Exposure-Response Modeling in Adults and Adolescents With Schizophrenia to Support the Extrapolation of Brexpiprazole Efficacy to Adolescents

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.

Adjunctive Brexpiprazole for Patient Life Engagement in Major Depressive Disorder: A Canadian, Phase 4, Open-Label, Interventional Study: Brexpiprazole d'appoint pour l'engagement dans la vie des patients souffrant de trouble dépressif majeur: une étude interventionnelle canadienne ouverte de phase 4

OBJECTIVES

To characterize the effects of adjunctive brexpiprazole on patient life engagement and depressive symptoms in patients with major depressive disorder (MDD) using patient-reported outcomes.

METHODS

An 8-week, Phase 4, open-label, interventional study was conducted at 15 Canadian trial sites between April 2021 and May 2022. Adult outpatients with MDD (at least moderately severe) and inadequate response to 1-2 antidepressants continued their current antidepressant and received oral adjunctive brexpiprazole 0.5-2 mg/day. Co-primary endpoints were change from baseline to Week 8 in Inventory of Depressive Symptomatology Self-Report (IDS-SR) 10-item Life Engagement subscale score, and IDS-SR 30-item total score. Safety was assessed by standard variables.

RESULTS

Of 122 enrolled patients, 120 (98.4%) were treated (mean [SD] dose: 1.2 [0.4] mg/day) and analyzed, and 111 (91.0%) completed the study. Statistically significant least squares mean improvements to Week 8 were observed on IDS-SR10 Life Engagement subscale score (baseline mean [SD]: 16.1 [4.7]; change [95% confidence interval]: -8.11 [-9.34, -6.88]; p < 0.001) and IDS-SR total score (baseline mean [SD]: 41.3 [9.8]; change [95% confidence interval]: -17.38 [-20.08, -14.68]; p < 0.001). Improvements were observed from Week 2, onwards. Treatment-emergent adverse events with incidence ≥5% were fatigue (n = 13, 10.8%), headache (n = 13, 10.8%), insomnia (n = 12, 10.0%), nausea (n = 9, 7.5%), tremor (n = 8, 6.7%), and weight increase (n = 7, 5.8%). Six patients (5.0%) discontinued due to adverse events. Mean (SD) change in body weight from baseline to last visit was +1.9 (3.4) kg.

CONCLUSIONS

Using an exploratory patient-reported outcome measure, patients with MDD and inadequate response to antidepressants who received open-label adjunctive brexpiprazole showed early and clinically meaningful improvement in patient life engagement, which should be further assessed in a prospective randomized controlled trial. Patient-rated depressive symptoms (on the validated 30-item IDS-SR) also improved. Adjunctive brexpiprazole was well tolerated, and no new safety signals were observed.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04830215.

Brexpiprazole: A new option in treating agitation in Alzheimer's dementia-Insights from transgenic mouse models

AIM

Brexpiprazole is the first FDA-approved treatment for agitation associated with dementia due to Alzheimer's disease. Agitation in Alzheimer's dementia (AAD) occurs in high prevalence and is a great burden for patients and caregivers. Efficacy, safety, and tolerability of brexpiprazole were demonstrated in the AAD clinical trials. To demonstrate the agitation-ameliorating effect of brexpiprazole in animals, we evaluated brexpiprazole in two AAD mouse models.

METHODS

The resident-intruder test was conducted in 5- to 6-month-old Tg2576 mice, given vehicle or brexpiprazole (0.01 or 0.03 mg/kg) orally 1 h before the test. Locomotor activity was measured in 6-month-old APPSL-Tg mice given vehicle or brexpiprazole (0.01 or 0.03 mg/kg) orally the evening before the start of locomotor measurement for 3 days.

RESULTS

In the resident-intruder test, Tg2576 mice showed significantly higher attack number and shorter latency to first attack compared to non-Tg mice. In the Tg mice, brexpiprazole treatment (0.03 mg/kg) significantly delayed the latency to first attack and showed a trend toward a decrease in attack number. APPSL-Tg mice (≧6 months old) showed significantly higher locomotion during dark period Phase II (Zeitgeber time [ZT] 16-20) and Phase III (ZT20-24) compared to non-Tg mice, correlating with the clinical observations of late afternoon agitation in Alzheimer's disease. Brexpiprazole treatment (0.01 and 0.03 mg/kg) significantly decreased hyperlocomotion during the Phase III in APPSL-Tg mice.

CONCLUSION

The suppression of attack behavior and the reduction of nocturnal hyperlocomotion in these Tg mice may be indicative of the therapeutic effect of brexpiprazole on AAD, as demonstrated in the clinical trials.

Comparative analysis of third-generation antipsychotics in first-episode schizophrenia: efficacy, safety, and cognitive impacts. A narrative review

BACKGROUND AND OBJECTIVES

Schizophrenia is a chronic, complex mental health disorder requiring effective management to mitigate its broad personal and societal impacts. This narrative review assesses the efficacy, effectiveness, and side effects of third-generation antipsychotics (TGAs) like aripiprazole, brexpiprazole, and cariprazine, focusing on their use in first-episode schizophrenia. These drugs aim to reduce side effects typical of earlier antipsychotics while more effectively addressing positive and cognitive symptoms.

METHODS

Our extensive literature review, using PubMed and Scopus, includes randomized controlled trials and observational studies, showing TGAs may match older antipsychotics in efficacy with fewer side effects, notably in reducing extrapyramidal symptoms and enhancing cognitive outcomes.

RESULTS

Aripiprazole appears effective in both acute and maintenance phases of schizophrenia, while brexpiprazole and cariprazine show potential in managing negative symptoms and improving social functioning, essential for patient recovery.

CONCLUSIONS

This review emphasizes the need for personalized treatment and further research to fully determine the long-term benefits and safety of TGAs. These findings can inform clinical decisions and underline the ongoing need for innovation in schizophrenia pharmacotherapy.

Emerging therapies for treatment of agitation, psychosis, or apathy in Alzheimer's disease

INTRODUCTION

Agitation, psychosis, and apathy are prevalent and highly distressing neuropsychiatric symptoms (NPS) of Alzheimer's disease (AD) that have been linked to numerous negative outcomes, including increased mortality, worsened cognitive decline, and caregiver burden. Current treatments for AD-associated agitation, namely atypical antipsychotics, provide some benefits but may increase the risk of serious adverse events and death. Meanwhile, no pharmacotherapies have been approved by regulatory agencies for the treatment of psychosis or apathy in AD. Over the past decade, many new and repurposed drugs have emerged as potential therapeutic options for managing these challenging NPS.

AREAS COVERED

This review aims to provide a comprehensive summary of pharmacotherapies that have recently been investigated in phase 2 and 3 clinical trials for the treatment of agitation, psychosis, or apathy in AD.

EXPERT OPINION

Novel atypical antipsychotics, serotonergic antidepressants, cannabinoids, and dextromethorphan combination drugs have shown promising results for alleviating agitation. Pimavanserin appears to be the most effective emerging therapy for psychosis, while methylphenidate has demonstrated good efficacy for apathy. Further research on biomarkers of NPS severity and treatment response, as well as continued improvements in methodological approaches are needed to advance the field.

Efficacy and safety of brexpiprazole for the treatment of agitation in Alzheimer's disease: a meta-analysis of randomized controlled trials

Recent randomized controlled trials (RCTs) have shown a benefit of brexpiprazole in managing agitation in patients with Alzheimer's disease (AD). However, its efficacy and safety remain unclear. We systematically searched PubMed, Embase, and Cochrane Library for RCTs comparing brexpiprazole with placebo in patients with agitation and AD. Three studies comprising 1,048 patients were included. In patients with agitation and AD, brexpiprazole significantly improved the Cohen-Mansfield Agitation Inventory total score (CMAI) at any dose (MD -3.05; 95% CI -5.12, -0.98; p < 0.01; I2 = 19%) and at 2 mg (MD -4.36; 95% CI -7.02, -1.70; p < 0.01; I2 = 0%) over 12 weeks. Brexpiprazole at any dose and 2 mg also showed benefit in the Clinical Global Impression - Severity of illness (CGI-S) score as related to agitation over 12 weeks (MD -0.20; 95% CI -0.36, -0.05; p < 0.01; I2 = 35%). There is no significant difference between the groups in the incidence of at least one treatment-emergent adverse events (TEAEs; RR 1.14; 95% CI 0.95, 1.37; p = 0.16; I2 = 45%) and all-cause mortality (RR 1.99; 95% CI 0.37, 10.84; p = 0.42; I2 = 0%). Brexpiprazole at any dose significantly increased the Simpson-Angus Scale (SAS; MD 0.47; 95% CI 0.28, 0.66; p < 0.01). Our results suggest that brexpiprazole is more efficacious than placebo in the treatment of agitation in AD patients. Further studies are still necessary to confirm long-term effects of brexpiprazole.Prospero registry: CRD42023486694.

