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

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.

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-Induced Weight Gain: Dose-Response Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Weight gain is among the most important side-effects of antipsychotics. It is, however, unclear whether it is associated with antipsychotic doses. We aimed to fill this gap with a dose-response meta-analysis.

METHODS

We searched multiple electronic databases (last update search June 2021) for all fixed-dose studies that investigated 16 second-generation antipsychotics and haloperidol in adults with acute exacerbation of schizophrenia or with negative symptoms. We estimated the dose-response curves by conducting random-effects dose-response meta-analyses. We used the restricted cubic spline to model the dose-response relationship. The primary outcome was mean weight gain in kg from baseline to endpoint, the secondary outcome was the number of patients with clinically important weight gain.

FINDINGS

Ninety-seven studies with 333 dose arms (36 326 participants) provided data for meta-analyses. Most studies were short-term with median duration of 6 weeks (range 4 to 26 weeks). In patients with acute exacerbation, amisulpride, aripiprazole, brexpiprazole, cariprazine, haloperidol, lumateperone, and lurasidone produced mild weight gain in comparison to placebo (mean difference at any dose≤1 kg), while more significant weight gain was observed by all other drugs. For most drugs, dose-response curves showed an initial dose-related increase in weight which plateaued at higher doses, while for others there was no plateau and some even had bell-shaped curves, meaning less weight gain to be associated with higher doses.

INTERPRETATION

Second-generation antipsychotics do not only differ in their propensity to produce weight gain, but also in the shapes of their dose-response curves. This information is important for dosing decisions in clinical practice.

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.

Antipsychotics for negative and positive symptoms of schizophrenia: dose-response meta-analysis of randomized controlled acute phase trials

Determining the optimal antipsychotic target dose in acute phase treatment is of high clinical relevance. The effect of antipsychotics on negative symptoms should be taken into account because patients will often continue on the treatment received in the acute phase. Therefore, we conducted a formal dose-response meta-analysis of negative symptoms and positive symptoms based on a systematic review of fixed-dose randomized controlled trials (RCTs) that examined the effectiveness of antipsychotics for the acute exacerbation of schizophrenia. Forty RCTs included a total of 15,689 patients. The 95% effective doses per day for the 13 antipsychotics included and 3 long acting were mostly different for negative and positive symptoms: amisulpride (481 mg, 690.6 mg); aripiprazole (11.9 mg, 11 mg); asenapine (7.61 mg, 5.66 mg); brexpiprazole (2.1 mg, 4 mg); cariprazine (4 mg, 6.51 mg); haloperidol (6.34 mg, 7.36 mg); lurasidone (58.2 mg, 86.3 mg); olanzapine (15.5 mg, 9.52 mg); olanzapine long-acting injection (15.7 mg, 13.5 mg); paliperidone (7.2 mg, 7 mg); paliperidone long-acting injection (7.5 mg, 5.9 mg); quetiapine instant-release (264.2 mg, 316.5 mg); quetiapine extended-release (774 mg, 707.2 mg); risperidone (7.5 mg, 7.7 mg); risperidone long-acting injection (5.13 mg, 6.7 mg); sertindole (13.5 mg, 16.3 mg); and ziprasidone (71.6 mg, 152.6 mg). The shape of the dose-response curves varied across different drugs with most drugs showing a plateau at higher doses. Most dose-response curves suggested that the near-maximum effective doses could be in the lower-to-medium range of the licensed dose. Additional RCTs are necessary to establish the optimal dose.

