Cariprazine, A Broad-Spectrum Antipsychotic for the Treatment of Schizophrenia: Pharmacology, Efficacy, and Safety

Rhabdomyolysis during adjunctive treatment with cariprazine in a clozapine-resistant schizophrenia patient

We report the case of a 49-year-old male treatment-resistant schizophrenia patient, whose treatment with clozapine and sertraline was supplemented with cariprazine 1.5 mg/day while regularly presenting for electroconvulsive therapy. After 3 weeks of adjunctive treatment with cariprazine, blood tests revealed pronounced signs of rhabdomyolysis, including a creatine kinase serum level of 20 386 U/L and an AST serum level of 696 U/L. Clinically, the patient did not report somatic symptoms other than mild back pain. After discontinuation of cariprazine and normal saline infusion, the above-mentioned findings resolved rapidly. Although very rare, rhabdomyolysis can be a potentially dangerous side effect of cariprazine and clinicians should be aware of its possible occurrence.

Neuroleptic malignant syndrome and serotonin syndrome: a comparative bibliometric analysis

OBJECTIVE

This study aimed to analyze and map scientific literature on Neuroleptic Malignant Syndrome (NMS) and Serotonin Syndrome (SS) from prestigious, internationally indexed journals. The objective was to identify key topics, impactful articles, prominent journals, research output, growth patterns, hotspots, and leading countries in the field, providing valuable insights for scholars, medical students, and international funding agencies.

METHODS

A systematic search strategy was implemented in the PubMed MeSH database using specific keywords for NMS and SS. The search was conducted in the Scopus database, renowned for its extensive coverage of scholarly publications. Inclusion criteria comprised articles published from 1950 to December 31st, 2022, restricted to journal research and review articles written in English. Data were analyzed using Microsoft Excel for descriptive analysis, and VOSviewer was employed for bibliometric mapping.

RESULTS

The search yielded 1150 articles on NMS and 587 on SS, with the majority being case reports. Growth patterns revealed a surge in NMS research between 1981 and 1991, while SS research increased notably between 1993 and 1997. Active countries and journals differed between NMS and SS, with psychiatry journals predominating for NMS and pharmacology/toxicology journals for SS. Authorship analysis indicated higher multi-authored articles for NMS. Top impactful articles focused on review articles and pathogenic mechanisms. Research hotspots included antipsychotics and catatonia for NMS, while SS highlighted drug interactions and specific medications like linezolid and tramadol.

CONCLUSIONS

NMS and SS represent rare but life-threatening conditions, requiring detailed clinical and scientific understanding. Differential diagnosis and management necessitate caution in prescribing medications affecting central serotonin or dopamine systems, with awareness of potential drug interactions. International diagnostic tools and genetic screening tests may aid in safe diagnosis and prevention. Reporting rare cases and utilizing bibliometric analysis enhance knowledge dissemination and research exploration in the field of rare drug-induced medical conditions.

D3 Receptor-Targeted Cariprazine: Insights from Lab to Bedside

Until the late 1800s, drug development was a chance finding based on observations and repeated trials and errors. Today, drug development must go through many iterations and tests to ensure it is safe, potent, and effective. This process is a long and costly endeavor, with many pitfalls and hurdles. The aim of the present review article is to explore what is needed for a molecule to move from the researcher bench to the patients' bedside, presented from an industry perspective through the development program of cariprazine. Cariprazine is a relatively novel antipsychotic medication, approved for the treatment of schizophrenia, bipolar mania, bipolar depression, and major depression as an add-on. It is a D3-preferring D3-D2 partial agonist with the highest binding to the D3 receptors compared to all other antipsychotics. Based on the example of cariprazine, there are several key factors that are needed for a molecule to move from the researcher bench to the patients' bedside, such as targeting an unmet medical need, having a novel mechanism of action, and a smart implementation of development plans.

Aromatic linker variations in novel dopamine D2 and D3 receptor ligands

Dopamine D2-like receptors, especially D2 and D3 receptor subtypes, are important targets of antipsychotic agents. Many of these antipsychotics share an aliphatic linker element between a protonable amine group and an acyl-like moiety. Here, we have modified this aliphatic linker into phenylmethyl and phenylethyl linkers substituted in different positions. The design, synthesis, and in vitro evaluation of 18 dopamine D2 and D3 receptor ligands were performed in this study. Using a radioligand displacement assay, all ligands were found to have modest nanomolar affinity to D2R and D3R. N-(4-{2-[4-(2-Methoxyphenyl)piperazin-1-yl]ethyl}phenyl)acetamide (6c) demonstrates the highest D3R and D2R affinity values (pKi values of 7.83 [D2R] and 8.04 [D3R]), featuring a slight preference to D3R. This derivative can be taken as a reference structure for the development of a new class of D2R and D3R ligands.

Role of adjunctive cariprazine for treatment-resistant depression in patients with major depressive disorder: A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Cariprazine is an orally active dopamine D3-preferring D3/D2 receptor and serotonin 5-HT1A receptor partial agonist, being considered as a treatment for refractory MDD. Therefore, we aim to perform the first meta-analysis of current literature, to collate changes in depression from baseline and assess tolerability of adjunctive cariprazine in MDD populace.

METHODS

PubMed, Embase, Google Scholar, ClinicalTrials.Gov, and Cochrane Library were searched from inception till 1st September 2023. RCTs of adult patients with refractory MDD under adjunctive cariprazine vs. placebo were included. Primary outcomes included improvement in MADRS, CGI-S, and HAM-D 17 scores. Secondary outcomes included treatment-emergent adverse events. The statistical analysis was performed using generic inverse variance with random-effects model. The overall risk ratios (RR) were calculated for dichotomous outcomes.

