Efficacy and Safety of Cariprazine in Acute Exacerbation of Schizophrenia: Results From an International, Phase III Clinical Trial

Antipsychotic augmentation vs. monotherapy in schizophrenia: systematic review, meta-analysis and meta-regression analysis

Antipsychotic polypharmacy in schizophrenia is much debated, since it is common and costly with unclear evidence for its efficacy and safety. We conducted a systematic literature search and a random effects meta-analysis of randomized trials comparing augmentation with a second antipsychotic vs. continued antipsychotic monotherapy in schizophrenia. Co-primary outcomes were total symptom reduction and study-defined response. Antipsychotic augmentation was superior to monotherapy regarding total symptom reduction (16 studies, N=694, standardized mean difference, SMD=-0.53, 95% CI: -0.87 to -0.19, p=0.002). However, superiority was only apparent in open-label and low-quality trials (both p<0.001), but not in double-blind and high-quality ones (p=0.120 and 0.226, respectively). Study-defined response was similar between antipsychotic augmentation and monotherapy (14 studies, N=938, risk ratio = 1.19, 95% CI: 0.99 to 1.42, p=0.061), being clearly non-significant in double-blind and high-quality studies (both p=0.990). Findings were replicated in clozapine and non-clozapine augmentation studies. No differences emerged regarding all-cause/specific-cause discontinuation, global clinical impression, as well as positive, general and depressive symptoms. Negative symptoms improved more with augmentation treatment (18 studies, N=931, SMD=-0.38, 95% CI: -0.63 to -0.13, p<0.003), but only in studies augmenting with aripiprazole (8 studies, N=532, SMD=-0.41, 95% CI: -0.79 to -0.03, p=0.036). Few adverse effect differences emerged: D2 antagonist augmentation was associated with less insomnia (p=0.028), but more prolactin elevation (p=0.015), while aripiprazole augmentation was associated with reduced prolactin levels (p<0.001) and body weight (p=0.030). These data suggest that the common practice of antipsychotic augmentation in schizophrenia lacks double-blind/high-quality evidence for efficacy, except for negative symptom reduction with aripiprazole augmentation.

Brexpiprazole and cariprazine: distinguishing two new atypical antipsychotics from the original dopamine stabilizer aripiprazole

BACKGROUND

Brexpiprazole and cariprazine are the latest US Food and Drug Administration approved atypical antipsychotics available in the United States. Both function as partial agonists of the dopamine-2 receptor (D2R), a mechanism of action shared with aripiprazole. However, all three differ in their affinities for the D2R as well as for serotonin receptors (5-HTRs). This paper seeks to delineate these pharmacodynamic and clinical differences amongst the three dopamine partial agonist atypical antipsychotic drugs.

METHODS

PubMed and clinicaltrials.gov searches were used to generate preclinical and clinical evidence for review. Data derived from animal models and human subjects were used to provide insight on clinical mechanisms and adverse effect potentials. Clinical trial data were reviewed to compare clinical efficacy and adverse effects.

RESULTS

Efficacies among the three drugs are comparable for their shared indications. Side-effect profile and underlying pharmacodynamic mechanism of action for each drug may differ.

CONCLUSION

Partial agonism of the D2R is a similarity of the three drugs reviewed. Each drug varies in affinity for both the D2R and a diverse group of 5-HTRs, generating a distinct profile of clinical indications and adverse effects for each.

Safety and tolerability of cariprazine in the long-term treatment of schizophrenia: results from a 48-week, single-arm, open-label extension study

RATIONALE

Cariprazine, a dopamine D3/D2 receptor partial agonist antipsychotic, demonstrated efficacy and tolerability in 6-week, randomized, placebo-controlled schizophrenia trials. Schizophrenia is a chronic disorder that requires continuous treatment; therefore, the long-term safety and tolerability profile of antipsychotic agents is an important factor in guiding clinician decisions.

OBJECTIVE

This single-arm, open-label extension study evaluated the long-term safety and tolerability of cariprazine in patients with schizophrenia.

METHODS

Patients enrolled in this study completed a 6-week, randomized, placebo- and active-controlled study and had responded (Clinical Global Impressions-Severity [CGI-S] ≤3; ≥20 % reduction in Positive and Negative Syndrome Scale [PANSS] total score) to treatment at the end of the lead-in study. Patients (N = 93) received flexibly dosed, open-label cariprazine (1.5-4.5 mg/day) for up to 48 weeks.

