Asenapine: a novel psychopharmacologic agent with a unique human receptor signature

Mining clinical data for novel medications to treat alcohol use disorder

BACKGROUND

Alcohol use disorder (AUD) is a highly prevalent and often debilitating condition associated with high morbidity and mortality. Current AUD medications have limited efficacy and uptake. Alternative pharmacological options are needed.

METHODS

We constructed a mechanistic tree of all US Food and Drug Administration approved medications and used a tree-based scan statistic, TreeScan, to identify medications associated with greater than expected improvements in alcohol consumption. Our cohort included all United States (US) Department of Veterans Affairs (VA) patients with a diagnosis of AUD between 10/1/1999 and 9/30/2019 with multiple Alcohol Use Disorders Identification Test-Consumption Module scores within the VA electronic health record data.

RESULTS

Medications statistically associated with decreased alcohol consumption had, at large, minor effect sizes. Medications used in the treatment of chronic or life-threatening conditions like diabetes, chronic kidney disease, hepatitis C virus, or cancer produced larger effect sizes. Asenapine, an atypical antipsychotic, had a large effect with an observed to expected ratio of 1.78 (p = 0.003). Our findings were replicated in a propensity score matched population.

CONCLUSION

Most medications significantly associated with decreased alcohol consumption in our analysis were either contraindicated with alcohol or likely attributable to patients abstaining from alcohol due to severe illness. However, the large effect of asenapine is notable, and a worthwhile candidate for more careful analysis.

Pharmacological fingerprint of antipsychotic drugs at the serotonin 5-HT2A receptor

The intricate involvement of the serotonin 5-HT2A receptor (5-HT2AR) both in schizophrenia and in the activity of antipsychotic drugs is widely acknowledged. The currently marketed antipsychotic drugs, although effective in managing the symptoms of schizophrenia to a certain extent, are not without their repertoire of serious side effects. There is a need for better therapeutics to treat schizophrenia for which understanding the mechanism of action of the current antipsychotic drugs is imperative. With bioluminescence resonance energy transfer (BRET) assays, we trace the signaling signature of six antipsychotic drugs belonging to three generations at the 5-HT2AR for the entire spectrum of signaling pathways activated by serotonin (5-HT). The antipsychotic drugs display previously unidentified pathway preference at the level of the individual Gα subunits and β-arrestins. In particular, risperidone, clozapine, olanzapine and haloperidol showed G protein-selective inverse agonist activity. In addition, G protein-selective partial agonism was found for aripiprazole and cariprazine. Pathway-specific apparent dissociation constants determined from functional analyses revealed distinct coupling-modulating capacities of the tested antipsychotics at the different 5-HT-activated pathways. Computational analyses of the pharmacological and structural fingerprints support a mechanistically based clustering that recapitulate the clinical classification (typical/first generation, atypical/second generation, third generation) of the antipsychotic drugs. The study provides a new framework to functionally classify antipsychotics that should represent a useful tool for the identification of better and safer neuropsychiatric drugs and allows formulating hypotheses on the links between specific signaling cascades and in the clinical outcomes of the existing drugs.

Asenapine versus olanzapine for the treatment of nausea and vomiting in patients with cancer: A retrospective study

AIM

Patients with cancer often experience nausea and vomiting (N/V), but may have difficulty using olanzapine (OLZ), a common antiemetic. Asenapine (ASE) is a multi-acting receptor-targeted antipsychotic like OLZ, although there is little evidence that ASE serves as an antiemetic. The aim of this study was to evaluate the efficacy and tolerability of ASE compared to those of OLZ for the treatment of N/V in patients with cancer.

METHODS

This retrospective study involved patients who received 5 mg ASE, 5 mg OLZ, or 2.5 mg OLZ for 2 days. Daily worst N/V was rated on a scale of 0 (none) to 3 (very much). The primary endpoint was the proportion of patients who had a response, defined as any reduction in N/V score. A complete response (CR) was defined as a score reduction to 0. Secondary endpoints included the proportion of patients with CR and adverse events.

RESULTS

Between April 2017 and March 2023, 212 patients were enrolled to receive treatment: 5 mg ASE (n = 34), 5 mg OLZ (n = 102), or 2.5 mg OLZ (n = 76). No significant differences in response rates (52.9% vs. 58.8% vs. 52.6%, p = 0.671) or secondary endpoints were observed between the groups. Patients receiving ASE were more likely to experience oral hypoesthesia (p = 0.004).

CONCLUSION

This preliminary study suggests that ASE may be effective for N/V. Further studies are required to confirm these findings.

Exploratory focused pharmacogenetic testing reveals novel markers associated with risperidone pharmacokinetics in Saudi children with autism

Background: Autism spectrum disorders (ASDs) encompass a broad range of phenotypes characterized by diverse neurological alterations. Genomic studies have revealed considerable overlap between the molecular mechanisms implicated in the etiology of ASD and genes involved in the pharmacokinetic (PK) and pharmacodynamic (PD) pathways of antipsychotic drugs employed in ASD management. Given the conflicting data originating from candidate PK or PD gene association studies in diverse ethnogeographic ASD populations, dosage individualization based on "actionable" pharmacogenetic (PGx) markers has limited application in clinical practice. Additionally, off-label use of different antipsychotics is an ongoing practice, which is justified given the shortage of approved cures, despite the lack of satisfactory evidence for its safety according to precision medicine. This exploratory study aimed to identify PGx markers predictive of risperidone (RIS) exposure in autistic Saudi children. Methods: This prospective cohort study enrolled 89 Saudi children with ASD treated with RIS-based antipsychotic therapy. Plasma levels of RIS and 9-OH-RIS were measured using a liquid chromatography-tandem mass spectrometry system. To enable focused exploratory testing, genotyping was performed with the Axiom PharmacoFocus Array, which included a collection of probe sets targeting PK/PD genes. A total of 720 PGx markers were included in the association analysis. Results: A total of 27 PGx variants were found to have a prominent impact on various RIS PK parameters; most were not located within the genes involved in the classical RIS PK pathway. Specifically, 8 markers in 7 genes were identified as the PGx markers with the strongest impact on RIS levels (p < 0.01). Four PGx variants in 3 genes were strongly associated with 9-OH-RIS levels, while 5 markers in 5 different genes explained the interindividual variability in the total active moiety. Notably, 6 CYP2D6 variants exhibited strong linkage disequilibrium; however, they significantly influenced only the metabolic ratio and had no considerable effects on the individual estimates of RIS, 9-OH-RIS, or the total active moiety. After correction for multiple testing, rs78998153 in UGT2B17 (which is highly expressed in the brain) remained the most significant PGx marker positively adjusting the metabolic ratio. For the first time, certain human leukocyte antigen (HLA) markers were found to enhance various RIS exposure parameters, which reinforces the gut-brain axis theory of ASD etiology and its suggested inflammatory impacts on drug bioavailability through modulation of the brain, gastrointestinal tract and/or hepatic expression of metabolizing enzymes and transporters. Conclusion: Our hypothesis-generating approach identified a broad spectrum of PGx markers that interactively influence RIS exposure in ASD children, which indicated the need for further validation in population PK modeling studies to define polygenic scores for antipsychotic efficacy and safety, which could facilitate personalized therapeutic decision-making in this complex neurodevelopmental condition.