Investigation of the impact of grapefruit juice, pomegranate juice and tomato juice on pharmacokinetics of brexpiprazole in rats using UHPLC-QTOF-MS

Brexpiprazole (BRX) is approved for the treatment of schizophrenia and major depressive disorders and it is mainly metabolized by CYP3A4 and CYP2D6. Grapefruit juice (GFJ), pomegranate juice (PJ) and tomato juice (TJ) have the potential to inhibit CYP3A4 enzymes in the body. However, fruit juice-drug interactions between BRX and GFJ, PJ and TJ have not been studied extensively. The present study describes the influence of GFJ, PJ and TJ on the pharmacokinetic parameters of BRX in rats. The study samples were analyzed using a mass-accurate and single-step bioanalytical method by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry over a wide calibration range of 20-1,500 ng/ml. The results of the pharmacokinetic study denoted that the combined administration of GFJ and PJ could increase systemic exposure of BRX. The area under the curve of BRX increased 3.43- and 1.88-fold with co-administration of GFJ and PJ, respectively, while TJ with BRX had no effect on the area under the curve. Time to peak concentration and half-life were not significantly changed by any juice co-administration. The results show that GFJ and PJ affect the pharmacokinetic profile of BRX and hence advice needs to be given to patients.

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.

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.

Efficacy and safety of brexpiprazole in patients with schizophrenia presenting with severe symptoms: Post-hoc analysis of short- and long-term studies

BACKGROUND

The treatment of patients with severe schizophrenia symptoms can be complicated and expensive.

AIMS

The purpose of this study was to evaluate the short- and long-term effects of brexpiprazole in patients with schizophrenia presenting with severe symptoms.

METHODS

Data were pooled from three six-week, randomized, double-blind, placebo-controlled studies and two 52-week, open-label extension studies. In the short-term studies, 1405 patients received placebo or brexpiprazole 2-4 mg/day; 412 brexpiprazole-treated patients rolled over into the long-term studies and received brexpiprazole 1-4 mg/day. More severe symptoms were defined as a Positive and Negative Syndrome Scale Total score >95 (median score at baseline). Outcomes included change in Positive and Negative Syndrome Scale Total and Personal and Social Performance scale scores.

RESULTS

Brexpiprazole improved Positive and Negative Syndrome Scale Total score over 6 weeks among more severely ill patients, with a least squares mean difference versus placebo of -6.76 (95% confidence limits: -9.80, -3.72; p<0.0001; Cohen's d: 0.43). Brexpiprazole also improved Personal and Social Performance scale score over 6 weeks in more severely ill patients (least squares mean difference: 4.38; limits: 2.14, 6.62; p=0.0001; Cohen's d: 0.38). Improvement of functioning was greatest in the 'Self-care' domain, followed by 'Personal and social relationships'. Among less severely ill patients, brexpiprazole was superior to placebo on Positive and Negative Syndrome Scale Total and Personal and Social Performance scale at Week 6. Improvements were maintained over 58 weeks. No new safety or tolerability concerns were observed.

CONCLUSIONS

Brexpiprazole is an efficacious and well-tolerated treatment for schizophrenia in patients with more severe, and less severe, symptoms.

Aripiprazole vs. brexpiprazole for acute schizophrenia: a systematic review and network meta-analysis

RATIONALE

What is the difference between aripiprazole and brexpiprazole?

OBJECTIVES

This systematic review, network meta-analysis of randomized trials evaluated the efficacy and safety/tolerability of aripiprazole and brexpiprazole for treating acute schizophrenia.

METHODS

We searched Scopus, MEDLINE, and Cochrane Library from inception until May 22, 2019. The response rate was set as the primary outcome. Other outcomes were discontinuation rate and incidence of individual adverse events. The risk ratio (RR) and 95% credible interval (95%CrI) were calculated.

RESULTS

Fourteen studies were identified (n = 3925). Response rates of both aripiprazole and brexpiprazole were superior to that of the placebo (RR [95%CrI]: aripiprazole = 0.84 [0.78, 0.92], brexpiprazole = 0.84 [0.77, 0.92]). Aripiprazole and brexpiprazole were associated with a lower incidence of all-cause discontinuation (0.80 [0.71, 0.89], 0.83 [0.72, 0.95]), adverse events (0.67 [0.47, 0.97], 0.64 [0.46, 0.94]), and inefficacy (0.56 [0.40, 0.77], 0.68 [0.48, 0.99]) compared with the placebo. Although brexpiprazole was associated with a lower incidence of schizophrenia as an adverse event compared with the placebo (0.57 [0.37, 0.85]), aripiprazole and brexpiprazole were associated with a higher incidence of weight gain compared with the placebo (2.12 [1.28, 3.68], 2.14 [1.35, 3.42]). No significant differences were found in other individual adverse events, such as somnolence, akathisia, extrapyramidal symptoms, and dizziness between aripiprazole or brexpiprazole and placebo. Any outcome between aripiprazole and brexpiprazole were not different.

