Pharmacokinetic Evaluation of a 1-Day Treatment Initiation Option for Starting Long-Acting Aripiprazole Lauroxil for Schizophrenia

Antidepressant aripiprazole induces adverse effects on neural development during cortex organoid generation

A significant number of women experience anxiety and depressive symptoms during pregnancy, leading to the prescription of antidepressants, including aripiprazole. However, although a few animal studies have reported its developmental toxicity, there is a lack of research on the potential risks aripiprazole may pose to the fetus, particularly regarding neural development, as well as an absence of appropriate models to verify these effects. Therefore, this study investigates the impact of aripiprazole on neural development using cortex organoids, which can effectively model human brain development and function while overcoming interspecies differences. Cortex organoids were generated and exposed to aripiprazole at concentrations of 0.3-9 µM over 4 weeks. We assessed morphological changes, cell viability, gene expression, immunofluorescence staining, and electrophysiological function. The results revealed that aripiprazole led to significant reductions in organoid size and increased cell death, particularly at higher concentrations. Immunofluorescence analysis showed abnormalities in the expression patterns of neural stem cells and neuronal markers. Additionally, real-time PCR demonstrated decreased expression of genes related to neural stem cells, neural differentiation and migration, maturation, synaptogenesis, and gliogenesis, along with increased apoptosis-related gene expression. Electrophysiological recordings indicated impaired neural activity, evidenced by reduced mean firing rates. Our study is the first to demonstrate that aripiprazole induces adverse effects on neural development across functional, molecular, and morphological aspects. The findings will aid in a better understanding of the risks associated with antidepressant use during pregnancy in terms of neural development and suggest that cortex organoids are a valuable model for evaluating potential neurodevelopmental toxicants.

Aripiprazole Lauroxil: Development and Evidence-Based Review of a Long-Acting Injectable Atypical Antipsychotic for the Treatment of Schizophrenia

This review article describes why and how aripiprazole was formulated as aripiprazole lauroxil (AL), an extended-release antipsychotic agent that is delivered via a long-acting injectable formulation, and the clinical trials investigating its use. AL was formulated as an inactive prodrug of aripiprazole using LinkeRx® technology to provide a prolonged-release antipsychotic with predictable dissolution over time. The resulting AL pharmacokinetic profile is characterized by a long half-life and little peak-to-trough aripiprazole concentration variability across dosing intervals of every 1 month, every 6 weeks, and every 2 months. The prodrug technology was further refined to develop an AL initiation formulation with a somewhat faster release of aripiprazole, eliminating the need for a 21-day oral aripiprazole supplementation period. With this initiation formulation, AL treatment can be started in 1 day. Key AL characteristics, including pharmacokinetic profile and efficacy, safety, and tolerability data, are presented. In addition to the efficacy and safety established in clinical trials of oral aripiprazole, a placebo-controlled 12-week pivotal study investigated AL 441 mg and 882 mg monthly regimens in patients with acutely exacerbated schizophrenia and provided efficacy and safety information that led to US Food and Drug Administration approval in 2015. Thereafter, studies established the long-term safety profile and durability of the AL treatment effect. The 25-week, active-controlled ALPINE study evaluated the feasibility and effectiveness of AL 1064 mg every 2 months, initiated using the 1-day AL initiation regimen, without further oral supplementation beyond day 1, in patients hospitalized for acutely exacerbated schizophrenia with subsequent transition to outpatient care. In short-term and long-term studies, AL was generally well tolerated at initiation and during acute and maintenance treatment. Pharmacokinetic, efficacy, and safety characteristics support the use of AL across inpatient and outpatient treatment settings.

Switching to long-acting injectable antipsychotics: pharmacological considerations and practical approaches

INTRODUCTION

Long-acting injectable antipsychotics (LAIs) are an effective, but potentially underutilized treatment option in schizophrenia and other severe mental illnesses. Prescribing information typically focuses on how to initiate treatment from the corresponding oral formulations. However, in clinical practice other scenarios, such as switching from other oral antipsychotics or other LAIs, occur frequently, requiring guidance.

AREAS COVERED

Pharmacodynamic properties of antipsychotics and their relation to rebound symptoms. Pharmacokinetic properties of LAIs and their implications for switching approaches. Specific approaches to switching to LAIs.

