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In order to accelerate drug development and avoid unnecessary drug trials in vulnerable pediatric populations, the US Food and Drug Administration (FDA) released a general advice letter to sponsors permitting the effectiveness of atypical antipsychotics for the treatment of schizophrenia in adults to be extrapolated to adolescents. Extrapolation is based on the evidence-based assumptions that (1) disease characteristics and (2) response to therapy, are similar in adults and adolescents. Whereas the FDA validated the extrapolation approach using data from multiple drug development programs, aripiprazole data are the most relevant to confirm the validity of the extrapolation approach for brexpiprazole, since aripiprazole and brexpiprazole both modulate dopaminergic and serotonergic signaling in the brain. The aims of this analysis were (1) to quantitatively assess the aripiprazole exposure (average steady-state concentration)-response (Positive and Negative Syndrome Scale total score change from baseline) similarity between adults and adolescents with schizophrenia, (2) to extend the aripiprazole exposure-response modeling to brexpiprazole using adult data, and (3) to use the brexpiprazole model to predict schizophrenia symptom response in adolescents. Disease-drug-dropout models were developed using patient-level data from clinical studies of aripiprazole (1007 adults, 294 adolescents) and brexpiprazole (1235 adults) in schizophrenia. The aripiprazole model demonstrated similar exposure-response between adults and adolescents with schizophrenia, validating the extrapolation approach. Extrapolation of the brexpiprazole adult exposure-response model to adolescents predicted the efficacy of brexpiprazole in adolescents aged 13-17 years with schizophrenia., (© 2024 The Author(s). The Journal of Clinical Pharmacology published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

A ready-to-use (RTU) long-acting injectable (LAI) formulation of aripiprazole monohydrate for administration once every 2 months, available in 960 mg (Ari 2MRTU 960) or 720 mg doses, has been developed for the treatment of schizophrenia or bipolar I disorder. A previously developed and validated population pharmacokinetic model for characterizing aripiprazole plasma concentrations following administration of oral aripiprazole or aripiprazole once-monthly (AOM) intramuscular injection was expanded to include the RTU LAI formulation of aripiprazole (Ari RTU LAI). Overall, 8899 aripiprazole pharmacokinetic samples from 1191 adults from 10 clinical trials were included in the final combined analysis data set. Aripiprazole plasma concentration-time profiles were simulated for various Ari RTU LAI initiation and maintenance scenarios in 1000 virtual patients. Diagnostic plots demonstrated that the final population pharmacokinetic model, which incorporated data for oral aripiprazole, AOM, and Ari RTU LAI, adequately described aripiprazole concentrations following Ari RTU LAI administration. Absorption of Ari RTU LAI was modeled by a parallel zero-order and lagged first-order process. Simulations across multiple scenarios were performed to inform dosing recommendations, including various treatment initiation regimens for a 2-monthly formulation of Ari RTU LAI in patients with or without prior stabilization on oral aripiprazole, and for patients switching from AOM. Additional simulations accounted for missed/delayed doses, cytochrome (CYP) 2D6 metabolizer status, and concomitant use of CYP2D6 or CYP3A4 inhibitors. Overall, simulations across a variety of scenarios demonstrated an Ari RTU LAI pharmacokinetic exposure profile that was comparable to AOM, with a longer dosing interval., (© 2024 Otsuka Pharmaceutical Development & Commercialization, Inc. Clinical Pharmacology in Drug Development published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