CONCLUSIONS

Differences in short-term efficacy and safety for acute schizophrenia were not apparent between aripiprazole and brexpiprazole. Future studies are warranted to evaluate whether there are differences in the long-term outcome between treatments.

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.

Dose-Response Meta-Analysis of Antipsychotic Drugs for Acute Schizophrenia

OBJECTIVE

The dose-response relationships of antipsychotic drugs for schizophrenia are not well defined, but such information would be important for decision making by clinicians. The authors sought to fill this gap by conducting dose-response meta-analyses.

METHODS

A search of multiple electronic databases (through November 2018) was conducted for all placebo-controlled dose-finding studies for 20 second-generation antipsychotic drugs and haloperidol (oral and long-acting injectable, LAI) in people with acute schizophrenia symptoms. Dose-response curves were constructed with random-effects dose-response meta-analyses and a spline model. The outcome measure was total score reduction from baseline on the Positive and Negative Syndrome Scale or the Brief Psychiatric Rating Scale. The authors identified 95% effective doses, explored whether higher or lower doses than the currently licensed ones might be more appropriate, and derived dose equivalencies from the 95% effective doses.

RESULTS

Sixty-eight studies met the inclusion criteria. The 95% effective doses and the doses equivalent to 1 mg of oral risperidone, respectively, were as follows: amisulpride for patients with positive symptoms, 537 mg/day and 85.8 mg; aripiprazole, 11.5 mg/day and 1.8 mg; aripiprazole LAI (lauroxil), 463 mg every 4 weeks and 264 mg; asenapine, 15.0 mg/day and 2.4 mg; brexpiprazole, 3.36 mg/day and 0.54 mg; haloperidol, 6.3 mg/day and 1.01 mg; iloperidone, 20.13 mg/day and 3.2 mg; lurasidone, 147 mg/day and 23.5 mg; olanzapine, 15.2 mg/day and 2.4 mg; olanzapine LAI, 277 mg every 2 weeks and 3.2 mg; paliperidone, 13.4 mg/day and 2.1 mg; paliperidone LAI, 120 mg every 4 weeks and 1.53 mg; quetiapine, 482 mg/day and 77 mg; risperidone, 6.3 mg/day and 1 mg; risperidone LAI, 36.6 mg every 2 weeks and 0.42 mg; sertindole, 22.5 mg/day and 3.6 mg; and ziprasidone, 186 mg/day and 30 mg. For amisulpride and olanzapine, specific data for patients with predominant negative symptoms were available. The authors have made available on their web site a spreadsheet with this method and other updated methods that can be used to estimate dose equivalencies in practice.

CONCLUSIONS

In chronic schizophrenia patients with acute exacerbations, doses higher than the identified 95% effective doses may on average not provide more efficacy. For some drugs, higher than currently licensed doses might be tested in further trials, because their dose-response curves did not plateau.