RESULTS

Approximately 50 % (46/93) of patients completed the 48 weeks of open-label treatment. The most common adverse events (AEs) were akathisia (14 %), insomnia (14 %), and weight increased (12 %). Serious AEs (SAEs) occurred in 13 % of patients; 11 % discontinued due to AEs. Mean changes in metabolic parameters were generally small and not clinically relevant. Mean body weight increased by 1.9 kg from the start of the lead-in study to the end of the extension study. There were no discontinuations associated with change in metabolic parameters or body weight. Long-term cariprazine treatment was not associated with prolactin elevation or clinically significant changes in cardiovascular parameters.

CONCLUSIONS

In this 48-week, single-arm trial, open-label cariprazine (1.5-4.5 mg/day) treatment was generally safe and well tolerated with no new safety concerns associated with long-term treatment.

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.

Tolerability and Safety Profile of Cariprazine in Treating Psychotic Disorders, Bipolar Disorder and Major Depressive Disorder: A Systematic Review with Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Cariprazine is a novel antipsychotic agent recently approved for treating schizophrenia and bipolar mania in the USA. The sample sizes of published randomized controlled trials (RCTs) of the drug are small; previous meta-analyses included few RCTs and did not specifically investigate the tolerability/safety profile of cariprazine.

OBJECTIVE

Our objective was to conduct a meta-analysis of published RCTs to systematically review the tolerability and safety of cariprazine versus placebo.

METHODS

We searched the clinical trial registers (the metaRegister of controlled trials, ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform) and electronic databases (PubMed, Embase, PsycINFO and Cochrane library) up to June 2016 to identify phase II/III RCTs of cariprazine in patients with schizophrenia, bipolar disorder or major depressive disorder. We conducted a meta-analysis to investigate outcomes, including risks of discontinuation due to adverse events (AEs), extrapyramidal side effects (EPS) or related events, metabolic syndrome and cardiovascular-related events.

RESULTS

We included nine RCTs, with a total of 4324 subjects. The risk of discontinuation due to AEs for cariprazine was similar to that for placebo (risk ratio [RR] 1.13, 95 % confidence interval [CI] 0.77-1.66). Cariprazine was associated with higher risks of EPS-related events than was placebo, including risk of akathisia (RR 3.92, 95 % CI 2.83-5.43), tremor (RR 2.41, 95 % CI 1.53-3.79) and restlessness (RR 2.17, 95 % CI 1.38-3.40). The cariprazine treatment group was more likely to have clinically significant weight gain (RR 1.68, 95 % CI 1.12-2.52). No statistically significant differences in results were found in other metabolic parameters or cardiovascular-related events.

CONCLUSION

There was a statistically significant higher risk of EPS-related AEs and a slight increase in mean body weight with cariprazine. There were no statistically significant effects on prolactin level or cardiovascular parameters. EPSs were the main short-term adverse reactions reported in the limited number of patients studied. Further clinical and post-marketing pharmacovigilance studies are needed to investigate the long-term safety of cariprazine.

Long-term cariprazine treatment for the prevention of relapse in patients with schizophrenia: A randomized, double-blind, placebo-controlled trial

Cariprazine, a dopamine D3/D2 receptor partial agonist with preference for D3 receptors, has demonstrated efficacy in randomized controlled trials in schizophrenia. This multinational, randomized, double-blind, placebo-controlled, parallel-group study evaluated the efficacy, safety, and tolerability of cariprazine for relapse prevention in adults with schizophrenia; total study duration was up to 97weeks. Schizophrenia symptoms were treated/stabilized with cariprazine 3-9mg/d during 20-week open-label treatment consisting of an 8-week, flexible-dose run-in phase and a 12-week fixed-dose stabilization phase. Stable patients who completed open-label treatment could be randomized to continued cariprazine (3, 6, or 9mg/d) or placebo for double-blind treatment (up to 72weeks). The primary efficacy parameter was time to relapse (worsening of symptom scores, psychiatric hospitalization, aggressive/violent behavior, or suicidal risk); clinical measures were implemented to ensure safety in case of impending relapse. A total of 264/765 patients completed open-label treatment; 200 eligible patients were randomized to double-blind placebo (n=99) or cariprazine (n=101). Time to relapse was significantly longer in cariprazine- versus placebo-treated patients (P=.0010, log-rank test). Relapse occurred in 24.8% of cariprazine- and 47.5% of placebo-treated patients (hazard ratio [95% CI]=0.45 [0.28, 0.73]). Akathisia (19.2%), insomnia (14.4%), and headache (12.0%) were reported in ≥10% of patients during open-label treatment; there were no cariprazine adverse events ≥10% during double-blind treatment. Long-term cariprazine treatment was significantly more effective than placebo for relapse prevention in patients with schizophrenia. The long-term safety profile in this study was consistent with the safety profile observed in previous cariprazine clinical trials. ClincalTrials.gov identifier: NCT01412060.