Direct interrogation of context-dependent GPCR activity with a universal biosensor platform

G protein-coupled receptors (GPCRs) are the largest family of druggable proteins encoded in the human genome, but progress in understanding and targeting them is hindered by the lack of tools to reliably measure their nuanced behavior in physiologically relevant contexts. Here, we developed a collection of compact ONE vector G-protein Optical (ONE-GO) biosensor constructs as a scalable platform that can be conveniently deployed to measure G-protein activation by virtually any GPCR with high fidelity even when expressed endogenously in primary cells. By characterizing dozens of GPCRs across many cell types like primary cardiovascular cells or neurons, we revealed insights into the molecular basis for G-protein coupling selectivity of GPCRs, pharmacogenomic profiles of anti-psychotics on naturally occurring GPCR variants, and G-protein subtype signaling bias by endogenous GPCRs depending on cell type or upon inducing disease-like states. In summary, this open-source platform makes the direct interrogation of context-dependent GPCR activity broadly accessible.

A multicenter, single-arm, open-label interventional study of adherence to brexpiprazole during switching from previous antipsychotic drugs in patients with schizophrenia or schizoaffective disorder

The rate of medication persistence was examined in patients with schizophrenia or schizoaffective disorder during switching from previously administered antipsychotics to brexpiprazole, a new dopamine D2 receptor partial agonist. A multicenter, single-arm, open-label 24-week interventional study was conducted, consisting of two 12-week consecutive periods: an initial switch (by plateau cross-titration) with the subsequent period, followed by a second maintenance period. Prior antipsychotics were olanzapine or risperidone/paliperidone. The primary and secondary outcome measures were medication persistence rates after the first 12 weeks and changes from baseline in the Specific Levels of Functioning Scale (SLOF), Subjective Well-being under Neuroleptic drug treatment Short form (SWNS), and Positive and Negative Syndrome Scale (PANSS) scores, respectively. In total, 79 patients were administered brexpiprazole and the medication persistence rate at 12 weeks was 78.5%, which was significantly higher than the predefined threshold of 65%. Regarding the prior medication, the persistence rate at 12 weeks was 84.6% for olanzapine and 72.5% for risperidone/paliperidone. Significant improvements from baseline were observed in the SLOF, SWNS, and PANSS scores. There were no adverse events of concern. Thus, brexpiprazole appeared to be a suitable antipsychotic on switching from olanzapine, risperidone, or paliperidone.

Effects of Adjunctive Brexpiprazole on Individual Depressive Symptoms and Functioning in Patients With Major Depressive Disorder and Anxious Distress: Post Hoc Analysis of Three Placebo-Controlled Studies

PURPOSE/BACKGROUND

Anxiety symptoms in major depressive disorder (MDD) are frequent, and they decrease response to antidepressant treatment (ADT), and affect patient functioning. This post hoc analysis examined the efficacy of adjunctive brexpiprazole on individual depressive symptoms and functioning in patients with MDD with anxious distress.

METHODS/PROCEDURES

Data were included from three 6-week, randomized, double-blind, placebo-controlled studies of adjunctive brexpiprazole in patients with MDD and inadequate response to ADTs (ClinicalTrials.gov identifiers: NCT01360645, NCT01360632, NCT02196506). Patients were stratified using proxy criteria for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, anxious distress. Changes in Montgomery-Åsberg Depression Rating Scale item scores and Sheehan Disability Scale mean score from baseline to week 6 were determined for ADT + brexpiprazole (2 and 2-3 mg) versus ADT + placebo.

FINDINGS/RESULTS

At baseline, 450 of 746 patients (60.3%, 2 mg analysis) and 670 of 1162 patients (57.7%, 2-3 mg analysis) had anxious distress. In patients with anxious distress, ADT + brexpiprazole 2 mg or 2 to 3 mg showed greater improvements than ADT + placebo (P < 0.05) on the Montgomery-Åsberg Depression Rating Scale items of apparent sadness, reported sadness, inner tension, reduced sleep, reduced appetite, lassitude, inability to feel, and pessimistic thoughts (Cohen d effect sizes, 0.18-0.44), and on Sheehan Disability Scale mean score (effect sizes, 0.21-0.23).

IMPLICATIONS/CONCLUSIONS

Adjunctive brexpiprazole is efficacious in reducing core depressive symptoms, sleep, and appetite, as well as improving functioning, in patients with MDD and anxious distress who have inadequate response to ADTs.

Brexpiprazole Attenuates Aggression, Suicidality and Substance Use in Borderline Personality Disorder: A Case Series

Background: Borderline personality disorder (BPD) is a heterogeneous and highly comorbid disorder. Suicidality, aggression and substance abuse are common presentations of BPD. Our case series is the first to highlight the role of brexpiprazole in improving these symptoms in patients with BPD. Case presentation: We describe three cases demonstrating the role of brexpiprazole in improving BPD's prominent features and comorbidities. All cases improved when brexpiprazole was added to their treatment regime. Case 1: A 26-year-old woman who was diagnosed with BPD and cyclothymia, presented to the psychiatric emergency unit with impulsive suicidal behaviour. Case 2: A 43-year-old woman suffering from BPD sought help due to her violent behaviour and emotional dysregulation. Case 3: A 22-year-old woman with underlying attention deficit and hyperactivity disorder, polysubstance use disorder and BPD presented with dysregulated emotions. Conclusions: Our case series provides anecdotal evidence of the potential role of brexpiprazole in attenuating suicidality, aggression and substance abuse in patients with BPD. We postulate that brexpiprazole's high affinity for the 5HT1A/5HT2A receptors, coupled with its low intrinsic effect on the D2/D3 receptor system, is fundamental in its actions to stabilise the aberrant dopaminergic and serotonergic signalling in BPD. Future research should focus on well-designed clinical trials investigating the efficacy of brexpiprazole in patients with BPD.

Adjunctive brexpiprazole 1 mg and 2 mg daily for Japanese patients with major depressive disorder following inadequate response to antidepressants: a phase 2/3, randomized, double-blind (BLESS) study

AIMS

Inadequate antidepressant response interrupts effective treatment of major depressive disorder (MDD). The BLESS study evaluates the dosage, efficacy, and safety of brexpiprazole adjunctive therapy in Japanese patients with inadequate antidepressant therapy (ADT) response.

METHODS

This placebo-controlled, randomized, multicenter, parallel-group phase 2/3 study randomized Japanese MDD patients (Hamilton Rating Scale for Depression 17-item total score ≥ 14; historical inadequate response to 1-3 ADTs) with inadequate response to 8-week single-blind, prospective SSRI/SNRI treatment to 6-week adjunctive treatment with brexpiprazole 1 mg, 2 mg, or placebo. The primary endpoint was change in Montgomery-Åsberg Depression Rating Scale (MADRS) total score from baseline. Secondary endpoints included MADRS response, remission rate, and Clinical Global Impression-Improvement score. Safety was comprehensively evaluated, especially regarding antipsychotic adverse events (AEs).

RESULTS

Of 1194 screened patients, 740 were randomized and 736 (1 mg, n = 248; 2 mg, n = 245; placebo, n = 243) had ≥1 baseline/post-baseline MADRS total score. The LSM (SE) change from baseline in MADRS total score at Week 6 by MMRM analysis was -8.5 (0.47) with brexpiprazole 1 mg, -8.2 (0.47) with brexpiprazole 2 mg, and -6.7 (0.47) with placebo (placebo-adjusted LSM difference [95% CI]: 1 mg, -1.7 [-3.0, -0.4]; P = 0.0089; 2 mg, -1.4 [-2.7, -0.1]; P = 0.0312). Secondary efficacy results supported the primary endpoint. Brexpiprazole was generally well tolerated.

CONCLUSION

Brexpiprazole 1 mg daily was an appropriate starting dose and both 1 mg and 2 mg daily were effective and well tolerated as adjunctive therapy for Japanese MDD patients not adequately responsive to ADT.

Third-Generation Antipsychotics and Lurasidone in the Treatment of Substance-Induced Psychoses: A Narrative Review

This narrative review explores the efficacy and tolerability of third-generation antipsychotics (TGAs)-aripiprazole, cariprazine, brexpiprazole, and lurasidone-for the management of substance-induced psychosis (SIP). SIP is a psychiatric condition triggered by substance misuse or withdrawal, characterized by unique features distinct from those of primary psychotic disorders. These distinctive features include a heightened prevalence of positive symptoms, such as hallucinations and delusions, in addition to a spectrum of mood and cognitive disturbances. This review comprehensively investigates various substances, such as cannabinoids, cocaine, amphetamines, and LSD, which exhibit a greater propensity for inducing psychosis. TGAs exhibit substantial promise in addressing both psychotic symptoms and issues related to substance misuse. This review elucidates the distinctive pharmacological properties of each TGA, their intricate interactions with neurotransmitters, and their potential utility in the treatment of SIP. We advocate for further research to delineate the long-term effects of TGAs in this context and underscore the necessity for adopting an integrated approach that combines pharmacological and psychological interventions. Our findings underscore the intricate and multifaceted nature of treating SIP, highlighting the potential role of TGAs within therapeutic strategies.