Due to the customary delay between medication approvals in adult and adolescent populations, adolescents with schizophrenia may receive off-label antipsychotic treatment, without empirically justified dosing recommendations. In order to accelerate pediatric drug development, the US Food and Drug Administration (FDA) released a general advice letter to sponsors permitting the effectiveness of atypical antipsychotics for the treatment of schizophrenia in adults to be extrapolated to adolescents based on a pharmacokinetic (PK) analysis to support dose selection, plus a safety study. The aim of the present article is to describe the population PK analysis that was submitted to the FDA to inform brexpiprazole dose selection in adolescents with schizophrenia. Using a population PK model with brexpiprazole clearance and volume of distribution allometrically scaled by body weight, PK simulations showed comparable brexpiprazole dose-exposure between adults and adolescents aged 13-17 years following oral daily doses of brexpiprazole 1-4 mg, indicating that the target brexpiprazole dose of 2-4 mg/day in adults with schizophrenia is also suitable for adolescents. Based on this population PK analysis, together with a safety study in adolescents, the FDA approved brexpiprazole for the treatment of schizophrenia in adolescents aged 13-17 years, via extrapolation of the efficacy of brexpiprazole from adults to adolescents., (© 2023 Otsuka Pharmaceutical Inc and H. Lundbeck A/S. The Journal of Clinical Pharmacology published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

Objective: Aripiprazole 2-month ready-to-use 960 mg (Ari 2MRTU 960) is a new long-acting injectable antipsychotic formulation for administration every 2 months. A randomized, open-label, 32-week trial evaluated the safety, tolerability, and pharmacokinetics of Ari 2MRTU 960 in clinically stable adults with schizophrenia or bipolar I disorder (per DSM-5 criteria). This secondary analysis evaluated the safety and efficacy of Ari 2MRTU 960 in the subpopulation of patients with schizophrenia., Methods: Patients were randomized to receive Ari 2MRTU 960 every 56 ± 2 days (4 injections scheduled) or aripiprazole once-monthly 400 mg (AOM 400) every 28 ± 2 days (8 injections scheduled). Data were collected during August 2019-July 2020 across 16 US sites. Primary endpoints included safety and tolerability, evaluated throughout. Secondary endpoints for efficacy in patients with schizophrenia included change from baseline at week 32 in Positive and Negative Syndrome Scale, Clinical Global Impression - Severity, and Subjective Well-being under Neuroleptic Treatment - Short Form scores, along with Clinical Global Impression - Improvement at week 32., Results: Patients with schizophrenia were randomized to Ari 2MRTU 960 (n = 92) or AOM 400 (n = 93). The incidence of treatment-emergent adverse events (TEAEs) was similar between Ari 2MRTU 960 (66.3%) and AOM 400 (63.4%). The most frequently reported TEAE was increased weight (Ari 2MRTU 960: 21.7%; AOM 400: 18.3%). Patients in both treatment groups remained clinically stable throughout, with minimal change from baseline observed in efficacy parameters at week 32., Conclusions: Ari 2MRTU 960 was well tolerated in clinically stable patients with schizophrenia, with efficacy similar to AOM 400., Trial Registration: ClinicalTrials.gov identifier: NCT04030143., (© Copyright 2023 Physicians Postgraduate Press, Inc.)