Molecular basis of human trace amine-associated receptor 1 activation

The human trace amine-associated receptor 1 (hTAAR1, hTA1) is a key regulator of monoaminergic neurotransmission and the actions of psychostimulants. Despite preclinical research demonstrating its tractability as a drug target, its molecular mechanisms of activation remain unclear. Moreover, poorly understood pharmacological differences between rodent and human TA1 complicate the translation of findings from preclinical disease models into novel pharmacotherapies. To elucidate hTA1's mechanisms on the molecular scale and investigate the underpinnings of its divergent pharmacology from rodent orthologs, we herein report the structure of the human TA1 receptor in complex with a Gαs heterotrimer. Our structure reveals shared structural elements with other TAARs, as well as with its closest monoaminergic orthologue, the serotonin receptor 5-HT4R. We further find that a single mutation dramatically shifts the selectivity of hTA1 towards that of its rodent orthologues, and report on the effects of substituting residues to those found in serotonin and dopamine receptors. Strikingly, we also discover that the atypical antipsychotic medication and pan-monoaminergic antagonist asenapine potently and efficaciously activates hTA1. Together our studies provide detailed insight into hTA1 structure and function, contrast its molecular pharmacology with that of related receptors, and uncover off-target activities of monoaminergic drugs at hTA1.

Effects of trazodone and dexmedetomidine on fentanyl-mediated reduction of isoflurane minimum alveolar concentration in cats

OBJECTIVE

To screen modulators of biogenic amine (BA) neurotransmission for the ability to cause fentanyl to decrease isoflurane minimum alveolar concentration (MAC) in cats, and to test whether fentanyl plus a combination of modulators decreases isoflurane MAC more than fentanyl alone.

STUDY DESIGN

Prospective, experimental study.

ANIMALS

A total of six adult male Domestic Short Hair cats.

METHODS

Each cat was anesthetized in three phases with a 1 week washout between studies. In phase 1, anesthesia was induced and maintained with isoflurane, and MAC was measured in duplicate using a tail clamp stimulus and standard bracketing technique. A 21 ng mL-1 fentanyl target-controlled infusion was then administered and MAC measured again. In phase 2, a single cat was administered a single BA modulator (buspirone, haloperidol, dexmedetomidine, pregabalin, ramelteon or trazodone) in a pilot drug screen, and isoflurane MAC was measured before and after fentanyl administration. In phase 3, isoflurane MAC was measured before and after fentanyl administration in cats co-administered trazodone and dexmedetomidine, the two BA modulator drugs associated with fentanyl MAC-sparing in the screen. Isoflurane MAC-sparing by fentanyl alone, trazodone-dexmedetomidine and trazodone-dexmedetomidine-fentanyl was evaluated using paired t tests with p < 0.05 denoting significant effects.

RESULTS

The MAC of isoflurane was 1.87% ± 0.09 and was not significantly affected by fentanyl administration (p = 0.09). In the BA screen, cats administered trazodone or dexmedetomidine exhibited 26% and 22% fentanyl MAC-sparing, respectively. Trazodone-dexmedetomidine co-administration decreased isoflurane MAC to 1.50% ± 0.14 (p < 0.001), and the addition of fentanyl further decreased MAC to 0.95% ± 0.16 (p < 0.001).

CONCLUSIONS AND CLINICAL RELEVANCE

Fentanyl alone does not affect isoflurane MAC in cats, but co-administration of trazodone and dexmedetomidine causes fentanyl to significantly decrease isoflurane requirement.

Ligand selectivity hotspots in serotonin GPCRs

Serotonin is a neurotransmitter regulating numerous physiological processes also modulated by drugs, for example, schizophrenia, depression, migraine, and obesity. However, these drugs typically have adverse effects caused by promiscuous binding across 12 serotonin and more than 20 homologous receptors. Recently, structures of the entire serotonin receptor family uncovered molecular ligand recognition. Here, we present a map of 19 'selectivity hotspots', that is, nonconserved binding site residues governing selectivity via favorable target interactions or repulsive 'off-target' contacts. Furthermore, we review functional rationale from observed ligand-binding affinities and mutagenesis effects. Unifying knowledge underlying specific probes and drugs is critical toward the functional characterization of different receptors and alleviation of adverse effects.

Molecular Basis of Human Trace Amine-Associated Receptor 1 Activation

The human trace amine-associated receptor 1 (hTAAR1, hTA1) is a key regulator of monoaminergic neurotransmission and the actions of psychostimulants. Despite preclinical research demonstrating its tractability as a drug target, its molecular mechanisms of activation remain unclear. Moreover, poorly understood pharmacological differences between rodent and human TA1 complicate the translation of findings from preclinical disease models into novel pharmacotherapies. To elucidate hTA1's mechanisms on the molecular scale and investigate the underpinnings of its divergent pharmacology from rodent orthologs, we herein report the structure of the human TA1 receptor in complex with a Gαs heterotrimer. Our structure reveals shared structural elements with other TAARs, as well as with its closest monoaminergic ortholog, the serotonin receptor 5-HT4R. We further find that a single mutation dramatically shifts the selectivity of hTA1 towards that of its rodent orthologs, and report on the effects of substituting residues to those found in serotonin and dopamine receptors. Strikingly, we also discover that the atypical antipsychotic medication and pan-monoaminergic antagonist asenapine potently and efficaciously activates hTA1. Together our studies provide detailed insight into hTA1 structure and function, contrast its molecular pharmacology with that of related receptors, and uncover off-target activities of monoaminergic drugs at hTA1.

Long-term safety and efficacy of sublingual asenapine for the treatment of schizophrenia: A phase III extension study with follow-up for 52 weeks (P06125)-Secondary publication

After completion of a 6-week double-blind trial of asenapine sublingual tablets (10 or 20 mg/day) versus placebo in Asian patients with acute exacerbation of schizophrenia, including Japanese patients, this open-label study evaluated the safety and efficacy of a 52-week treatment with asenapine at flexible doses. In 201 subjects, including 44 who had received placebo (P/A group) and 157 who had received asenapine (A/A group) in the feeder trial, adverse events occurred at rates of 90.9% and 85.4% and serious adverse events at rates of 11.4% and 20.4%, respectively. One patient in the P/A group died. No clinically significant abnormal measurements of body weight, body mass index, or glycated hemoglobin, fasting plasma glucose, insulin, and prolactin levels were observed. The sustained efficacy rate, as evaluated by the Positive and Negative Syndrome Scale total score and other measures, remained at approximately 50% between 6 and 12 months of treatment. These results suggest that long-term treatment with asenapine is well tolerated and provides sustained efficacy.

