Overview of short- and long-term tolerability and safety of brexpiprazole in patients with schizophrenia

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.

An overview of the efficacy and safety of brexpiprazole for the treatment of schizophrenia in adolescents

INTRODUCTION

Onset of psychotic symptoms occurs prior to age 19 in 39% of patients with schizophrenia. There are limited approved treatment options for adolescents with schizophrenia. Brexpiprazole was approved by the United States Food and Drug Administration (FDA) for treatment of schizophrenia in adolescents in 2022.

AREAS COVERED

Extrapolation of adult data to youth and use of pharmacologic modeling coupled with open long-term safety data were used by the FDA to approve brexpiprazole for adolescent schizophrenia. These were all reviewed herein.

EXPERT OPINION

D2 receptor partial agonist antipsychotic agents are preferred in the early phase of treatment of psychotic disorders. Approval of brexpiprazole in adolescent schizophrenia provides an additional option. Brexpiprazole was approved by the FDA on the basis of extrapolation of adult data without controlled trials in adolescents. This reduces placebo exposure in young people. Two previous agents (asenapine and ziprasidone) approved for adult schizophrenia failed to separate from placebo in adolescent schizophrenia studies; this partially undermines the process of extrapolation. For brexpiprazole, the paucity of data in adolescents relegates it to second-line agent. More research on brexpiprazole is needed to delineate its relative role in the management of adolescent schizophrenia.

Differential Outcomes of Placebo Treatment Across 9 Psychiatric Disorders: A Systematic Review and Meta-Analysis

Importance

Placebo is the only substance systematically evaluated across common psychiatric diagnoses, but comprehensive cross-diagnostic comparisons are lacking.

Objective

To compare changes in placebo groups in recent high-quality randomized clinical trials (RCTs) across a broad spectrum of psychiatric disorders in adult patients.

Data Sources

MEDLINE and the Cochrane Database of Systematic Reviews were systematically searched in March 2022 for the latest systematic reviews meeting predetermined high-quality criteria for 9 major psychiatric diagnoses.

Study Selection

Using these reviews, the top 10 highest-quality (ie, lowest risk of bias, according to the Cochrane Risk of Bias tool) and most recent placebo-controlled RCTs per diagnosis (totaling 90 RCTs) were selected, adhering to predetermined inclusion and exclusion criteria.

Data Extraction and Synthesis

Following the Cochrane Handbook, 2 authors independently carried out the study search, selection, and data extraction. Cross-diagnosis comparisons were based on standardized pre-post effect sizes (mean change divided by its SD) for each placebo group. This study is reported following the Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guideline.

Main Outcome and Measure

The primary outcome, pooled pre-post placebo effect sizes (dav) with 95% CIs per diagnosis, was determined using random-effects meta-analyses. A Q test assessed statistical significance of differences across diagnoses. Heterogeneity and small-study effects were evaluated as appropriate.

Results

A total of 90 RCTs with 9985 placebo-treated participants were included. Symptom severity improved with placebo in all diagnoses. Pooled pre-post placebo effect sizes differed across diagnoses (Q = 88.5; df = 8; P < .001), with major depressive disorder (dav = 1.40; 95% CI, 1.24-1.56) and generalized anxiety disorder (dav = 1.23; 95% CI, 1.06-1.41) exhibiting the largest dav. Panic disorder, attention-deficit/hyperactivity disorder, posttraumatic stress disorder, social phobia, and mania showed dav between 0.68 and 0.92, followed by OCD (dav = 0.65; 95% CI, 0.51-0.78) and schizophrenia (dav = 0.59; 95% CI, 0.41-0.76).

Conclusion and Relevance

This systematic review and meta-analysis found that symptom improvement with placebo treatment was substantial in all conditions but varied across the 9 included diagnoses. These findings may help in assessing the necessity and ethical justification of placebo controls, in evaluating treatment effects in uncontrolled studies, and in guiding patients in treatment decisions. These findings likely encompass the true placebo effect, natural disease course, and nonspecific effects.

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.

Nociceptin Receptor-Related Agonists as Safe and Non-addictive Analgesics

As clinical use of currently available opioid analgesics is often impeded by dose-limiting adverse effects, such as abuse liability and respiratory depression, new approaches have been pursued to develop safe, effective, and non-addictive pain medications. After the identification of the nociceptin/orphanin FQ (N/OFQ) peptide (NOP) receptor more than 25 years ago, NOP receptor-related agonists have emerged as a promising target for developing novel and effective opioids that modulate the analgesic and addictive properties of mu-opioid peptide (MOP) receptor agonists. In this review, we highlight the effects of the NOP receptor-related agonists compared with those of MOP receptor agonists in experimental rodent and more translational non-human primate (NHP) models and the development status of key NOP receptor-related agonists as potential safe and non-addictive analgesics. Several lines of evidence demonstrated that peptidic and non-peptidic NOP receptor agonists produce potent analgesic effects by intrathecal delivery in NHPs. Moreover, mixed NOP/MOP receptor partial agonists (e.g., BU08028, BU10038, and AT-121) display potent analgesic effects when administered intrathecally or systemically, without eliciting adverse effects, such as respiratory depression, itch behavior, and signs of abuse liability. More importantly, cebranopadol, a mixed NOP/opioid receptor agonist with full efficacy at NOP and MOP receptors, produces robust analgesic efficacy with reduced adverse effects, conferring promising outcomes in clinical studies. A balanced coactivation of NOP and MOP receptors is a strategy that warrants further exploration and refinement for the development of novel analgesics with a safer and effective profile.

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.

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.

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.

Antipsychotic Drug Development: From Historical Evidence to Fresh Perspectives

Schizophrenia is a complex disorder of varied etiology, manifesting symptoms that can differ between patients and change throughout an individual's lifespan. Antipsychotic drugs have evolved through first (e.g., haloperidol), second (olanzapine and clozapine) and a possible third (aripiprazole) generation of drugs in an attempt to improve efficacy and tolerability, with minimal side-effects. Despite robust scientific efforts over the past 70 years, there remains a need to develop drugs with greater efficacy, particularly in relation to the negative and cognitive symptoms of schizophrenia, addressing treatment resistance, with a lower side-effects profile compared to existing antipsychotic drugs. Identifying and investigating novel therapeutic targets remains an important component of future antipsychotic drug discovery; however, mounting evidence demonstrates neurobiological, neuroanatomical and functional heterogeneity in cohorts of individuals with schizophrenia. This presents an opportunity to refresh the approach to drug trials to a more targeted strategy. By increasing understanding of the basic science and pharmacological mechanisms underlying the potential antipsychotic efficacy of novel therapeutics prior to clinical trials, new drugs may be appropriately directed to a target population of schizophrenia subjects based on the drug mechanisms and correlating biological sub-groupings of patient characteristics. Improving the lives of sub-populations of people with schizophrenia that share common biological characteristics and are likely to be responsive to a particular compound may be more achievable than aiming to treat the complexities of schizophrenia as a homogenous disorder. This approach to clinical trials in antipsychotic research is discussed in the present review.

New and emerging treatments for schizophrenia: a narrative review of their pharmacology, efficacy and side effect profile relative to established antipsychotics

Schizophrenia is associated with substantial unmet needs, highlighting the necessity for new treatments. This narrative review compares the pharmacology, clinical trial data and tolerability of novel medications to representative antipsychotics. Cariprazine, brexpiprazole and brilaroxazine are partial dopamine agonists effective in acute relapse. Lumateperone (serotonin and dopamine receptor antagonist) additionally benefits asocial and depressive symptoms. F17464 (D3 antagonist and 5-HT1A partial agonist) has one positive phase II study. Lu AF35700 (dopamine and serotonin receptor antagonist) was tested in treatment-resistance with no positive results. Pimavanserin, roluperidone, ulotaront and xanomeline do not act directly on the D2 receptor at clinical doses. Initial studies indicate pimavanserin and roluperidone improve negative symptoms. Ulotaront and xanomeline showed efficacy for positive and negative symptoms of schizophrenia in phase II trials. BI 409306, BI 425809 and MK-8189 target glutamatergic dysfunction in schizophrenia, though of these only BI 425809 showed efficacy. These medications largely have favourable cardiometabolic side-effect profiles. Overall, the novel pharmacology, clinical trial and tolerability data indicate these compounds are promising new additions to the therapeutic arsenal.