Objective: Aripiprazole 2-month ready-to-use 960 mg (Ari 2MRTU 960) is a new long-acting injectable antipsychotic formulation for administration every 2 months. A 32-week trial evaluated the safety, tolerability, and pharmacokinetics of Ari 2MRTU 960 in clinically stable adults with schizophrenia or bipolar I disorder (BP-I) (per DSM-5 criteria). This secondary analysis evaluated the safety and efficacy of Ari 2MRTU 960 in the subpopulation of patients with BP-I., Methods: Patients with BP-I were randomized to receive Ari 2MRTU 960 ( n  = 40) every 56 ± 2 days (4 injections scheduled) or aripiprazole once-monthly 400 mg (AOM 400; n  = 41) every 28 ± 2 days (8 injections scheduled). Data were collected during August 2019-July 2020 across 16 US sites. Primary safety endpoints included reported adverse events (coded by the Medical Dictionary for Regulatory Activities preferred term), injection site reactions (assessments included a Visual Analog Scale [VAS] to evaluate patient-reported injection-site pain), and motoric symptoms. Secondary endpoints for efficacy included change from baseline at Week 32 in the Young Mania Rating Scale (YMRS), Montgomery-Åsberg Depression Rating Scale (MADRS), Clinical Global Impression - Bipolar Version (CGI-BP), and Subjective Well-being under Neuroleptic Treatment - Short Form (SWN-S) scores, and Clinical Global Impression - Improvement (CGI-I) at Week 32., Results: The incidence of treatment-emergent adverse events (TEAEs) was similar between Ari 2MRTU 960 (82.5% [33/40]) and AOM 400 (87.8% [36/41]; p  = .5468). The most frequently reported TEAE was increased weight (Ari 2MRTU 960: 25.0% [10/40]; AOM 400: 26.8% [11/41]; p  = 1). Injection-site pain was experienced by more patients in the Ari 2MRTU 960 group (25% [10/40]) versus the AOM 400 group (7.3% [3/41]; p  = .0622). Mean (standard deviation [SD]) VAS scores for patient-reported injection-site pain following the last injection were 1.2 (2.07) for Ari 2MRTU 960 group and 1.3 (2.19) for AOM 400 ( p  = .9479) (VAS scale range 0-100 [no pain-extreme pain]). No notable improvement or decline from baseline was observed in motoric symptoms in either treatment group. Patients in both treatment groups remained clinically stable for the entire 32-week trial duration, with minimal difference between treatment groups in the least squares (LS) mean change from baseline at Week 32 in the YMRS Total ( p  = .8995), MADRS Total ( p  = .3185), and CGI-BP scores ( p  = .8485), and in mean CGI-I score ( p  = .7960). LS mean change from baseline in SWN-S score was greater for Ari 2MRTU 960 than for AOM 400 at Week 32 ( p  = .0169)., Conclusions: Ari 2MRTU 960 was well tolerated in patients with BP-I, with efficacy similar to AOM 400., Trial Registration: ClinicalTrials.gov identifier: NCT04030143.

Background: Aripiprazole 2-month ready-to-use 960 mg (Ari 2MRTU 960) is a new long-acting injectable antipsychotic formulation for gluteal administration every 2 months, currently being investigated for the treatment of schizophrenia and bipolar I disorder (BP-I). The objectives of this trial were to evaluate the safety and tolerability of Ari 2MRTU 960, and the similarity of aripiprazole plasma concentrations following administration of Ari 2MRTU 960 or aripiprazole once-monthly 400 mg (AOM 400), in adults with schizophrenia or BP-I., Methods: This was a 32-week open-label study. Eligible participants were randomized 1:1 to receive Ari 2MRTU 960 every 56 ± 2 days (four injections scheduled) or AOM 400 every 28 ± 2 days (eight injections scheduled). Participants received overlapping oral antipsychotic treatment with the first administration of study drug (there was no oral overlap for participants stabilized on AOM 400). Safety, tolerability, and pharmacokinetics (PK) were evaluated throughout the study. Primary safety endpoints included reported adverse events, injection site reactions, and extrapyramidal symptoms. Primary PK endpoints were plasma concentration of aripiprazole 56 days after the fourth dose of Ari 2MRTU 960 and 28 days after the eighth dose of AOM 400, and area under the concentration-time curve (AUC) from Day 0 to 56 postdose after the fourth dose of Ari 2MRTU 960, or AUC from Day 0 to 28 after the seventh and eighth doses of AOM 400., Results: Of the 266 participants enrolled (schizophrenia, n = 185; BP-I, n = 81), 132 were randomized to receive Ari 2MRTU 960 and 134 were randomized to receive AOM 400. The majority (66.2%) of participants were male; 72.9% were Black or African American, and mean age was 47.3 years; demographic characteristics and baseline disease characteristics were generally well balanced between groups. Study completion rate was 77.3% in the Ari 2MRTU 960 group and 68.7% in the AOM 400 group. The incidence of treatment-emergent adverse events (TEAEs) was similar between Ari 2MRTU 960 (71.2%) and AOM 400 (70.9%). The most frequently reported TEAEs were increased weight (Ari 2MRTU 960: 22.7%; AOM 400: 20.9%) and injection-site pain (Ari 2MRTU 960: 18.2%; AOM 400: 9.0%). The geometric means ratio (GMR) of aripiprazole plasma concentrations on the last day following the final dosing for Ari 2MRTU 960 versus AOM 400 was 1.011 (90% confidence interval [CI] 0.893-1.145), and the GMR of aripiprazole plasma exposure (area under the concentration-time curve) over the fourth Ari 2MRTU 960 dosing interval versus the seventh and eighth AOM 400 dosing intervals was 1.006 (90% CI 0.851-1.190)., Conclusions: Ari 2MRTU 960 was generally well tolerated in adults with schizophrenia or BP-I, with a safety profile comparable with that of AOM 400, and aripiprazole exposure equivalent to that with AOM 400 (ClinicalTrials.gov identifier: NCT04030143, registered on 23 July 2019)., (© 2023. The Author(s).)