RESULTS

A total of five RCTs were analysed, enrolling 2013 participants (cariprazine: 959 participants, Placebo: 1054). Supplementation of ADT with cariprazine demonstrated a significant improvement in MADRAS, CGI-S and HAMD-17 scores from baseline (LSMD: -1.88, 95% CI [-2.94, -0.83], p=0.0005), (LSMD: -0.18, 95% CI [-0.29, -0.07], p=0.002), and (LSMD: -0.96, 95% CI [-1.70, -0.21], p=0.01) respectively. Treatment with adjunctive cariprazine therapy demonstrated significantly increased incidence of akathisia, nausea, dizziness, fatigue, restlessness, somnolence, and tremors when compared with placebo.

CONCLUSION

Our meta-analysis provides evidence supporting the efficacy of adjunctive cariprazine in patients with refractory MDD. However, it is essential to consider the safety profile of cariprazine, particularly the increased risk of adverse events. The vigilant monitoring and management of these side effects should be integrated into clinical practice to minimize discontinuation rates and optimize patient outcomes.

Mining and analysis of adverse event signals of Cariprazine based on the real-world data of FAERS database

OBJECTIVE

This study aims to analyze the adverse events (AEs) of Cariprazine based on the FAERS database, providing evidence for its safety surveillance.

METHODS

For signal quantification of Cariprazine-related AEs, we used disproportionality analysis including the Ratio of Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), and Multi-Item Gamma Poisson Shrinker (MGPS) algorithms.

RESULTS

We selected Cariprazine-related AE reports from the FAERS database from the fourth quarter of 2015 to the first quarter of 2023, and performed a detailed data analysis. Out of a total of 12,278,580 case reports, 3659 were found to be directly related to Cariprazine. We identified 140 Preferred Terms (PT) to describe these AEs, finding that they involved 27 organ systems. Specifically, AEs related to eye disorders such as Cataract cortical, Cataract nuclear, Accommodation disorder, Lenticular opacities, Oculogyric crisis, Dyschromatopsia were not explicitly mentioned in the drug's leaflet, indicating the presence of new ADR signals.

CONCLUSION

Analysis of the FAERS database identified AEs associated with Cariprazine, notably in eye disorders not previously documented in the drug's official leaflet. These findings emphasize the need for continuous post-market surveillance and awareness among healthcare professionals regarding potential new ADR signals.

Multilevel evidence of MECP2-associated mitochondrial dysfunction and its therapeutic implications

We present a male patient carrying a pathogenic MECP2 p. Arg179Trp variant with predominant negative psychiatric features and multilevel evidence of mitochondrial dysfunction who responded to the cariprazine treatment. He had delayed speech development and later experienced severe social anxiety, learning disabilities, cognitive slowing, and predominant negative psychiatric symptoms associated with rigidity. Clinical examinations showed multisystemic involvement. Together with elevated ergometric lactate levels, the clinical picture suggested mitochondrial disease, which was also supported by muscle histopathology. Exploratory transcriptome analysis also revealed the involvement of metabolic and oxidative phosphorylation pathways. Whole-exome sequencing identified a pathogenic MECP2 variant, which can explain both the dopamine imbalance and mitochondrial dysfunction in this patient. Mitochondrial dysfunction was previously suggested in classical Rett syndrome, and we detected related phenotype evidence on multiple consistent levels for the first time in a MECP2 variant carrier male. This study further supports the importance of the MECP2 gene in the mitochondrial pathways, which can open the gate for more personalized therapeutic interventions. Good cariprazine response highlights the role of dopamine dysfunction in the complex psychiatric symptoms of Rett syndrome. This can help identify the optimal treatment strategy from a transdiagnostic perspective instead of a classical diagnostic category.

Role of Serotonergic System in Regulating Brain Tumor-Associated Neuroinflammatory Responses

Serotonin signaling regulates wide arrays of both neural and extra-neural functions. Serotonin is also found to affect cancer progression directly as well as indirectly by modulating the immune cells. In the brain, serotonin plays a key role in regulating various functions; disturbance of the normal activities of serotonin leads to various mental illnesses, including the neuroinflammatory response in the central nervous system (CNS). The neuroinflammatory response can be initiated in various psychological illnesses and brain cancer. Serotonergic signaling can impact the functions of both glial as well as the immune cells. It can also affect the tumor immune microenvironment and the inflammatory response associated with brain cancers. Apart from this, many drugs used for treatment of psychological illness are known to modulate serotonergic system and can cross the blood-brain barrier. Understanding the role of serotonergic pathways in regulating neuroinflammatory response and brain cancer will provide a new paradigm in modulating the serotonergic components in treating brain cancer and associated inflammation-induced brain damages.

Efficacy and Safety Profiles of Antipsychotic Drugs as Viewed by Psychiatrists: A Comparative Analysis of Cariprazine and Risperidone

BACKGROUND

Physicians hold the belief that the treatment outcomes and the treatment strategy they eventually adopt is largely determined by the differences in medications. Despite numerous studies focusing on the decision-making processes of psychiatrists, including the choice of antipsychotics when prescribing pharmacotherapy, the impact of therapeutic drug profiling on physicians' decision-making remains poorly comprehended.

AIM

The aim of this study is to assess the quantitative differences in perceptions of antipsychotics by psychiatrists using cariprazine and risperidone as examples.

METHODS

A total of 79 psychiatrists were interviewed anonymously in St. Petersburg, Russia. The physicians documented the clinical advantages they perceived drugs to possess relative to one another, following a predetermined principle: A B, A=B, A B (2-AC protocol). The comparison is based on eleven parameters that assess the effectiveness and safety of cariprazine or risperidone. It has been hypothesized that the pattern of responses (qualitative difference) and the degree of preference for each drug (quantitative difference) may not align with the data in the original meta-analyses.

RESULTS

The perception parameter exhibited a greater difference than anticipated (δ - 0.889), while the threshold for differentiating between the drugs was lower (τ - 1.001). The response pattern only aligned with theory by 44.37%. The dispersion of responses was associated with the length of work experience.

CONCLUSION

The perceived difference between the drugs significantly deviates from the theoretical data, both in terms of strength of perception and pattern (quantitative and qualitative differences).