Examining Side Effect Variability of Antipsychotic Treatment in Schizophrenia Spectrum Disorders: A Meta-analysis of Variance

Side effects of antipsychotic drugs play a key role in nonadherence of treatment in schizophrenia spectrum disorders (SSD). While clinical observations suggest that side effect variability between patients may be considerable, statistical evidence is required to confirm this. Here, we hypothesized to find larger side effect variability under treatment compared with control. We included double-blind, placebo-controlled, randomized controlled trials (RCTs) of adults with a diagnosis of SSD treated with 1 out of 14 antipsychotics. Standard deviations of the pre-post treatment differences of weight gain, prolactin levels, and corrected QT (QTc) times were extracted. The outcome measure was the variability ratio of treatment to control for individual antipsychotic drugs and the overall variability ratio of treatment to control across RCTs. Individual variability ratios were weighted by the inverse-variance method and entered into a random-effects model. We included N = 16 578 patients for weight gain, N = 16 633 patients for prolactin levels, and N = 10 384 patients for QTc time. Variability ratios (VR) were significantly increased for weight gain (VR = 1.08; 95% CI: 1.02-1.14; P = .004) and prolactin levels (VR = 1.38; 95% CI: 1.17-1.62; P < .001) but did not reach significance for QTc time (VR = 1.05; 95% CI: 0.98-1.12; P = 0.135). We found marked differences between individual antipsychotics and increased variability in side effects in patients under treatment with antipsychotics suggesting that subgroups of patients or individual patients may benefit from treatment allocation through stratified or personalized medicine.

An Evidence-Based Review of OLZ/SAM for Treatment of Adults with Schizophrenia or Bipolar I Disorder

Olanzapine effectively treats schizophrenia and bipolar I disorder (BD-I); however, its use is limited by the risk of significant weight gain and metabolic effects. OLZ/SAM, a combination of olanzapine and samidorphan, was recently approved in the United States for the treatment of adults with schizophrenia or BD-I. OLZ/SAM provides the efficacy of olanzapine while mitigating olanzapine-associated weight gain through opioid-receptor blockade. Here, we summarize OLZ/SAM clinical data characterizing pharmacokinetics, antipsychotic efficacy, weight mitigation efficacy, safety, and long-term treatment effects. In an acute exacerbation of schizophrenia, OLZ/SAM and olanzapine provided similar symptom improvements versus placebo at week 4. In stable outpatients with schizophrenia, OLZ/SAM treatment resulted in significantly less weight gain, reducing the risk for clinically significant weight gain and waist circumference increases of ≥5 cm by half, compared with olanzapine at week 24. Based on open-label extension studies, OLZ/SAM is safe and well tolerated for up to 3.5 years of treatment, while maintaining schizophrenia symptom control and stabilizing weight. The olanzapine component of OLZ/SAM was bioequivalent to branded olanzapine (Zyprexa); adjunctive OLZ/SAM had no clinically significant effects on lithium or valproate pharmacokinetics. Additionally, OLZ/SAM had no clinically relevant effect on electrocardiogram parameters in a dedicated thorough QT study. Overall, safety and tolerability findings from clinical studies with OLZ/SAM indicate a similar safety profile to that of olanzapine, with the exception of less weight gain. As OLZ/SAM contains the opioid antagonist samidorphan, it is contraindicated in patients using opioids and in those undergoing acute opioid withdrawal. Clinical trial results from more than 1600 subjects support the use of OLZ/SAM as a new treatment option for patients with schizophrenia or BD-I.

Long-term safety and durability of effect with a combination of olanzapine and samidorphan in patients with schizophrenia: results from a 1-year open-label extension study

BACKGROUND

Combination olanzapine and samidorphan (OLZ/SAM), in development for schizophrenia and bipolar I disorder, is intended to provide the efficacy of olanzapine while mitigating olanzapine-associated weight gain. OLZ/SAM safety, tolerability, and efficacy from a 52-week open-label extension study in patients with schizophrenia are reported.

METHODS

Patients previously completing the 4-week, double-blind ENLIGHTEN-1 study switched from OLZ/SAM, olanzapine, or placebo to OLZ/SAM. Assessments included adverse events (AEs), weight, vital signs, Positive and Negative Syndrome Scale (PANSS), and Clinical Global Impression-Severity (CGI-S) scores. Baseline was prior to first dose of OLZ/SAM in the extension study.

RESULTS

In total, 281 patients enrolled, 277 received ≥1 OLZ/SAM dose, and 183 (66.1%) completed 52 weeks. Reasons for discontinuation included patient withdrawal (15.5%), loss to follow-up (6.9%), AEs (5.8%), and lack of efficacy (1.8%). AEs were reported in 136 (49.1%) patients; increased weight (13%) and somnolence (8%) were most common. Ten serious AEs were reported in eight patients (2.9%); none were considered treatment related. There were no deaths. Mean (SD) baseline weight was 79.1 (17.8) kg. Mean weight change from baseline to week 52 was 1.86 kg (2.79% increase). PANSS total and CGI-S scores continued to decline over 52 weeks (mean [95% CI] changes from baseline to week 52: -16.2 [-18.5, -14.0] and -0.9 [-1.0, -0.8], respectively).

CONCLUSION

OLZ/SAM was generally well tolerated in this extension study; most patients completed the 52-week treatment period with sustained improvement in schizophrenia symptoms. Mean increases in weight stabilized by week 6 with limited subsequent change through end of treatment.

Discovery research and development history of the dopamine D2 receptor partial agonists, aripiprazole and brexpiprazole

Otsuka Pharmaceutical Co., Ltd. successfully developed the first dopamine D₂ receptor partial agonist approved for schizophrenia, the antipsychotic aripiprazole (Abilify^®). The drug was approved for this indication in the United States in 2002 and has received approval in the United States, Europe, Japan, and many other countries for several indications including schizophrenia, acute mania, adjunctive treatment of major depressive disorder (MDD), irritability associated with autistic disorder, and Tourette's disorder. Otsuka next developed brexpiprazole (Rexulti^®), another D₂ receptor partial agonist, which was granted marketing approval in the United States in 2015 as adjunctive therapy in major depressive disorder and for the treatment of schizophrenia. In Japan, brexpiprazole also received approval as a treatment for schizophrenia in 2018. In this review, we describe Otsuka's research history and achievements over the preceding 40 years in the area of antipsychotic drug discovery for dopamine D₂ receptor partial agonists.

“Dopamine‐system stabilizer” activity of aripiprazole.

Continuation rate for asenapine and brexpiprazole treatment in patients with schizophrenia

INTRODUCTION

The current study sought to compare the treatment continuation rates of asenapine and brexpiprazole while specifically investigating the factors influencing this index and the clinical efficacy of brexpiprazole.

METHODS

Retrospective study on patients with schizophrenia who were prescribed either asenapine (n = 73) or brexpiprazole (n = 136), as part of their routine medical care.