EXPERT OPINION

The LAI landscape has evolved significantly in the last decade with more formulations available, longer dosing intervals, and extended indications. However, currently available LAIs have various shortcomings, e.g. short dosing intervals, need for oral supplementation, loading regimens, deep intramuscular injection and/or restricted indications. Recent improvements include a one-day initiation option for aripiprazole lauroxil, aripiprazole monohydrate once-monthly, risperidone in situ microparticles and subcutaneous risperidone. Future LAI developments should focus on longer dosing intervals, subcutaneous administration, expansion of LAIs beyond currently available antipsychotic agents and indications beyond schizophrenia and bipolar disorder. In the future, LAIs might become a first-line treatment after initial oral stabilization for chronic mental disorders with need for maintenance treatment and presence of significant non-adherence.

New Antipsychotic Medications in the Last Decade

PURPOSE OF REVIEW

Over the last ten years, the treatment of psychosis has seen a near explosion of creative development in both novel agents and new delivery modalities. The current review summarizes these developments over the past decade (2011-2020). We performed a systematic review utilizing PubMed and PsychInfo with the aim of identifying all the RCT and related analyses in adults with psychosis (schizophrenia and mania).

RECENT FINDINGS

We identified 11 significant developments: the introduction of new antipsychotics cariprazine, brexpiprazole, lumateperone, and pimavanserin; introduction of new delivery methods: subcutaneous long-acting risperidone, aripiprazole lauroxil, transdermal asenapine, and inhaled loxapine; and the introduction of new approaches such as olanzapine/samidorphan for olanzapine-associated weight gain, examination of the TAAR1 agonist SEP 363,856 as a test of concept, and the combination of Xanomeline/Trospium, an M₁ and M₄ muscarinic receptor agonist in conjunction with a peripheral anticholinergic. Last decade has seen a tremendous development in second-generation antipsychotics which provides unprecedented treatment options for clinicians in treating psychosis.

Effects of the combination of second-generation antipsychotics on serum concentrations of aripiprazole and dehydroaripiprazole in Chinese patients with schizophrenia

Background

Aripiprazole (ARI) is often prescribed alone or in combination with other second-generation antipsychotics (SGAs) to treat patients with schizophrenia. However, this may increase the potential clinical significance of drug–drug interactions. Therapeutic drug monitoring (TDM) is an important and fundamental tool both when administering ARI alone and in combination with other SGAs to monitor ARI pharmacokinetics, adjust the dosage and thereby achieve more effective and safer treatment.

Aims

This study retrospectively investigated the effects of four SGA comedications (clozapine, risperidone, quetiapine (QTP) and olanzapine) and other potential factors (sex, age and ARI dose) on the serum concentrations of ARI and dehydroaripiprazole (DARI) in Chinese patients with schizophrenia using TDM data.

Methods

High-performance liquid chromatography was used to test the serum concentrations of ARI, DARI and ARI+DARI. In addition, steady-state dose-adjusted serum concentrations (ie, concentration-to-dose ratios, C:D ratios) of ARI, DARI and ARI+DARI; sex; age; ARI dose and SGA comedication dose between 299 inpatients with schizophrenia who received ARI or SGA comedication were all collected and analysed. Spearman’s correlation and multiple linear regression analysis were used to evaluate bivariate associations between ARI dose and serum ARI and DARI concentrations and describe the effect of independent variables on serum ARI and DARI concentrations, respectively.

Results

There were significant differences in the C:D ratios of ARI (χ²=−3.21, p=0.001) and ARI+DARI (χ²=−2.50, p=0.01) between the ARI and SGA groups, as well as in the C:D ratios of ARI (χ²=−3.59, p<0.001) and ARI+DARI (χ²=−3.10, p=0.002) between the female patients in the two groups. Of the four SGAs, only QTP had significant effects on the C:D ratios of ARI (Z=−4.12, p<0.001) and ARI+DARI (Z=−3.62, p<0.001) when compared with the ARI group in the whole sample and on the C:D ratios of ARI, DARI and ARI+DARI (Z=−3.96, p<0.001; Z=−2.22, p=0.03; Z=−3.75, p<0.001, respectively) in women when compared with their counterparts in the ARI group.

Conclusion

Comedication with SGAs resulted in lower C:D ratios of ARI and ARI+DARI compared with ARI monotherapy, and comedication with QTP resulted in lower C:D ratios of ARI and ARI+DARI than ARI monotherapy. Despite this statistical significance of our findings, whether the presently observed effect has clinical significance requires exploration by further research. TDM and dosage regulation of ARI should be performed in Chinese inpatients with schizophrenia who are receiving SGA comedication (especially QTP) to maintain a safe and effective dose-adjusted serum concentration of ARI and DARI.