The role of the D3 dopamine receptor and its partial agonist cariprazine in patients with schizophrenia and substance use disorder

INTRODUCTION

Comorbidity of substance use disorder (SUD) with schizophrenia, referred to as dual disorder (DD), significantly increases morbidity and mortality compared to schizophrenia alone. A dopaminergic dysregulation seems to be a common pathophysiological basis of the comorbidity.

AREAS COVERED

This article reports the current evidence on the role of dopamine dysregulations in DD, the pharmacological profile of cariprazine, a partial agonist of D3 and D2 dopamine receptors, and first clinical observations that may support its usefulness in the therapy of DD. PubMed/MEDLINE was searched for the keywords 'cariprazine,' 'schizophrenia,' 'dual disorder,' 'dopamine,' and 'dopamine receptor.' Preclinical and clinical studies, and reviews published in English were retrieved.

EXPERT OPINION

Although the management of DD remains challenging, and the evidence for pharmacologic treatments is still unsatisfactory, cariprazine may be a candidate medication in DD due to its unique mechanism of action. Preliminary clinical experiences suggest that cariprazine has both antipsychotic and anticraving properties and should be considered early in patients with DD.

Effects of the atypical antipsychotic and D3/D2 dopamine partial agonist cariprazine on effort-based choice behavior: implications for modeling avolition

RATIONALE

Cariprazine is an atypical antipsychotic that acts as a D3/D2 receptor partial agonist. In addition to treating positive symptoms of schizophrenia, cariprazine may have utility for treating negative symptoms. Rodent studies have focused on the effects of cariprazine on cognitive functions and behaviors thought to be related to anhedonia. Avolition, which is characterized by reduced initiation and persistence of goal-directed behavior, is another important negative symptom.

OBJECTIVES

Effort-related choice tasks have been used as animal models of avolition. In these studies, cariprazine was assessed for its effects on effort-based choice in both rats and mice. Previous work has shown that D2 antagonists such as haloperidol and eticlopride produce a low-effort bias in rodents tested on effort-based choice tasks.

RESULTS

Low doses of cariprazine produced a low-effort bias in rats tested on the fixed ratio 5/chow feeding choice task, decreasing lever pressing for high carbohydrate pellets but increasing chow intake. Cariprazine did not alter preference or intake of these foods in free-feeding tests. The effort-related effects of cariprazine were reversed by co-administration of the adenosine A2A antagonist istradefylline, and cariprazine failed to reverse the effort-related effects of the dopamine-depleting agent tetrabenazine. In mouse touchscreen choice tests, low doses of cariprazine also produced a low-effort bias, shifting behavior away from panel pressing.

CONCLUSIONS

These results demonstrate that with these rodent models of avolition, cariprazine appears to act like a D2-family antagonist even at very low doses. Furthermore, the pharmacological regulation of avolition may differ from that of other negative symptoms.

Comparing the pharmacology and pharmacokinetics of antipsychotics: Choosing an antipsychotic and dosing a long-acting injectable

In this paper, we will discuss the pharmacologic properties of antipsychotics, including those that are the same in structure and those that differentiate one from another. We will bring to you how differential pharmacologic properties can explain differential efficacy and differential tolerability. We will review how to use plasma drug levels and long-acting injectables to enhance compliance early in the illness, and to manage both forms of treatment resistance (pharmacokinetic and pharmacodynamic failures). Through inadequate pharmacokinetic processes (poor absorption, rapid metabolism, enzymatic polymorphisms, etc.), antipsychotic plasma levels do not reach sufficient concentration. Pharmacodynamic treatment failure (receptor binding and sensitivity, post-receptor effects, etc.) is the inability to provide a significant effect on psychotic symptoms despite therapeutic plasma levels. Long-Acting Injectable (LAI) antipsychotics employ technology that can provide a useful treatment tool in the armamentarium of a modern psychopharmacologist. The pharmacologic properties of antipsychotics differentiate one from another and can help explain differences in efficacy and tolerability. Utilizing plasma drug levels can enhance understanding of treatment failures and lead to specific patient management strategies for best outcomes. This kind of personalized approach to antipsychotic dosage would mean a big shift in the treatment of psychiatric patients.

The Role of Gasotransmitter-Dependent Signaling Mechanisms in Apoptotic Cell Death in Cardiovascular, Rheumatic, Kidney, and Neurodegenerative Diseases and Mental Disorders

Cardiovascular, rheumatic, kidney, and neurodegenerative diseases and mental disorders are a common cause of deterioration in the quality of life up to severe disability and death worldwide. Many pathological conditions, including this group of diseases, are based on increased cell death through apoptosis. It is known that this process is associated with signaling pathways controlled by a group of gaseous signaling molecules called gasotransmitters. They are unique messengers that can control the process of apoptosis at different stages of its implementation. However, their role in the regulation of apoptotic signaling in these pathological conditions is often controversial and not completely clear. This review analyzes the role of nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H₂S), and sulfur dioxide (SO₂) in apoptotic cell death in cardiovascular, rheumatic, kidney, and neurodegenerative diseases. The signaling processes involved in apoptosis in schizophrenia, bipolar, depressive, and anxiety disorders are also considered. The role of gasotransmitters in apoptosis in these diseases is largely determined by cell specificity and concentration. NO has the greatest dualism; scales are more prone to apoptosis. At the same time, CO, H₂S, and SO₂ are more involved in cytoprotective processes.

Cariprazine - an Alternative Treatment for Clozapine-resistant Schizophrenia?