RESULTS

The treatment continuation rates for asenapine and brexpiprazole were 19.0% and 38.6% at 52 weeks, with that of brexpiprazole found to be significantly higher than that of asenapine (p = .002). Moreover, age was found to be a significant factor affecting the treatment continuation rate for brexpiprazole (p = .03). Additionally, patients with a longer continuation duration had significantly lower Clinical Global Impression-Severity of Illness (CGI-S) scale scores compared to those who discontinued early (p = .04). The continuation rate was also significantly higher for those who began using the drug as outpatients compared to those first administered the drug as inpatients (p = .04). Furthermore, disease duration, CGI-S scale, and continuation duration significantly affected the clinical efficacy of brexipiprazole (p < .05 for all).

CONCLUSIONS

The continuation rate for brexpiprazole increases as the age of the patient increases, as disease severity decreases, and if the patient first uses the drug as an outpatient. Shorter disease duration and longer drug administration may lead to improved clinical efficacy. These results suggest that brexpiprazole is an effective treatment option for maintenance therapy of schizophrenia.

Effects of Brexpiprazole Across Symptom Domains in Patients With Schizophrenia: Post Hoc Analysis of Short- and Long-Term Studies

The successful treatment of schizophrenia entails improvement across a spectrum of symptoms. The aim of this post hoc analysis was to characterize the short- and long-term effects of brexpiprazole on Positive and Negative Syndrome Scale (PANSS) ‘Marder factors.’ Data were included from three 6-week, randomized, double-blind, placebo-controlled studies; a 52-week, randomized, double-blind, placebo-controlled maintenance treatment study; and two 52-week open-label extension (OLEx) studies—all in schizophrenia (DSM-IV-TR criteria). Patients receiving oral brexpiprazole were dosed at 2–4 mg/day (short-term studies) or 1–4 mg/day (long-term studies). At Week 6, least squares mean differences (LSMDs, with 95% confidence limits [CLs]) for brexpiprazole (n = 868) vs placebo (n = 517) were: Positive symptoms: −1.55 (−2.30, −0.80), P < .0001, Cohen’s d effect size (ES) = 0.27; Negative symptoms: −1.12 (−1.63, −0.61), P < .0001, ES = 0.29; Disorganized thought: −1.26 (−1.78, −0.74), P < .0001, ES = 0.32; Uncontrolled hostility/excitement: −0.76 (−1.15, −0.37), P = .0002, ES = 0.26; Anxiety/ depression: −0.56 (−0.91, −0.22), P = .0014, ES = 0.22. At last visit of the maintenance study, LSMDs (95% CLs) for brexpiprazole (n = 96) vs placebo (n = 104) were: Positive symptoms: −3.44 (−4.99, −1.89), P < .0001, ES = 0.62; Negative symptoms: −1.23 (−2.52, 0.07), P = .063, ES = 0.27; Disorganized thought: −1.69 (−2.81, −0.56), P = .0035, ES = 0.42; Uncontrolled hostility/excitement: −1.26 (−2.12, −0.39), P = .0046, ES = 0.41; Anxiety/depression: −0.72 (−1.47, 0.03), P = .061, ES = 0.27. In the OLEx studies, improvements were maintained over 58 (6 + 52) weeks of brexpiprazole treatment. In conclusion, these data suggest that brexpiprazole treats the continuum of schizophrenia symptoms, in the short- and long-term. Trial Registration: Data used in this post hoc analysis came from ClinicalTrials.gov identifiers: NCT01396421, NCT01393613, NCT01810380, NCT01668797, NCT01397786, NCT01810783.

Brexpiprazole for the Treatment of Schizophrenia in Adults: An Overview of Its Clinical Efficacy and Safety and a Psychiatrist's Perspective

While the prognosis of patients with schizophrenia has dramatically improved after the advent of chlorpromazine, the antipsychotics currently available are so numerous that it has become a challenge for psychiatrists to choose from among these drugs for each patient presenting for care. In addition, while numerous studies show that an effective antipsychotic should be continued indefinitely to prevent relapses or worsening, many patients appear to have difficulty remaining on any drug thus initiated. Brexpiprazole, a dopamine D₂ receptor partial agonist, appears to provide a unique profile that has much to offer in this light. Specifically, this novel drug is potentially better suited for long-term use, with decreased risk of extrapyramidal side effects, hyperprolactinemia, weight gain, psychosis, insomnia, akathisia, nausea/vomiting or restlessness, thus potentially facilitating patients' reintegration into society. Indeed, brexpiprazole has been shown in randomized, double-blind, placebo-controlled trials to have proven efficacy not only in improving the symptoms of schizophrenia but in preventing relapses. It is also suggested in both short- and long-term studies that brexpiprazole offers a favorable safety and tolerability profile. This review also includes a proposed treatment algorithm incorporating brexpiprazole, based on the clinical trial results available, as well as on the authors' clinical experience, where brexpiprazole may be best used as a drug of first choice for the treatment of schizophrenia. Thus, overall, brexpiprazole appears to play a more significant role in the treatment of schizophrenia than other antipsychotics.

An open-label, positron emission tomography study of the striatal D2/D3 receptor occupancy and pharmacokinetics of single-dose oral brexpiprazole in healthy participants

Purpose

The aim of this Phase 1, open-label, positron emission tomography (PET) study was to determine the degree of striatal D₂/D₃ receptor occupancy induced by the serotonin–dopamine activity modulator, brexpiprazole, at different single dose levels in the range 0.25–6 mg.

Methods

Occupancy was measured at 4 and 23.5 h post-dose using the D₂/D₃ receptor antagonist [¹¹C]raclopride. The pharmacokinetics, safety and tolerability of brexpiprazole were assessed in parallel.

Results

Fifteen healthy participants were enrolled (mean age 33.9 years; 93.3% male). Mean D₂/D₃ receptor occupancy in the putamen and caudate nucleus increased with brexpiprazole dose, leveled out at 77–88% with brexpiprazole 5 mg and 6 mg at 4 h post-dose, and remained at a similar level at 23.5 h post-dose (74–83%). Estimates of maximum obtainable receptor occupancy (O_max) were 89.2% for the putamen and 95.4% for the caudate nucleus; plasma concentrations predicted to provide 50% of O_max (EC₅₀) were 8.13 ng/mL and 7.75 ng/mL, respectively. Brexpiprazole area under the concentration–time curve (AUC_∞) and maximum plasma concentration (C_max) increased approximately proportional to dose. No notable subjective or objective adverse effects were observed in this cohort.

Conclusion

By extrapolating the observed single-dose D₂/D₃ receptor occupancy data in healthy participants, multiple doses of brexpiprazole 2 mg/day and above are expected to result in an efficacious brexpiprazole concentration, consistent with clinically active doses in schizophrenia and major depressive disorder.

Trial registration

ClinicalTrials.gov NCT00805454 December 9, 2008.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-03021-9) contains supplementary material, which is available to authorized users.

Up-to-date expert opinion on the safety of recently developed antipsychotics

Introduction There are several new and emerging antipsychotic medication strategies recently marketed or under clinical development for the treatment of several mental disorders. There is the need to provide an up-to-date overview on the safety of this new generation of antipsychotic medications, which includes also the third-generation antipsychotics (TGA). Areas covered The authors aimed at providing a synthesis of the most current evidence about the safety profile of the recently developed and/or marketed antipsychotics. Qualitative synthesis followed an electronic search made inquiring of the following databases: MEDLINE, Embase, PsycINFO, and the Cochrane Library from inception until March 2020, combining free terms and MESH headings for the topics of TGA and recently developed and/or marketed antipsychotics as following: ((safety OR adverse events OR side effects) AND ((brexpiprazole OR cariprazine OR inhaled loxapine OR lumateperone (ITI-007) OR lurasidone OR pimavanserin OR roluperidone (MIN-101) OR transdermal patch asenapine)). Expert opinion Overall, newer antipsychotics display a good safety profile, with a well-demonstrated lower metabolic liability compared to second-generation antipsychotics. Furthermore, TGA appear to specifically target negative symptomatology and improving cognitive domains. Abbreviations Aps=Antipsychotic Drugs; AEs = Adverse Effects; EPS = Extrapyramidal Symptoms; NMS = Neuroleptic malignant syndrome; D = Dopamine; K_i = Inhibitory Constant; 5-HT = Serotonin; ECG = Electrocardiogram; H = Histamine; M = Muscarinic; BMI = Body Mass Index.