[Preclinical pharmacological profiles and clinical efficacy of the novel antipsychotic drug brexpiprazole (REXULTI® Tablets 1 mg, 2 mg)]

Brexpiprazole (Rexulti^®) is the second antipsychotic agent in the world with dopamine D2 receptor partial agonist which was developed by Otsuka Pharmaceutical Co. Ltd. It is categorized as 〝Serotonin- dopamine Activity Modulator (SDAM)〟 that regulates both serotoninergic and dopaminergic systems by acting as a partial agonist for serotonin 5-HT1A receptors and D2 receptors and as an antagonist for 5-HT2A receptors. In preclinical pharmacological studies, brexpiprazole showed the equivalent antipsychotic-like effects to those of other atypical antipsychotics. And it was suggested that brexpiprazole has the low potentials to induce extrapyramidal symptoms, hyperprolactinemia and tardive dyskinesia, with improvement effects on cognitive dysfunction. Furthermore, brexpiprazole has the weak effects on histamine H1 receptors which are associated with sedation and weight gain in clinical. In the clinical trials in patients with schizophrenia in both acute and maintenance phase, brexpiprazole showed improvement of antipsychotic effects against placebo, and low incidence of adverse events, e.g., extrapyramidal symptoms, hyperprolactinemia, and weight gain, as suggested in preclinical studies. Furthermore, brexpiprazole showed low incidence of metabolic abnormalities. In particular, brexpiprazole showed relatively low incidences of akathisia, insomnia and agitation which has been commonly reported with aripiprazole. This would be based on the pharmacological features of brexpiprazole that is more potent antagonism at 5-HT2A receptors and D2 receptors partial agonism with lower intrinsic activity compared to those of aripiprazole. In conclusion, brexpiprazole could be one of the antipsychotics with the most rational mechanism of action, and the better efficacy and safety/tolerability profiles would contribute to the treatment of patients with schizophrenia.

Evaluation of Differences in Individual Treatment Response in Schizophrenia Spectrum Disorders: A Meta-analysis

IMPORTANCE

An assumption among clinicians and researchers is that patients with schizophrenia vary considerably in their response to antipsychotic drugs in randomized clinical trials (RCTs).

OBJECTIVE

To evaluate the overall variation in individual treatment response from random variation by comparing the variability between treatment and control groups.

DATA SOURCES

Cochrane Schizophrenia, MEDLINE/PubMed, Embase, PsycINFO, Cochrane CENTRAL, BIOSIS Previews, ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform from January 1, 1955, to December 31, 2016.

STUDY SELECTION

Double-blind, placebo-controlled, RCTs of adults with a diagnosis of schizophrenia spectrum disorders and prescription for licensed antipsychotic drugs.

DATA EXTRACTION AND SYNTHESIS

Means and SDs of the Positive and Negative Syndrome Scale pretreatment and posttreatment outcome difference scores were extracted. Data quality and validity were ensured by following the PRISMA guidelines.

MAIN OUTCOMES AND MEASURES

The outcome measure was the overall variability ratio of treatment to control in a meta-analysis across RCTs. Individual variability ratios were weighted by the inverse-variance method and entered into a random-effects model. A personal element of response was hypothesized to be reflected by a substantial overall increase in variability in the treatment group compared with the control group.

RESULTS

An RCT was simulated, comprising 30 patients with schizophrenia randomized to either the treatment or the control group. The different components of variation in RCTs were illustrated with simulated data. In addition, we assessed the variability ratio in 52 RCTs involving 15 360 patients with a schizophrenia or schizoaffective diagnosis. The variability was slightly lower in the treatment compared with the control group (variability ratio = 0.97; 95% CI, 0.95-0.99; P = .01).

CONCLUSIONS AND RELEVANCE

In this study, no evidence was found in RCTs that antipsychotic drugs increased the outcome variance, suggesting no personal element of response to treatment but instead indicating that the variance was slightly lower in the treatment group than in the control group; although the study cannot rule out that subsets of patients respond differently to treatment, it suggests that the average treatment effect is a reasonable assumption for the individual patient.

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.

In silico, in vitro and in vivo metabolite identification of brexpiprazole using ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry

RATIONALE

Brexpiprazole is a novel serotonin-dopamine activity modulator approved by the USFDA in July 2015 for the treatment of schizophrenia and as an adjunctive therapy with other antidepressants for major depressive disorder in adults. However, limited numbers of metabolites are reported in the literature for brexpiprazole. Our prime intent behind this study is to revisit metabolite profiling of brexpiprazole and to identify and characterize all possible in vitro and in vivo metabolites.