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.

Therapeutic Drug Monitoring of Long-Acting Injectable Antipsychotic Drugs

BACKGROUND

The use of therapeutic drug monitoring (TDM) to guide treatment with long-acting injectable (LAI) antipsychotics, which are increasingly prescribed, remains a matter of debate. The aim of this review was to provide a practical framework for the integration of TDM when switching from an oral formulation to the LAI counterpart, and in maintenance treatment.

METHODS

The authors critically reviewed 3 types of data: (1) positron emission tomography data evaluating dopamine (D2/D3) receptor occupancy related to antipsychotic concentrations in serum or plasma; D2/D3 receptors are embraced as target sites in the brain for antipsychotic efficacy and tolerability, (2) pharmacokinetic studies evaluating the switch from oral to LAI antipsychotics, and (3) pharmacokinetic data for LAI formulations. Based on these data, indications for TDM and therapeutic reference ranges were considered for LAI antipsychotics.

RESULTS

Antipsychotic concentrations in blood exhibited interindividual variability not only under oral but also under LAI formulations because these concentrations are affected by demographic characteristics such as age and sex, genetic peculiarities, and clinical variables, including comedications and comorbidities. Reported data combined with positron emission tomography evidence indicated a trend toward lower concentrations under LAI administration than under oral medications. However, the available evidence is insufficient to recommend LAI-specific therapeutic reference ranges.

CONCLUSIONS

Although TDM evidence for newer LAI formulations is limited, this review suggests the use of TDM when switching an antipsychotic from oral to its LAI formulation. The application of TDM practice is more accurate for dose selection than the use of dose equivalents as it accounts more precisely for individual characteristics.

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.

Size matters: the importance of particle size in a newly developed injectable formulation for the treatment of schizophrenia

One of the challenges with initiating long-acting injectable (LAI) antipsychotic regimens is achieving relevant drug levels quickly. After first injection of the LAI antipsychotic aripiprazole lauroxil (AL), the lag to reaching relevant plasma aripiprazole levels was initially addressed using supplemental oral aripiprazole for 21 days. A 1-day AL initiation regimen using a NanoCrystal® Dispersion formulation of AL (ALNCD; Aristada Initio®) combined with a single 30 mg dose of oral aripiprazole has been developed as an alternative approach. We compared the 1-day AL initiation regimen (ALNCD + 30 mg oral aripiprazole for 1 day) with the 21-day AL initiation regimen (AL + 15 mg/day of oral aripiprazole for 21 days) using kinetic modeling. Observed and modeled data demonstrate that the 1-day AL initiation regimen provides continuous aripiprazole exposure comparable to the 21-day AL initiation regimen. Each component of the 1-day AL initiation regimen (30 mg oral aripiprazole, ALNCD, and AL) contributes to aripiprazole plasma levels at different times, with oral aripiprazole predominating in the first week, then ALNCD and AL over time. In a double-blind, placebo-controlled, phase 1 study in patients with schizophrenia, the 1-day initiation regimen resulted in rapid achievement of relevant plasma aripiprazole levels comparable to those from the 21-day initiation regimen. Safety and tolerability of the 1-day regimen were consistent with the known profile of aripiprazole. Each part of the 1-day initiation regimen, together with AL, is necessary for continuous aripiprazole exposure from treatment initiation until the next regularly scheduled AL injection is administered.

Long-Acting Injections in Schizophrenia: a 3-Year Update on Randomized Controlled Trials Published January 2016-March 2019

PURPOSE OF REVIEW

This study was conducted in order to review randomized controlled trial (RCT) data published January 2016-March 2019 on long-acting injectable antipsychotics (LAIs) for schizophrenia.

RECENT FINDINGS

Thirty-one RCTs (primary studies = 7; post hoc analyses = 24; n = 4738) compared LAIs vs. placebo (studies = 11, n = 1875), LAIs vs. oral antipsychotics (OAPs) (studies = 7, n = 658), and LAI vs. LAI (studies = 13, n = 2205). LAIs included two new formulations, aripiprazole lauroxil nanocrystal dispersion and subcutaneously injectable risperidone Perseris, as well as aripiprazole lauroxil, aripiprazole once-monthly, paliperidone once-monthly, paliperidone 3-monthly, and risperidone-LAI. Regarding prevention of relapse and hospitalization, LAIs consistently outperformed placebo, being partly superior to OAPs, without relevant LAI-LAI differences. LAIs were comparable to OAPs regarding all-cause discontinuation, functioning, quality of life, and tolerability, being associated with higher patient satisfaction and service engagement. Recent meta-analyses yielded mixed results, but never favoring OAPs over LAIs. In RCTs, LAIs are superior to placebo, but only in some aspects, superior to OAPs. Comparative effectiveness of LAIs vs. OAPs requires further study, ideally in generalizable/real-world samples.