2B Determined: The Future of the Serotonin Receptor 2B in Drug Discovery

The cardiotoxicity associated with des-ethyl-dexfenfluramine (norDF) and related agonists of the serotonin receptor 2B (5-HT2B) has solidified the receptor's place as an "antitarget" in drug discovery. Conversely, a growing body of evidence has highlighted the utility of 5-HT2B antagonists for the treatment of pulmonary arterial hypertension (PAH), valvular heart disease (VHD), and related cardiopathies. In this Perspective, we summarize the link between the clinical failure of fenfluramine-phentermine (fen-phen) and the subsequent research on the role of 5-HT2B in disease progression, as well as the development of drug-like and receptor subtype-selective 5-HT2B antagonists. Such agents represent a promising class for the treatment of PAH and VHD, but their utility has been historically understudied due to the clinical disasters associated with 5-HT2B. Herein, it is our aim to examine the current state of 5-HT2B drug discovery, with an emphasis on the receptor's role in the central nervous system (CNS) versus the periphery.

G protein-coupled receptors in neurodegenerative diseases and psychiatric disorders

Neuropsychiatric disorders are multifactorial disorders with diverse aetiological factors. Identifying treatment targets is challenging because the diseases are resulting from heterogeneous biological, genetic, and environmental factors. Nevertheless, the increasing understanding of G protein-coupled receptor (GPCR) opens a new possibility in drug discovery. Harnessing our knowledge of molecular mechanisms and structural information of GPCRs will be advantageous for developing effective drugs. This review provides an overview of the role of GPCRs in various neurodegenerative and psychiatric diseases. Besides, we highlight the emerging opportunities of novel GPCR targets and address recent progress in GPCR drug development.

Exhaustive in silico design and screening of novel antipsychotic compounds with improved pharmacodynamics and blood-brain barrier permeation properties

Antipsychotic drugs or neuroleptics are widely used in the treatment of psychosis as a manifestation of schizophrenia and bipolar disorder. However, their effectiveness largely depends on the blood-brain barrier (BBB) permeation (pharmacokinetics) and drug-receptor pharmacodynamics. Therefore, in this study, we developed and implemented the in silico pipeline to design novel compounds (n = 260) as leads using the standard drug scaffolds with improved PK/PD properties from the standard scaffolds. As a result, the best candidates (n = 3) were evaluated in molecular docking to interact with serotonin and dopamine receptors. Finally, haloperidol (HAL) derivative (1-(4-fluorophenyl)-4-(4-hydroxy-4-{4-[(2-phenyl-1,3-thiazol-4-yl)methyl]phenyl}piperidin-1-yl)butan-1-one) was identified as a "magic shotgun" lead compound with better affinity to the 5-HT2A, 5-HT1D, D2, D3, and 5-HT1B receptors than the control molecule. Additionally, this hit substance was predicted to possess similar BBB permeation properties and much lower toxicological profiles in comparison to HAL. Overall, the proposed rational drug design platform for novel antipsychotic drugs based on the BBB permeation and receptor binding might be an invaluable asset for a medicinal chemist or translational pharmacologist.Communicated by Ramaswamy H. Sarma.

Dopamine Dynamics and Neurobiology of Non-Response to Antipsychotics, Relevance for Treatment Resistant Schizophrenia: A Systematic Review and Critical Appraisal

Treatment resistant schizophrenia (TRS) is characterized by a lack of, or suboptimal response to, antipsychotic agents. The biological underpinnings of this clinical condition are still scarcely understood. Since all antipsychotics block dopamine D2 receptors (D2R), dopamine-related mechanisms should be considered the main candidates in the neurobiology of antipsychotic non-response, although other neurotransmitter systems play a role. The aims of this review are: (i) to recapitulate and critically appraise the relevant literature on dopamine-related mechanisms of TRS; (ii) to discuss the methodological limitations of the studies so far conducted and delineate a theoretical framework on dopamine mechanisms of TRS; and (iii) to highlight future perspectives of research and unmet needs. Dopamine-related neurobiological mechanisms of TRS may be multiple and putatively subdivided into three biological points: (1) D2R-related, including increased D2R levels; increased density of D2Rs in the high-affinity state; aberrant D2R dimer or heteromer formation; imbalance between D2R short and long variants; extrastriatal D2Rs; (2) presynaptic dopamine, including low or normal dopamine synthesis and/or release compared to responder patients; and (3) exaggerated postsynaptic D2R-mediated neurotransmission. Future points to be addressed are: (i) a more neurobiologically-oriented phenotypic categorization of TRS; (ii) implementation of neurobiological studies by directly comparing treatment resistant vs. treatment responder patients; (iii) development of a reliable animal model of non-response to antipsychotics.

Efficacy of Asenapine in Drug-resistant Psychotic Patients with Dopamine Supersensitivity Psychosis: Two Cases

Dopamine supersensitivity psychosis (DSP) is an unstable clinical condition observed in individuals with schizophrenia who have been treated with an antipsychotic medication at a high dosage and/or for a long period. An up-regulation of dopamine D2 receptors (DRD2) is thought to be involved in the essential pathology of DSP. An antipsychotic agent with both tight binding to DRD2 and a long half-life is generally effective for treating DSP, but a patient who meets the criteria of treatment-resistant schizophrenia sometimes needs treatment with clozapine. We report the case details of two patients whose DSP was not controlled with several antipsychotics but was successfully controlled with asenapine. Asenapine binds to a broad range of dopamine receptors and serotonin receptors, and it is thus distinct from other atypical antipsychotics. The unique profile of asenapine may contribute to the control of severe DSP symptoms in individuals with schizophrenia.

A Postsynaptic Density Immediate Early Gene-Based Connectome Analysis of Acute NMDAR Blockade and Reversal Effect of Antipsychotic Administration

Although antipsychotics' mechanisms of action have been thoroughly investigated, they have not been fully elucidated at the network level. We tested the hypothesis that acute pre-treatment with ketamine (KET) and administration of asenapine (ASE) would modulate the functional connectivity of brain areas relevant to the pathophysiology of schizophrenia, based on transcript levels of Homer1a, an immediate early gene encoding a key molecule of the dendritic spine. Sprague-Dawley rats (n = 20) were assigned to KET (30 mg/kg) or vehicle (VEH). Each pre-treatment group (n = 10) was randomly split into two arms, receiving ASE (0.3 mg/kg), or VEH. Homer1a mRNA levels were evaluated by in situ hybridization in 33 regions of interest (ROIs). We computed all possible pairwise Pearson correlations and generated a network for each treatment group. Acute KET challenge was associated with negative correlations between the medial portion of cingulate cortex/indusium griseum and other ROIs, not detectable in other treatment groups. KET/ASE group showed significantly higher inter-correlations between medial cingulate cortex/indusium griseum and lateral putamen, the upper lip of the primary somatosensory cortex, septal area nuclei, and claustrum, in comparison to the KET/VEH network. ASE exposure was associated with changes in subcortical-cortical connectivity and an increase in centrality measures of the cingulate cortex and lateral septal nuclei. In conclusion, ASE was found to finely regulate brain connectivity by modelling the synaptic architecture and restoring a functional pattern of interregional co-activation.