METHODS

Firstly, the site of metabolism for brexpiprazole was predicted by a Xenosite web predictor model. Secondly, in vitro metabolite profiling was performed by incubating the drug individually with rat liver microsomes, human liver microsomes and rat S9 fraction at 37°C for 1 h in incubator shaker. Finally, for in vivo metabolite identification, a 50 mg kg^-1 dose of brexpiprazole was administered to male Sprague-Dawley rats and the presence of various metabolites was confirmed in rat plasma, urine and feces.

RESULTS

The predicted atomic site of metabolism was obtained as a color gradient by the Xenosite web predictor tool and, from this study, probable metabolites were listed. In total, 14 phase I and 2 phase II metabolites were identified and characterized in the in vitro and in vivo matrices using ultra-high-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (UHPLC/QTOF-MS/MS). The majority of metabolites were found in the sample incubated with human liver microsomes and in rat urine, while in the other matrices only a few metabolites were detected.

CONCLUSIONS

All the 16 metabolites were identified and characterized using UHPLC/QTOF-MS/MS. The study revealed that brexpiprazole is metabolized via hydroxylation, glucuronidation, S-oxidation, N-oxidation, dioxidation, oxidative deamination, N-dealkylation, etc.

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.

Treating depressive episodes or symptoms in patients with schizophrenia

Depressive episodes or symptoms occur frequently in patients with schizophrenia and may have far-reaching consequences. Despite the high prevalence rate and clinical relevance of this comorbidity, knowledge about treatment options is still limited. The aim of this review is to provide an overview of the literature concerning treatment options for depressive episodes or symptoms in schizophrenia. Based on the current evidence, we present a stepwise treatment approach. The first step is to evaluate the current antipsychotic treatment of psychotic symptoms and consider lowering the dosage, since increased blockade of the dopamine D2 receptors may be associated with a worse subjective sense of well-being and dysphoria. A second step is to consider switching antipsychotics, since there are indications that some antipsychotics (including sulpiride, clozapine, olanzapine, aripiprazole, quetiapine, lurasidone, or amisulpride) are slightly more effective in reducing depressive symptoms compared to other antipsychotics or placebo. In the case of a persistent depressive episode, additional therapeutic interventions are indicated. However, the evidence is indecisive regarding the treatment of choice: either starting cognitive-behavioral therapy or adding an antidepressant. A limited number of studies examined the use of antidepressants in depressed patients with schizophrenia showing modest effectiveness. Overall, additional research is needed to determine the most effective treatment approach for patients with schizophrenia and depressive episodes.

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.

Changes in metabolic parameters and body weight in brexpiprazole-treated patients with acute schizophrenia: pooled analyses of phase 3 clinical studies

OBJECTIVE

To analyze the effect of brexpiprazole on metabolic parameters and body weight in adults with schizophrenia, including clinically relevant sub-groups of patients, based on data from two pivotal phase 3 studies (NCT01393613; NCT01396421) and a long-term extension study (NCT01397786).

METHODS

The short-term studies were randomized, double-blind, placebo-controlled, fixed-dose (2 and 4 mg/day), 6-week phase 3 studies. The long-term study was an open-label 52-week study, recruiting de novo patients and those completing either short-term study. Maximum exposure to brexpiprazole was 58 weeks. Fasting metabolic parameters and weight were measured throughout the studies. Metabolic values were characterized as normal, borderline, or high (cholesterol, triglycerides, and glucose) and low or normal (HDL), using commonly reported thresholds. The incidences of all possible shifts in metabolic parameters were measured from baseline to any time post-baseline during the first 6 weeks, first 6 months, and last 6 months of treatment.

RESULTS

In short-term studies, the proportion of brexpiprazole-treated patients with unfavorable shifts in metabolic parameters was low and like that of placebo-treated patients; the incidence of these shifts was not dose-dependent. During both short- and long-term treatment, the incidence of unfavorable shifts with brexpiprazole was lower than that of favorable shifts. During short-term studies, the mean increase in body weight was 1.2 kg with brexpiprazole treatment and 0.2 kg with placebo. The mean increase in body weight during long-term treatment was 3.2 kg at week 58.