Treatment-resistant schizophrenia (TRS) poses a significant therapeutic challenge in psychiatric practice. Clozapine is recognized as a treatment of choice in TRS but is not always effective in alleviating patients' symptoms. Additionally, clozapine therapy is associated with multiple side effects and monitoring requirements that often limit its use and negatively affect patients' compliance with the treatment. Although clozapine augmentation options are available, there is currently no alternative monotherapy proven to be effective in TRS. We present a case of a young man with TRS who failed to respond to appropriate trials of risperidone, aripiprazole and also clozapine, and who experienced impairing adverse effects of clozapine that made further clozapine treatment not only futile but also detrimental to his health. He was successfully treated with cariprazine monotherapy, which culminated in the remission of his both positive and negative symptoms of psychosis as well as in the marked improvement in social functioning. Cariprazine, a newer atypical antipsychotic endowed with a D3-preferring mode of action, may offer a better tolerated and more acceptable treatment option for patients with difficult-to-treat psychotic symptoms.

Dopamine D3/D2 Receptor Ligands Based on Cariprazine for the Treatment of Psychostimulant Use Disorders That May Be Dual Diagnosed with Affective Disorders

Highly selective dopamine D3 receptor (D3R) partial agonists/antagonists have been developed for the treatment of psychostimulant use disorders (PSUD). However, none have reached the clinic due to insufficient potency/efficacy or potential cardiotoxicity. Cariprazine, an FDA-approved drug for the treatment of schizophrenia and bipolar disorder, is a high-affinity D3R partial agonist (Ki = 0.22 nM) with 3.6-fold selectivity over the homologous dopamine D2 receptor (D2R). We hypothesized that compounds that are moderately D3R/D2R-selective partial agonists/antagonists may be effective for the treatment of PSUD. By systematically modifying the parent molecule, we discovered partial agonists/antagonists, as measured in bioluminescence resonance energy transfer (BRET)-based assays, with high D3R affinities (Ki = 0.14-50 nM) and moderate selectivity (<100-fold) over D2R. Cariprazine and two lead analogues, 13a and 13e, decreased cocaine self-administration (FR2; 1-10 mg/kg, i.p.) in rats, suggesting that partial agonists/antagonists with modest D3R/D2R selectivity may be effective in treating PSUD and potentially comorbidities with other affective disorders.

A descriptive study of aripiprazole, brexpiprazole, and cariprazine exposures in children ages 0 to 5 years reported to United States poison centers

INTRODUCTION

Increased prescribing of antipsychotics and availability of new antipsychotics has resulted in increased exposures in children. Current data on aripiprazole, brexpiprazole, and cariprazine are limited.

METHODS

This was a retrospective database study utilizing the National Poison Data System from 2015 through 2021. We included cases of single substance exposures to aripiprazole, brexpiprazole, cariprazine, or lumateperone in children ages 0 to 5 years old with follow-up to a known outcome. Key outcomes were medical outcomes, clinical effects, and level of care if treated in a healthcare facility.

RESULTS

There were 3,573 aripiprazole, 137 brexpiprazole, 249 cariprazine, and one lumateperone exposure over the period. Primary outcomes were evaluated in 2,655 cases (2,390 aripiprazole, 96 brexpiprazole, and 169 cariprazine). Fifty-one percent were male and 77% were between 0 and 2 years old. Moderate effect was coded in 16.6% of aripiprazole, 23% of brexpiprazole, and 12% of cariprazine exposures. Major effect was coded in 0.6% of aripiprazole, 1% of brexpiprazole, and 2.4% of cariprazine exposures. Duration of symptoms was mostly between 8 and 24 h for 34.6% of aripiprazole, 30% of brexpiprazole, and 32% of cariprazine exposures. Over 60% of the children seen in a health care facility were discharged from the emergency department. The lowest doses resulting in at least a moderate effect and admission to a health care facility was 0.46 mg/kg for aripiprazole, 2.1 mg/kg for brexpiprazole, and 1.9 mg/kg for cariprazine. Important clinical effects included central nervous system depression, tremors, tachycardia, agitation, and vomiting.

CONCLUSION

Reported ingestions of aripiprazole, brexpiprazole, or cariprazine may result in neurologic symptoms like central nervous system depression or seizures in children. The prolonged duration of symptoms resulted in admission for at least a day for many cases. Further research should address optimal monitoring time and location for these exposures.

Successful switching from risperidone to cariprazine in a schizophrenic patient with pronounced functional deficit. Case report

A 22-year-old male was admitted to an in-patient psychiatric unit for treatment, after a period of 2 years of increasing psychotic symptoms corresponding to a very severe case of schizophrenia across the entire scale of symptom disorder domains along with some drug abuse comorbidity. Previous treatments with olanzapine (OLA) and risperidone (RIS) had been at best partly successful toward his positive symptoms with no, or even worsening effects on the negative symptomatology. Given the gravity of the latter symptoms and functional impairment of our patient, he might thus have been a candidate for clozapine (CLZ) treatment. It was however decided to switch his antipsychotic treatment to cariprazine (CAR), an agent with a novel pharmacological and clinical profile, because of its favorable pharmacodynamic, pharmacokinetic, and tolerability/safety properties. In a follow-up on the patient 6 months after discharge he is not fully recovered, but the recovery attained reflects a marked functional improvement compared to before the RIS-to-CAR switch. The remarkable response to CAR observed may, speculatively, be in line with the suggestion that CAR could offer an alternative, safer, and more tolerable monotherapy approach (vs. CLZ) for patients with severe negative symptoms and functional deficiency resistant to standard antipsychotic treatment. He appears to occasionally still be taking drugs, but no worsening of positive symptoms has been noted. Whether or not he could reach full recovery if he would abstain entirely from drugs of abuse remains an open question.