Agonistic properties of a series of psychotropic drugs at 5-HT1A receptors in rat and human brain membranes determined by [35S]GTPγS binding assay

BACKGROUND

Many psychoactive compounds have been developed to have more beneficial clinical efficacy than conventional drugs by adding agonistic action at 5-HT_1A receptors. The aim of the present study was to evaluate several psychotropic drugs that had been reported to behave as an agonist at 5-HT_1A receptor (aripiprazole, brexpiprazole, asenapine, lurasidone, and vortioxetine) in both rat and postmortem human brain membranes.

METHODS

The [³⁵S]GTPγS binding assay for G_i/o proteins coupled with 5-HT_1A receptors was performed in rat brain membranes and postmortem human brain membranes.

RESULTS

The specific binding was stimulated by brexpiprazole in rat hippocampus, human hippocampus, and human prefrontal cortex. Aripiprazole also behaved as an agonist in the same brain regions. Interestingly, its potency was much higher in rat hippocampal membranes than in human brain membranes, indicating the possibility of species differences. Although vortioxetine was an efficacious stimulator at high concentrations, its potency was undeterminable because of a lack of saturability. In addition to 5-HT_1A receptor agonism, involvement of other components, e.g., 5-HT_1B receptor agonism, was speculated by the biphasic inhibitory effects of the selective 5-HT_1A receptor neutral antagonist. Negligible stimulatory effects were obtained as to lurasidone and asenapine.

CONCLUSIONS

Our previous studies have raised the concept of a psychoactive drug group with a common pharmacological mechanism of action, i.e., 5-HT_1A receptor agonism, consisting of perospirone, aripiprazole, ziprasidone, clozapine, quetiapine, nemonapride, and trazodone. The present study demonstrates the data indicating that brexpiprazole and probably vortioxetine are included in this drug group. Lurasidone and asenapine are excluded from this group.

Polypharmacy Management of Antipsychotics in Patients with Schizophrenia

Schizophrenia is a chronic psychiatric disease that is characterized by psychotic symptoms, including positive, negative, affective, and aggressive symptoms, as well as cognitive dysfunction, and is primarily treated using drug therapy, the continuation of which is essential to prevent recurrence/recrudescence. Various second-generation antipsychotics with pharmacological properties or adverse events that differ from those of conventional antipsychotics have recently been introduced, and pharmaceutical management is required for drug efficacy assessments and adverse event monitoring/management of these drugs. Antipsychotic monotherapy (APM) is the gold standard treatment for schizophrenia and is recommended in various guidelines. However, a subgroup of patients with schizophrenia do not or only partially respond to APM. Therefore, antipsychotic polypharmacy (APP), in which ≥2 antipsychotics are combined, has been routinely utilized to compensate for insufficient responses to APM in clinical practice. APP has recently been proposed as an evidence-based treatment option, but does not consider clinicians' experience. However, the risk of APP-related adverse events is high. The application of APP needs to be carefully reviewed, whilst taking into consideration patient backgrounds. Furthermore, the risk of APP-related adverse events is higher in elderly patients than in the general population; therefore, caution is needed. This review discusses the merits of APP, matters that need to be considered, and a switch from APP to APM, and also focuses on the application of APP in clinical practice.

The dilemma of polypharmacy in psychosis: is it worth combining partial and full dopamine modulation?

Antipsychotic polypharmacy in psychotic disorders is widespread despite international guidelines favoring monotherapy. Previous evidence indicates the utility of low-dose partial dopamine agonist (PDAs) add-ons to mitigate antipsychotic-induced metabolic adverse effects or hyperprolactinemia. However, clinicians are often concerned about using PDAs combined with high-potency, full dopaminergic antagonists (FDAs) due to the risk of psychosis relapse. We, therefore, conducted a literature review to find studies investigating the effects of combined treatment with PDAs (i.e. aripiprazole, cariprazine and brexpiprazole) and FDAs having a strong D 2 receptor binding affinity. Twenty studies examining the combination aripiprazole - high-potency FDAs were included, while no study was available on combinations with cariprazine or brexpiprazole. Studies reporting clinical improvement suggested that this may require a relatively long time (~11 weeks), while studies that found symptom worsening observed this happening in a shorter timeframe (~3 weeks). Patients with longer illness duration who received add-on aripiprazole on ongoing FDA monotherapy may be at greater risk for symptomatologic worsening. Especially in these cases, close clinical monitoring is therefore recommended during the first few weeks of combined treatment. These indications may be beneficial to psychiatrists who consider using this treatment strategy. Well-powered randomized clinical trials are needed to derive more solid clinical recommendations.

Two New HPLC Methods, Assessed by GAPI, for Simultaneous Determination of Four Antipsychotics in Pharmaceutical Formulations: A Comparative Study

Antipsychotics are widely used to treat various mental disorders. Combination therapies were approved by the FDA to treat manic states. Quetiapine fumarate, aripiprazole, asenapine maleate, and chlorpromazine HCl are frequently used for treatment of these disorders. Green analytical chemistry is primarily concerned with reducing waste generated during sample preparation or analysis. Green solvents, such as ethanol, are being used in HPLC as an alternative to acetonitrile. To this purpose, two new chromatographic methods were developed to determine these four drugs simultaneously in their bulk and pharmaceutical formulations. The greenness of both methods was assessed by the green analytical procedure index (GAPI)—one of them was found to be green ecofriendly, and the other had some environmental hazards (conventional)—and this helps laboratories to choose a method that suits their capabilities. The chromatographic separation for both methods was carried out on a Thermo® C18 column. The total separation times were about 11 min and 9 min for the green and the conventional methods, respectively. Using the Student’s t-test and the F-ratio, there was no significant difference between the results of the two methods. These methods have been validated and successfully applied to the analysis of commercial pharmaceutical formulations. Our study could successfully be used in central quality control laboratories, which need a single analytical method to separate more than one compound with similar pharmacological action.

Multitargeting the Action of 5-HT6 Serotonin Receptor Ligands by Additional Modulation of Kinases in the Search for a New Therapy for Alzheimer's Disease: Can It Work from a Molecular Point of View?

