Quality-adjusted life year difference in patients with predominant negative symptoms of schizophrenia treated with cariprazine and risperidone

Dopamine partial agonists: a discrete class of antipsychotics

Worldwide, there are now three marketed dopamine D2 partial agonists: aripiprazole, brexpiprazole and cariprazine. These three drugs share a number of properties other than their action at D2 receptors. Pharmacologically, they are 5HT2 antagonists and D3 and 5HT1A partial agonists but with little or no alpha-adrenergic, anticholinergic or antihistaminic activity. They also share a long duration of action. Clinically, D2 partial agonists are effective antipsychotics and generally have useful antimanic and antidepressant activity. They are usually well tolerated, causing akathisia and insomnia only at the start of treatment, and are non-sedating. These drugs also share a very low risk of increased prolactin and of weight gain and accompanying metabolic effects. They may also have a relatively low risk of tardive dyskinesia. There is some evidence that they are preferred by patients to dopamine antagonists. Individual dopamineD2 partial agonists have much in common and as a group they differ importantly from dopamine D2 antagonists. Dopamine D2 partial agonists should be considered a distinct class of antipsychotics.Key pointsD2 partial agonists share many pharmacological and clinical propertiesD2 partial agonists differ in several important respects from D2 antagonistsD2 partial agonists should be considered a discrete class of antipsychotics.

Canonical and Non-Canonical Antipsychotics' Dopamine-Related Mechanisms of Present and Next Generation Molecules: A Systematic Review on Translational Highlights for Treatment Response and Treatment-Resistant Schizophrenia

Schizophrenia is a severe psychiatric illness affecting almost 25 million people worldwide and is conceptualized as a disorder of synaptic plasticity and brain connectivity. Antipsychotics are the primary pharmacological treatment after more than sixty years after their introduction in therapy. Two findings hold true for all presently available antipsychotics. First, all antipsychotics occupy the dopamine D2 receptor (D2R) as an antagonist or partial agonist, even if with different affinity; second, D2R occupancy is the necessary and probably the sufficient mechanism for antipsychotic effect despite the complexity of antipsychotics' receptor profile. D2R occupancy is followed by coincident or divergent intracellular mechanisms, implying the contribution of cAMP regulation, β-arrestin recruitment, and phospholipase A activation, to quote some of the mechanisms considered canonical. However, in recent years, novel mechanisms related to dopamine function beyond or together with D2R occupancy have emerged. Among these potentially non-canonical mechanisms, the role of Na²⁺ channels at the dopamine at the presynaptic site, dopamine transporter (DAT) involvement as the main regulator of dopamine concentration at synaptic clefts, and the putative role of antipsychotics as chaperones for intracellular D2R sequestration, should be included. These mechanisms expand the fundamental role of dopamine in schizophrenia therapy and may have relevance to considering putatively new strategies for treatment-resistant schizophrenia (TRS), an extremely severe condition epidemiologically relevant and affecting almost 30% of schizophrenia patients. Here, we performed a critical evaluation of the role of antipsychotics in synaptic plasticity, focusing on their canonical and non-canonical mechanisms of action relevant to the treatment of schizophrenia and their subsequent implication for the pathophysiology and potential therapy of TRS.

Efficacy and Safety of Roluperidone for the Treatment of Negative Symptoms of Schizophrenia

BACKGROUND

This is a placebo-controlled multi-national trial of roluperidone, a compound with antagonist properties for 5-HT2A, sigma2, and α1A-adrenergic receptors, targeting negative symptoms in patients with schizophrenia. This trial follows a previous trial that demonstrated roluperidone superiority over placebo in a similar patient population.

METHODS

Roluperidone 32 mg/day, roluperidone 64 mg/day, or placebo was administered for 12 weeks to 513 patients with schizophrenia with moderate to severe negative symptoms. The primary endpoint was the PANSS-derived Negative Symptom Factor Score (NSFS) and the key secondary endpoint was Personal and Social Performance scale (PSP) total score.

RESULTS

NSFS scores were lower (improved) for roluperidone 64 mg compared to placebo and marginally missing statistical significance for the intent-to-treat (ITT) analysis data set (P ≤ .064), but reached nominal significance (P ≤ .044) for the modified-ITT (m-ITT) data set. Changes in PSP total score were statistically significantly better on roluperidone 64 mg compared to placebo for both ITT and m-ITT (P ≤ .021 and P ≤ .017, respectively).