Mini Review on Cariprazine: A Promising Antipsychotic Agent

Cariprazine is a piperazine derivative approved by the USFDA in 2015 as a novel atypical antipsychotic drug (APD) to treat adults with schizophrenia and bipolar manic or mixed episodes in adults. However, due to the partial agonist action on dopamine D₂, D₃ receptors, and serotonin 5-HT_1A receptors as well as the antagonist effect on 5-HT_2A, 5-HT_2B, and H₁ receptors, cariprazine differs pharmacologically from other APDs, both typical and atypical. Moreover, cariprazine also has a unique pharmacokinetic profile due to the formation of two clinically significant metabolites: desmethyl-cariprazine (DCAR) and desmethyl-cariprazine (DDCAR). They are eliminated by CYP3A4 and also, to a lesser extent, by CYP2D6. Here, we also review the effectiveness, safety, as well as current clinical update of cariprazine in bipolar I disorder associated with/without mania and schizophrenia through randomized and post-hoc analysis. The potential benefits of cariprazine as a promising therapeutic alternative in addressing major clinical requirements for better therapy of such severe neuropsychiatric conditions were demonstrated in this summarized review study.

Case report: Successful administration of cariprazine in a young, severely ill patient with recurrent relapses of schizophrenia and persistent negative symptoms

The present case report describes a young man diagnosed with schizophrenia and presents a "revolving door" (RD) phenomenon. He was hospitalized in an acute psychiatric clinic three times in 1 year. After each hospitalization, he was discharged with incompletely reduced psychotic symptoms, persistent negative symptoms, low functioning, lack of insight, and adherence. He had an insufficient response to maximally tolerated doses of antipsychotic monotherapy with haloperidol and risperidone. Moreover, his treatment was complicated due to the low accessibility of long-acting injectable atypical antipsychotics (LAI) in the country and his refusal of the only available atypical LAI paliperidone palmitate and refusal to take clozapine. Due to limited alternatives, the decision to administer combinations of antipsychotics was made. Since his diagnosis, he received several combinations of antipsychotics, i.e., haloperidol + quetiapine, risperidone + quetiapine, haloperidol + olanzapine, risperidone + olanzapine, but without sufficient clinical effectiveness. Although combinations of antipsychotics reduced his positive symptoms to some degree, persistent negative symptoms and extrapyramidal side effects were observed. After initiating cariprazine, which was combined with olanzapine, improvement in the patient's positive symptoms, negative symptoms, and overall functioning was detected. The combination of medications mentioned above facilitated the therapeutic alliance, thus providing control over the symptoms and preventing psychiatric hospitalizations.

A highly D3R-selective and efficacious partial agonist (S)-ABS01-113 compared to its D3R-selective antagonist enantiomer (R)-ABS01-113 as potential treatments for opioid use disorder

The non-medical use of opioids has become a national crisis in the USA. Developing non-opioid pharmacotherapies for controlling this opioid epidemic is urgent. Dopamine D₃ receptor (D₃R) antagonists and low efficacy partial agonists have shown promising profiles in animal models of opioid use disorders (OUD). However, to date, advancement to human studies has been limited. Here we report the effects of (S)- and (R)-enantiomers of (±)-ABS01-113, structural analogs of the D₃R partial agonist, (±)-VK4-40, in which the 3-OH in the linking chain is replaced by 3-F group. (S)- and (R)-ABS01-113 are identical in chemical structure but with opposite chirality. In vitro receptor binding and functional assays indicate that (S)-ABS01-113 is an efficacious (55%) and potent (EC₅₀ = 7.6 ± 3.9 nM) D₃R partial agonist, while the (R)-enantiomer is a potent D₃R antagonist (IC₅₀ = 11.4 nM). Both (S)- and (R)-ABS01-113 bind with high affinity to D₃R (K_i = 0.84 ± 0.16 and 0.37 ± 0.06 nM, respectively); however, the (S)-enantiomer is more D₃/D₂-selective (>1000-fold). Pharmacokinetic analyses indicate that both enantiomers display excellent oral bioavailability and high brain penetration. Systemic administration of (S)- or (R)-ABS01-113 alone failed to alter open-field locomotion in male rats and mice. Interestingly, pretreatment with (S)- or (R)-ABS01-113 attenuated heroin-enhanced hyperactivity, heroin self-administration, and (heroin + cue)-induced reinstatement of drug-seeking behavior. Together, these findings reveal that both enantiomers, particularly the highly selective and efficacious D₃R partial agonist (S)-ABS01-113, demonstrate promising translational potential for the treatment of OUD.

Amisulpride augmentation therapy improves cognitive performance and psychopathology in clozapine-resistant treatment-refractory schizophrenia: a 12-week randomized, double-blind, placebo-controlled trial

BACKGROUND

Although clozapine is an effective option for treatment-resistant schizophrenia (TRS), there are still 1/3 to 1/2 of TRS patients who do not respond to clozapine. The main purpose of this randomized, double-blind, placebo-controlled trial was to explore the amisulpride augmentation efficacy on the psychopathological symptoms and cognitive function of clozapine-resistant treatment-refractory schizophrenia (CTRS) patients.

METHODS

A total of 80 patients were recruited and randomly assigned to receive initial clozapine plus amisulpride (amisulpride group) or clozapine plus placebo (placebo group). Positive and Negative Syndrome Scale (PANSS), Scale for the Assessment of Negative Symptoms (SANS), Clinical Global Impression (CGI) scale scores, Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Treatment Emergent Symptom Scale (TESS), laboratory measurements, and electrocardiograms (ECG) were performed at baseline, at week 6, and week 12.

RESULTS

Compared with the placebo group, amisulpride group had a lower PANSS total score, positive subscore, and general psychopathology subscore at week 6 and week 12 (P_Bonferroni < 0.01). Furthermore, compared with the placebo group, the amisulpride group showed an improved RBANS language score at week 12 (P_Bonferroni < 0.001). Amisulpride group had a higher treatment response rate (P = 0.04), lower scores of CGI severity and CGI efficacy at week 6 and week 12 than placebo group (P_Bonferroni < 0.05). There were no differences between the groups in body mass index (BMI), corrected QT (QTc) intervals, and laboratory measurements. This study demonstrates that amisulpride augmentation therapy can safely improve the psychiatric symptoms and cognitive performance of CTRS patients.