In view of the unsatisfactory treatment of cognitive disorders, in particular Alzheimer’s disease (AD), the aim of this review was to perform a computer-aided analysis of the state of the art that will help in the search for innovative polypharmacology-based therapeutic approaches to fight against AD. Apart from 20-year unrenewed cholinesterase- or NMDA-based AD therapy, the hope of effectively treating Alzheimer’s disease has been placed on serotonin 5-HT₆ receptor (5-HT₆R), due to its proven, both for agonists and antagonists, beneficial procognitive effects in animal models; however, research into this treatment has so far not been successfully translated to human patients. Recent lines of evidence strongly emphasize the role of kinases, in particular microtubule affinity-regulating kinase 4 (MARK4), Rho-associated coiled-coil-containing protein kinase I/II (ROCKI/II) and cyclin-dependent kinase 5 (CDK5) in the etiology of AD, pointing to the therapeutic potential of their inhibitors not only against the symptoms, but also the causes of this disease. Thus, finding a drug that acts simultaneously on both 5-HT₆R and one of those kinases will provide a potential breakthrough in AD treatment. The pharmacophore- and docking-based comprehensive literature analysis performed herein serves to answer the question of whether the design of these kind of dual agents is possible, and the conclusions turned out to be highly promising.

Divergence of dose-response with asenapine: a cluster analysis of randomized, double-blind, and placebo control study

BACKGROUND

Differences in psychiatric background and dose-response to asenapine in patients with schizophrenia were examined based on efficacy and safety, using data obtained in a double-blind, placebo-controlled trial.

METHODS

Patients with schizophrenia were classified into three clusters by a cluster analysis based on the Positive and Negative Symptom Scale (PANSS) subscores at baseline, using the data from a 6-week, double-blind, placebo-controlled trial. PANSS Marder factor scores were calculated for each cluster. The efficacy of 10 or 20 mg/day of asenapine on PANSS score was used as the primary endpoint, with the incidence of adverse events evaluated as the secondary endpoint.

RESULTS

A total of 529 asenapine-treated patients were classified into 3 clusters: Cluster-P with the higher scores in positive symptoms, disorganized thoughts, and hostility/excitement, Cluster-N with higher scores in negative symptoms, and Cluster-L with overall lower scores. In Cluster-N and Cluster-L, both 10 and 20 mg/day groups showed significant improvement in PANSS scores, while only the 20 mg/day group showed a significant difference in Cluster-P. Cluster-N and Cluster-L had differences in the incidence of adverse events, but this was not seen in Cluster-P.

CONCLUSIONS

The efficacy and safety of asenapine 10 and 20 mg/day differed between the 3 clusters of patients. This suggests that background information regarding baseline psychiatric symptoms may affect the therapeutic response in patients with schizophrenia.

Effects of adding a neurokinin-1 receptor antagonist to 5 mg olanzapine, a 5-hydroxytryptamine-3 receptor antagonist, and dexamethasone for preventing carboplatin-induced nausea and vomiting: a propensity score-matched analysis

BACKGROUND

Olanzapine has been reported to be an effective antiemetic in patients receiving carboplatin-based chemotherapy. However, the efficacy of a neurokinin-1 receptor antagonist (NK₁RA) added to olanzapine, a 5-hydroxytryptamine-3 receptor antagonist (5-HT₃RA), and dexamethasone (DEX) has not been proven. This study aimed to assess the efficacy and safety of NK₁RA, in combination with three-drug antiemetic regimens containing olanzapine, in preventing nausea and vomiting induced by carboplatin-based chemotherapy.

METHODS

Data were pooled for 140 patients receiving carboplatin-based chemotherapy from three multicenter, prospective, single-arm, open-label phase II studies that evaluated the efficacy and safety of olanzapine for chemotherapy-induced nausea and vomiting. The propensity score of the co-administration of NK₁RA was estimated for each patient using a logistic regression model that included age, sex, and carboplatin dose. We analyzed a total of 62 patients, who were treated without NK₁RA (non-NK₁RA group: 31 patients) and with NK₁RA (NK₁RA group: 31 patients). The patients were selected using propensity score matching.

RESULTS

The complete response rate (without emetic episodes or with no administration of rescue medication) in the overall period (0-120 h post carboplatin administration) was 93.5% in the non-NK₁RA group and 96.8% in the NK₁RA group, with a difference of -3.2% (95% confidence interval, -18.7% to 10.9%; P = 1.000). In terms of safety, there was no significant difference between the groups in daytime sleepiness and concentration impairment, which are the most worrisome adverse events induced by olanzapine.

CONCLUSIONS

The findings suggest that antiemetic regimens consisting of olanzapine, 5HT₃RA, and DEX without NK₁RA may be a treatment option for patients receiving carboplatin-based chemotherapy.

Potential Mechanisms for Why Not All Antipsychotics Are Able to Occupy Dopamine D3 Receptors in the Brain in vivo

Dysfunctions of the dopaminergic system are believed to play a major role in the core symptoms of schizophrenia such as positive, negative, and cognitive symptoms. The first line of treatment of schizophrenia are antipsychotics, a class of medications that targets several neurotransmitter receptors in the brain, including dopaminergic, serotonergic, adrenergic and/or muscarinic receptors, depending on the given agent. Although the currently used antipsychotics display in vitro activity at several receptors, majority of them share the common property of having high/moderate in vitro affinity for dopamine D₂ receptors (D₂Rs) and D₃ receptors (D₃Rs). In terms of mode of action, these antipsychotics are either antagonist or partial agonist at the above-mentioned receptors. Although D₂Rs and D₃Rs possess high degree of homology in their molecular structure, have common signaling pathways and similar in vitro pharmacology, they have different in vivo pharmacology and therefore behavioral roles. The aim of this review, with summarizing preclinical and clinical evidence is to demonstrate that while currently used antipsychotics display substantial in vitro affinity for both D₃Rs and D₂Rs, only very few can significantly occupy D₃Rs in vivo. The relative importance of the level of endogenous extracellular dopamine in the brain and the degree of in vitro D₃Rs receptor affinity and selectivity as determinant factors for in vivo D₃Rs occupancy by antipsychotics, are also discussed.

Olanzapine-Related Somnambulism: A Systematic Review of Literature and a Case Report of Anorexia Nervosa

BACKGROUND

Somnambulism, or sleepwalking (SW), is one of the most common forms of arousal parasomnias. It is characterized by different complex motor behaviors leading to unwanted movements in bed or walking during sleep. It can be the consequence of psychological stress, abnormal breathing during sleep, high fever, or drug adverse effects. There is evidence of an association between antipsychotic treatment, including olanzapine, and SW.

METHODS

We present the case of a patient experiencing treatment-resistant anorexia nervosa whose somnambulism re-exacerbated after the addition of a low dose of olanzapine, following the CARE (CAse REport) Statement and Checklist. We also conducted a systematic review of the literature on olanzapine-induced somnambulism following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, PsychINFO, and the Cochrane Library databases were independently reviewed up to January 2021 for articles reporting olanzapine-related somnambulism cases, without language or time restriction.