Cariprazine: First Global Approval

Cariprazine (Vraylar) is an oral atypical antipsychotic originated by Gedeon Richter. It is a potent dopamine D3 and D2 receptor partial agonist, which preferentially binds to the D3 receptor. Cariprazine also has partial agonist activity at serotonin 5-HT1A receptors. In September 2015, cariprazine received its first global approval in the USA for the treatment of schizophrenia and for the acute treatment of manic or mixed episodes associated with bipolar I disorder. It is also in development in a variety of countries for the treatment of schizophrenia with predominant negative symptoms (phase III), as adjunctive therapy for major depressive disorder (phase II/III) and for the treatment of bipolar depression (phase II). This article summarizes the milestones in the development of cariprazine leading to this first approval for schizophrenia and manic or mixed episodes associated with bipolar I disorder.

Update on schizophrenia and bipolar disorder: focus on cariprazine

Schizophrenia and bipolar disorder are severe psychiatric disorders that are frequently associated with persistent symptoms and significant dysfunction. While there are a multitude of psychopharmacologic agents are available for treatment of these illnesses, suboptimal response and significant adverse consequences limit their utility. Cariprazine is a new, novel antipsychotic medication with dopamine D2 and D3 partial agonist effects. Its safety and efficacy have been investigated in acute psychosis of schizophrenia, bipolar mania, bipolar depression, and unipolar depression. Efficacy has been demonstrated in schizophrenia and mania. It is unclear if cariprazine is effective in depression associated with unipolar or bipolar illness. Adverse consequences include extrapyramidal symptoms including akathisia, and various gastrointestinal symptoms. The US Food and Drug Administration (FDA) has recently approved cariprazine. This review will provide clinicians with basic information regarding the research program of cariprazine.

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.

Update on New and Emerging Treatments for Schizophrenia

Although there has been more than 50 years of development, there remains a great need for better antipsychotic medications. This article looks at the recent advances in treatment of schizophrenia. New hypotheses have been suggested that may replace or complement the dopamine hypotheses. The article explores the different novel drugs that impact some of the key neurotransmitter systems currently. Phosphodiesterase 10A inhibitors and α-7 neuronal nicotinic acetylcholine receptor modulators constitute the majority. The marketing of these medications eventually may result in change about how schizophrenia is treated.

Targeting the dopamine D3 receptor: an overview of drug design strategies

INTRODUCTION

Dopamine is a neurotransmitter widely distributed in both the periphery and the central nervous system (CNS). Its physiological effects are mediated by five closely related G protein-coupled receptors (GPCRs) that are divided into two major subclasses: the D1-like (D1, D5) and the D2-like (D2, D3, D4) receptors. D3 receptors (D3Rs) have the highest density in the limbic areas of the brain, which are associated with cognitive and emotional functions. These receptors are therefore attractive targets for therapeutic management.

AREAS COVERED

This review summarizes the functional and pharmacological characteristics of D3Rs, including the design and clinical relevance of full agonists, partial agonists and antagonists, as well as the capacity of these receptors to form active homodimers, heterodimers or higher order receptor complexes as pharmacological targets in several neurological and neurodegenerative disorders.

EXPERT OPINION

The high sequence homology between D3R and the D2-type challenges the development of D3R-selective compounds. The design of new D3R-preferential ligands with improved physicochemical properties should provide a better pharmacokinetic/bioavailability profile and lesser toxicity than is found with existing D3R ligands. It is also essential to optimize D3R affinity and, especially, D3R vs. D2-type binding and functional selectivity ratios. Developing allosteric and bitopic ligands should help to improve the D3R selectivity of these drugs. As most evidence points to the ability of GPCRs to form homomers and heteromers, the most promising therapeutic strategy in the future is likely to involve the application of heteromer-selective drugs. These selective ligands would display different affinities for a given receptor depending on the receptor partners within the heteromer. Therefore, designing novel compounds that specifically target and modulate D1R-D3R heteromers would be an interesting approach for the treatment of levodopa (L-DOPA)-induced dyskinesias.