Direct interrogation of context-dependent GPCR activity with a universal biosensor platform

G protein-coupled receptors (GPCRs) are the largest family of druggable proteins in the human genome, but progress in understanding and targeting them is hindered by the lack of tools to reliably measure their nuanced behavior in physiologically-relevant contexts. Here, we developed a collection of compact ONE vector G-protein Optical (ONE-GO) biosensor constructs as a scalable platform that can be conveniently deployed to measure G-protein activation by virtually any GPCR with high fidelity even when expressed endogenously in primary cells. By characterizing dozens of GPCRs across many cell types like primary cardiovascular cells or neurons, we revealed new insights into the molecular basis for G-protein coupling selectivity of GPCRs, pharmacogenomic profiles of anti-psychotics on naturally-occurring GPCR variants, and G-protein subtype signaling bias by endogenous GPCRs depending on cell type or upon inducing disease-like states. In summary, this open-source platform makes the direct interrogation of context-dependent GPCR activity broadly accessible.

Brexpiprazole in patients with schizophrenia with or without substance use disorder: an observational study

Background

Partial dopamine D2 receptor agonists are used for psychotic symptoms in adults with schizophrenia spectrum disorders. Recently, interest surged for partial dopamine D2 receptor agonists in substance use disorders (SUDs). Since it is believed that SUDs decrease the efficacy of pharmacotherapy of underlying psychiatric disorders, we tested the efficacy of the partial D2 agonist brexpiprazole in patients with schizophrenia who were either comorbid with a SUD (SUD group) or not comorbid (non-SUD) to assess treatment response and the effect of brexpiprazole on substance craving in SUD.

Methods

We included patients with DSM-5/DSM-5-TR schizophrenia (using SCID-5-CV) aged 18-66 years with either comorbid SUD or non-SUD to treat with brexpiprazole 4 mg/day for 6 months during February-October 2022. Patients were assessed with the Clinical Global Impressions-Severity (CGI-S) scale, the 24-item Brief Psychiatric Rating Scale (BPRS), and the Positive And Negative Syndrome Scale (PANSS) at baseline, weekly for the first 2 months and monthly for the next four. Furthermore, we assessed substance craving in SUD with a visual analog scale for craving (VAScrav) at the same timepoints.

Results

The total sample was 86 (85 analysable) 18- to 64-year-old (mean 39.32 ± 14.09) patients with schizophrenia [51 men (59.3%) and 35 women (40.7%)], of whom 48 SUD (55.8%) (37 men and 11 women) and 38 non-SUD (44.2%) (14 men and 24 women). No serious or persistent adverse events developed over the study period, but one patient dropped out for subjective akathisia. Results indicated the main effects of time with improvements over the course of the study for CGI-S, BPRS, and PANSS in both SUD and non-SUD groups and the entire sample, and for VAScrav in SUD. Brexpiprazole was associated with similar significant improvements in both groups at the 6 month endpoint compared to baseline.

Conclusion

Treatment with brexpiprazole for 6 months improved psychotic symptoms in patients with schizophrenia, independently from whether they belonged to the SUD or the non-SUD group; hence, SUD comorbidity did not confer treatment resistance to brexpiprazole. Furthermore, in the SUD group, we observed reduced substance craving.

Structure, function and drug discovery of GPCR signaling

G protein-coupled receptors (GPCRs) are versatile and vital proteins involved in a wide array of physiological processes and responses, such as sensory perception (e.g., vision, taste, and smell), immune response, hormone regulation, and neurotransmission. Their diverse and essential roles in the body make them a significant focus for pharmaceutical research and drug development. Currently, approximately 35% of marketed drugs directly target GPCRs, underscoring their prominence as therapeutic targets. Recent advances in structural biology have substantially deepened our understanding of GPCR activation mechanisms and interactions with G-protein and arrestin signaling pathways. This review offers an in-depth exploration of both traditional and recent methods in GPCR structure analysis. It presents structure-based insights into ligand recognition and receptor activation mechanisms and delves deeper into the mechanisms of canonical and noncanonical signaling pathways downstream of GPCRs. Furthermore, it highlights recent advancements in GPCR-related drug discovery and development. Particular emphasis is placed on GPCR selective drugs, allosteric and biased signaling, polyphamarcology, and antibody drugs. Our goal is to provide researchers with a thorough and updated understanding of GPCR structure determination, signaling pathway investigation, and drug development. This foundation aims to propel forward-thinking therapeutic approaches that target GPCRs, drawing upon the latest insights into GPCR ligand selectivity, activation, and biased signaling mechanisms.

Brexpiprazole for the Treatment of Agitation in Alzheimer Dementia: A Randomized Clinical Trial

Importance

Agitation is a prevalent, distressing, and burdensome manifestation of Alzheimer dementia in need of an efficacious, safe, and well-tolerated treatment.

Objective

To confirm the efficacy, safety, and tolerability of brexpiprazole in patients with agitation in Alzheimer dementia.

Design, Setting, and Participants

This randomized clinical trial was a 12-week, double-blind, placebo-controlled, fixed-dose, parallel-arm trial that ran from May 2018 to June 2022 at 123 clinical trial sites in Europe and the United States. Participants included patients with agitation in Alzheimer dementia in a care facility or community-based setting. Stable Alzheimer disease medications were permitted.

Interventions

In this 2-arm trial, patients were randomized to receive oral brexpiprazole or placebo (2:1 ratio) for 12 weeks. Within the brexpiprazole arm, patients were further randomized to receive fixed doses of 2 mg/d or 3 mg/d in a 1:2 ratio.

Main Outcomes and Measures

The primary end point was change in Cohen-Mansfield Agitation Inventory total score (which measures the frequency of 29 agitated behaviors) from baseline to week 12 for brexpiprazole, 2 or 3 mg, vs placebo. Safety was assessed by standard measures, including treatment-emergent adverse events.

Results

A total of 345 patients were randomized to receive brexpiprazole (n = 228) or placebo (n = 117); completion rates were 198 (86.8%) for brexpiprazole and 104 (88.9%) for placebo. Mean (SD) age was 74.0 (7.5) years, and 195 of 345 patients were female (56.5%). Patients receiving brexpiprazole, 2 or 3 mg (n = 225), demonstrated statistically significantly greater improvement than those taking placebo (n = 116) in Cohen-Mansfield Agitation Inventory total score from baseline to week 12 (brexpiprazole baseline, 80.6, mean change, -22.6; placebo baseline, 79.2, mean change, -17.3; least-squares mean difference, -5.32; 95% CI, -8.77 to -1.87; P = .003; Cohen d effect size, 0.35). No treatment-emergent adverse events had an incidence of 5% or more with brexpiprazole and greater incidence than placebo. The proportion of patients who discontinued because of adverse events was 12 of 226 (5.3%) for brexpiprazole and 5 of 116 (4.3%) for placebo.

Conclusions and Relevance

In this study, patients with Alzheimer dementia who took brexpiprazole, 2 or 3 mg, showed a statistically significant improvement vs placebo in agitation over 12 weeks. Brexpiprazole was generally well tolerated over 12 weeks in this vulnerable patient population.

Trial Registration

ClinicalTrials.gov Identifier: NCT03548584.

Population Pharmacokinetic Analysis of Brexpiprazole to Support its Indication and Dose Selection in Adolescents With Schizophrenia

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.

Can brexpiprazole be switched safely in patients with schizophrenia and dopamine supersensitivity psychosis? A retrospective analysis in a real-world clinical practice

BACKGROUND

Several studies have reported that a switch to the dopamine partial agonist (DPA) aripiprazole (ARP), especially when the switch is abrupt, is likely to fail and sometimes worsen psychosis in schizophrenia patients already under high-dose antipsychotic treatment. Such a switching failure is speculated to be related to be the dopamine supersensitivity state. The risks of switching to the DPA brexpiprazole (BREX) have not been reported.

AIMS AND METHODS

We retrospectively analyzed the cases of 106 patients with schizophrenia to identify any factors related to the success or failure of switching to BREX.

RESULTS

The comparison between the patients with dopamine supersensitivity psychosis (n = 44) and those without (n = 62) revealed no significant difference in the switching failure judged at the sixth week. A comparison of the patients with successful switching (n = 80) and those who failed (n = 26) revealed that patients with treatment-resistant schizophrenia (TRS) were significantly more likely to fail. A logistic regression analysis also revealed that patients with past failure of switching to ARP are likely to succeed in switching to BREX. The 2-year follow-up of the patients with successful switching to BREX suggested that the patients who were treated with BREX, even temporarily, experienced some improvement in their Global Assessment of Functioning and Clinical Global Impression-Severity scores.