Comparative Tolerability of Dopamine D2/3 Receptor Partial Agonists for Schizophrenia

Aripiprazole, brexpiprazole and cariprazine differ from all other second-generation antipsychotics due to partial agonism at the dopamine D2 and D3 receptors. In contrast to aripiprazole, brexpiprazole has lower intrinsic dopamine D2 activity and higher affinity for the serotonin 5-HT1A and 5-HT2A receptors, while cariprazine has the highest affinity for the dopamine D3 receptor, and the longest half-life. The main adverse effect of dopamine receptor partial agonists (DRPAs) is akathisia of low-to-moderate severity, which occurs in a small proportion of patients, usually in the first few weeks of treatment. While definitive conclusions concerning differences between the DRPAs require head-to-head comparison studies, on the available evidence, akathisia is probably least likely to occur with brexpiprazole and most likely with cariprazine; the risk of akathisia with aripiprazole lies in between. Weight-gain risk is low with aripiprazole and cariprazine, but moderate with brexpiprazole. Risk of sedation is low with DRPAs, as is risk of insomnia and nausea. Partial dopamine agonism leads to a low risk for hyperprolactinaemia (and probably a low risk of sexual dysfunction). Prolactin concentrations fall in some patients (particularly those with elevated levels prior to initiating the drugs). Rates of discontinuation due to adverse effects in pivotal studies were low, and on the whole, DRPAs are well tolerated. Aripiprazole has been implicated in pathological gambling and other impulse control behaviours, likely due to partial dopamine agonist activity (there have been no reports with brexpiprazole and cariprazine). The risks for diabetes and tardive dyskinesia with DRPAs are unknown, but are likely to be low. On the basis of tolerability, DRPAs should be considered as first-line treatment options, particularly in patients with early schizophrenia.

Effect of Brexpiprazole on Agitation and Hostility in Patients With Schizophrenia: Post Hoc Analysis of Short- and Long-Term Studies

BACKGROUND

Managing agitation and hostility represents a significant treatment challenge in schizophrenia. The aim of this analysis was to evaluate the short- and long-term efficacy of brexpiprazole for reducing agitation and hostility in schizophrenia.

METHODS

This was a post hoc analysis of data from two 6-week, randomized, double-blind, placebo-controlled studies (ClinicalTrials.gov identifiers, NCT01396421 and NCT01393613) and a 52-week, open-label, extension study (NCT01397786). In the short-term studies, 1094 patients received placebo, 2 mg/d of brexpiprazole, or 4 mg/d of brexpiprazole; 346 brexpiprazole-treated patients rolled over into the long-term study and received 1 to 4 mg/d of brexpiprazole. Agitation was assessed using the Positive and Negative Syndrome Scale (PANSS) Excited Component (EC), and hostility was assessed using the PANSS hostility item (P7).

RESULTS

Brexpiprazole improved PANSS-EC score over 6 weeks, with least squares mean differences versus placebo of -0.69 (95% confidence limits, -1.28, -0.11) for 2 mg/d (P = 0.020) and -1.11 (-1.70, -0.53) for 4 mg/d (P = 0.0002). In the subgroup with hostility at baseline (P7 score ≥3; 50.8% of the randomized sample), least squares mean differences versus placebo at week 6 on the PANSS-EC were -0.63 (-1.54, 0.28) for 2 mg/d (P = 0.18) and -1.03 (-1.92, -0.14) for 4 mg/d (P = 0.024), and on P7 (adjusted for positive symptoms) were -0.27 (-0.53, -0.01) for 2 mg/d (P = 0.038) and -0.34 (-0.59, -0.09) for 4 mg/d (P = 0.0080). The improvements were maintained over 58 weeks. Adverse events were generally comparable between treatment groups over 6 weeks; the incidence of akathisia among patients with hostility was 5.9% with placebo, 5.2% with 2 mg/d, and 8.6% with 4 mg/d.

CONCLUSIONS

Brexpiprazole has the potential to be an efficacious and well-tolerated treatment for agitation and hostility among patients with schizophrenia.

Efficacy and Safety of Brexpiprazole for the Treatment of Agitation in Alzheimer's Dementia: Two 12-Week, Randomized, Double-Blind, Placebo-Controlled Trials

OBJECTIVE

To assess the efficacy, safety, and tolerability of brexpiprazole in patients with agitation in Alzheimer's dementia (AAD).

DESIGN

Two 12-week, randomized, double-blind, placebo-controlled, parallel-arm studies (NCT01862640; NCT01922258).

SETTING

Study 1: 81 sites in 7 countries. Study 2: 62 sites in 9 countries.

PARTICIPANTS

Patients with AAD (Study 1: 433 randomized; Study 2: 270 randomized) in a care facility or community-based setting. Stable Alzheimer disease medications were permitted.

INTERVENTION

Study 1 (fixed dose): brexpiprazole 2 mg/day, brexpiprazole 1 mg/day, or placebo (1:1:1) for 12 weeks. Study 2 (flexible dose): brexpiprazole 0.5-2 mg/day or placebo (1:1) for 12 weeks.

MEASUREMENTS

Cohen-Mansfield Agitation Inventory (CMAI) (Total score range: 29-203; higher scores indicate more frequent agitated behaviors), and Clinical Global Impression - Severity of illness (CGI-S) as related to agitation. Safety was also assessed.

RESULTS

In Study 1, brexpiprazole 2 mg/day demonstrated statistically significantly greater improvement in CMAI Total score from baseline to Week 12 than placebo (adjusted mean difference, -3.77; confidence limits, -7.38, -0.17; t₍₃₁₆₎ = -2.06; p = 0.040; MMRM). Brexpiprazole 1 mg/day did not show meaningful separation from placebo (0.23; -3.40, 3.86; t₍₃₁₄₎ = 0.12; p = 0.90; MMRM). In Study 2, brexpiprazole 0.5-2 mg/day did not achieve statistical superiority over placebo (-2.34; -5.49, 0.82; t₍₂₃₀₎ = -1.46; p = 0.15; MMRM). However, a benefit was observed in post hoc analyses among patients titrated to the maximum brexpiprazole dose of 2 mg/day compared with similarly titrated placebo patients (-5.06; -8.99, -1.13; t₍₁₄₄₎ = -2.54; p = 0.012; MMRM). On the CGI-S, a greater numerical improvement than placebo was demonstrated for brexpiprazole 2 mg/day in Study 1 (-0.16; -0.39, 0.06; t₍₃₃₇₎ = -1.42; nominal p = 0.16; MMRM), and a greater improvement for brexpiprazole 0.5-2 mg/day in Study 2 (-0.31; -0.55, -0.06; t₍₂₂₂₎ = -2.42; nominal p = 0.016; MMRM). In Study 1, treatment-emergent adverse events (TEAEs) with incidence ≥5% among patients receiving brexpiprazole 2 mg/day were headache (9.3% versus 8.1% with placebo), insomnia (5.7% versus 4.4%), dizziness (5.7% versus 3.0%), and urinary tract infection (5.0% versus 1.5%). In Study 2, TEAEs with incidence ≥5% among patients receiving brexpiprazole 0.5-2 mg/day were headache (7.6% versus 12.4% with placebo) and somnolence (6.1% versus 3.6%). In both studies, the majority of TEAEs were mild or moderate in severity.