RESULTS

We describe a case of somnambulism in a patient initially admitted to our hospital for anorexia nervosa and treated with a low dose of olanzapine. This is the first case of SW induced by olanzapine in eating disorders to be reported. Up-to-date olanzapine-related somnambulism was described in 8 patients experiencing psychiatric disorders (ie, schizophrenia and bipolar disorder).

CONCLUSIONS

To provide a reliable estimate of incidence and prevalence for olanzapine-related somnambulism, large-scale, pharmacovigilance studies are required, to allow for comparisons of overall clinical characteristics, outcomes, including time to recovery, between different treatment options. Clinician awareness should be enhanced, and attention should be given to such infrequent adverse effects associated with antipsychotics.

Scaffold Hybridization Strategy Leads to the Discovery of Dopamine D3 Receptor-Selective or Multitarget Bitopic Ligands Potentially Useful for Central Nervous System Disorders

In the search for novel bitopic compounds targeting the dopamine D₃ receptor (D₃R), the N-(2,3-dichlorophenyl)piperazine nucleus (primary pharmacophore) has been linked to the 6,6- or 5,5-diphenyl-1,4-dioxane-2-carboxamide or the 1,4-benzodioxane-2-carboxamide scaffold (secondary pharmacophore) by an unsubstituted or 3-F-/3-OH-substituted butyl chain. This scaffold hybridization strategy led to the discovery of potent D₃R-selective or multitarget ligands potentially useful for central nervous system disorders. In particular, the 6,6-diphenyl-1,4-dioxane derivative 3 showed a D₃R-preferential profile, while an interesting multitarget behavior has been highlighted for the 5,5-diphenyl-1,4-dioxane and 1,4-benzodioxane derivatives 6 and 9, respectively, which displayed potent D₂R antagonism, 5-HT_1AR and D₄R agonism, as well as potent D₃R partial agonism. They also behaved as low-potency 5-HT_2AR antagonists and 5-HT_2CR partial agonists. Such a profile might be a promising starting point for the discovery of novel antipsychotic agents.

Case report: asenapine and anticholinergic toxicity

While antipsychotic medications have long been associated with anticholinergic effects, asenapine has been purported to have no capacity for muscarinic cholinergic antagonism based on in vitro studies. Research in rat brain tissue has yielded different results, with one study finding more cholinergic M1-5 binding in the medial prefrontal cortex, dorsolateral frontal cortex and hippocampal CA1 and CA3 areas than would be predicted from in vitro findings. Moreover, it is structurally similar to other anticholinergic antipsychotics such as loxapine and, to a lesser degree, quetiapine, olanzapine and clozapine. This case report describes the anticholinergic toxidrome in a patient treated with benztropine and paroxetine at stable doses, with the emergence of the toxidrome after upward titration of asenapine. A broad differential was considered. With further consideration of the history, time-course, clinical features and physical examination, the presentation is most indicative of the anticholinergic toxidrome. Although not employed, physostigmine, the antidote for anticholinergic delirium, could help to differentiate this toxidrome and serve as a diagnostic and therapeutic intervention. We have presented this case to highlight the importance for clinicians to integrate history and bedside examination data with principles of pharmacology. In particular, asenapine should be added to the list of compounds with recognized anticholinergic potential.

N,N-Dimethyltryptamine attenuates spreading depolarization and restrains neurodegeneration by sigma-1 receptor activation in the ischemic rat brain

Dimethyltryptamine (DMT), an endogenous ligand of sigma-1 receptors (Sig-1Rs), acts against systemic hypoxia, but whether DMT may prevent cerebral ischemic injury is unexplored. Here global forebrain ischemia was created in anesthetized rats and aggravated with the induction of spreading depolarizations (SDs) and subsequent short hypoxia before reperfusion. Drugs (DMT, the selective Sig-1R agonist PRE-084, the Sig-1R antagonist NE-100, or the serotonin receptor antagonist asenapine) were administered intravenously alone or in combination while physiological variables and local field potential from the cerebral cortex was recorded. Neuroprotection and the cellular localization of Sig-1R were evaluated with immunocytochemistry. Plasma and brain DMT content was measured by 2D-LC-HRMS/MS. The affinity of drugs for cerebral Sig-1R was evaluated with a radioligand binding assay. Both DMT and PRE-084 mitigated SDs, counteracted with NE-100. Further, DMT attenuated SD when co-administered with asenapine, compared to asenapine alone. DMT reduced the number of apoptotic and ferroptotic cells and supported astrocyte survival. The binding affinity of DMT to Sig-1R matched previously reported values. Sig-1Rs were associated with the perinuclear cytoplasm of neurons, astrocytes and microglia, and with glial processes. According to these data, DMT may be considered as adjuvant pharmacological therapy in the management of acute cerebral ischemia.

Determination of Asenapine Maleate in Pharmaceutical and Biological Matrices: A Critical Review of Analytical Techniques over the Past Decade

Asenapine maleate is a second-generation atypical antipsychotic agent used in the treatment of schizophrenia, a neuropsychiatric disorder. It is available as a fast-dissolving sublingual tablet to avoid extensive first-pass metabolism with higher bioavailability as compared to oral formulations. Although, the established therapeutic solutions do not sufficiently satisfy the patient's safety and efficacy needs. Thus, the core research emphasis is to investigate strategies to produce novel formulations with enhanced safety and efficacy. This necessitates the development of robust, precise, and accurate methods for quantification of asenapine maleate in different sample matrices. Given the foregoing information, the current analysis concentrates on the different analytical techniques used to assess asenapine maleate in bulk, pharmaceutical formulations, and biological specimens. Reverse-phase HPLC coupled with UV detection is a majorly (nearly 50% of papers investigated) used technique for the estimation of asenapine maleate in formulations. On the other hand, for its quantification in the biological matrix, hyphenated techniques using mass spectrometry are widely used. This critical review reveals different analytical methodologies, including spectrophotometric, chromatographic, capillary electrophoresis techniques reported from 2011 to 2020, for the measurement of asenapine maleate in various sample matrices. The information presented in this review would be useful in future research for robust analytical method development for asenapine maleate utilizing a more scientific and risk-based approach. Also, it would aid to minimize analytical failure as well as method fine-tuning throughout the product life cycle. Further, this review may also direct scientists toward the development of methodologies for green research.

Chronic antipsychotic treatment exerts limited effects on the mania-like behavior of dopamine transporter knockdown mice

BACKGROUND

Bipolar disorder is a life-threatening disorder linked to dopamine transporter (DAT) polymorphisms, with reduced DAT levels seen in positron emission tomography and postmortem brains.

AIMS

The purpose of this study was to examine the effects of approved antipsychotics on DAT dysfunction-mediated mania behavior in mice.