CONCLUSIONS

Results of this trial confirm the potential of roluperidone as a treatment of negative symptoms and improving everyday functioning in patients with schizophrenia. Study registration: Eudra-CT: 2017-003333-29; NCT03397134.

Efficacy and safety of cariprazine augmentation in patients treated with clozapine: a pilot study

BACKGROUND

Cariprazine, a novel antipsychotic drug, is a partial agonist of dopamine D2/D3 receptors with preferential binding to the D3 receptor. There has been an increasing interest in cariprazine augmentation to clozapine; however, the evidence thus far has been only limited to case reports and case series.

OBJECTIVES

To evaluate the efficacy and safety of the augmentation of clozapine with cariprazine in patients with sub-optimal treatment response.

METHODS

Demographic and clinical information of the study population were collected from the electronic records and PANSS scale administered at baseline and 3 months. Tolerability and discontinuation reasons where applicable were also recorded.

RESULTS

Ten patients (four men and six women) with a mean age of 36.5 years (range = 26-45) were included. Reasons for cariprazine initiation included inadequate treatment response, persistent negative symptoms and/or tolerability issues with clozapine or previous augmentation options. Two patients discontinued cariprazine within the first 6 weeks due to restlessness and poor response, respectively. There was a significant reduction in the median total PANSS score from baseline to 3 months (from 59 to 22.5, p < 0.05), median positive PANSS score (from 11.5 to 5.5, p < 0.05) and in the median negative PANSS score (from 15.5 to 3, p < 0.05) which correspond to a 48%, 33.8% and 65.8% mean score reduction, respectively.

CONCLUSION

This is the first pilot study evaluating the effectiveness of clozapine augmentation. The preliminary evidence suggests that this may be a safe and effective practice in patients failing to adequately respond to or tolerate clozapine and/or previous augmentation strategies.

Newer antipsychotics: Brexpiprazole, cariprazine, and lumateperone: A pledge or another unkept promise?

Antipsychotic agents are used for various indications in the treatment of psychiatric disorders. Despite their proven roles in multiple conditions, the treatment-emergent side effects of antipsychotic medications, such as metabolic side effects, are often the limiting factor for their long-term and short-term uses. Moreover, antipsychotic medications are often criticized for being less effective in treating different disabling symptoms such as negative symptoms of schizophrenia. As a result, the search for safer and more efficacious antipsychotic agents is ongoing. Newer antipsychotic agents are gaining attention related to emerging efficacy and tolerability data in treating neuropsychiatric conditions. In this review, we attempt to appraise the scientific data on psychopharmacology, safety profile, and efficacy of the newer additions to the list of second-generation antipsychotics, namely brexpiprazole, cariprazine, and lumateperone. We conducted a selective review utilizing PubMed, clinicaltrials.gov, and Cochrane databases to gather appropriate publications, keeping broad inclusion criteria. There were no restrictions on the age of the study population or the year of publication. We also cross-referenced articles and references to capture all existing studies. Our review of the current literature indicates that all three antipsychotic agents appear to be promising based on their short-term studies, while long-term studies remain limited. There is also a need for a head to head comparison between the newer antipsychotics with the other antipsychotic agents to ascertain if the newer agents are any better than the others.

New Antipsychotic Medications in the Last Decade

PURPOSE OF REVIEW

Over the last ten years, the treatment of psychosis has seen a near explosion of creative development in both novel agents and new delivery modalities. The current review summarizes these developments over the past decade (2011-2020). We performed a systematic review utilizing PubMed and PsychInfo with the aim of identifying all the RCT and related analyses in adults with psychosis (schizophrenia and mania).

RECENT FINDINGS

We identified 11 significant developments: the introduction of new antipsychotics cariprazine, brexpiprazole, lumateperone, and pimavanserin; introduction of new delivery methods: subcutaneous long-acting risperidone, aripiprazole lauroxil, transdermal asenapine, and inhaled loxapine; and the introduction of new approaches such as olanzapine/samidorphan for olanzapine-associated weight gain, examination of the TAAR1 agonist SEP 363,856 as a test of concept, and the combination of Xanomeline/Trospium, an M₁ and M₄ muscarinic receptor agonist in conjunction with a peripheral anticholinergic. Last decade has seen a tremendous development in second-generation antipsychotics which provides unprecedented treatment options for clinicians in treating psychosis.