CONCLUSIONS

Brexpiprazole 2 mg/day has the potential to be efficacious, safe, and well tolerated in the treatment of AAD.

Metformin add-on vs. antipsychotic switch vs. continued antipsychotic treatment plus healthy lifestyle education in overweight or obese youth with severe mental illness: results from the IMPACT trial

Antipsychotics are used for many psychiatric conditions in youth. Although developmentally inappropriate weight gain and metabolic abnormalities, which are risk factors for premature cardiovascular mortality, are especially frequent in youth, optimal strategies to reduce pediatric antipsychotic-induced overweight/obesity are unclear. The Improving Metabolic Parameters in Antipsychotic Child Treatment (IMPACT) was a randomized, parallel group, 24-week clinical trial which enrolled overweight/obese, psychiatrically stable youth, aged 8-19 years, with a DSM-IV diagnosis of severe mental illness (schizophrenia spectrum disorder, bipolar spectrum disorder or psychotic depression), at four US universities. All of them had developed substantial weight gain following treatment with a second-generation antipsychotic. The centralized, computer-based randomization system assigned participants to unmasked treatment groups: metformin (MET); antipsychotic switch (aripiprazole or, if already exposed to that drug, perphenazine or molindone; SWITCH); or continued baseline antipsychotic (CONTROL). All participants received healthy lifestyle education. The primary outcome was body mass index (BMI) z-score change from baseline, analyzed using estimated least squares means. Altogether, 127 participants were randomized: 49 to MET, 31 to SWITCH, and 47 to CONTROL. BMI z-score decreased significantly with MET (week 24: -0.09±0.03, p=0.002) and SWITCH (week 24: -0.11±0.04, p=0.003), while it increased non-significantly with CONTROL (week 24: +0.04±0.03). On 3-way comparison, BMI z-score changes differed significantly (p=0.001). MET and SWITCH were each superior to CONTROL (p=0.002), with effect sizes of 0.68 and 0.81 respectively, while MET and SWITCH did not differ. More gastrointestinal problems occurred in MET than in SWITCH or CONTROL. The data safety monitoring board closed the perphenazine-SWITCH arm because 35.2% of subjects discontinued treatment due to psychiatric worsening. These data suggest that pediatric antipsychotic-related overweight/obesity can be reduced by adding metformin or switching to a lower risk antipsychotic. Healthy lifestyle education is not sufficient to prevent ongoing BMI z-score increase.

Long-Term Efficacy and Safety of Brexpiprazole in Elderly Japanese Patients with Schizophrenia: A Subgroup Analysis of an Open-Label Study

PURPOSE

This study was performed to assess the long-term efficacy, safety, and tolerability of brexpiprazole in elderly Japanese patients with schizophrenia.

METHODS

This is a post hoc analysis of a previous open-label study conducted over 56 weeks which consisted of two consecutive phases: a 4-week switching period and a 52-week open-label period. Mean change in the Positive and Negative Syndrome Scale (PANSS) total score, response rates, number and incidence of treatment-emergent adverse events (TEAEs), and other safety parameters were analyzed using descriptive statistics based on age group (elderly, ≥65 and non-elderly, <65).

RESULTS

This post hoc analysis included 208 de novo patients of which 33 were elderly. The continuation rate in elderly patients was 54.5%, and the mean daily dose and treatment duration of brexpiprazole in elderly patients at week 56 were similar to those of non-elderly patients. The mean change in the PANSS total score from the baseline to week 56 was -13.8 in elderly patients and this improvement was maintained throughout the open-label phase. This outcome was comparable to that of the non-elderly patients (-9.0). The incidence rate of TEAEs was 97.0% in elderly patients and 82.3% in non-elderly patients. Most of the TEAEs were either mild (75.8%) or moderate (18.2%) in severity in the elderly patients and the incidence of TEAEs leading to discontinuation was lower in elderly (9.1%) than in non-elderly patients (13.1%). The most commonly observed adverse events in elderly patients were nasopharyngitis (30.3%) and worsening of schizophrenia (27.3%). The safety profiles in both groups were similar.

CONCLUSION

Brexpiprazole was shown to be safe and effective in the treatment of elderly Japanese patients with schizophrenia.

Brexpiprazole has a low risk of dopamine D2 receptor sensitization and inhibits rebound phenomena related to D2 and serotonin 5-HT2A receptors in rats

Background

Long‐term antipsychotic treatment in patients with schizophrenia can induce supersensitivity psychosis and tardive dyskinesia which is thought to be caused by dopamine D₂ receptor sensitization. We evaluated the effects of brexpiprazole on D₂ receptor sensitivity after subchronic treatment in rats. We also evaluated whether brexpiprazole could suppress enhanced response to D₂ receptors in rats subchronically dosed with another atypical antipsychotic.

Methods

The maximum D₂ receptor density (B_max) and apomorphine (a D₂ receptor agonist)‐induced stereotypy were measured in rats orally dosed with vehicle, haloperidol (1 mg/kg), or brexpiprazole (4 or 30 mg/kg for B_max, 6 or 30 mg/kg for stereotypy) for 21 days. Then, effects of oral administrations of brexpiprazole (3 mg/kg), aripiprazole (10 mg/kg), and olanzapine (3 mg/kg) against increases in apomorphine‐induced hyperlocomotion and (±)‐2,5‐dimethoxy‐4‐iodoamphetamine hydrochloride (DOI: a 5‐HT_2A receptor agonist)‐induced head twitches were evaluated in rats subcutaneously treated with risperidone (1.5 mg/kg/d) via minipumps for 21 days.

Results

Haloperidol and brexpiprazole (30 mg/kg: approximately tenfold ED₅₀ of anti‐apomorphine‐induced stereotypy) but not brexpiprazole (4 or 6 mg/kg) significantly increased the B_max and apomorphine‐induced stereotypy. Brexpiprazole (3 mg/kg) and olanzapine (3 mg/kg) significantly suppressed both increases in apomorphine‐induced hyperlocomotion and also DOI‐induced head twitches in rats subchronically treated with risperidone, but aripiprazole (10 mg/kg) significantly suppressed only apomorphine‐induced hyperlocomotion.

Conclusion

Brexpiprazole has a low risk of D₂ receptor sensitization after a repeated administration and suppresses the rebound phenomena related to D₂ and 5‐HT_2A receptors after a repeated administration of risperidone.

Brexpiprazole has less potential to evoke dopamine D2 receptor supersensitivity in rats after repeated administration compared to haloperidol. In addition, brexpiprazole may have a lower risk for producing rebound symptoms associated with D2 receptor, 5‐HT2A receptor sensitization when switching from other antipsychotics such as risperidone.

Major Depressive Disorder (MDD) and Schizophrenia- Addressing Unmet Needs With Partial Agonists at the D2 Receptor: A Review

Second-generation antipsychotics are common candidates for the adjunctive treatment of major depressive disorder and for the treatment of schizophrenia. However, unmet needs remain in the treatment of both disorders. Considering schizophrenia, antipsychotics are the most common treatment and have demonstrated good efficacy. Still, side effects of these treatments are commonly reported and may impact adherence to the medication and functioning in patients with schizophrenia. Regarding major depressive disorder, despite the availability of several classes of antidepressants, many patients do not achieve remission. Adjunctive treatment with antipsychotics may improve clinical and functional outcomes. Compared with dopamine D2 receptor antagonism that is exhibited by most antipsychotics, partial agonism may result in improved outcomes in major depressive disorder and in schizophrenia. Aripiprazole, cariprazine, and brexpiprazole have partial agonism at the dopamine D2 receptor and could potentially overcome limitations associated with D2 antagonism. The objectives of this review were (1) to discuss the goal of treatment with second-generation antipsychotics in major depressive disorder and schizophrenia, and the clinical factors that should be considered, and (2) to examine the short- and long-term existing data on the efficacy and safety of D2 receptor partial agonists (aripiprazole, cariprazine, and brexpiprazole) in the adjunctive treatment of major depressive disorder and in the treatment of schizophrenia.