METHODS

DAT knockdown mice received either D2-family receptor antagonist risperidone or asenapine and mania-related behaviors were assessed in the clinically-relevant behavioral pattern monitor to assess spontaneous exploration.

RESULTS

Chronic risperidone did not reverse mania-like behavior in DAT knockdown mice. Chronic asenapine reduced mania behavior but this effect was more pronounced in wild-type littermates than in DAT knockdown mice.

CONCLUSION

Taken together, these findings suggest that while acute antipsychotic treatment may be beneficial in management of bipolar mania, more targeted therapeutics may be necessary for long-term treatment. Specific investigation into DAT-targeting drugs could improve future treatment of bipolar mania.

Continuation rate for asenapine and brexpiprazole treatment in patients with schizophrenia

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

G-Protein-Coupled Receptor and Ion Channel Genes Used by Influenza Virus for Replication

Influenza epidemics result in morbidity and mortality each year. Vaccines are the most effective preventive measure but require annual reformulation, since a mismatch of vaccine strains can result in vaccine failure.

Influenza virus causes epidemics and sporadic pandemics resulting in morbidity, mortality, and economic losses. Influenza viruses require host genes to replicate. RNA interference (RNAi) screens can identify host genes coopted by influenza virus for replication. Targeting these proinfluenza genes can provide therapeutic strategies to reduce virus replication. Nineteen proinfluenza G-protein-coupled receptor (GPCR) and 13 proinfluenza ion channel genes were identified in human lung (A549) cells by use of small interfering RNAs (siRNAs). These proinfluenza genes were authenticated by testing influenza virus A/WSN/33-, A/CA/04/09-, and B/Yamagata/16/1988-infected A549 cells, resulting in the validation of 16 proinfluenza GPCR and 5 proinfluenza ion channel genes. These findings showed that several GPCR and ion channel genes are needed for the production of infectious influenza virus. These data provide potential targets for the development of host-directed therapeutic strategies to impede the influenza virus productive cycle so as to limit infection.

IMPORTANCE Influenza epidemics result in morbidity and mortality each year. Vaccines are the most effective preventive measure but require annual reformulation, since a mismatch of vaccine strains can result in vaccine failure. Antiviral measures are desirable particularly when vaccines fail. In this study, we used RNAi screening to identify several GPCR and ion channel genes needed for influenza virus replication. Understanding the host genes usurped by influenza virus during viral replication can help identify host genes that can be targeted for drug repurposing or for the development of antiviral drugs. The targeting of host genes is refractory to drug resistance generated by viral mutations, as well as providing a platform for the development of broad-spectrum antiviral drugs.

Neuronal Dopamine D3 Receptors: Translational Implications for Preclinical Research and CNS Disorders

Dopamine (DA), as one of the major neurotransmitters in the central nervous system (CNS) and periphery, exerts its actions through five types of receptors which belong to two major subfamilies such as D1-like (i.e., D1 and D5 receptors) and D2-like (i.e., D2, D3 and D4) receptors. Dopamine D3 receptor (D3R) was cloned 30 years ago, and its distribution in the CNS and in the periphery, molecular structure, cellular signaling mechanisms have been largely explored. Involvement of D3Rs has been recognized in several CNS functions such as movement control, cognition, learning, reward, emotional regulation and social behavior. D3Rs have become a promising target of drug research and great efforts have been made to obtain high affinity ligands (selective agonists, partial agonists and antagonists) in order to elucidate D3R functions. There has been a strong drive behind the efforts to find drug-like compounds with high affinity and selectivity and various functionality for D3Rs in the hope that they would have potential treatment options in CNS diseases such as schizophrenia, drug abuse, Parkinson’s disease, depression, and restless leg syndrome. In this review, we provide an overview and update of the major aspects of research related to D3Rs: distribution in the CNS and periphery, signaling and molecular properties, the status of ligands available for D3R research (agonists, antagonists and partial agonists), behavioral functions of D3Rs, the role in neural networks, and we provide a summary on how the D3R-related drug research has been translated to human therapy.

Asenapine: an atypical antipsychotic with atypical formulations

Asenapine is a second-generation (atypical) antipsychotic medication not available in a pill that can be swallowed; rather, it is commercialized in sublingual and transdermal formulations. This is a consequence of extensive first-pass metabolism if ingested. The sublingual formulation is approved in many jurisdictions for the treatment of schizophrenia and manic or mixed episodes associated with bipolar I disorder and is available generically. The efficacy profile is well characterized in a number of clinical trials, including an off-label use for the management of agitation. Obstacles to its use include food and drink restrictions, twice-daily dosing and adverse effects such as dysgeusia (distorted, altered, or unpleasant taste) and oral hypoesthesia (numbness). Transdermal asenapine was approved by the US Food and Drug Administration in 2019 for the treatment of schizophrenia in adults. Efficacy was established in a registrational study examining acutely ill inpatients with schizophrenia. The patch needs to changed once daily. Obstacles to its use include the potential for skin reactions such as erythema and pruritis, and being a branded product, it is more costly than other options. This is a narrative review of the chemistry and pharmacokinetics/pharmacodynamics of asenapine, as well as summarizing the efficacy and tolerability of both sublingual and transdermal asenapine, and its possible place in treatment.

Inhibitory Effects of Antipsychotics on the Contractile Response to Acetylcholine in Rat Urinary Bladder Smooth Muscles

The clinical applications of antipsychotics for symptoms unrelated to schizophrenia, such as behavioral and psychological symptoms, in patients with Alzheimer's disease, and the likelihood of doctors prescribing antipsychotics for elderly people are increasing. In elderly people, drug-induced and aging-associated urinary disorders are likely to occur. The most significant factor causing drug-induced urinary disorders is a decrease in urinary bladder smooth muscle (UBSM) contraction induced by the anticholinergic action of therapeutics. However, the anticholinergic action-associated inhibitory effects of antipsychotics on UBSM contraction have not been sufficiently assessed. In this study, we examined 26 clinically available antipsychotics to determine the extent to which they inhibit acetylcholine (ACh)-induced contraction in rat UBSM to predict the drugs that should not be used by elderly people to avoid urinary disorders. Of the 26 antipsychotics, six (chlorpromazine, levomepromazine (phenothiazines), zotepine (a thiepine), olanzapine, quetiapine, clozapine (multi-acting receptor targeted antipsychotics (MARTAs))) competitively inhibited ACh-induced contractions at concentrations corresponding to clinically significant doses. Further, 11 antipsychotics (perphenazine, fluphenazine, prochlorperazine (phenothiazines), haloperidol, bromperidol, timiperone, spiperone (butyrophenones), pimozide (a diphenylbutylpiperidine), perospirone, blonanserin (serotonin-dopamine antagonists; SDAs), and asenapine (a MARTA)) significantly suppressed ACh-induced contraction; however, suppression occurred at concentrations substantially exceeding clinically achievable blood levels. The remaining nine antipsychotics (pipamperone (a butyrophenone), sulpiride, sultopride, tiapride, nemonapride (benzamides), risperidone, paliperidone (SDAs), aripiprazole, and brexpiprazole (dopamine partial agonists)) did not inhibit ACh-induced contractions at concentrations up to 10-5 M. These findings suggest that chlorpromazine, levomepromazine, zotepine, olanzapine, quetiapine, and clozapine should be avoided by elderly people with urinary disorders.