Safety and tolerability of antipsychotic co-treatment in patients with schizophrenia: results from a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Antipsychotic co-treatment is common in schizophrenia, despite lacking evidence for its efficacy and safety. Areas: We conducted a systematic search of PubMed/PsycInfo/CJN/WangFan/CBM without language restrictions from database inception until 05/25/2015 for randomized trials comparing antipsychotic monotherapy with antipsychotic co-treatment in ≥20 adults with schizophrenia reporting meta-analyzable adverse events (AEs) data. Meta-analyzing 67 studies (n=4,861, duration=10.3±5.2 weeks), antipsychotic co-treatment was similar to monotherapy regarding intolerability-related discontinuation (risk ratio (RR)=0.84, 95% confidence interval (CI)=0.53-1.33, p=0.455). While incidence of ≥1 AE was lower with antipsychotic co-treatment (RR=0.77, 95%CI=0.66-0.90, p=0.001), these results were solely driven by open-label and efficacy-focused studies. Adjunctive D2-antagonists lead to less nausea (RR=0.220, 95%CI=0.06-0.87, p=0.030) and insomnia (RR=0.26, 95%CI=0.08-0.86, p=0.028), but higher prolactin (SMD=2.20, 95%CI=0.43-3.96, p=0.015). Conversely, adjunctive partial D2-agonists (aripiprazole=100%) resulted in lower electrocardiogram abnormalities (RR=0.43, 95%CI=0.25-0.73, p=0.002), constipation (RR=0.45, 95%CI=0.25-0.79, p=0.006), drooling/hypersalivation (RR=0.14, 95%CI=0.07-0.29, p<0.001), prolactin (SMD=-1.77, 95%CI=-2.38, -1.15, p<0.001), total and LDL-cholesterol (SMD=-0.33, 95%CI=-0.55, -0.11, p=0.003; SMD=-0.33, 95%CI=-0.54, -0.10, p=0.004).

EXPERT OPINION

No double-blind evidence for altered AE burden associated with antipsychotic co-treatment was found. However, AEs were insufficiently and incompletely reported and follow-up duration was modest. Adjunctive partial D2-agonists might be beneficial for counteracting several AEs. High-quality, long-term studies that comprehensively assess AEs are needed.

Mechanism of action of cariprazine

Cariprazine is a new therapeutic agent recently approved for the treatment of both schizophrenia and manic or mixed episodes associated with bipolar disorder, and is under investigation for the treatment of both bipolar depression and major depressive disorder.

Cariprazine in the treatment of schizophrenia: a proof-of-concept trial

This 6-week, double-blind, placebo-controlled, proof-of-concept study evaluated the efficacy, safety, and tolerability of low-dose (1.5-4.5 mg/day) and high-dose (6-12 mg/day) cariprazine in patients with acute exacerbation of schizophrenia (NCT00404573). The primary efficacy measure was change in the Positive and Negative Syndrome Scale (PANSS) total score, analyzed using a last observation carried forward approach. Other efficacy measures included the Clinical Global Impression-Severity (secondary) and PANSS subscales (additional). There were no significant differences between the two doses of cariprazine and placebo in PANSS total score change or any other efficacy parameter after multiplicity adjustment. However, low-dose cariprazine versus placebo showed significantly greater reductions in PANSS total (P=0.033) and PANSS negative (P=0.027) scores without multiplicity adjustment. Common treatment-emergent adverse events (incidence≥5% and twice that in the placebo group in either cariprazine dose group) were akathisia, restlessness, tremor, back pain, and extrapyramidal disorder. In this study, the overall cariprazine treatment effect was not statistically significant, but patients treated with low-dose cariprazine showed significantly greater improvement in schizophrenia symptoms relative to placebo-treated patients. Cariprazine was generally well tolerated. Results of this study suggest that cariprazine may be effective in treating schizophrenia and future research is warranted.

The dopamine D₃-preferring D₂/D₃ dopamine receptor partial agonist, cariprazine, reverses behavioural changes in a rat neurodevelopmental model for schizophrenia