Cariprazine as a therapeutic option for schizophrenia: a drug evaluation

Introduction: Schizophrenia is a very disabling condition that may result in a significant impairment of individual, professional, and social adjustments. Antipsychotics (APs), the first-line treatment for schizophrenia, in many cases modify the course of the disease, by reducing the institutionalization risk, at the price of severe and invalidating side effects. Cariprazine is one of the latest second-generation APs (SGAs) acting as a partial agonist of type 2 and 3 dopamine receptors, which was recently approved for the treatment of adult schizophrenia.Areas covered: The authors provide a critical review and commentary on the currently available data on the effectiveness and tolerability of cariprazine in schizophrenic patients, with a particular focus on its specific target symptoms.Expert opinion: Cariprazine appears significantly effective on both acute and maintenance treatment of schizophrenia, and in improving positive, negative, and cognitive symptoms, slightly more than other SGAs. It shows a good safety and tolerability profile, with akathisia being its most common side effect. Although further independent studies are needed to clarify its precise advantages over other SGAs, cariprazine seems a promising compound not only in schizophrenia, but also in a broad range of psychiatric conditions, including perhaps bipolar and addictive disorders.

Cariprazine in Three Special Different Areas: A Real-World Experience

Cariprazine is an antipsychotic medication which received approval from the US Food and Drug Administration for the treatment of schizophrenia in September 2015. Cariprazine is a dopamine D₃ and D₂ receptor partial agonist, with a preference for the D₃ receptor. Furthermore, although to a more limited extent, cariprazine also exhibits partial agonism at the level of 5-HT_1A receptors, thus exerting an antidepressant effect in addition to the antipsychotic effect. The most commonly encountered adverse events are extrapyramidal symptoms and akathisia. Short-term weight gain appears infrequently. Cariprazine is not associated with any clinically meaningful alterations in metabolic variables, prolactin, or ECG QT interval. Cariprazine is also approved for the acute treatment of manic or mixed episodes associated with bipolar I disorder. Clinical trials of cariprazine are ongoing in patients with acute bipolar I depression and as adjunctive treatment to antidepressant therapy in patients with major depressive disorder. In this article, we present some significant clinical cases regarding the use of cariprazine, with the hope that our experience can provide insight or suggestions to be used in clinical practice.

Negative Symptoms of Schizophrenia: New Prospects of Cariprazine Treatment

Background

Cariprazine is a new piperazine derivative atypical antipsychotic, like aripiprazole and brexpiprazole. It has been approved for treating schizophrenia in many countries and has recently been included on the List of Essential Medicines in Russia. Unlike most other atypical antipsychotics, it shows high in vivo occupancy of dopamine D2 and D3 receptors at clinically relevant doses. In animal models, cariprazine has demonstrated dopamine D3 receptor-dependent pro-cognitive and anti-anhedonic effects, suggesting its potential for treating negative symptoms. This review summarizes the efficacy of cariprazine in the treatment of negative symptoms of schizophrenia.

Methods

A literature search of databases covering international and Russian journals, for articles published between 1st January 2010 and 1st June 2020.

Results

Cariprazine demonstrated at least comparable efficacy in the treatment of schizophrenia symptoms to active comparators including risperidone, olanzapine or aripiprazole. The drug has a good safety profile. It appeared to be associated with a lower risk of metabolic syndromes and most extrapyramidal symptoms. The positive effect of cariprazine on the negative symptoms of schizophrenia may be associated with the elimination of secondary negative symptoms. However, of all the atypical antipsychotics to date, only cariprazine has a convincingly, methodologically robust proven advantage over risperidone in eliminating the predominant negative symptoms of schizophrenia. Yet only four studies have investigated the effect of cariprazine on the negative symptoms of schizophrenia. There is a lack of research into its direct impact on emotional-volitional disorders, anhedonia, cognitive symptoms and personality changes. However, there is evidence to suggest cariprazine is effective in treatment-resistant cases, but this requires further confirmation.

Conclusion

Cariprazine is an effective and well-tolerated agent for the treatment of schizophrenia and may be effective in cases where other antipsychotics have failed. Cariprazine has been shown to have a positive effect on negative symptoms. Further studies are needed to collect more data on long-term treatment of schizophrenia and especially negative symptoms.

Using informative prior based on expert opinion in Bayesian estimation of the transition probability matrix in Markov modelling-an example from the cost-effectiveness analysis of the treatment of patients with predominantly negative symptoms of schizophrenia with cariprazine

Background

When patient health state transition evidence is missing from clinical literature, analysts are inclined to make simple assumptions to complete the transition matrices within a health economic model. Our aim was to provide a solution for estimating transition matrices by the Bayesian statistical method within a health economic model when empirical evidence is lacking.