CONCLUSIONS

Overall, the results indicate that patients with schizophrenia can be switched more safely to BREX compared to ARP. However, the failure of switching to BREX could be higher in patients with TRS, and thus, starting BREX treatment in refractory patients warrants careful monitoring.

A Novel Gliotransmitter, L-β-Aminoisobutyric Acid, Contributes to Pathophysiology of Clinical Efficacies and Adverse Reactions of Clozapine

Clozapine is listed as one of the most effective antipsychotics and has been approved for treating treatment-resistant schizophrenia (TRS); however, several type A and B adverse reactions, including weight gain, metabolic complications, cardiotoxicity, convulsions, and discontinuation syndromes, exist. The critical mechanisms of clinical efficacy for schizophrenia, TRS, and adverse reactions of clozapine have not been elucidated. Recently, the GABA isomer L-β-aminoisobutyric acid (L-BAIBA), a protective myokine in the peripheral organs, was identified as a candidate novel transmission modulator in the central nervous system (CNS). L-BAIBA activates adenosine monophosphate-activated protein kinase (AMPK) signalling in both the peripheral organs and CNS. Activated AMPK signalling in peripheral organs is an established major target for treating insulin-resistant diabetes, whereas activated AMPK signalling in the hypothalamus contributes to the pathophysiology of weight gain and metabolic disturbances. Clozapine increases L-BAIBA synthesis in the hypothalamus. In addition, the various functions of L-BAIBA in the CNS have recently been elucidated, including as an activator of GABA-B and group-III metabotropic glutamate (III-mGlu) receptors. Considering the expressions of GABA-B and III-mGlu receptors (localised in the presynaptic regions), the activation of GABA-B and III-mGlu receptors can explain the distinct therapeutic advantages of clozapine in schizophrenia or TRS associated with N-methyl-D-aspartate (NMDA) receptor disturbance compared with other atypical antipsychotics via the inhibition of the persistent tonic hyperactivation of thalamocortical glutamatergic transmission in the prefrontal cortex. L-BAIBA has also been identified as a gliotransmitter, and a detailed exploration of the function of L-BAIBA in tripartite synaptic transmission can further elucidate the pathophysiology of effectiveness for treating TRS and/or specific adverse reactions of clozapine.

Creation of a ready-to-use brexpiprazole suspension and the inflammation-mediated pharmacokinetics by intramuscular administration

Brexpiprazole (BPZ), which is approved for the treatment of schizophrenia and major depressive disorder, has the potential to meet diverse clinical needs. This study aimed to develop a long-acting injectable (LAI) formulation of BPZ that could provide sustained therapeutic benefits. A library of BPZ prodrugs was screened through esterification, and BPZ laurate (BPZL) was identified as an optimal candidate. To achieve stable aqueous suspensions, a pressure- and nozzle size-controlled microfluidization homogenizer was utilized. The pharmacokinetics (PK) profiles, considering dose and particle size modulation, were investigated following a single intramuscular injection in beagles and rats. BPZL treatment resulted in sustained plasma concentrations above the median effective concentration (EC₅₀) for 2∼3 weeks, without exhibiting an initial burst release. Histological examination of foreign body reaction (FBR) in rats revealed the morphological evolution of an inflammation-mediated drug depot, confirming the sustained release mechanism of BPZL. These findings provide strong support for the further development of a ready-to-use LAI suspension of BPZL, which could potentially enhance treatment outcomes, improve patient adherence, and address the clinical challenges associated with long-term regimens of schizophrenia spectrum disorders (SSD).

Pharmacotherapy for Treatment-Resistant Depression: Antidepressants and Atypical Antipsychotics

Treatment-resistant depression (TRD) affects one in three patients with major depressive disorder and is associated with increased risk of all-cause mortality. Studies of real-world practices suggest that antidepressant monotherapy continues to be the most widely used treatment after inadequate response to a first-line treatment. However, rates of remission with antidepressants in TRD are suboptimal. Atypical antipsychotics are the most widely studied augmentation agent and aripiprazole, brexpiprazole, cariprazine, quetiapine extended-release, and olanzapine-fluoxetine combination are approved for depression. Benefits of using atypical antipsychotics for TRD has to be weighted against their potential adverse events, such as weight gain, akathisia, and tardive dyskinesia.

Antipsychotic-induced bone loss: the role of dopamine, serotonin and adrenergic receptor signalling

Antipsychotics are commonly used in treating psychiatric disorders. These medications primarily target dopamine the serotonin receptors, they have some affinity to adrenergic, histamine, glutamate and muscarinic receptors. There is clinical evidence that antipsychotic use decreases BMD and increases fracture risk, with dopamine, serotonin and adrenergic receptor-signalling becoming an increasing area of focus where the presence of these receptors in osteoclasts and osteoblasts have been demonstrated. Osteoclasts and osteoblasts are the most important cells in the bone remodelling and the bone regeneration process where the activity of these cells determine the bone resorption and formation process in order to maintain healthy bone. However, an imbalance in osteoclast and osteoblast activity can lead to decreased BMD and increased fracture risk, which is also believed to be exacerbated by antipsychotics use. Therefore, the aim of this review is to provide an overview of the mechanisms of action of first, second and third generation antipsychotics and the expression profiles of dopamine, serotonin and adrenergic receptors during osteoclastogenesis and osteoblastogenesis.

G protein-coupled receptors in neurodegenerative diseases and psychiatric disorders

Neuropsychiatric disorders are multifactorial disorders with diverse aetiological factors. Identifying treatment targets is challenging because the diseases are resulting from heterogeneous biological, genetic, and environmental factors. Nevertheless, the increasing understanding of G protein-coupled receptor (GPCR) opens a new possibility in drug discovery. Harnessing our knowledge of molecular mechanisms and structural information of GPCRs will be advantageous for developing effective drugs. This review provides an overview of the role of GPCRs in various neurodegenerative and psychiatric diseases. Besides, we highlight the emerging opportunities of novel GPCR targets and address recent progress in GPCR drug development.

Preclinical evidence for the use of the atypical antipsychotic, brexpiprazole, for opioid use disorder

Opioid addiction is characterized by adaptations in the mesolimbic dopamine system that occur during chronic opioid use. Alterations in dopaminergic transmission contribute to pathological drug-seeking behavior and other symptoms associated with opioid withdrawal following drug discontinuation, making drug abstinence challenging and contributing to high rates of relapse among those suffering from substance use disorder. Recently, the use of dopamine partial agonists has been proposed as a potential strategy to restore dopaminergic signalling during drug withdrawal, while avoiding the adverse side effects associated with stronger modulators of dopaminergic transmission. We investigated the effects of the atypical antipsychotic brexpiprazole, which is a partial agonist at dopamine D2 and D3 receptors, in a mouse model of opioid dependence. The development of opioid dependence in mice is characterized by locomotor sensitization, analgesic tolerance, opioid-induced hyperalgesia, and drug-seeking behavior. We set up four paradigms to model the effects of brexpiprazole on each of these adaptations that occur during chronic opioid use in male and female C57BL/6J mice. Concomitant treatment of brexpiprazole during chronic morphine administration attenuated the development of locomotor sensitization. Brexpiprazole treatment abolished morphine place preference and blocked reinstatement of this behavior following extinction. Brexpiprazole treatment did not alter morphine analgesia, nor did it impact the development of morphine tolerance. However, brexpiprazole treatment did prevent the expression of opioid-induced hyperalgesia in a tail-withdrawal assay, while failing to improve somatic withdrawal symptoms. Altogether, these results provide preclinical evidence for the efficacy of brexpiprazole as a modulator of dopamine-dependent behaviors during opioid use and withdrawal.

Effects of adjunctive brexpiprazole on patient life engagement in major depressive disorder: Post hoc analysis of Inventory of Depressive Symptomatology Self-Report data

BACKGROUND

Patient-reported outcomes can capture domains that are meaningful to patients, such as life engagement in major depressive disorder (MDD), which reflects life fulfillment, well-being, and participation in valued and meaningful activities. This analysis investigated the effects of brexpiprazole adjunct to antidepressant treatment (ADT) on patient life engagement over the short and long term, using the 10-item Inventory of Depressive Symptomatology Self-Report (IDS-SR₁₀) Life Engagement subscale.

METHODS

Short-term data were pooled from three 6-week, randomized, double-blind studies of ADT + brexpiprazole 2-3 mg/day versus ADT + placebo in adult outpatients with MDD (DSM-IV-TR criteria) and inadequate response to ADTs. Long-term data were from a 26-52-week, open-label extension study of ADT + brexpiprazole 0.5-3 mg/day.