Current antipsychotic medication is largely ineffective against the negative and cognitive symptoms of schizophrenia. One promising therapeutic development is to design new molecules that balance actions on dopamine D2 and D3 receptors to maximise benefits and limit adverse effects. This study used two rodent paradigms to investigate the action of the dopamine D3-preferring D3/D2 receptor partial agonist cariprazine. In adult male rats, cariprazine (0.03-0.3 mg/kg i.p.), and the atypical antipsychotic aripiprazole (1-3 mg/kg i.p.) caused dose-dependent reversal of a delay-induced impairment in novel object recognition (NOR). Treating neonatal rat pups with phencyclidine (PCP) and subsequent social isolation produced a syndrome of behavioural alterations in adulthood including hyperactivity in a novel arena, deficits in NOR and fear motivated learning and memory, and a reduction and change in pattern of social interaction accompanied by increased ultrasonic vocalisations (USVs). Acute administration of cariprazine (0.1 and 0.3 mg/kg) and aripiprazole (3 mg/kg) to resultant adult rats reduced neonatal PCP-social isolation induced locomotor hyperactivity and reversed NOR deficits. Cariprazine (0.3 mg/kg) caused a limited reversal of the social interaction deficit but neither drug affected the change in USVs or the deficit in fear motivated learning and memory. Results suggest that in the behavioural tests investigated cariprazine is at least as effective as aripiprazole and in some paradigms it showed additional beneficial features further supporting the advantage of combined dopamine D3/D2 receptor targeting. These findings support recent clinical studies demonstrating the efficacy of cariprazine in treatment of negative symptoms and functional impairment in schizophrenia patients.

Clinical pharmacology study of cariprazine (MP-214) in patients with schizophrenia (12-week treatment)

PURPOSE

Cariprazine is a potent dopamine D3-preferring D3/D2 receptor partial agonist in development for the treatment of schizophrenia, bipolar mania, and depression. Pharmacokinetics of cariprazine and the two clinically relevant metabolites (desmethyl- and didesmethyl-cariprazine) was evaluated in a clinical pharmacology study.

METHODS

This was a multicenter, randomized, open-label, parallel-group, fixed-dose (3, 6, or 9 mg/day) study of 28-week duration (≤4-week observation, 12-week open-label treatment, and 12-week follow-up). Once-daily cariprazine was administered to 38 adult patients with schizophrenia. The pharmacokinetics of cariprazine, metabolites, and total active moieties (sum of cariprazine and two metabolites) was evaluated; efficacy and safety were also assessed.

RESULTS

Steady state was reached within 1-2 weeks for cariprazine and desmethyl-cariprazine, 4 weeks for didesmethyl-cariprazine, and 3 weeks for total active moieties. Cariprazine and desmethyl-cariprazine levels decreased >90% within 1 week after the last dose, didesmethyl-cariprazine decreased ~50% at 1 week, and total active moieties decreased ~90% within 4 weeks. Terminal half-lives of cariprazine, desmethyl-cariprazine, and didesmethyl-cariprazine ranged from 31.6 to 68.4, 29.7 to 37.5, and 314 to 446 hours, respectively. Effective half-life (calculated from time to steady state) of total active moieties was ~1 week. Incidence of treatment-emergent adverse events was 97.4%; 15.8% of patients discontinued due to adverse events. No abnormal laboratory values or major differences from baseline in extrapyramidal symptoms were observed.

CONCLUSION

Cariprazine and its active metabolites reached steady state within 4 weeks, and exposure was dose proportional over the range of 3-9 mg/day. Once-daily cariprazine was generally well tolerated in adult patients with schizophrenia.

Effects of cariprazine, a novel antipsychotic, on cognitive deficit and negative symptoms in a rodent model of schizophrenia symptomatology

Negative symptoms and cognitive impairment associated with schizophrenia are strongly associated with poor functional outcome and reduced quality of life and remain an unmet clinical need. Cariprazine is a dopamine D3/D2 receptor partial agonist with preferential binding to D3 receptors, recently approved by the FDA for the treatment of schizophrenia and manic or mixed episodes associated with bipolar I disorder. The aim of this study is to evaluate effects of cariprazine in an animal model of cognitive deficit and negative symptoms of schizophrenia. Following sub-chronic PCP administration (2mg/kg, IP for 7 days followed by 7 days drug-free), female Lister Hooded rats were administered cariprazine (0.05, 0.1, or 0.25mg/kg, PO) or risperidone (0.16 or 0.1mg/kg, IP) before testing in novel object recognition (NOR), reversal learning (RL), and social interaction (SI) paradigms. As we have consistently demonstrated, sub-chronic PCP significantly impaired behavior in these tests. Deficits were significantly improved by cariprazine, in a dose dependent manner in the operant RL test with efficacy at lower doses in the NOR and SI tests. Locomotor activity was reduced at the highest doses of 0.1mg/kg and 0.25mg/kg in NOR and SI. Risperidone also reversed the PCP-induced deficit in all tests. In conclusion, cariprazine was effective to overcome PCP-induced deficits in cognition and social behavior in a thoroughly validated rat model in tests representing specific symptom domains in schizophrenia patients. These findings support very recent results showing efficacy of cariprazine in the treatment of negative symptoms in schizophrenia patients.