Pharmacokinetics and safety of deltoid or gluteal injection of aripiprazole lauroxil NanoCrystal® Dispersion used for initiation of the long-acting antipsychotic aripiprazole lauroxil

BACKGROUND

Aripiprazole lauroxil (AL), a long-acting injectable antipsychotic for the treatment of schizophrenia in adults, can be started with either 21 days of daily oral aripiprazole supplementation or a 1-day initiation regimen consisting of a single injection of a NanoCrystal^® Dispersion formulation of AL (AL_NCD) and a single dose of 30 mg oral aripiprazole. This phase I study assessed the pharmacokinetics and safety of deltoid versus gluteal AL_NCD injections.

METHODS

Patients with schizophrenia or schizoaffective disorder (N = 47) were randomized 1:1 to receive a single intramuscular dose of AL_NCD in the deltoid or gluteal muscle. Plasma samples were collected over 85 days to measure AL_NCD concentration by injection site. Relative aripiprazole bioavailability for deltoid versus gluteal injection was assessed based on area under the curve (AUC_∞ and AUC_last) and maximum concentration (C_max) values. Adverse events were monitored throughout the study.

RESULTS

Plasma aripiprazole concentrations after a single AL_NCD injection were comparable between deltoid and gluteal administration. Mean maximum plasma aripiprazole concentrations were 196.1 ng/ml (deltoid) and 175.0 ng/ml (gluteal). Exposure to aripiprazole was similar, with mean AUC_∞ values of 6591 day × ng/ml for deltoid and 6437 day × ng/ml for gluteal. Aripiprazole bioavailability was not significantly different between injection sites. AL_NCD administration in the deltoid or gluteal muscle was well tolerated, with similar safety profiles at both sites.

CONCLUSION

AL_NCD demonstrated similar exposure and safety profiles between the two administration sites, suggesting that AL_NCD can be given in either the gluteal or the deltoid muscles as a component of the 1-day initiation regimen for AL.

Population Pharmacokinetic Analysis and Model-Based Simulations of Aripiprazole for a 1-Day Initiation Regimen for the Long-Acting Antipsychotic Aripiprazole Lauroxil

Background and Objectives

Aripiprazole lauroxil (AL), a long-acting injectable antipsychotic for the treatment of schizophrenia, requires 21 days of oral aripiprazole supplementation upon initiation (21-day initiation regimen). An alternative 1-day initiation regimen utilizing a nano-crystalline milled dispersion of AL (AL_NCD) plus a single 30 mg oral aripiprazole dose achieved aripiprazole concentrations associated with therapeutic doses of aripiprazole in the same time frame as the 21-day initiation regimen when starting AL (441 or 882 mg). A population pharmacokinetic (PopPK) model was developed to describe aripiprazole pharmacokinetics following administration of AL_NCD, AL and oral aripiprazole, and evaluate dosing scenarios likely to be encountered in clinical practice.

Methods

In total, 12,768 plasma aripiprazole concentrations from 343 patients (from 4 clinical studies) were included in the PopPK analysis and used to construct the model.

Results

Concomitant administration of the 1-day initiation regimen with all approved AL dosing regimens (441, 662, or 882 mg monthly, 882 mg every 6 weeks, or 1064 mg every 2 months) is predicted to achieve aripiprazole concentrations associated with therapeutic doses of AL using the 21-day initiation regimen within 4 days, maintaining these concentrations until the next AL dose. Administration of the first AL injection 10 days after the 1-day initiation regimen resulted in median aripiprazole concentrations just before the second dose of AL ≥ 77% of that when coadministered on the same day. Coadministration of AL with a single AL_NCD injection was predicted to be effective in rapidly re-establishing concentrations associated with therapeutic doses of AL following dose delay.

Conclusions

Model-based simulations demonstrate that the 1-day initiation regimen is suitable for starting treatment with all AL doses, allowing a window of ≤ 10 days between initiation and AL administration. AL_NCD may also be used to re-establish concentrations associated with therapeutic doses of AL in conjunction with a delayed AL dose.

Electronic supplementary material

The online version of this article (10.1007/s13318-018-0488-4) contains supplementary material, which is available to authorized users.