Methods

We used a previously published cost-effectiveness analysis of the use of cariprazine compared to that of risperidone in patients with predominantly negative symptoms of schizophrenia. We generated the treatment-specific state transition probability matrices in three different ways: (1) based only on the observed clinical trial data; (2) based on Bayesian estimation where prior transition probabilities came from experts’ opinions; and (3) based on Bayesian estimation with vague prior transition probabilities (i.e., assigning equal prior probabilities to the missing transitions from one state to the others). For the second approach, we elicited Dirichlet prior distributions by three clinical experts. We compared the transition probability matrices and the incremental quality-adjusted life years (QALYs) across the three approaches.

Results

The estimates of the prior transition probabilities from the experts were feasible to obtain and showed considerable consistency with the clinical trial data. As expected, the estimated health benefit of the treatments was different when only the clinical trial data were considered (QALY difference 0.0260), its combination with the experts’ beliefs were used in the economic model (QALY difference 0.0253), and when vague prior distributions were used (QALY difference 0.0243).

Conclusions

Imputing zeros to missing transition probabilities in Markov models might be untenable from the clinical perspective and may result in inappropriate estimates. Bayesian statistics provides an appropriate framework for imputing missing values without making overly simple assumptions. Informative priors based on expert opinions might be more appropriate than vague priors.

Cost-effectiveness analysis of olanzapine and risperidone in schizophrenic patients in the Indian healthcare settings of Andhra Pradesh, India

Objectives

The prevalence of schizophrenia in Andhra Pradesh, India is 279, and the crude disability-adjusted life year is 177 per 100 thousand people. It is one of the major mental health problems of the state. However, there is a dearth of information regarding the pharmacoeconomics of schizophrenia treatment. The purpose of this study was to evaluate the cost and effectiveness of the two most commonly used drugs olanzapine and risperidone for schizophrenia.

Methods

A prospective observational study was carried out in a tertiary care teaching hospital (Department of psychiatry) for a period of 1 year among 124 schizophrenia patients. The data were collected in a specially designed patient data form, and the cost and effectiveness of the treatment were evaluated. Then, the ICER for olanzapine 71 and risperidone 53 users were calculated. Sensitivity analysis was run creating a model to identify uncertainties and its effect on the results.

Key findings

The mean cost per patient for olanzapine was 89.96 USD, and risperidone was 85.56 USD for 8 weeks from the start of the treatment. The incremental effects and value of the treatment score with the Positive and Negative Syndrome Scale (PANSS) for olanzapine (27.33) were greater than that of risperidone (20.38). The cost (USD) per PANSS reduction for olanzapine was 3.29 and risperidone was 4.20. The overall incremental cost-effectiveness ratio (ICER) of olanzapine compared to risperidone was 0.63 USD/PANSS.

Conclusion

The results showed that olanzapine was a cost-effective drug and an alternative to risperidone in the Indian healthcare settings. With further revision and validation, the cost-effectiveness outcome of olanzapine and risperidone can be used to inform any comprehensive healthcare financing mechanism in Indian healthcare settings.

The role of dopamine D3 receptors in the mechanism of action of cariprazine

Cariprazine is a new atypical antipsychotic drug (APD) with a unique pharmacodynamic profile, different from both typical and atypical APDs. Specifically, cariprazine acts as a partial agonist at the dopamine (DA) D2 and D3 receptors and serotonin 5-HT1A receptors, and as an antagonist at the 5-HT2B receptors. Moreover, it shows moderate affinities for adrenergic, histaminergic, and cholinergic receptors that are involved in mediating the side effects characteristic of typical APDs. In this review, we discuss the contribution of DA D3 receptors (D3Rs) in the etiology and pathophysiology of schizophrenia and the potential benefits that may be associated with a more selective targeting of D3R by APDs, as compared to other dopaminergic and non-dopaminergic receptor subtypes. Cariprazine, by acting on D3Rs, ameliorates anhedonia and cognitive deficits in animal models based on environmental or pharmacological manipulation. The reviewed results support the potential benefits of cariprazine in treating negative symptoms and cognitive deficits of schizophrenia, and therefore representing a promising approach in addressing the unmet clinical needs for the improved treatment of this serious neuropsychiatric disorder.