RESULTS

Over 6 weeks, ADT + brexpiprazole (n = 579) showed greater improvement in IDS-SR₁₀ Life Engagement subscale score than ADT + placebo (n = 583), with a least squares mean difference of -1.19 (95% confidence limits: -1.78, -0.59; p = 0.0001; Cohen's d effect size: 0.23). Greater improvement for ADT + brexpiprazole versus ADT + placebo (p < 0.05) was also observed on eight life engagement items, with effect sizes ranging from 0.12 to 0.24. In the long-term study, mean (standard deviation) IDS-SR₁₀ Life Engagement subscale score changed by -2.4 (4.9) points to Week 26 (n = 2047), and -3.7 (5.3) points to Week 52 (n = 768), with mean improvements on all ten items.

CONCLUSIONS

Beyond its efficacy on depressive symptoms, adjunctive brexpiprazole may improve patient life engagement, thereby helping patients with MDD to achieve personally meaningful functional outcomes.

An exploratory database study of factors influencing the continuation of brexpiprazole treatment (prescription) in patients with schizophrenia using information from psychiatric electronic medical records processed with natural language processing

Using natural language processing (NLP) technology to analyze and organize textual information in psychiatric electronic medical records can identify undiscovered factors associated with treatment discontinuation. This study aimed to evaluate brexpiprazole treatment continuation rate and factors affecting brexpiprazole discontinuation using a database that employs the MENTAT® system with NLP technology. This retrospective observational study evaluated patients with schizophrenia who were newly initiated on brexpiprazole (April 18, 2018-May 15, 2020). The first prescriptions of brexpiprazole were followed up for 180 days. Factors associated with brexpiprazole discontinuation were assessed using structured and unstructured patient data (April 18, 2017-December 31, 2020). The analysis population comprised 515 patients; mean (standard deviation) age of patients was 48.0 (15.3) years, and 47.8 % were male. Using Kaplan-Meier analysis, the cumulative brexpiprazole continuation rate at 180 days was 29 % (estimate: 0.29; 95 % confidence interval, 0.25-0.33). Univariate Cox proportional hazards analysis identified 16 variables independently associated with brexpiprazole discontinuation. Multivariate analysis identified eight variables associated with treatment discontinuation: variables with hazard ratio <1 were the presence of physical complications, longer hospitalization duration, and maximum chlorpromazine-equivalent dose of antipsychotics of >200 to ≤400 mg/day vs ≤200 mg/day in the past year; variables with hazard ratio >1 were previous electroconvulsive therapy, availability of key contact person information, a history of crime committed/reported, increase in brexpiprazole dose to 2 mg in >28 days, and appearance/worsening of symptoms other than positive symptoms. In conclusion, we identified potential new factors that may be associated with brexpiprazole discontinuation, which may improve the treatment strategy and continuation rate in patients with schizophrenia.

A 2023 update on the advancements in the treatment of agitation in Alzheimer's disease

INTRODUCTION

Neuropsychiatric symptoms (NPS) in Alzheimer's Disease (AD) are associated with negative outcomes for patients and their care partners. Agitation is one of the most common and distressing NPS, yet we lack safe and effective treatment options. While nonpharmacologic interventions are considered first line treatment, these may not be effective or appropriate for every patient. Our current approaches to the pharmacologic treatment of agitation in AD consist of the off-label use of antipsychotics, sedative/hypnotics, anxiolytics, mood-stabilizing anticonvulsants, acetylcholinesterase inhibitors, NMDA receptor antagonists, and antidepressants. Despite their prevalent use, they have questionable efficacy and significant safety concerns.

AREAS COVERED

Advances in the understanding of neurobiological mechanisms of agitation have fueled recent clinical trials. This article is an update to our 2017 review. A comprehensive search of ClinicalTrials.gov was completed from January 2017 to June 2022 using the search terms "Alzheimer's Disease" and "Agitation". A subsequent scoping review was completed in PubMed and Google Scholar. Several agents were identified for promise in treating agitation, including: brexpiprazole, cannabinoids, dexmedetomidine, dextromethorphan, escitalopram, masupirdine, and prazosin.

EXPERT OPINION

Clinical trials remain underway utilizing both novel and repurposed agents to address symptoms of agitation in AD. With increasing understanding of the neurobiological mechanisms that fuel the development of agitation in AD, the use of enhanced trial design and conduct, advanced statistical approaches, and accelerated pathways for regulatory approval, we are advancing closer to having safe and efficacious treatment options for agitation in AD.

Dopamine Dynamics and Neurobiology of Non-Response to Antipsychotics, Relevance for Treatment Resistant Schizophrenia: A Systematic Review and Critical Appraisal

Treatment resistant schizophrenia (TRS) is characterized by a lack of, or suboptimal response to, antipsychotic agents. The biological underpinnings of this clinical condition are still scarcely understood. Since all antipsychotics block dopamine D2 receptors (D2R), dopamine-related mechanisms should be considered the main candidates in the neurobiology of antipsychotic non-response, although other neurotransmitter systems play a role. The aims of this review are: (i) to recapitulate and critically appraise the relevant literature on dopamine-related mechanisms of TRS; (ii) to discuss the methodological limitations of the studies so far conducted and delineate a theoretical framework on dopamine mechanisms of TRS; and (iii) to highlight future perspectives of research and unmet needs. Dopamine-related neurobiological mechanisms of TRS may be multiple and putatively subdivided into three biological points: (1) D2R-related, including increased D2R levels; increased density of D2Rs in the high-affinity state; aberrant D2R dimer or heteromer formation; imbalance between D2R short and long variants; extrastriatal D2Rs; (2) presynaptic dopamine, including low or normal dopamine synthesis and/or release compared to responder patients; and (3) exaggerated postsynaptic D2R-mediated neurotransmission. Future points to be addressed are: (i) a more neurobiologically-oriented phenotypic categorization of TRS; (ii) implementation of neurobiological studies by directly comparing treatment resistant vs. treatment responder patients; (iii) development of a reliable animal model of non-response to antipsychotics.

Brexpiprazole prevents colitis-induced depressive-like behavior through myelination in the prefrontal cortex

Patients with inflammatory bowel disease (IBD) have higher rates of psychiatric pathology including depression. The dextran sulfate sodium (DSS)-treated mice exhibit IBD- and depressive-like phenotypes. A disturbed intestinal environment causes a decrease in serotonin and abnormal myelination in the brain, along with depressive-like behavior in rodents. However, the involvement of these factors in DSS-induced depressive-like behavior in mice remains unclear. In this study, we examined whether myelin proteins in the prefrontal cortex (PFC) and hippocampi were altered in DSS-treated mice, along with the changes in the serotonergic system in the PFC by western blotting and HPLC. The effects of brexpiprazole (Brx), a serotonin modulator, on DSS-induced depressive-like behavior using the tail-suspension test were evaluated. Subsequently, we investigated Brx's effects on the levels of myelin, nodal proteins, and neurotrophic molecules in the PFC with western blotting, and examined the altered node of Ranvier formation by immunohistochemistry. DSS-treated mice showed a reduction in myelin and nodal proteins, dysfunction of the serotonergic system, and impaired formation of the nodes of Ranvier in the PFC. Brx administration prevented the DSS-induced depressive-like behavior and demyelination in the PFC. However, the Brx-mediated effects were inhibited by the selective 5-HT_1A antagonist, WAY100635, or the selective TrkB antagonist, ANA-12. Brx decreased the phosphorylation of ERK, CREB, and TrkB along with the expression of BDNF in the PFC of DSS-treated mice. Moreover, the effects of Brx were blocked by WAY100635. These findings indicated that myelination regulated by the activation of the ERK1/2-CREB-BDNF-TrkB pathway in the PFC may be involved in mediating the antidepressant effects of Brx.

Analysis of the effect of brexpiprazole on sleep architecture in patients with schizophrenia: A preliminary study

BACKGROUND

Brexpiprazole is an atypical antipsychotic drug widely used in Japan for the treatment of schizophrenia. Previous studies have investigated the therapeutic effects of some antipsychotics on sleep variables; however, to our knowledge, the effects of brexpiprazole on sleep architecture have not been examined in patients with schizophrenia. Therefore, we aimed to exploratorily investigate the effect of brexpiprazole on sleep variables measured by polysomnography in patients with schizophrenia.

METHODS

This study included 10 patients with schizophrenia who were originally treated with haloperidol alone. Sleep variables of the participants were measured using polysomnography. After excluding those who did not meet the study criteria, seven patients (five men and two women; mean age [SD], 59.0 [10.0] years) were eligible for further analysis. Polysomnography was repeated at 4 weeks after the participants were prescribed brexpiprazole in addition to haloperidol. We compared the sleep architecture of the participants, measured using polysomnography, before and after taking brexpiprazole.

RESULTS

Add-on brexpiprazole significantly prolonged rapid eye movement latency, increased the duration and percentage of stage N2 and stage N3 sleep (min, %), and decreased the duration and percentage of stage rapid eye movement sleep (min, %) at a significance level of nominal p < 0.05.

CONCLUSION

Although not significant after correcting for multiple comparisons, the present results showed that add-on brexpiprazole could alter the sleep architecture of patients with schizophrenia. Future studies are warranted to replicate these findings and to further investigate the beneficial influence of brexpiprazole on sleep.