Background: The single-injection start regimen for aripiprazole once-monthly 400 mg (AOM 400) in patients with schizophrenia requires a single intramuscular injection in the gluteal or deltoid site and 14 days of concurrent oral therapy. A simplified, single-day regimen of two injections at separate gluteal and/or deltoid injection sites, together with a single 20-mg dose of oral aripiprazole on the 1st day, was assessed., Patients and Methods: A previously developed population-pharmacokinetic (popPK) model for characterizing aripiprazole PK following oral administration and gluteal intramuscular depot injection was expanded to include deltoid injection. Simulations were conducted to assess PK profiles following various (including two-injection) start regimens. Postmarketing data on patients who received higher-than-recommended AOM doses were used to assess overall safety/tolerability., Results: The two-injection start regimen with a single concurrent oral dose displayed a comparable PK profile to the single-injection start regimen with concurrent 14-day oral administration in simulations. The safety assessment indicated the two-injection start regimen was unlikely to be associated with safety concerns beyond those expected with a single-injection start regimen., Conclusion: These data support use of the two-injection start regimen in clinical practice to reduce reliance on daily oral administration and optimize the therapeutic benefits of AOM 400 in patients with schizophrenia.

Background: Two open-label, randomized, parallel-arm studies compared pharmacokinetics, safety, and tolerability of aripiprazole once-monthly 400 mg following deltoid vs gluteal injection in patients with schizophrenia., Methods: In the single-dose study, 1 injection of aripiprazole once-monthly 400 mg in the deltoid (n=17) or gluteal (n=18) muscle (NCT01646827) was administered. In the multiple-dose study, the first aripiprazole once-monthly 400 mg injection was administered in either the deltoid (n=71) or gluteal (n=67) muscle followed by 4 once-monthly deltoid injections (NCT01909466)., Results: After single-dose administration, aripiprazole exposure (area under the concentration-time curve) was similar between deltoid and gluteal administrations, whereas median time to maximum plasma concentration was shorter (7.1 [deltoid] vs 24.1 days [gluteal]) and maximum concentration was 31% higher after deltoid administration. In the multiple-dose study, median time to maximum plasma concentration for deltoid administration was shorter (3.95 vs 7.1 days), whereas aripiprazole mean trough concentrations, maximum concentration, and area under the concentration-time curve were comparable between deltoid and gluteal muscles (historical data comparison). Multiple-dose pharmacokinetic results for the major metabolite, dehydro-aripiprazole, followed a similar pattern to that of the parent drug for both deltoid and gluteal injection sites. Safety and tolerability profiles were similar after gluteal or deltoid injections. Based on observed data, minimum aripiprazole concentrations achieved by aripiprazole once-monthly 400 mg are comparable with those of oral aripiprazole 15 to 20 mg/d., Conclusions: The deltoid muscle is a safe alternative injection site for aripiprazole once-monthly 400 mg in patients with schizophrenia., (© The Author 2017. Published by Oxford University Press on behalf of CINP.)