Pharmacological treatment of negative symptoms in schizophrenia: update and proposal of a clinical algorithm

The clinical presentation of schizophrenia encompasses symptoms divided into three dimensions: positive, negative, and cognitive. Negative symptoms (NS), in particular, have a major impact on the quality of life of the affected subject, and, differing from positive symptoms, are often associated with a limited response to pharmacotherapy. To date, studies specifically investigating NS in schizophrenia are scant; therefore, proper selection of therapy for NS remains a major unmet medical need. Given the heterogeneity of the clinical presentation of schizophrenia, the treatment of NS, as well as therapy for other associated symptoms, should be largely individualized according to a patient's specific characteristics. In this paper, we review current knowledge on NS and construct a clinical algorithm for the treatment of schizophrenic conditions with pronounced NS. Overall, data from the literature suggest that second-generation antipsychotics, such as cariprazine and amisulpride, should be preferred over first-generation antipsychotics (FGAs), as they are associated with better functional outcomes and lower cognitive impairment. The combination of antipsychotics and antidepressants may also improve NS while addressing some affective disorders associated with schizophrenia; however, no clear information is available on the effects of this combination on primary NS or on the mechanism of action of the combination. In the proposed clinical algorithm, we suggest that cariprazine should be used as first-line treatment for patients with predominant NS, and that amisulpride should be considered as an alternative in cases of cariprazine failure. Further treatment lines may include the use of olanzapine and quetiapine, and add-on therapy with antidepressants.

Cariprazine for acute and maintenance treatment of adults with schizophrenia: an evidence-based review and place in therapy

Cariprazine is an oral antipsychotic approved in the US and EU for the treatment of schizophrenia. Cariprazine differs from other antipsychotics in that it is a dopamine D3- and D2-receptor partial agonist, with tenfold higher affinity for D3 receptors than for D2 receptors. Cariprazine is metabolized in two steps by CYP3A4 to didesmethyl-cariprazine (DDCAR). DDCAR has a long half-life of 1-3 weeks and is the predominant circulating active moiety. Efficacy and safety in persons with acute schizophrenia were assessed in four similarly designed, short-term, randomized, placebo-controlled clinical trials in nonelderly adults, with three studies considered positive and yielding a number needed to treat vs placebo for response (change from baseline ≥30% in Positive and Negative Syndrome Scale total score) of ten for the approved dose range of cariprazine 1.5-6 mg/day. The most common adverse reactions were extrapyramidal symptoms (15% and 19% for 1.5-3 and 4.5-6 mg/day, respectively, vs 8% for placebo) and akathisia (9% and 12.5% for 1.5-3 and 4.5-6 mg/day, respectively, vs 4% for placebo). For the approved dose range, rates of discontinuation because of an adverse event were lower overall for patients receiving cariprazine vs placebo (9% vs 12%). Weight and metabolic profile appear favorable. Cariprazine does not increase prolactin levels or prolong the electrocardiographic QT interval. Cariprazine has also been found to be effective for the maintenance treatment of schizophrenia by delaying time to relapse when compared with placebo (HR 0.45). A 26-week randomized clinical trial evidenced superiority of cariprazine over risperidone for the treatment of predominantly negative symptoms in patients with schizophrenia. Cariprazine is also approved in the US for the acute treatment of manic or mixed episodes associated with bipolar I disorder in adults and is being studied for the treatment of bipolar I depression and major depressive disorder.

A systematic review of health economic models and utility estimation methods in schizophrenia

INTRODUCTION

There is a growing need for economic evaluations describing the disease course, as well as the costs and clinical outcomes related to the treatment of schizophrenia.

AREAS COVERED

A systematic review on studies describing health economic models in schizophrenia and a targeted literature review on utility mapping algorithms in schizophrenia were carried out. Models found in the review were collated and assessed in detail according to their type and various other attributes. Fifty-nine studies were included in the review. Modeling techniques varied from simple decision trees to complex simulation models. The models used various clinical endpoints as value drivers, 47% of the models used quality-adjusted life years, and eight percent used disability-adjusted life years to measure benefits, while others applied various clinical outcomes. Most models considered patients switching between therapies, and therapeutic adherence, compliance or persistence. The targeted literature review identified four main approaches to map PANSS scores to utility values.

EXPERT COMMENTARY

Health economic models developed for schizophrenia showed great variability, with simulation models becoming more frequently used in the last decade. Using PANSS scores as the basis of utility estimations is justifiable.