CONCLUSIONS

Brexpiprazole treatment was associated with moderate weight gain and small changes in metabolic parameters during both short- and long-term treatment.

Improving neurocognitive functioning in schizophrenia by addition of cognitive remediation therapy to a standard treatment of metacognitive training

Cognitive dysfunctions are a common clinical feature of schizophrenia and represent important indicators of outcome among patients who are affected. Therefore, a randomized, controlled, monocentric, singleblind trial was carried out to compare two different rehabilitation strategies adopted for the restoration and recovery of cognitive functioning of residential patients with schizophrenia. A sample of 110 residential patients were selected and, during the experimental period, a group of 55 patients was treated with sets of domain-specific exercises (SRT+CRT), whereas an equal control group was treated with sets of nondomain- specific exercises (SRT+PBO) belonging to the Cogpack® software. The effects on the scores (between T0 and T1) of the variables treatment and time and of the interaction time X treatment were analyzed: for the total BACS, the main effect of the between-factors variable treatment is statistically significant (F=201.562 P=0.000), as well as the effect of the within-factors variable “time” (F=496.68 P=0.000).The interaction of these two factors is also statistically significant (F=299.594 P=0.000). The addition of cognitive remediation therapy (CRT) to a standard treatment of metacognitive training (MCT) resulted in a significant improvement in global neurocognitive functioning and has reported positive effects with regard to the strengthening of verbal and working memory, selective and sustained attention at T1. A relevant result is the statistically significance of “time X treatment” for all the tests administered: we can assume that the domain-specific cognitive training amplifies the effects of SRT, as the primary and secondary goals of the present study were achieved.

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.

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.

Comparison of the efficacy and safety of 4 and 2 mg/day brexpiprazole for acute schizophrenia: a meta-analysis of double-blind, randomized placebo-controlled trials

PURPOSE

The purpose of this study was to compare the efficacy and safety of brexpiprazole 4 mg/day (B4) and 2 mg/day (B2) for treating acute schizophrenia.

PATIENTS AND METHODS

We performed three categorical meta-analyses (B4 vs placebo, B2 vs placebo, and B4 vs B2) of double-blind, randomized placebo-controlled trials (DBRCTs) that reported improvements in the Positive and Negative Syndrome Scale (PANSS) scores, response rate, Clinical Global Impression-Improvement and Severity (CGI-I and CGI-S) scores, discontinuation rate, and incidence of individual adverse events.

RESULTS

We identified three DBRCTs with 1,444 patients. Both B4 and B2 were superior to placebo for PANSS total score (B4: standardized mean difference [SMD] =-0.30, 95% CI =-0.43, -0.17; B2: SMD =-0.30, 95% CI =-0.46, -0.13), PANSS negative score, response rate, CGI-S score, and CGI-I score. B2, but not B4, was superior to placebo for the PANSS positive score. However, there was considerable heterogeneity in the meta-analysis for B4's PANSS positive score, which disappeared after excluding a 2018 Japanese study from the meta-analysis that included more patients on a high-dose antipsychotic prior to their participation. A meta-analysis that excluded the data from the abovementioned patients showed B4 to be superior to the placebo in terms of the PANSS positive score (SMD =-0.22, 95% CI =-0.40, -0.03). B2, but not B4, was associated with a lower incidence of all-cause discontinuation compared with placebo. Both B4 and B2 were superior to placebo for discontinuation due to adverse events and schizophrenia, but both were associated with a higher incidence of weight gain compared with placebo. B4 was also associated with a higher risk of extrapyramidal symptoms than B2.

CONCLUSION

Both B4 and B2 benefitted patients with schizophrenia, particularly those who were not previously on high-dose antipsychotics. Both the regimens were well-tolerated, but carried a risk of weight gain and extrapyramidal symptoms, although the latter risk was higher for B4 than B2.