Medication-Induced Akathisia with Newly Approved Antipsychotics in Patients with a Severe Mental Illness: A Systematic Review and Meta-Analysis

BACKGROUND

Akathisia is a common and distressing movement disorder that can be associated with the use of antipsychotics. It is characterized by a subjective (inner restlessness) and an objective (excessive movements) component. Akathisia can have a negative impact on clinical outcome and even lead to treatment discontinuation. Although medication-induced akathisia is more commonly associated with the use of first-generation antipsychotics (FGAs), it also occurs with second-generation antipsychotics (SGAs), including the newly approved antipsychotics (NAPs) asenapine, lurasidone, iloperidone, cariprazine, and brexpiprazole. Until now, no meta-analysis has been published on the risk of akathisia for all NAPs, as monotherapy or adjunctive treatment, in patients with a severe mental illness.

OBJECTIVE

The primary objectives of this systematic review and meta-analysis were to (i) compare akathisia incidence rates of the NAPs, as monotherapy or adjunctive treatment, in adult patients with a severe mental illness (i.e., schizophrenia, bipolar disorder, or major depressive disorder), using data from published and unpublished randomized controlled trials; and (ii) examine the role of several study characteristics explaining differences in akathisia incidence rates between studies.

METHODS

A systematic literature search, using the PubMed, EMBASE, and Cochrane Library databases (until October 2018), was conducted for English-language placebo- as well as active-controlled clinical trials, including subjective (percentage of patients reporting akathisia) and/or scale-defined medication-induced akathisia incidence rates with NAPs (as monotherapy or as adjunctive treatment) in adult patients with schizophrenia, bipolar disorder, or major depressive disorder. Additional unpublished clinical trials were identified through the ClinicalTrials.gov electronic database. Two meta-analyses (incidence rates and odds ratio [OR] [placebo vs. active] of medication-induced akathisia with NAPs) were performed to obtain an optimal estimation of akathisia risks of adult patients with a severe mental illness under these treatment conditions and to assess the role of study characteristics.

RESULTS

Two hundred and thirteen reports were selected as potentially eligible for our meta-analysis. Of these, 48 met the inclusion criteria. Eight records, identified through the ClinicalTrials.gov database and cross-referencing, and which fulfilled the inclusion criteria, were added, resulting in a total of 56 records (iloperidone = 5, asenapine = 11, lurasidone = 15, brexpiprazole = 13, cariprazine = 12). The estimated weighted mean incidence rate of akathisia was 7.7% (95% confidence interval [CI] 6.5-9.1), with estimates being 3.9% (95% CI 2.4-6.3) for iloperidone, 6.8% (95% CI 5.1-9.0) for asenapine, 10.0% (95% CI 7.4-13.5) for brexpiprazole, 12.7% (95% CI 10.1-16.1) for lurasidone, and 17.2% (95% CI 13.4-22.1) for cariprazine. After Tukey-adjustment for multiple testing, the incidence rate of akathisia was significantly (p < 0.05) lower for iloperidone than for brexpiprazole, lurasidone, and cariprazine. In addition, the incidence rate of akathisia was significantly (p < 0.05) lower for asenapine than for lurasidone and cariprazine. Finally, the incidence rate of akathisia was significantly (p < 0.05) lower for brexpiprazole than for cariprazine. Type of medication (p < 0.0001), diagnosis (p = 0.02), and race (p = 0.0003) significantly explained part of the heterogeneity of the incidence estimates of akathisia between studies. The estimated weighted OR of akathisia under medication, compared with placebo, was 2.43 (95% CI 1.91-3.10). The OR was smallest for iloperidone (OR 1.20; 95% CI 0.42-3.45) and increased for brexpiprazole (OR 2.04; 95% CI 1.09-3.83), asenapine (OR 2.37; 95% CI 1.32-4.27), lurasidone (OR 3.74; 95% CI 2.32-6.02), and cariprazine (OR 4.35; 95% CI 2.80-6.75). Only type of medication (p = 0.03) explained systematic differences in the OR for akathisia between placebo versus active treatment across studies. After Tukey-adjustment for multiple testing, no significant differences between these ORs were found. The severity of akathisia with NAPs generally is mild to moderate, only leading to treatment discontinuation in a minority of cases (< 5%).

CONCLUSIONS

The use of a NAP raises the akathisia risk more than two-fold when compared with patients receiving placebo. Although distinctions between the different NAPs were not clear in placebo-controlled trials, the results of our meta-analyses and systematic review generally indicate that these differences more than likely reflect real differences, with iloperidone showing the most and cariprazine showing the least benign akathisia profile. Moreover, due to patient characteristics and methodological issues, incidence rates of akathisia with NAPs found in this meta-analysis may even be an underestimation of true incidence rates.

Brexpiprazole: A Review in Schizophrenia

Brexpiprazole (Rxulti^®, Rexulti^®) is an oral atypical antipsychotic agent approved for the treatment of schizophrenia in the EU (in adult patients) and the USA, as well as in some other countries, including Japan. Like aripiprazole, it is a partial agonist at dopamine D₂ and serotonin 5-HT_1A receptors and an antagonist at serotonin 5-HT_2A receptors. However, brexpiprazole displays less intrinsic activity at D₂ receptors and, coupled with actions at 5HT_1A, 5HT_2A and noradrenaline α_1B receptors that are at least as potent as its action at D₂ receptors, is predicted to demonstrate a lower propensity for activating adverse events and extrapyramidal symptoms than aripiprazole. Brexpiprazole 2-4 mg/day produced statistically significant and clinically meaningful improvements in overall symptomatology and psychosocial functioning compared with placebo in adults with acute exacerbation of schizophrenia. As maintenance treatment, brexpiprazole 1-4 mg/day significantly delayed the time to relapse compared with placebo in patients who were already stabilized on the drug and was associated with stabilization or continued improvement in patients' symptoms and functioning. Brexpiprazole was generally well tolerated, exhibiting an adverse event profile characterized by a relatively low incidence of activating and sedating adverse effects, small changes in QT interval and metabolic parameters that were not clinically significant, and moderate weight gain. Clinical evidence to date suggests it usefully extends the range of therapeutic options for schizophrenia.

Maximizing response to first-line antipsychotics in schizophrenia: a review focused on finding from meta-analysis

RATIONALE

There are many psychotropic drugs available for treatment of schizophrenia. The clinician's choice of the most effective first-line antipsychotic treatment for patients with schizophrenia should balance considerations of differential efficacy of antipsychotics against the relative risk of different side effects.

METHOD

We reviewed recent studies using meta-analytic techniques and additional studies of new antipsychotics which quantitatively evaluate the efficacy of side effects of first- and second-generation antipsychotics and studies of the efficacy on add-on secondary medications. We present an integrated summary of these results to guide a clinician's decision-making.