Synergistic anti-depressive effect of combination treatment of Brexpiprazole and selective serotonin reuptake inhibitors on forced swimming test in mice

AIM

Selective serotonin reuptake inhibitors (SSRIs) are used to treat major depressive disorder (MDD) and other psychiatric disorders (e.g., obsessive compulsive disorder, social anxiety disorder, and panic disorder). In MDD treatment, SSRIs do not show remission in approximately 30% of patients, indicating a need for a better treatment option. Forced swimming test (FST) is a behavioral assay to evaluate depression-like behavior and antidepressant efficacy in rodents. In the present study, we evaluated the combination effect of brexpiprazole with SSRIs on FST in mice, in order to investigate their synergistic effect.

METHODS

Brexpiprazole (0.003 mg/kg) was intraperitoneally injected to mice 15 min before testing. Escitalopram (10 mg/kg), fluoxetine (75 mg/kg), paroxetine (10 mg/kg), or sertraline (15 mg/kg) were orally administered to mice 60 min before testing. Then, the mice were placed in water and immobility time was measured. Data from animals treated with escitalopram, fluoxetine, paroxetine, and sertraline were pooled as SSRI-treated group data.

RESULTS

Combination treatment of brexpiprazole with SSRIs reduced immobility time in FST more than vehicle or each single treatment. A significant interaction effect was confirmed in the combination of brexpiprazole and SSRIs (p = 0.0411).

CONCLUSION

Efficacy of adjunctive brexpiprazole has already been demonstrated in clinical trials in MDD patients not adequately responding to antidepressants including escitalopram, fluoxetine, paroxetine, and sertraline. The synergistic antidepressant-like effect of brexpiprazole with SSRIs found in this study supports the already known clinical findings.

Pharmacotherapies for Treatment-Resistant Depression: How Antipsychotics Fit in the Rapidly Evolving Therapeutic Landscape

One in three adults with major depressive disorder (MDD) do not experience clinically significant improvement after multiple sequential courses of antidepressants and have treatment-resistant depression (TRD). The presence of TRD contributes to the morbidity and excess mortality associated with MDD and has been linked to significantly increased health care expenses. In the absence of a consensus definition of TRD, this report takes a broad approach by considering inadequate response to one or more courses of antidepressants and focuses on atypical antipsychotics that are approved by the U.S. Food and Drug Administration for treatment of depression (aripiprazole, brexpiprazole, cariprazine, extended-release quetiapine, and olanzapine-fluoxetine combination). While multiple acute-phase studies have demonstrated the efficacy of these medications in improving depressive symptoms, clinically meaningful improvement (i.e., remission) remains limited, with significant concerns about side effects (including weight gain, metabolic dysfunction, extrapyramidal symptoms, and tardive dyskinesia), especially with long-term use. With the rapidly evolving landscape of antidepressant treatments over the past few years, which has witnessed approval of rapid-acting antidepressants (e.g., esketamine nasal spray and dextromethorphan-bupropion combination) and several more in the late-stage pipeline (e.g., zuranolone and psilocybin), it remains to be seen whether the use of atypical antipsychotics will go the way of the older and rarely prescribed antidepressants (such as tricyclics and monoamine oxidase inhibitors). Pragmatic clinical trials are needed to compare the effectiveness of atypical antipsychotics with TRD-specific pharmacotherapies and neuromodulation treatments and to identify the optimal sequencing of these varied approaches for patients with MDD. When using atypical antipsychotics, clinicians and patients are encouraged to use a shared decision-making approach by personalizing treatment selection based on anticipated side effects, tolerability, cost, and feasibility.

Brexpiprazole—Pharmacologic Properties and Use in Schizophrenia and Mood Disorders

In 2002, the first III generation antipsychotic drug was registered—aripiprazole. Its partial dopaminergic agonism underlies its unique mechanism of action and the potentially beneficial influence on the positive, negative, or cognitive symptoms. Due to its relatively high intrinsic activity, the drug could often cause agitation, anxiety, or akathisia. For this reason, efforts were made to develop a drug which would retain the positive favorable actions of aripiprazole but present a more advantageous clinical profile. This turned out to be brexpiprazole, which was registered in 2015. Its pharmacodynamic and pharmacokinetic profile (similarly to the other most recent antipsychotics, i.e., lurasidone or cariprazine) shows promise of increasing the effectiveness of schizophrenia treatment in the dimensions in which the previous antipsychotics were not sufficiently effective, including negative, depressive, or cognitive symptoms. Like other new antipsychotics, it can also be useful in the treatment of mood disorders, for instance drug-resistant depression. Previous reviews focused on the use of brexpiprazole in specific diagnostic groups. The aim of this article is to provide the readers with an overview of data on the mechanism of action, clinical effectiveness in all studied diagnostic groups, as well as potential drug–food interactions, and the safety of brexpiprazole.

Therapeutic Potential and Limitation of Serotonin Type 7 Receptor Modulation

Although a number of mood-stabilising atypical antipsychotics and antidepressants modulate serotonin type 7 receptor (5-HT7), the detailed contributions of 5-HT7 function to clinical efficacy and pathophysiology have not been fully understood. The mood-stabilising antipsychotic agent, lurasidone, and the serotonin partial agonist reuptake inhibitor, vortioxetine, exhibit higher binding affinity to 5-HT7 than other conventional antipsychotics and antidepressants. To date, the initially expected rapid onset of antidepressant effects-in comparison with conventional antidepressants or mood-stabilising antipsychotics-due to 5-HT7 inhibition has not been observed with lurasidone and vortioxetine; however, several clinical studies suggest that 5-HT7 inhibition likely contributes to quality of life of patients with schizophrenia and mood disorders via the improvement of cognition. Furthermore, recent preclinical studies reported that 5-HT7 inhibition might mitigate antipsychotic-induced weight gain and metabolic complication by blocking other monoamine receptors. Further preclinical studies for the development of 5-HT7 modulation against neurodevelopmental disorders and neurodegenerative diseases have been ongoing. To date, various findings from various preclinical studies indicate the possibility that 5-HT7 modifications can provide two independent strategies. The first is that 5-HT7 inhibition ameliorates the dysfunction of inter-neuronal transmission in mature networks. The other is that activation of 5-HT7 can improve transmission dysfunction due to microstructure abnormality in the neurotransmission network-which could be unaffected by conventional therapeutic agents-via modulating intracellular signalling during the neurodevelopmental stage or via loss of neural networks with aging. This review attempts to describe the current and novel clinical applications of 5-HT7 modulation based on preclinical findings.

Agonistic properties of a series of psychotropic drugs at 5-HT1A receptors in rat and human brain membranes determined by [35S]GTPγS binding assay

BACKGROUND

Many psychoactive compounds have been developed to have more beneficial clinical efficacy than conventional drugs by adding agonistic action at 5-HT_1A receptors. The aim of the present study was to evaluate several psychotropic drugs that had been reported to behave as an agonist at 5-HT_1A receptor (aripiprazole, brexpiprazole, asenapine, lurasidone, and vortioxetine) in both rat and postmortem human brain membranes.

METHODS

The [³⁵S]GTPγS binding assay for G_i/o proteins coupled with 5-HT_1A receptors was performed in rat brain membranes and postmortem human brain membranes.

RESULTS

The specific binding was stimulated by brexpiprazole in rat hippocampus, human hippocampus, and human prefrontal cortex. Aripiprazole also behaved as an agonist in the same brain regions. Interestingly, its potency was much higher in rat hippocampal membranes than in human brain membranes, indicating the possibility of species differences. Although vortioxetine was an efficacious stimulator at high concentrations, its potency was undeterminable because of a lack of saturability. In addition to 5-HT_1A receptor agonism, involvement of other components, e.g., 5-HT_1B receptor agonism, was speculated by the biphasic inhibitory effects of the selective 5-HT_1A receptor neutral antagonist. Negligible stimulatory effects were obtained as to lurasidone and asenapine.

CONCLUSIONS

Our previous studies have raised the concept of a psychoactive drug group with a common pharmacological mechanism of action, i.e., 5-HT_1A receptor agonism, consisting of perospirone, aripiprazole, ziprasidone, clozapine, quetiapine, nemonapride, and trazodone. The present study demonstrates the data indicating that brexpiprazole and probably vortioxetine are included in this drug group. Lurasidone and asenapine are excluded from this group.

