefined dosing regimens using paliperidone palmitate and oral paliperidone extended release (ER) population pharmacokinetic models (one-compartment model with two saturable absorption processes for PP3M; one-compartment model with parallel zero- and first-order absorption for PP1M; two-compartment model with sequential zero- and first-order absorption for ER) versus clinical trial data. Covariates were obtained by resampling subject covariates from the pharmacokinetics database for PP1M and PP3M. Simulation scenarios with varying doses and covariate values were generated. The population median and 90% prediction interval of the simulated concentration-time profiles were plotted for simulation outcomes evaluation. Simulations described in this paper provide (a) simulated plasma exposures for switching from PP1M to PP3M, (b) support for a once-every-3-months injection cycle, (c) information on dosing windows and managing missed doses of PP3M, (d) important guidance on PP3M dosing in special patient populations, and (e) key PP3M pharmacokinetic exposure metrics based on the population pharmacokinetic PP3M model. Population pharmacokinetics provided practical guidance to establish dosing regimens for PP3M.

Paliperidone for the treatment of schizophrenia and schizoaffective disorders - a drug safety evaluation

INTRODUCTION

Paliperidone, the major active metabolite of risperidone, is a second-generation antipsychotic that has been developed as an extended-release (ER) oral formulation and a long-acting injectable paliperidone palmitate (PP) formulation. Paliperidone has demonstrated efficacy in the reduction of acute schizophrenia symptoms and clinical benefits were maintained also in the long-term treatments. Paliperidone ER and PP are generally well tolerated with a predictable adverse event profile. Areas covered: Data from studies evaluating safety and tolerability in the acute and maintenance treatment of schizophrenia with paliperidone are reviewed. The reported treatment-emergent adverse events of these formulations are discussed. Expert opinion: In the treatment of schizophrenia and schizoaffective disorders the safety profile has a central role because it can enhance patient compliance. In fact treatment-emergent adverse events are one of the main causes of discontinuation in these patients. In particular the main limitation in the administration of paliperidone could be represented by the onset of hyperprolactinemia (especially in women) and of mild parkinsonism. Paliperidone has a high impact on current long-term drug strategies, especially given the new 3 month long-acting injectable formulation of PP.

Role of 3-monthly long-acting injectable paliperidone in the maintenance of schizophrenia

AIMS

Paliperidone palmitate 3-month (PP3M) represents a new long-acting injectable antipsychotic therapeutic option. This review aims: 1) to summarize available data relating to efficacy, safety, tolerability and costs of PP3M; 2) to describe hospitalization rate, occupational status, treatment preference, satisfaction, adherence and caregiver burden of patients with schizophrenia who participate in PP3M clinical trials; 3) to examine ethical implications, pros and cons of PP3M use and 4) to propose study designs to further assess PP3M.

METHODS

On August 21, 2017, a search on PubMed about PPM3, without any filter restriction, was conducted and all available records were analyzed. Records written in a language other than English were excluded.

RESULTS

Twenty-two records were included in this review: 6 reviews, 1 report, 4 pharmacokinetic studies, 2 cost-effectiveness analyses, 1 open-label clinical trial, 2 randomized controlled trials (RCTs), 5 studies based on these 2 RCTs and 1 observational study.

DISCUSSION

According to these last 9 studies, when compared with placebo, PP3M showed a longer time to relapse and good safety and tolerability profiles. Furthermore, when compared with paliperidone palmitate 1 month (PP1M), PP3M treatment showed: 1) non-inferiority in terms of efficacy, safety, tolerability, rate of hospitalization, symptomatic and functional remission, treatment preference and variations of the occupational status; 2) a longer time to relapse after treatment discontinuation and 3) a similar reduction of the caregiver burden.

CONCLUSION

PP3M is the only 3-monthly long-acting injectable antipsychotic available on the market. This makes it a unique option of treatment, which could be chosen both in early and advanced phases of illness. Nonetheless, longer naturalistic follow-up studies, two-arm head-to-head superiority trials and mirror studies, based on real-world samples of patients, are needed to further assess long-term safety and advantages of this new option of treatment and to define patients' sub-populations that would most beneficiate from it.