Objective: This article provides rationale for recommendations on how to initiate aripiprazole once-monthly 400 mg (AOM 400), an injectable suspension, in patients with schizophrenia, supported by pharmacokinetic (PK) data and based on clinical studies., Methods: An overview of data from a PK study, PK simulations, controlled clinical trials, and a naturalistic study is presented., Results: Pharmacokinetic data support 400 mg as the starting and maintenance dose of AOM; the plasma concentration profile of aripiprazole after initiating AOM 400 was consistent with therapeutic concentrations observed with oral aripiprazole 10 to 30 mg/d. PK simulations and observed data from a single-dose clinical trial indicate that median aripiprazole plasma concentrations reach therapeutic levels within 7 days of initiating AOM 400. Because of interpatient variability, a 14-day overlap with oral aripiprazole or another antipsychotic medication is considered sufficient to ensure therapeutic concentrations. In clinical studies, when patients initiated AOM 400 with concomitant oral aripiprazole (10-15 mg/d based on stabilized dose) or continued their previous antipsychotic for ≤14 days, mean aripiprazole plasma concentration after 4 weeks (93 to 112 ng/mL) was in range of the therapeutic window established for aripiprazole (94.0-534.0 ng/mL). In clinical studies, the 400-mg starting dose of AOM was efficacious and well tolerated. Across studies of variable duration and design, 1296/1439 (90.1%) patients initiated AOM 400 and required no dose change. Overall rates of discontinuation due to lack of efficacy across clinical studies were low in patients treated with AOM 400 (range, 2.3%-10.0%). In a post hoc analysis from a naturalistic study, cross-titration from other oral antipsychotic therapies to oral aripiprazole before initiating AOM 400 was better tolerated with a >1- to 4-week cross-titration period versus a ≤1-week period, as evidenced by lower rates of discontinuation due to adverse events during cross-titration (2.7% [7/239] vs 10.4% [5/48]). The efficacy and safety of AOM 400 in the month after initiation in the pivotal maintenance studies were comparable between subpopulations of patients previously stabilized on 10- or 30-mg doses of oral aripiprazole., Conclusions: Findings from PK data, PK simulations, and clinical studies all support that 400 mg is the appropriate initiation dose of AOM for patients with schizophrenia. When switching to oral aripiprazole before initiating AOM 400, tapering the prior oral antipsychotic while titrating up the oral aripiprazole dose (target dose 10-30 mg/d) over >1 to 4 weeks may be an effective strategy. The efficacy, safety, and tolerability of AOM 400 were comparable regardless of whether patients were previously stabilized on oral aripiprazole 10 or 30 mg/d or other antipsychotic therapy and continued to receive the same oral antipsychotic for the first 14 days after initiating AOM 400.

Background: Schizophrenia and bipolar disorder have partly overlapping clinical profiles, which include an over-representation of substance-use behaviour. There are few previous studies directly comparing substance-use patterns in the two disorders. The objective of the present study was to compare the prevalence of substance use in schizophrenia and bipolar disorder, and investigate possible differences in pattern and frequency of use., Method: A total of 336 patients with schizophrenia or bipolar spectrum disorder from a catchment area-based hospital service were included in a cross-sectional study. In addition to thorough clinical assessments, patients were interviewed about drug-use history, habits and patterns of use. The prevalence and drug-use patterns were compared between groups., Results: Patients with bipolar disorder had higher rates of alcohol consumption, while schizophrenia patients more often used centrally stimulating substances, had more frequent use of non-alcoholic drugs and more often used more than one non-alcoholic drug. Single use of cannabis was more frequent in bipolar disorder., Conclusion: The present study showed diagnosis-specific patterns of substance use in severe mental disorder. This suggests a need for more disease-specific treatment strategies, and indicates that substance use may be an important factor in studies of overlapping disease mechanisms.