Seventy Years of Antipsychotic Development: A Critical Review

Since the mid-1950s discovery of the first effective antipsychotic medications (APM), we have only been able to improve the tolerability but not the overall efficacy of currently available APMs, as reflected by effectiveness trials in Europe and the United States. This inability to develop more effective APMs is attributable to multiple factors, including failure to create and use assessment tools to assess core symptom domains in schizophrenia, move beyond the dopaminergic hypothesis and to develop "me too" drugs, imposing ill-defined research domain criteria, and lacking federal funding for clinical trials. The classification of APMs is also confusing, including second-generation, partial agonists, and multimodal APMs in the same class of APMs, despite significant differences in their mechanisms of action. Other factors stagnating drug development include inadequate sample sizes to address heterogeneity, lack of statistical measures correlating with clinical significance, using the atheoretical basis of psychiatric diagnoses, failure to control placebo response, and high cost of newer and perhaps more tolerable APMs. Furthermore, there has been a failure to develop early predictors of antipsychotic response and various tools to optimize an APM response. Finally, some mental health providers are also responsible for the suboptimal use of APMs, by using excessive maintenance doses, often with irrational polypharmacy, further compromising effectiveness and medication adherence. However, some bright spots in antipsychotic development include improved tolerability of APMs and long-acting injectables to address the high prevalence of medication nonadherence. This review critically reviews 70 years of antipsychotic development, the reasons behind the failure to develop more effective APMs, and suggestions for future direction.

Recent advances in dopamine D2 receptor ligands in the treatment of neuropsychiatric disorders

Dopamine is a biologically active amine synthesized in the central and peripheral nervous system. This biogenic monoamine acts by activating five types of dopamine receptors (D_1-5 Rs), which belong to the G protein-coupled receptor family. Antagonists and partial agonists of D₂ Rs are used to treat schizophrenia, Parkinson's disease, depression, and anxiety. The typical pharmacophore with high D₂ R affinity comprises four main areas, namely aromatic moiety, cyclic amine, central linker and aromatic/heteroaromatic lipophilic fragment. From the literature reviewed herein, we can conclude that 4-(2,3-dichlorophenyl), 4-(2-methoxyphenyl)-, 4-(benzo[b]thiophen-4-yl)-1-substituted piperazine, and 4-(6-fluorobenzo[d]isoxazol-3-yl)piperidine moieties are critical for high D₂ R affinity. Four to six atoms chains are optimal for D₂ R affinity with 4-butoxyl as the most pronounced one. The bicyclic aromatic/heteroaromatic systems are most frequently occurring as lipophilic appendages to retain high D₂ R affinity. In this review, we provide a thorough overview of the therapeutic potential of D₂ R modulators in the treatment of the aforementioned disorders. In addition, this review summarizes current knowledge about these diseases, with a focus on the dopaminergic pathway underlying these pathologies. Major attention is paid to the structure, function, and pharmacology of novel D₂ R ligands, which have been developed in the last decade (2010-2021), and belong to the 1,4-disubstituted aromatic cyclic amine group. Due to the abundance of data, allosteric D₂ R ligands and D₂ R modulators from patents are not discussed in this review.

Promising candidates from drug clinical trials: Implications for clinical treatment of Alzheimer's disease in China

Alzheimer's disease is the most common neurodegenerative disease. Prior to 2017, National Medical Products Administration approved only four drugs to treat Alzheimer's disease, including three cholinesterase inhibitors and one N-methyl-D-aspartate receptor antagonist. We queried ClinicalTrials.gov to better understand Alzheimer's drug development over the past 5 years and found 16 promising candidates that have entered late-stage trials and analyzed their impact on clinical treatment of Alzheimer's disease in China. The 16 compounds selected include disease-modifying therapies and symptomatic therapies. The research and development pipeline now focuses on disease-modifying therapies such as gantenerumab, aducanumab, ALZ-801, ALZT-OP1, donanemab, lecanemab, simufilam, NE3107, semaglutide, and GV-971, which could put an end to the situation where Alzheimer's patients in China have no effective treatment alternatives. The reuse of drugs or combinations currently under investigation for the psychiatric treatment of Alzheimer's disease, including AXS-05, AVP-786, nabilone, brexpiprazole, methylphenidate, and pimavanserin, could provide physicians with additional treatment options. Although most of these drugs have not been explored in China yet, due to the current development trend in this field in China, it is expected that China will be involved in research on these drugs in the future.

Efficacy of adjunctive brexpiprazole on symptom clusters of major depressive disorder: A post hoc analysis of four clinical studies

BACKGROUND

Major depressive disorder (MDD) is a clinically heterogenous condition and its treatment should be individualized according to the presence of particular symptom clusters. The aim of this pooled analysis was to investigate the effects of adjunctive brexpiprazole on different symptom clusters in MDD.

METHODS

Data were included from four similarly designed, short-term, randomized, double-blind, placebo-controlled studies of adjunctive brexpiprazole in adults with MDD and inadequate response to 2-4 antidepressant treatments (ADTs), including 1 administered by investigators. Mean changes from baseline and Cohen's d effect sizes (ES) versus placebo were determined for the following Montgomery-Åsberg Depression Rating Scale symptom clusters: core, anhedonia, dysphoria, retardation, vegetative, loss of interest, and lassitude.

RESULTS

Over 6 weeks, ADT + brexpiprazole 2 mg (n = 486) showed greater improvement than ADT + placebo (n = 585) for all symptom clusters: core (ES = 0.36; p < 0.0001), anhedonia (ES = 0.43; p < 0.0001), dysphoria (ES = 0.27; p < 0.0001), retardation (ES = 0.32; p < 0.0001), vegetative (ES = 0.29; p < 0.0001), loss of interest (ES = 0.30; p < 0.0001), and lassitude (ES = 0.33; p < 0.0001). Improvements of similar magnitude were observed for ADT + brexpiprazole 2-3 mg (n = 770) versus ADT + placebo (n = 788) (ES = 0.24-0.38; all clusters p < 0.0001). In most cases, improvement over ADT + placebo was observed from Week 1 onwards.

LIMITATIONS

Post hoc analysis with no adjunctive active comparator.

CONCLUSIONS

Patients receiving adjunctive brexpiprazole versus adjunctive placebo showed improvements across a range of MDD symptom clusters. Improvements appeared early (generally from Week 1) and were maintained over 6 weeks. These data indicate that adjunctive brexpiprazole may benefit multiple subtypes of patient with MDD and inadequate response to ADTs.

Visualizing classification of drugs used in psychotic disorders: A 'subway map' representing mechanisms, established classes and informal categories

Drugs used to treat psychotic disorders ('antipsychotics') have been widely used in psychiatry since the introduction of chlorpromazine in the mid-1950s. The categorization of these drugs evolved in a piecemeal way, relying initially on grouping by chemical structure (e.g. phenothiazines, butyrophenones), then by epoch of introduction (e.g. first generation ('conventional') vs second generation ('atypical')). As psychopharmacological expertise has advanced, it has become possible to quantify affinities for each drug in this class for relevant receptors including dopamine D2, 5HT2A, 5HT2C, histamine H1 and others. However, until the recent emergence of a new generation of agents known collectively as dopamine D2 receptor partial agonists (e.g. aripiprazole, brexpiprazole and cariprazine), there had been little reference in drug classification to specific pharmacological properties. An overview of data on receptor affinities across multiple drugs and receptor types would permit categorization according to binding affinities and putative pharmacological mechanisms. In this paper, we have attempted to construct a 'subway map' of 32 drugs used for treatment of psychotic disorders. This design allows a visualization of both the historical classifications by structure and epoch of introduction, and of the binding affinities for key receptors based on appraisal of scientific literature. The map represents a step towards categorization by mechanism, allowing prescribers and patients to understand which drugs share common biological features and the extent to which drugs may have similarities and differences in their mechanisms. In addition, this approach may encourage more logical groupings of drugs to be used in systematic reviews and meta-analyses.

Dose-Dependent Biphasic Action of Quetiapine on AMPK Signalling via 5-HT7 Receptor: Exploring Pathophysiology of Clinical and Adverse Effects of Quetiapine

Recent pharmacological studies indicated that the modulation of tripartite-synaptic transmission plays important roles in the pathophysiology of schizophrenia, mood disorders and adverse reactions. Therefore, to explore the mechanisms underlying the clinical and adverse reactions to atypical antipsychotics, the present study determined the effects of the sub-chronic administration of quetiapine (QTP: 3~30 μM) on the protein expression of 5-HT7 receptor (5-HT7R), connexin43 (Cx43), cAMP level and intracellular signalling, Akt, Erk and adenosine monophosphate-activated protein kinase (AMPK) in cultured astrocytes and the rat hypothalamus, using ultra-high-pressure liquid chromatography with mass spectrometry and capillary immunoblotting systems. QTP biphasically increased physiological ripple-burst evoked astroglial D-serine release in a concentration-dependent manner, peaking at 10 μM. QTP enhanced the astroglial signalling of Erk concentration-dependently, whereas both Akt and AMPK signalling’s were biphasically enhanced by QTP, peaking at 10 μM and 3 μM, respectively. QTP downregulated astroglial 5-HT7R in the plasma membrane concentration-dependently. Protein expression of Cx43 in astroglial cytosol and intracellular cAMP levels were decreased and increased by QTP also biphasically, peaking at 3 μM. The dose-dependent effects of QTP on the protein expression of 5-HT7R and Cx43, AMPK signalling and intracellular cAMP levels in the hypothalamus were similar to those in astrocytes. These results suggest several complicated pharmacological features of QTP. A therapeutically relevant concentration/dose of QTP activates Akt, Erk and AMPK signalling, whereas a higher concentration/dose of QTP suppresses AMPK signalling via its low-affinity 5-HT7R inverse agonistic action. Therefore, 5-HT7R inverse agonistic action probably plays important roles in the prevention of a part of adverse reactions of QTP, such as weight gain and metabolic complications.