The antipsychotic drug brexpiprazole reverses phencyclidine-induced disruptions of thalamocortical networks

Brexpiprazole (BREX), a recently approved antipsychotic drug in the US and Canada, improves cognitive dysfunction in animal models, by still largely unknown mechanisms. BREX is a partial agonist at 5-HT_1A and D₂ receptors and antagonist at α_1B- and α_2C-adrenergic and 5-HT_2A receptors all with a similar potency. The NMDA receptor antagonist phencyclidine (PCP), used as pharmacological model of schizophrenia, activates thalamocortical networks and decreases low frequency oscillations (LFO; <4 Hz). These effects are reversed by antipsychotics. Here we assessed the ability of BREX to reverse PCP-induced hyperactivity of thalamocortical circuits, and the involvement of 5-HT_1A receptors in its therapeutic action. BREX reversed PCP-induced neuronal activation at a lower dose in centromedial/mediodorsal thalamic nuclei (CM/MD; 0.5mg/kg) than in pyramidal medial prefrontal cortex neurons (mPFC, 2mg/kg), perhaps due to antagonism at α_1B-adrenoceptors, abundantly expressed in the thalamus. Conversely, a cumulative 0.5 mg/kg dose reversed a PCP-induced LFO decrease in mPFC but not in CM/MD. BREX reduced LFO in both areas, yet with a different dose-response, and moderately excited mPFC neurons. The latter effect was reversed by the 5-HT_1A receptor antagonist WAY-100635. Thus, BREX partly antagonizes PCP-induced thalamocortical hyperactivity, differentially in mPFC versus CM/MD. This regional selectivity may be related to the differential expression of α_1B-, α_2C-adrenergic and 5-HT_2A receptors in both regions and/or different neuronal types. Furthermore, the pro-cognitive properties of BREX may be related to the 5-HT_1A receptor-mediated increase in mPFC pyramidal neuron activity. Overall, the present data provide new insight on the brain elements involved in BREX's therapeutic actions.

Clinical role of brexpiprazole in depression and schizophrenia

Brexpiprazole, a serotonin-dopamine activity modulator, is the second D2 partial agonist to come to market and has been approved for the treatment of schizophrenia and as an adjunctive treatment in major depressive disorder. With less intrinsic activity than aripiprazole at the D2 receptor and higher potency at 5-HT2A, 5-HT1A, and α1B receptors, the pharmacological properties of brexpiprazole suggest a more tolerable side effect profile with regard to akathisia, extrapyramidal dysfunction, and sedation. While no head-to-head data are currently available, double-blind placebo-controlled studies show favorable results, with the number needed to treat (NNT) vs placebo of 6-15 for response in acute schizophrenia treatment and 4 for maintenance. NNT is 12 for response and 17-31 for remission vs placebo in major depression. In schizophrenia trials, treatment-emergent adverse effects (TEAEs) and discontinuation rates due to TEAEs were lower in treatment groups vs placebo (7.1%-9.2% vs 14.7%, respectively). Meanwhile, discontinuation rates due to TEAEs in depression studies were higher in treatment groups vs placebo (1.3%-3.5% vs 0-1.4%, respectively) and appeared dose dependent. Rates of akathisia are lower compared to those with aripiprazole and cariprazine, weight gain is more prominent than with aripiprazole, cariprazine, or ziprasidone, and sedation is less than with aripiprazole but more than with cariprazine. Brexpiprazole target dosing is 2-4 mg in schizophrenia and 2 mg in depression augmentation. Dose adjustments should be considered in hepatic or renal dysfunction and/or in poor cytochrome P450 2D6 metabolizers. While brexpiprazole represents an exciting second entry for D2 partial agonists with positive studies thus far, direct head-to-head comparisons will shed more light on the efficacy and side effect profile of brexpiprazole.