CONCLUSION

This study indicates that amisulpride augmentation therapy has important clinical significance for treating CTRS to improve clinical symptoms and cognitive function with tolerability and safety. Trial registration Clinicaltrials.gov identifier- NCT03652974. Registered August 31, 2018, https://clinicaltrials.gov/ct2/show/NCT03652974.

Design, Synthesis and Pharmacological Evaluation of Novel Conformationally Restricted N-arylpiperazine Derivatives Characterized as D2/D3 Receptor Ligands, Candidates for the Treatment of Neurodegenerative Diseases

Most neurodegenerative diseases are multifactorial, and the discovery of several molecular mechanisms related to their pathogenesis is constantly advancing. Dopamine and dopaminergic receptor subtypes are involved in the pathophysiology of several neurological disorders, such as schizophrenia, depression and drug addiction. For this reason, the dopaminergic system and dopamine receptor ligands play a key role in the treatment of such disorders. In this context, a novel series of conformationally restricted N-arylpiperazine derivatives (5a–f) with a good affinity for D₂/D₃ dopamine receptors is reported herein. Compounds were designed as interphenylene analogs of the drugs aripiprazole (2) and cariprazine (3), presenting a 1,3-benzodioxolyl subunit as a ligand of the secondary binding site of these receptors. The six new N-arylpiperazine compounds were synthesized in good yields by using classical methodologies, and binding and guanosine triphosphate (GTP)-shift studies were performed. Affinity values below 1 μM for both target receptors and distinct profiles of intrinsic efficacy were found. Docking studies revealed that Compounds 5a–f present a different binding mode with dopamine D₂ and D₃ receptors, mainly as a consequence of the conformational restriction imposed on the flexible spacer groups of 2 and 3.

Remission of Persistent Negative Symptoms and Psychosocial Consequences by Combined Clozapine and Cariprazine Treatment in a Patient With Long-Standing Treatment-Resistant Schizoaffective Disorder

This patient case report describes a 45-year old white unmarried man with disability pension due to schizoaffective disorder, diagnosed at the age of 24. He lives in an apartment and has housing support. Retrospectively, the patient displayed prodromal markers of a disorder within the schizophrenia spectrum many years before the onset of frank psychosis, indeed since childhood. Over the years several symptoms and signs across schizophrenia domains have been manifest: positive, negative, cognitive, and affective, among which the negative and affective symptoms and signs were the earliest to appear. While the positive, disorganized, and catatonic symptoms responded to treatment - when duly tested and complied with - the negative and affective symptoms have been notoriously difficult to handle. We now report on the successful introduction of cariprazine (CAR) to his ongoing clozapine (CLZ) medication, the result of which has been a near-complete remission of his persistent negative and psychosocial issues. We interpret this remarkable alleviation of the patient's disease - and concomitant improvement of his quality of life - in terms of neuroreceptor target complementarity between CLZ and CAR, with particular emphasis on the contributions from the D3 and D2 receptor partial agonist components of the latter agent.

Real-Life Clinical Experience With Cariprazine: A Systematic Review of Case Studies

Background

The hierarchy of evidence coming from evidence-based medicine favors meta-analyses and randomized controlled trials over observational studies and clinical cases. Nonetheless, in the field of psychiatry, where conditions are much more complex, additional evidence coming from real-world clinical practice is necessary to complement data from these gold standards. Thus, in this systematic review, the aim is to summarize the evidence coming from clinical case reports regarding cariprazine, a third-generation antipsychotic drug that has been approved for the treatment of schizophrenia and bipolar I disorder with manic, depressive or mixed features in adults.

Methods

A systematic review was performed using Embase and Pubmed databases searching for English-language cases published in peer-reviewed journals between 2000 January and 2021 September with the following search terms: (cariprazin* OR "rgh-188" OR rgh188 OR vraylar OR reagila) AND ("case report*" OR "case report"/de OR "case stud*" OR "case study"/de OR "case seri*").

Results

After the removal of duplicates, 49 articles were retrieved via the search, from which 22 were suitable for this review. These 22 articles encompassed 38 cases from which 71% described patients with schizophrenia, 16% patients with psychotic disorders, 5% patients with mood disorder and 8% described patients with other disorders such as Wernicke-Korsakoff syndrome, borderline personality disorder and obsessive-compulsive disorder with paranoid schizophrenia. The median age of patients was 31, and half of them were female. The majority of patients (76%) started cariprazine with 1.5 mg/day, and the most common maintenance dose was 4.5 mg/day (34%) and 3.0 mg/day (29%).

Conclusion

Cariprazine was found to be safe and effective in a wide range of psychiatric conditions with different symptom profiles from acute psychotic symptoms through addiction to negative and cognitive symptoms. The results are in-line with the established evidence from clinical trials, however, they also show how cariprazine can be successfully utilized for treating certain symptoms irrespective of the indication.

Effect of cariprazine on the 6 domains of schizophrenia in ICD-11: a narrative review

One of the innovations in the ICD-11 section "schizophrenia and other primary psychotic disorders" is the implementation of 6 additional domains, which should improve the diagnosis and treatment of these conditions. Cariprazine is a new atypical antipsychotic with a predominant affinity for D3 receptors, which is registered in Russia for the treatment of schizophrenia, mania, mixed and depressive episodes in bipolar I disorder. In modern algorithms for the treatment of schizophrenia with the dominance of negative disorders, pharmacotherapy is recommended to start with cariprazine, as the drug that has the best evidence base in the treatment of the ICD-11 "negative symptoms" domain. Cariprazine has been shown to be effective against the symptoms of the ICD-11 "positive symptoms" domain and can be considered the drug of choice in the treatment of first and multiple episodes of illness, disorganized thinking and disturbed behavior in the form of aggression. The pro-cognitive effect of cariprazine has been proven in nonclinical and clinical studies, where it developed independently of other symptoms within the ICD-11 domain "cognitive symptoms" and exceeded the similar effect of a number of other antipsychotics. The use of cariprazine in individuals with moderate to severe ICD-11 domain "manic symptoms" may be justified in view of its evidence-based anti-manic efficacy in bipolar I disorder, although it does not offer advantages over other anti-manic antipsychotics. The efficacy of cariprazine in schizophrenic patients with severe symptoms of the ICD-11 domain "depressive symptoms" needs additional research, since, on the one hand, it has not shown its effectiveness in comparison with placebo in relation to "depressive" PANSS items, but is registered for the treatment of bipolar depression. In the treatment of symptoms of the ICD-11 domain "psychomotor symptoms", the use of monotherapy with cariprazine, as well as other antipsychotics, is less justified, since the emphasis is on other types of therapy.