RESULTS

Recent meta-analyses have suggested that antipsychotics are not equivalent in efficacy. Clozapine (effect size [SMD] 0.88 vs. placebo), amisulpride (effect size 0.6 vs placebo), olanzapine (effect size 0.59 vs. placebo), and risperidone (effect size 0.56 vs placebo) show small but statistically significant differences compared to a number of other antipsychotics on measures of overall efficacy (effect sizes 0.33-0.50). However, increasing placebo response remains a concern in interpreting these data. Amisulpride (effect size 0.47 vs placebo) and cariprazine (effect size in one trial compared to risperidone 0.29) have the strongest evidence indicating greater efficacy for treating primary negative symptoms relative to other antipsychotics. In terms of side effects, clozapine and olanzapine have among the highest weight gain potential and sertindole and amisulpride have more effects on QTc prolongation than other commonly used antipsychotics. Prolactin elevation is highest with paliperidone, risperidone, and amisulpride. Adjunctive treatment with an antidepressant drug may improve response in patients with schizophrenia who also have severe depressive or negative symptoms. For multi-episode patients with an inadequate response to an adequate dose and duration of the initial antipsychotic choice, switching to another antipsychotic, with a different receptor profile, may improve response, although evidence is very limited. In first-episode patients, a recent study on switching to another antipsychotic, with a different receptor profile after 4 weeks demonstrated no beneficial effects. There is little evidence to support using doses above the therapeutic range other than in exceptional circumstances.

CONCLUSIONS

Our review of recent studies using meta-analytic techniques has provided evidence that all antipsychotics are not equal in the severity of different side effects and in some measures of clinical efficacy. Comparative analysis and rankings from network meta-analyses can provide guidance to clinicians in choosing the most appropriate antipsychotic for first-line treatment, if used in conjunction with available information of the patient's history of previous clinical response or higher risks for specific side effects.

Pharmacogenetic Correlates of Antipsychotic-Induced Weight Gain in the Chinese Population

Antipsychotic-induced weight gain (AIWG) is a common adverse effect of this treatment, particularly with second-generation antipsychotics, and it is a major health problem around the world. We aimed to review the progress of pharmacogenetic studies on AIWG in the Chinese population to compare the results for Chinese with other ethnic populations, identify the limitations and problems of current studies, and provide future research directions in China. Both English and Chinese electronic databases were searched to identify eligible studies. We determined that > 25 single-nucleotide polymorphisms in 19 genes have been investigated in association with AIWG in Chinese patients over the past few decades. HTR2C rs3813929 is the most frequently studied single-nucleotide polymorphism, and it seems to be the most strongly associated with AIWG in the Chinese population. However, many genes that have been reported to be associated with AIWG in other ethnic populations have not been included in Chinese studies. To explain the pharmacogenetic reasons for AIWG in the Chinese population, genome-wide association studies and multiple-center, standard, unified, and large samples are needed.

Effect of Brexpiprazole on Prolactin: An Analysis of Short- and Long-Term Studies in Schizophrenia

BACKGROUND

Hyperprolactinemia is an undesirable effect of most antipsychotics because of D2-receptor blockade. We assessed the effect of the D2-receptor partial agonist brexpiprazole on prolactin, based on pooled data from three 6-week, randomized, placebo-controlled studies and two open-label extension studies in patients with schizophrenia.

METHODS

In the short-term studies, patients received 0.25, 1, 2, 4 mg brexpiprazole or placebo; or flexible-dose brexpiprazole (2-4 mg/d), placebo, or active reference. The extension studies were 52-week, flexible-dose (1-4 mg/d) studies. We studied changes from baseline and shifts in prolactin status in patients with normal or elevated prolactin levels at baseline, and prolactin-related treatment-emergent adverse events (TEAEs).

RESULTS

Median changes from baseline to week 6 in brexpiprazole-treated patients in short-term studies were as follows: 3.63 ng/mL (females), 0.26 ng/mL (males); placebo: -2.15 ng/mL (females), -1.08 ng/mL (males).Median changes from baseline to week 52 in long-term studies were 0.60 ng/mL (females) and 0.18 ng/mL (males). Prolactin levels in patients with baseline values greater than 1× upper limit of normal tended to decrease over time regardless of previous treatment.The proportions of brexpiprazole-treated patients with greater than 3× upper limit of normal postbaseline prolactin values in short-term studies were as follows: 1.5% (females), 1.6% (males); placebo: 3.6% (females), 3.4% (males). Corresponding figures in long-term studies were 5.3% (females) and 2.0% (males).In short-term studies, the incidence of prolactin-related TEAEs was 1.8% for brexpiprazole and 0.6% for placebo. In long-term studies, the incidence of prolactin-related TEAEs was 1.7%.

CONCLUSIONS

Small changes in prolactin levels, low proportions of patients with postbaseline elevated prolactin values, and low incidence of prolactin-related TEAEs were observed after treatment with brexpiprazole.

Effects of NOP-Related Ligands in Nonhuman Primates

The nociceptin/orphanin FQ peptide (NOP) receptor-related ligands have been demonstrated in preclinical studies for several therapeutic applications. This article highlights (1) how nonhuman primates (NHP) were used to facilitate the development and application of positron emission tomography tracers in humans; (2) effects of an endogenous NOP ligand, nociceptin/orphanin FQ, and its interaction with mu opioid peptide (MOP) receptor agonists; and (3) promising functional profiles of NOP-related agonists in NHP as analgesics and treatment for substance use disorders. NHP models offer the most phylogenetically appropriate evaluation of opioid and non-opioid receptor functions and drug effects. Based on preclinical and clinical data of ligands with mixed NOP/MOP receptor agonist activity, several factors including their intrinsic efficacies for activating NOP versus MOP receptors and different study endpoints in NHP could contribute to different pharmacological profiles. Ample evidence from NHP studies indicates that bifunctional NOP/MOP receptor agonists have opened an exciting avenue for developing safe, effective medications with fewer side effects for treating pain and drug addiction. In particular, bifunctional NOP/MOP partial agonists hold a great potential as (1) effective spinal analgesics without itch side effects; (2) safe, nonaddictive analgesics without opioid side effects such as respiratory depression; and (3) effective medications for substance use disorders.

Efficacy and safety of brexpiprazole for the treatment of acute schizophrenia in Japan: A 6-week, randomized, double-blind, placebo-controlled study

AIM

This study aimed to evaluate the efficacy, safety, and tolerability of brexpiprazole compared to placebo in Japanese patients with acute schizophrenia (SCZ).

METHODS

We conducted a 6-week, multicenter, double-blind, placebo-controlled, phase 2/3 study in Japan. Patients with acute SCZ were randomized (1:1:1:1) to receive brexpiprazole 1 mg, 2 mg, 4 mg, or placebo once a day. The primary endpoint was the change from baseline to week 6 in Positive and Negative Syndrome Scale (PANSS) total scores.

RESULTS

In the 459 patients that were randomized, brexpiprazole 2 mg showed a significant improvement versus placebo (treatment difference: -7.32, P = 0.0124), although brexpiprazole 4 mg showed numerical improvements (treatment difference: -3.86, P = 0.1959), and brexpiprazole 1 mg showed only minimal change (treatment difference: -0.63, P = 0.8330). Treatment-emergent adverse events with an incidence of ≥5% and ≥2 times the rate of placebo in the brexpiprazole groups were vomiting, elevated blood prolactin, diarrhea, nausea, and dental caries. Most treatment-emergent adverse events were mild or moderate in severity. There were no clinically significant changes in electrocardiogram parameters, bodyweight, laboratory values, or vital signs in the brexpiprazole groups.

CONCLUSION

Brexpiprazole was efficacious and well tolerated in Japanese adult patients with acute SCZ.