Matthew Harlin,1,&ast; Craig Chepke,2,3,&ast; Frank Larsen,4,&ast; Karimah S Bell Lynum,5,&ast; Sanjeda R Chumki,5,&ast; Heather Fitzgerald,6,&ast; Pedro Such,7,&ast; Jessica Madera-McDonough,8,&ast; Murat Yildirim,7,&ast; Moeen Panni,8,&ast; Stephen R Saklad9,&ast; 1Quantitative Pharmacology, Clinical Pharmacology, Early Phase & Translational Medicine, Otsuka Pharmaceutical Development & Commercialization Inc., Princeton, NJ, USA; 2Department of Psychiatry, University of North Carolina School of Medicine, Chapel Hill, NC, USA; 3Excel Psychiatric Associates, Huntersville, NC, USA; 4Pharmacokinetic and Pharmacodynamic Modelling & Simulation, H. Lundbeck A/S, Valby, Denmark; 5US Medical Affairs, Otsuka Pharmaceutical Development & Commercialization Inc., Princeton, NJ, USA; 6Medical Affairs, Lundbeck LLC, Deerfield, IL, USA; 7Medical Affairs, H. Lundbeck A/S, Valby, Denmark; 8Global Medical Affairs, Otsuka Pharmaceutical Development & Commercialization Inc., Princeton, NJ, USA; 9Division of Pharmacotherapy, College of Pharmacy, The University of Texas at Austin, San Antonio, TX, USA&ast;These authors contributed equally to this workCorrespondence: Matthew Harlin, Otsuka Pharmaceutical Development & Commercialization Inc., 508 Carnegie Center Dr, Princeton, NJ, 08540, USA, Tel +1-240-683-3055, Email Matthew.Harlin@otsuka-us.comAbstract: Aripiprazole 2-month ready-to-use 960 mg (Ari 2MRTU 960) is a novel long-acting injectable (LAI) formulation of aripiprazole monohydrate for administration once every 2 months, developed for the treatment of schizophrenia or maintenance monotherapy treatment of bipolar I disorder in adults (indication will vary by country). Aripiprazole lauroxil 1064 mg (AL 1064) is an LAI formulation of aripiprazole lauroxil, an aripiprazole prodrug, for administration once every 2 months, indicated for the treatment of schizophrenia in adults. This analysis provides an indirect comparison of aripiprazole plasma concentrations following multiple doses of either formulation. Clinical trial data were used to determine average steady-state aripiprazole plasma concentration (Cavg,ss), maximum aripiprazole plasma concentration (Cmax), and other pharmacokinetic parameters of either formulation following four administrations (96 patients received Ari 2MRTU 960; 28 patients received AL 1064). All pharmacokinetic parameters were considered in the context of a minimum aripiprazole therapeutic concentration (Cmin) of ≥ 95 ng/mL. An exposure–response analysis using data from two Phase III trials of aripiprazole once-monthly (an aripiprazole monohydrate LAI, administered monthly), showed that patients with a Cmin ≥ 95 ng/mL are 4.41 times less likely to relapse than patients with a Cmin < 95 ng/mL. A similar analysis has not been performed for AL 1064. However, consensus guidelines for therapeutic drug monitoring recommend a range of 100– 350 ng/mL for aripiprazole. Following four administrations, mean (standard deviation [SD]) Cavg,ss over the 2-month dosing interval was 263 (133) ng/mL for Ari 2MRTU 960 and 140.7 (57.3) ng/mL for AL 1064. Mean (SD) Cmax during the fourth dosing interval was 342 (157) ng/mL for Ari 2MRTU 960 and 188.8 (79.8) ng/mL for AL 1064. This indirect comparison showed that, following four administrations, Ari 2MRTU 960 and AL 1064 delivered mean aripiprazole plasma concentrations that remained above the minimum therapeutic concentration of aripiprazole over the 2-month dosing interval.Keywords: antipsychotic, bipolar I disorder, long-acting injectable, schizophrenia

Objective: Prevalence estimates of illicit drug use in psychotic disorders vary between studies, and only a few studies compared prevalence estimates with those in the general population. Method: Cross-sectional study comparing 148 stable-phase patients with schizophrenia or bipolar disorder with 329 representative general citizens of Oslo. A total of 849 patients from the same hospital department in the same time period constituted a patient reference group. Results: Lifetime illicit drug use was 44% higher ( P < 0.001) in study patients than in the general population sample; while lifetime use of amphetamine/cocaine was 160% higher ( P < 0.001). No differences were found between user groups for sociodemographic characteristics. Conclusion: Patients with psychotic disorders in stable phase had a markedly higher lifetime use of any illicit substance, especially amphetamine/cocaine, than the general population. They also seemed to use drugs more periodically. The same sociodemographic characteristics were associated with increased illicit drug use in both groups. [ABSTRACT FROM AUTHOR]