Transcranial direct current stimulation of the occipital lobes with adjunct lithium attenuates the progression of cognitive impairment in patients with first episode schizophrenia

BACKGROUND

There is no standard effective treatment for schizophrenia-associated cognitive impairment. Efforts to use non-invasive brain stimulation for this purpose have been focused mostly on the frontal cortex, with little attention being given to the occipital lobe.

MATERIALS AND METHODS

We compared the effects of nine intervention strategies on cognitive performance in psychometric measures and brain connectivity measured obtained from functional magnetic resonance imaging analyses. The strategies consisted of transcranial direct current stimulation (t-DCS) or repetitive transcranial magnetic stimulation (r-TMS) of the frontal lobe or of the occipital alone or with adjunct lithium, or lithium monotherapy. We measured global functional connectivity density (gFCD) voxel-wise.

RESULTS

Although all nine patient groups showed significant improvements in global disability scores (GDSs) following the intervention period (vs. before), the greatest improvement in GDS was observed for the group that received occipital lobe-targeted t-DCS with adjunct lithium therapy. tDCS of the occipital lobe improved gFCD throughout the brain, including in the frontal lobes, whereas stimulation of the frontal lobes had less far-reaching benefits on gFCD in the brain. Adverse secondary effects (ASEs) such as heading, dizziness, and nausea, were commonly experienced by patients treated with t-DCS and r-TMS, with or without lithium, whereas ASEs were rare with lithium alone.

CONCLUSION

The most effective treatment strategy for impacting cognitive impairment and brain communication was t-DCS stimulation of the occipital lobe with adjunct lithium therapy, though patients often experienced headache with dizziness and nausea after treatment sessions.

Cariprazine on Psychosis: Beyond Schizophrenia - A Case Series

Cariprazine is an atypical antipsychotic that has D2 and D3 partial agonism properties in addition to the usual 5-HT2A receptor antagonist action of second-generation antipsychotics. It has a distinctly higher affinity for D3 receptors, which is 10-fold higher than for D2 receptors. Cariprazine is also a 5-HT1A partial agonist, with a potential antidepressant effect. Cariprazine has been approved for treatment of both positive and negative symptoms of schizophrenia and for treatment of bipolar disorder. It could potentially be used in depression as an add-on treatment. There are few data reporting effectiveness of cariprazine in the broader spectrum of psychosis. In this paper, the authors report three cases where cariprazine was used in the treatment of psychotic conditions other than schizophrenia, namely a first episode psychosis, a case of delusional disorder, and a case of a patient with borderline personality disorder and psychotic symptoms. The authors suggest that cariprazine may be effective in the treatment of psychosis in a broader sense and should be considered a first-line treatment option.

Switching Clozapine to Cariprazine in Three Patients with Persistent Symptoms of Schizophrenia: A Case Series

Despite many available treatments for schizophrenia, several unmet needs persist in treating individuals with this disorder, and the response rate to first-line antipsychotics remains relatively low. Clozapine has shown efficacy in treating schizophrenia patients who failed to respond to previous antipsychotics. However, side effects and the need for routine blood tests have limited its use as a first-line treatment. Cariprazine is a D₂/D₃ partial agonist antipsychotic with a mechanism of action that differs from other antipsychotics due to its higher affinity for D₃ receptors. Several trials have demonstrated the efficacy of cariprazine on positive and negative symptoms of schizophrenia and have shown that it is a well-tolerated treatment. In this series, we present 3 cases of patients diagnosed with schizophrenia who were initially under treatment with clozapine. Despite some initial improvement, the patients showed persisting positive and negative symptoms or developed limiting side effects while in treatment with clozapine. Cariprazine treatment was titrated concurrently with clozapine tapering until its discontinuation. Significant improvement in both positive and negative symptoms was observed up to 14 months after starting cariprazine, and resolution of side effects was reported in all cases. Our case series supports cariprazine as an effective treatment for positive and negative symptoms in patients who failed to adequately respond or poorly tolerated treatment with clozapine, as well as a potential treatment in dual disorders, specifically psychotic disorders and cocaine use disorder.

Progress and Pitfalls in Developing Agents to Treat Neurocognitive Deficits Associated with Schizophrenia

Cognitive impairments associated with schizophrenia (CIAS) represent a central element of the symptomatology of this severe mental disorder. CIAS substantially determine the disease prognosis and hardly, if at all, respond to treatment with currently available antipsychotics. Remarkably, all drugs presently approved for the treatment of schizophrenia are, to varying degrees, dopamine D₂/D₃ receptor blockers. In turn, rapidly growing evidence suggests the immense significance of systems other than the dopaminergic system in the genesis of CIAS. Accordingly, current efforts addressing the unmet needs of patients with schizophrenia are primarily based on interventions in other non-dopaminergic systems. In this review article, we provide a brief overview of the available evidence on the importance of specific systems in the development of CIAS. In addition, we describe the promising targets for the development of new drugs that have been used so far. In doing so, we present the most important candidates that have been investigated in the field of the specific systems in recent years and present a summary of the results available at the time of drafting this review (May 2022), as well as the currently ongoing studies.

New approaches to antipsychotic medication adherence - safety, tolerability and acceptability

INTRODUCTION

Antipsychotic pharmacotherapy is considered a first-line treatment in schizophrenia-related disorders and is associated with favorable prognosis and lower mortality rates. However, low adherence rates present a major clinical challenge. In this paper, we will review contemporary approaches to improve adherence to antipsychotic treatment, considering their mechanism of action, safety, tolerability and acceptability.