Emerging pharmacological therapies in schizophrenia: what's new, what's different, what's next?

There are several new and emerging medication interventions for both the acute and maintenance treatment phases of schizophrenia. Recently approved are 2 new dopamine receptor partial agonists, brexpiprazole and cariprazine, as well as 2 new long-acting injectable antipsychotic formulations, aripiprazole lauroxil and 3-month paliperidone palmitate. Although differences in efficacy compared to other available choices are not expected, the new oral options offer different tolerability profiles that may be attractive for individual patients who have had difficulties with older medications. The new long-acting injectable options provide additional flexibility in terms of increasing the time interval between injections. In Phase III of clinical development is a novel antipsychotic, lumateperone (ITI-007), that appears to have little in the way of significant adverse effects. Deutetrabenazine and valbenazine are agents in Phase III for the treatment of tardive dyskinesia, a condition that can be found among persons receiving chronic antipsychotic therapy. On the horizon are additional injectable formulations of familiar antipsychotics, aripiprazole and risperidone, that may be more convenient than what is presently available.

Barriers to the Use of Long-Acting Injectable Antipsychotics in the Management of Schizophrenia

Schizophrenia and related disorders remain major disabling conditions, mainly due to antipsychotic treatment resistance and to relapses related to antipsychotic nonadherence. Treatment nonadherence rates are consistently high in long-term patients, but also in first-episode patients with schizophrenia. Long-acting injectable antipsychotics (LAIAs) were mainly developed to improve adherence to treatment and to reduce the rate of relapse and rehospitalization in schizophrenia due to treatment discontinuation. There is favorable clinical evidence, in terms of both efficacy and treatment adherence, that could support higher LAIA prescription rates, especially in patients in early phases of psychotic disorders. Several factors could be hindering wider use of LAIAs, mainly associated with perceptions and attitudes of patients, clinicians, and health managers or policy makers. The main aims of this review are (i) to summarize the existing data on the efficacy and tolerability of LAIAs compared with oral formulations in the management of schizophrenia and related disorders, focusing on the novel, second-generation LAIA options; (ii) to analyze the barriers that exist to the more widespread use of these formulations; and (iii) to discuss possible approaches to overcoming these barriers.

Prospective dose selection and acceleration of paliperidone palmitate 3-month formulation development using a pharmacometric bridging strategy

AIMS

To prospectively select the dose of the paliperidone palmitate 3-month (PP3M) formulation, using a pharmacometric bridging strategy based on the paliperidone palmitate 1-month (PP1M) formulation previously approved for schizophrenia treatment.

METHODS

Pharmacokinetic (PK) data from a 6-month interim analysis of a single dose PP3M Phase I clinical trial was integrated with a previously developed PP1M population-PK model. The model was updated to incorporate formulation as a covariate on absorption parameters and to explore the most critical design element of the Phase III study: the PP1M-to-PP3M dose multiplier for patients switching formulations. Plasma paliperidone concentrations were measured at predetermined intervals during Phase III, enabling comparison of the multiple-dose PK between PP1M and PP3M. Exposure matching was assessed graphically to determine whether paliperidone plasma concentrations from the two formulations overlapped.

RESULTS

Prospective steady-state PK simulations revealed that a 3.5 multiple of the PP1M dose would yield a corresponding PP3M dose with comparable exposure. The prospective pharmacometric simulation and observed Phase III PK data agreed closely. Phase III results confirmed the hypothesis that efficacy of PP3M was noninferior to that of PP1M. The similarity in exposures between the two formulations was likely a key determinant of the equivalent efficacy between the two products observed in the Phase III study.

CONCLUSIONS

Successful prospective PP3M Phase III clinical trial dose selection was achieved through the use of pharmacometric bridging, without conducting a Phase II study and using only limited Phase I data for PP3M. We estimate that this strategy reduced development time by 3-5 years and may be applicable to other drug development projects.