The Role of Norepinephrine and Its α-Adrenergic Receptors in the Pathophysiology and Treatment of Major Depressive Disorder and Schizophrenia: A Systematic Review

Norepinephrine (NE) is recognized as having a key role in the pathophysiology of major depressive disorder (MDD) and schizophrenia, although its distinct actions via α-adrenergic receptors (α-ARs) are not well defined. We performed a systematic review examining the roles of NE and α-ARs in MDD and schizophrenia. PubMed and ProQuest database searches were performed to identify English language papers published between 2008 and 2015. In total, 2,427 publications (PubMed, n = 669; ProQuest, n = 1,758) were identified. Duplicates, articles deemed not relevant, case studies, reviews, meta-analyses, preclinical reports, or articles on non-target indications were excluded. To limit the review to the most recent data representative of the literature, the review further focused on publications from 2010 to 2015, which were screened independently by all authors. A total of 16 research reports were identified: six clinical trial reports, six genetic studies, two biomarker studies, and two receptor studies. Overall, the studies provided indirect evidence that α-AR activity may play an important role in aberrant regulation of cognition, arousal, and valence systems associated with MDD and schizophrenia. Characterization of the NE pathway in patients may provide clinicians with information for more personalized therapy of these heterogeneous diseases. Current clinical studies do not provide direct evidence to support the role of NE α-ARs in the pathophysiology of MDD and schizophrenia and in the treatment response of patients with these diseases, in particular with relation to specific valence systems. Clinical studies that attempt to define associations between specific receptor binding profiles of psychotropics and particular clinical outcomes are needed.

Efficacy of Atypical Antipsychotics in the Management of Acute Agitation and Aggression in Hospitalized Patients with Schizophrenia or Bipolar Disorder: Results from a Systematic Review

Acute agitation and aggression are common symptoms in patients with bipolar disorder and schizophrenia. In this review, we discuss the prevalence, clinical assessment strategies, treatment options, and current Western and Chinese guidelines for the management of acute agitation and aggression in patients with bipolar disorder or schizophrenia. Among available approaches, we discuss in detail recent evidence supporting the use of intramuscular (IM) antipsychotics and some recently approved oral atypical antipsychotics for the management of acute aggression and agitation in hospitalized patients with bipolar disorder or schizophrenia presenting with acute agitation or aggression, highlighting some differences between individual antipsychotic agents.

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

Second-generation antipsychotics have demonstrated efficacy for patients with schizophrenia but are associated with wide-ranging side effects. Brexpiprazole, a serotonin-dopamine activity modulator, has demonstrated efficacy in adult patients with schizophrenia. This paper provides an overview of the safety and tolerability of brexpiprazole in patients with schizophrenia through examination of pooled safety data from one Phase 2 and two Phase 3 6-week, short-term studies, and two open-label, 52-week, long-term studies. In the short-term studies, there were no reports of treatment-emergent adverse events (TEAEs) with an incidence≥5% and twice that of placebo in patients treated with brexpiprazole 2-4mg. In the long-term studies, TEAEs reported by ≥5% of patients were schizophrenia (10.7%), insomnia (8.0%), weight increase (7.7%), headache (6.0%), and agitation (5.2%). Akathisia rates were low in the short- (5.8%, pooled brexpiprazole group) and long-term studies (4.6%). Sedation rates were low in the short- (2.3%, pooled brexpiprazole group) and long-term studies (0.9%). Mean body weight increase was 1.1kg in both short- and long-term studies. For all studies, changes from baseline to last visit in laboratory parameters, electrocardiogram values, and vital signs were small and not clinically relevant. Changes in lipid profiles or other metabolic parameters were also small. Collectively, these studies suggest that brexpiprazole was well tolerated, with a favorable safety profile that does not exhibit significant rates of important adverse events that can be seen with existing antipsychotics (akathisia, sedation, weight gain, or QTc prolongation), and therefore may provide a useful treatment option for patients with schizophrenia. ClinicalTrials.gov: NCT00905307; NCT01396421; NCT01393613; NCT01649557; NCT01397786.