The effects of brexpiprazole and aripiprazole on body weight as monotherapy in patients with schizophrenia and as adjunctive treatment in patients with major depressive disorder: an analysis of short-term and long-term studies

The aim of this analysis was to explore the effects of brexpiprazole and aripiprazole on body weight when used as monotherapy to treat schizophrenia and as adjunctive treatment to antidepressant treatment (ADT) for major depressive disorder (MDD) in short-term (4/6 weeks) and long-term (≤52 weeks) studies. Body weight data were obtained from the clinical studies of each drug (brexpiprazole and aripiprazole), in schizophrenia and adjunctive treatment of MDD. Data were pooled and analyzed to assess the mean change in body weight and to determine the incidence of a clinically relevant change in body weight from baseline (≥7% increase or decrease, at any time) in each treatment group. The overall weight profiles for brexpiprazole and aripiprazole in the short-term and long-term treatment of schizophrenia, and MDD (adjunctive to ADT), were similar. In short-term schizophrenia studies, the mean weight increase was 1.2 kg for brexpiprazole and 0.6 kg for aripiprazole. In short-term MDD studies (adjunctive to ADT), the mean weight increase was 1.5 kg for brexpiprazole and 1.6 kg for aripiprazole. In the long-term schizophrenia studies, at week 52, the mean weight increase was 2.1 kg for brexpiprazole and 3.0 kg for aripiprazole. In long-term MDD studies (adjunctive to ADT), at week 52, the mean weight increase was 3.2 kg for brexpiprazole and 4.0 kg for aripiprazole. Clinically relevant increases or decreases in body weight were also similar for brexpiprazole and aripiprazole. Overall, in the treatment of schizophrenia, and in adjunctive treatment of MDD, brexpiprazole and aripiprazole have a similar effect on body weight over the course of 1 year.

Relapse prevention: a cost-effectiveness analysis of brexpiprazole treatment in adult patients with schizophrenia in the USA

OBJECTIVE

This study used a decision-analytic framework to assess the cost-effectiveness of brexpiprazole vs comparator branded therapies for reducing relapses and hospitalizations among adults with schizophrenia from a US payer perspective.

METHODS

An economic model was developed to assess patients with stable schizophrenia initiating treatment with brexpiprazole (1-4 mg), cariprazine (1-6 mg), or lurasidone (40-80 mg) over a 1-year period. After 6 months, patients remained on treatment or discontinued due to relapse, adverse events, or other reasons. Patients who discontinued due to relapse or adverse events were assumed to have switched to other therapy, and those who discontinued due to other reasons were assumed to have received no therapy. Primary outcomes were incremental cost per relapse avoided and hospitalization avoided, and the secondary outcome was cost per quality-adjusted life-year (QALY) gained. Sensitivity and scenario analyses were also conducted.

RESULTS

Brexpiprazole was associated with the highest per-patient clinical effectiveness (avoided relapses 0.637, avoided hospitalizations 0.719, QALYs 0.707) among comparators, followed by cariprazine (avoided relapses 0.590, avoided hospitalizations 0.683, QALYs 0.683) and lurasidone (avoided relapses 0.400, avoided hospitalizations 0.536, QALYs 0.623). Annual per-patient health-care costs were lowest for brexpiprazole ($20,510), followed by cariprazine ($22,282) and lurasidone ($25,510). Brexpiprazole was the least costly and most effective treatment strategy for all outcomes. Results were sensitive to relapse rates and daily cost of brexpiprazole. Limitations include data principally obtained from drug-specific randomized withdrawal studies and lack of direct-comparison trials.

CONCLUSION

This analysis evaluated brexpiprazole treatment for the reduction of schizophrenia relapses and hospitalizations over a 1-year period compared to other recently available branded antipsychotics, and excluded generic antipsychotic treatments. Brexpiprazole treatment may lead to clinical benefits and medical cost savings, and provides a cost-effective treatment option for patients relatively to other branded second-generation antipsychotics.

Long-term safety and effectiveness of brexpiprazole in Japanese patients with schizophrenia: A 52-week, open-label study

AIM

This study assessed the long-term safety, tolerability, and maintenance of the therapeutic effect of brexpiprazole in Japanese patients with schizophrenia.

METHODS

This 52-week, open-label, flexible-dose (1-4 mg/day) study included patients with schizophrenia who continued treatment from a short-term randomized placebo-controlled fixed-dose (1, 2, or 4 mg/day) trial and de novo patients who switched from other antipsychotics.

RESULTS

A total of 282 patients (184 de novo and 98 rolled over from short-term trial) entered the 52-week treatment with brexpiprazole, and 150 (53.2%) patients completed the week-52 assessment. Treatment-emergent adverse events (TEAE) were experienced by 235/281 patients (83.6%), and TEAE reported by ≥10% of all patients were nasopharyngitis (23.1%) and worsening of schizophrenia (22.4%). During the study, most of the TEAE were mild or moderate in severity, and there were no deaths, and no clinically meaningful mean changes in laboratory values, vital signs, or electrocardiogram parameters. Mean scores for the Positive and Negative Syndrome Scale total and Clinical Global Impression-Severity remained stable until week 52.

CONCLUSION

Brexpiprazole was generally safe and well tolerated and maintained therapeutic effects in the long-term treatment of Japanese patients with schizophrenia.

Brexpiprazole: A review of a new treatment option for schizophrenia and major depressive disorder

Brexpiprazole is an atypical antipsychotic that works as a partial agonist at serotonin 5-hydroxytryptamine_1A and dopamine D₂ receptors and an antagonist at serotonin 5-hydroxytryptamine_2A. It has US Food and Drug Administration approval for monotherapy treatment of schizophrenia and adjunctive treatment to antidepressants for major depressive disorder. Two phase-3 clinical trials demonstrated efficacy and relatively fair tolerability with regard to adverse effects for each indication. Akathisia was frequently reported in the major depressive disorder trials but less so in the schizophrenia trials. Significant increases in body weight and triglycerides were seen across all studies. Brexpiprazole appears to be a viable option for treating an acute exacerbation of schizophrenia requiring hospitalization or adjunctive treatment of major depressive disorder in patients who showed an inadequate response to 1 to 3 antidepressants. Further clinical trials are warranted to determine the long-term efficacy of brexpiprazole, and comparison trials would be beneficial to establish its place in therapy.

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

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

Efficacy of brexpiprazole in patients with acute schizophrenia: Review of three randomized, double-blind, placebo-controlled studies

Brexpiprazole, a serotonin-dopamine activity modulator, is a partial agonist at 5-HT1A and dopamine D2 receptors, and antagonist at 5-HT2A and noradrenaline α1B and α2C receptors, all at similar potency. Efficacy of brexpiprazole was evaluated in patients with acutely exacerbated schizophrenia in three short-term, randomized, double-blind, placebo-controlled studies. In a Phase 2 study, patients were randomized to brexpiprazole 0.25mg (fixed dose), 1.0±0.5mg, 2.5±0.5mg, 5.0±1mg (flexible-dose ranges), placebo, or aripiprazole 15±5mg. In two Phase 3 studies, patients were randomized to fixed-dose brexpiprazole 0.25mg, 1mg, 2mg, or 4mg, or placebo. For this review, brexpiprazole 2mg and 4mg arms from the Phase 3 studies were combined. Primary efficacy endpoint was change in Positive and Negative Syndrome Scale (PANSS) total score from baseline at week 6; key secondary endpoint was change in Clinical Global Impression-Severity of illness (CGI-S) score at week 6. Primary outcome moderator analyses explored effects of sex, age, race, and illness duration. There were no statistically significant differences vs. placebo in the Phase 2 brexpiprazole and aripiprazole groups for primary and key secondary endpoints. Combined brexpiprazole 2mg (n=359) and 4mg (n=359) were superior to placebo (n=358) in change in PANSS total score (least square mean difference from placebo: -5.46, p=0.0004, and -6.69, p<0.0001, respectively) and CGI-S (-0.25, p=0.0035, and -0.38, p<0.0001, respectively). Changes from baseline in efficacy endpoints were minimal in the 0.25mg group, while the 1mg group exhibited suboptimal improvement. No relevant moderators were identified. Meta-analysis of the pivotal studies indicates brexpiprazole 2mg and 4mg are effective in treating acute schizophrenia.