Drug repurposing: re-inventing therapies for cancer without re-entering the development pipeline—a review

While majority of the current treatment approaches for cancer remain expensive and are associated with several side effects, development of new treatment modalities takes a significant period of research, time, and expenditure. An alternative novel approach is drug repurposing that focuses on finding new applications for the previously clinically approved drugs. The process of drug repurposing has also been facilitated by current advances in the field of proteomics, genomics, and information computational biology. This approach not only provides cheaper, effective, and potentially safer drugs with less side effects but also increases the processing pace of drug development. In this review, we wish to highlight some recent developments in the area of drug repurposing in cancer with a specific focus on the repurposing potential of anti-psychotic, anti-inflammatory and anti-viral drugs, anti-diabetic, antibacterial, and anti-fungal drugs.

Treatment Discontinuation Among Patients with Schizophrenia Treated with Brexpiprazole and Other Oral Atypical Antipsychotics in Japan: A Retrospective Observational Study

Introduction

Treatment continuation is essential for relapse prevention in patients with schizophrenia. The aim of this exploratory study was to compare the time to treatment discontinuation between patients with schizophrenia prescribed brexpiprazole (BRX group) and those prescribed other atypical antipsychotics (OAA group) in clinical settings in Japan using health insurance claims data.

Methods

De-identified data of working individuals with schizophrenia aged < 75 years and their dependents were assessed from April 2017 to May 2020 using a nationwide claims database. Cox proportional hazards models, adjusted for baseline patient variables, were used to compare the time to treatment discontinuation (primary outcome) for 180 days between BRX and OAA groups and to estimate the hazard ratio (HR) with 95% confidence interval (CI). The cumulative treatment continuation rates at 180 days were also estimated. Sensitivity and subgroup analyses were conducted for the primary outcome.

Results

The analysis included 978 and 4898 patients in the BRX and OAA groups, respectively. Patients in the BRX group were significantly less likely to discontinue treatment than those in the OAA group (HR 0.86, 95% CI 0.78–0.95; p = 0.0024). The cumulative treatment continuation rates were higher in the BRX group (45.9%, 95% CI 42.5–49.2]) than in the OAA group (39.5%, 95% CI 38.1–41.0; log-rank test, p < 0.0001). Based on patients matched by propensity score, the BRX group was significantly less likely to discontinue treatment than the OAA group (log-rank test, p = 0.0466). Similar results were obtained in sensitivity and subgroup analyses.

Conclusion

This real-world study showed that patients in the BRX group were less likely to discontinue treatments than those in the OAA group. These findings suggest that BRX may contribute to treatment continuation among patients with schizophrenia.

Trial Registration

University hospital Medical Information Network (UMIN) Clinical Trials Registry: UMIN000044682.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-022-02252-9.

Risk of Drug-induced Movement Disorders with Newer Antipsychotic Agents

Background:

The last decade has seen development of numerous novel antipsychotic drugs with unique mechanisms including long-acting formulations for clinical use. A comparative assessment of these new drugs with each other and previous antipsychotics have not been performed with regards to risk for drug-induced movement disorders (DIMD).

Methods:

Medline was searched from January 2010 to February 2022 for primary research articles and review articles in English using the search terms “extrapyramidal” and “tardive” with individual drug names of novel antipsychotics.

Results:

We identified articles describing the risk of DIMD with 6 novel antipsychotics, 4 novel formulations, and 3 experimental antipsychotics. Both short- and long-term data generally showed comparable to lower risk of DIMD with novel antipsychotics and recent long-acting formulations compared to previously marketed antipsychotics.

Discussion:

Several novel antipsychotics, particularly lumateperone and pimavanserin, show promise in being able to treat psychosis while reducing the risk of DIMD. Long-acting paliperidone may reduce risk of DIMD while other long-acting injectable formulations of SGA have similar risk of DIMD compared to oral formulations. New drug targets for treating psychosis without dopamine blockade also show promise.

Brexpiprazole Reduces 5-HT7 Receptor Function on Astroglial Transmission Systems

Several atypical antipsychotics exert mood-stabilising effects via the modulation of various monoamine receptors and intracellular signallings. Recent pharmacodynamic studies suggested that tripartite synaptic transmission can contribute to the pathophysiology of schizophrenia and mood disorders, their associated cognitive impairment, and several adverse reactions to atypical antipsychotics. Therefore, to explore the mechanisms underlying the antidepressive mood-stabilising and antipsychotic effects of brexpiprazole (Brex), we determined the effects of subchronic administration of therapeutically relevant concentrations/doses of Brex on the protein expression of 5-HT receptors, connexin43, cAMP levels, and intracellular signalling in cultured astrocytes and rat hypothalamus using ultra-high-pressure liquid chromatography with mass spectrometry and capillary immunoblotting systems. Subchronic administration of a therapeutically relevant concentration of Brex (300 nM) downregulated both 5-HT1A (5-HT1AR) and 5-HT7 (5-HT7R) receptors, in addition to phosphorylated Erk (pErk), without affecting phosphorylated Akt in the astroglial plasma membrane. Subchronic administration of 300 nM Brex decreased and increased phosphorylated AMPK and connexin43, respectively, in the astroglial cytosol fraction. A therapeutically relevant concentration of Brex acutely decreased the astroglial cAMP level, whereas, under the inhibition of 5-HT1AR, Brex did not affect astroglial cAMP levels. However, the 5-HT7R-agonist-induced increased astroglial cAMP level was inhibited by Brex. In contrast to the in vitro study, systemic subchronic administration of effective doses of Brex (3 and 10 mg/kg/day for 14 days) increased the cAMP level but did not affect phosphorylated AMPK in the rat hypothalamus. These results suggest several complicated pharmacological features of Brex. Partial 5-HT1AR agonistic action predominates in the low range of therapeutically relevant concentrations of Brex, whereas in the high range, 5-HT7R inverse agonist-like action is overlapped on the 5-HT1A agonistic action. These unique suppressive effects of Brex on 5-HT7R play important roles in the clinical features of Brex regarding its antidepressive mood-stabilising actions.

Pharmacological strategies for sexual recovery in men undergoing antipsychotic treatment

INTRODUCTION

: First- and second-generation antipsychotics are highly accountable for causing a plethora of medical side effects, ranging from metabolic imbalances to sexual dysfunction (SD), that frequently undermine patient-doctor relationships. Nevertheless, to date antipsychotics are one of the best treatment options for dealing with numerous either acute or chronic conditions like agitation, suicidality, depression, dementia, and of course psychosis. For these reasons, clinicians need to handle them wisely to preserve patients' sexual health, avoid poor therapeutic adherence and prevent high rates of therapy drop-out.

AREAS COVERED

: This article reviews the literature on pharmacologic approaches for management strategies in men who are administered with antipsychotics and developed SD. The etiology of antipsychotic-induced SD is also discussed.

EXPERT OPINION

: Clinicians must consider sexual life as a major health domain. To do so, a first step would be to measure and monitor sexual function by means of psychometric tools. Secondly, primary prevention should be conducted when choosing antipsychotics, i.e., picking sex-sparing compounds like aripiprazole or brexpiprazole. Thirdly, if sexolytic compounds cannot be dismissed, such as first-generation antipsychotics, risperidone, paliperidone, or amisulpride, then aripiprazole 5-20 mg/day adjunctive therapy has proven to be most effective in normalizing prolactin levels and consequently treating antipsychotic-induced SD.

A new paradigm shift in antidepressant therapy? From dual-action to multitarget-directed ligands

Major Depressive Disorder is a chronic, recurring, and potentially fatal disease affecting up to 20% of the global population. Since the monoamine hypothesis was proposed more than 60 years ago, only a few relevant advances have been achieved, with very little disease course changing, from a pharmacological perspective. Moreover, since negative efficacy studies with novel molecules are frequent, many pharmaceutical companies have put new studies on hold. Fortunately, relevant clinical studies are currently being performed, and extensive striving is being developed by universities, research centers, and other public and private institutions. Depression is no longer considered a simple disease but a multifactorial one. New research fields are emerging in what could be a paradigm shift: the multitarget approach beyond monoamines. In this review, we summarize the present and the past of antidepressant drug discovery, with the aim to shed some light on the current state of the art in clinical and preclinical advances to face this increasingly devastating disease.