AREAS COVERED

Novel pharmacological delivery methods included different routes of administration of registered medications (such as intramuscular clozapine preparation and transdermal asenapine), modifications of existing compounds (such as 3-monthly injectable formulation of paliperidone palmitate), and increased interest in oral long-acting medication formulations (such as with penfluridol). In addition, we reviewed innovative technology to monitor adherence, based on the use of electronic digital medicine systems and ingestible sensors.

EXPERT OPINION

All of these diverse approaches were clinically relevant in enhancing treatment adherence and found to be safe and tolerable. The place of each approach is predicated on a personalized approach in each patient, and future research could usefully use large comparative studies to establish robust treatment guidelines. The implementation of new and varied approaches to antipsychotic treatment adherence is welcomed and have the potential to make a significant impact on morbidity in this often difficult-to-treat population.

Schizophrenia: Antipsychotics and drug development

The introduction of chlorpromazine and the work that ensued provided the foundation to reposition schizophrenia as a biological illness. The present paper follows the evolution of antipsychotics and their shift from 'typical' to 'atypical'. Atypicality is reviewed in reference to its original definition, clozapine's role, and developments that now leave the concept's utility in question. In a similar fashion, drug development is reviewed in the context of the illness' multiple symptom domains, as well as differences captured by clinical staging and phenotyping. Collectively, the evidence argues for a more nuanced approach to drug development that aligns with the illness' heterogeneity and complexity. Just as 'atypical' as a descriptor for antipsychotics may be outdated, it may be time to set aside the notion of developing drugs that treat 'schizophrenia'.

Cariprazine in the Treatment of Bipolar Disorder: Within and Beyond Clinical Trials

Bipolar disorder (BD) is chronic psychiatric disorder associated with significant impairment in psychosocial functioning and quality of life. Although current pharmacological treatments for BD have improved its clinical management, many patients do not achieve remission, particularly those suffering from bipolar depression. In addition, available treatments are associated with a myriad of potential adverse effects, which highlights the need for novel therapeutic agents that can be effective for both phases of the illness with a reduced side effect burden. Cariprazine is a novel antipsychotic that is a dopamine D2/D3 partial agonist with a preference for D3 receptors. In this review, we examine the pharmacological properties, clinical efficacy and tolerability profile of cariprazine in patients with BD, taking into account the latest clinical trials data. We also review post hoc analyses addressing clinically relevant subgroups and symptom domains in BD. Current evidence suggests efficacy for cariprazine 3-12 mg/day in the treatment of acute manic and mixed episodes; for bipolar depression, the efficacy of cariprazine appears to be dose-related, with doses of 1.5-3 mg/day beneficial as monotherapy. Cariprazine is overall well-tolerated by patients in both manic and depressive episodes. Its most common side effects relative to placebo include akathisia, extrapyramidal symptoms and nausea. There are no metabolic concerns reported with cariprazine use. In summary, the latest evidence suggests that cariprazine is an effective and safe treatment option for BD.

Reducing Addiction in Bipolar Disorder via Hacking the Dopaminergic System

The dopaminergic system plays a central and decisive role in substance use disorder (SUD), bipolar disorder (BD), and possibly in a subgroup of patients with refractory depression. Common genetic markers and underlying cellular processes, such as kindling, support the close link between these disorders, which is also expressed by the high rate of comorbidity. Although partial dopamine agonists/antagonists acting on D₂ and D₃ receptors have an established role in treating BD, their usefulness in SUD is less clear. However, dopamine D₃ receptors were shown to play a central role in SUD and BD, making D₂/D₃ partial agonists/antagonists a potential target for both disorders. This narrative review examines whether these substances bear the promise of a future therapeutic approach especially in patients with comorbid BD and SUD.

Case Report: Cariprazine Efficacy in Young Patients Diagnosed With Schizophrenia With Predominantly Negative Symptoms

Negative symptoms of schizophrenia are among the most invalidating clinical manifestations of this disorder, and they are correlated with poorer prognosis, lower quality of life, and fewer chances for successful social reintegration and professional rehabilitation. Although atypical antipsychotics have been associated with higher efficacy on negative symptoms than typical agents, not all of them are equally effective. Cariprazine is a new D3 and D2 receptor partial agonist, and its high D3 affinity may be useful for decreasing several adverse events (e.g., extrapyramidal symptoms or hyperprolactinemia), and also for increasing this drug's efficacy over negative symptoms. This case series presents three young adults with predominantly negative symptoms during treatment with an atypical antipsychotic, administered in stable dose within the therapeutic range, and for at least 4 weeks prior to the cariprazine switch. These patients (two male and one female, mean age 35.7 years) were diagnosed with schizophrenia, according to the DSM-5 criteria. They were evaluated using Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression-Severity (CGI-S), and Global Assessment of Functioning (GAF). Their mean initial values were 80.3 on PANSS, 4.3 on CGI-S, and 48 on GAF. All these patients were already on a treatment with stable doses of atypical antipsychotics (olanzapine 10 mg/day, n = 1, risperidone 6 mg/day, n = 1, and quetiapine 600 mg/day, n = 1). Cross-titration to cariprazine was initiated, from 1.5 mg qd up to 6 mg qd, during a mean period of 2.7 weeks. After 12 weeks of cariprazine 6 mg/day, the positive scale of PANSS was relatively stable compared to baseline, while the negative mean score decreased by 22%. Also, the mean CGI-S improvement was 15.4% and the GAF mean score increased by 17%. The overall tolerability was good, without severe adverse events being reported. Conclusions: Cariprazine is well tolerated and efficient for patients diagnosed with schizophrenia who have significant negative symptoms that impair daily functioning. After 12 weeks cariprazine succeeded in improving negative symptoms, global functioning, and clinical global impression.