International Union of Basic and Clinical Pharmacology. CX. Classification of Receptors for 5-hydroxytryptamine; Pharmacology and Function

5-HT receptors expressed throughout the human body are targets for established therapeutics and various drugs in development. Their diversity of structure and function reflects the important role 5-HT receptors play in physiologic and pathophysiological processes. The present review offers a framework for the official receptor nomenclature and a detailed understanding of each of the 14 5-HT receptor subtypes, their roles in the systems of the body, and, where appropriate, the (potential) utility of therapeutics targeting these receptors. SIGNIFICANCE STATEMENT: This review provides a comprehensive account of the classification and function of 5-hydroxytryptamine receptors, including how they are targeted for therapeutic benefit.

A Randomized Controlled Trial to Compare the Efficacy, Safety and Tolerability of Asenapine versus Olanzapine in Management of Schizophrenia

Objective

Schizophrenia is a serious disease characterized by impairment in the perception or expression of reality, leading to occupational and social dysfunction. The use of antipsychotic medication is now universal in the first-line treatment of schizophrenia. This study was undertaken to compare the efficacy of asenapine with a standard atypical antipsychotic, olanzapine in treating this disease.

Methods

It was designed as a single blind, randomized, controlled, parallel group, single centre Phase IV trial of a newer atypical antipsychotic, asenapine versus existing standard atypical antipsychotic, olanzapine. Total 80 subjects were enrolled as per eligibility criteria.Each recruited subject received daily treatment with the trial medication (Olanzapine 10 mg or Asenapine 10 mg daily) for duration of 12 weeks. BPRS, CGI-S, CGI-I, Laboratory parameters and compliance was assessed and analyzed. Continuous variables were compared by t test and non-parametric data was analyzed by Mann−Whitney U test and Wilcoxon signed rank test. Likely categorical variables were analyzed by chi-square test or Fisher’s exact test, as appropriate.

Results

The duration of schizophrenia at presentation was comparable in both the treatment groups. There was significant reduction of BPRS score between any two visits of each treatment groups. The decline in CGI-S and CGI-I scores was statistically significant (p < 0.001) when compared between visits of any of the both treatment arms. Adherence to treatment was excellent for all patients.

Conclusion

Newer atypical antipsychotic asenapine is more effective than standard olanzapine in reducing the symptoms of schizophrenia in this study and further larger studies are to be done.

The Benefits of Olanzapine in Palliating Symptoms

OPINION STATEMENT

Olanzapine has become a major drug in the management of chemotherapy-induced nausea and vomiting as a prophylactic agent. In addition, a recent randomized trial has demonstrated its benefits in treating nausea and vomiting associated with advanced cancer. The added benefit to olanzapine is that it also stimulates appetite. As a result, since it treats multiple symptoms associated with advanced cancer, it is likely to become the antiemetic of choice in palliative care at least in the USA. The added benefit of treating insomnia and the avoidance of benzodiazepines should place olanzapine in at the top of the list of drugs to use for patients who do complain of insomnia. There is no good evidence that it potentiates the respiratory depression of opioids unlike benzodiazepines. The evidence is weak that olanzapine in as an adjuvant analgesic. Hopefully, future trials will explore this in greater depth. The benefits of adding olanzapine to potent opioids are that it may reduce craving, drug cues, and opioid misuse. Other symptoms like anxiety and depression may be addressed by the addition of olanzapine to standard antidepressants.

Dopamine, Cognitive Impairments and Second-Generation Antipsychotics: From Mechanistic Advances to More Personalized Treatments

The pharmacological treatment of cognitive impairments associated with schizophrenia is still a major unmet clinical need. Indeed, treatments with available antipsychotics generate highly variable cognitive responses among patients with schizophrenia. This has led to the general assumption that antipsychotics are ineffective on cognitive impairment, although personalized medicine and drug repurposing approaches might scale down this clinical issue. In this scenario, evidence suggests that cognitive improvement exerted by old and new atypical antipsychotics depends on dopaminergic mechanisms. Moreover, the newer antipsychotics brexpiprazole and cariprazine, which might have superior clinical efficacy on cognitive deficits over older antipsychotics, mainly target dopamine receptors. It is thus reasonable to assume that despite more than 50 years of elusive efforts to develop novel non-dopaminergic antipsychotics, dopamine receptors remain the most attractive and promising pharmacological targets in this field. In the present review, we discuss preclinical and clinical findings showing dopaminergic mechanisms as key players in the cognitive improvement induced by both atypical antipsychotics and potential antipsychotics. We also emphasize the concept that these mechanistic advances, which help to understand the heterogeneity of cognitive responses to antipsychotics, may properly guide treatment decisions and address the unmet medical need for the management of cognitive impairment associated with schizophrenia.

Serotonin-2B receptor antagonism increases the activity of dopamine and glutamate neurons in the presence of selective serotonin reuptake inhibition

Previous research has implicated the serotonin-2B (5-HT_2B) receptor as a possible contributor to the antidepressant-like response. Aripiprazole has been successfully used in combination with selective serotonin reuptake inhibitors (SSRIs) in treatment-resistant depression and it, among all receptors, exhibits the highest affinity for the 5-HT_2B receptor. However, the potential contribution of such an antagonistic action on 5-HT_2B receptors in the context of adjunct therapy is not known. In vivo electrophysiological recordings of ventral tegmental area (VTA) dopamine (DA) neurons, dorsal raphe nucleus (DRN) 5-HT neurons and pyramidal neurons in the medial prefrontal cortex (mPFC), and the hippocampus were conducted in anaesthetized Sprague-Dawley rats after the administration of 5-HT_2B receptor ligands alone or in combination with the SSRI escitalopram. An escitalopram-induced decrease in DA, but not 5-HT firing activity, was rescued by 2-day co-administration of the selective 5-HT_2B receptor antagonist LY266097. In the mPFC, 14-day escitalopram administration alone had no effect on pyramidal neuron firing and burst activity, whereas, aripiprazole administered alone or in combination with escitalopram for 14 days increased pyramidal neuron firing and burst activity. Likewise, the administration of LY266097 alone or its addition on the last 3 days of a 14-day escitalopram regimen increased pyramidal neuron firing and burst activity. These results indicated that 5-HT_2B receptors play, at least in part, a role in this enhancement. In the hippocampus, 5-HT_2B receptor activation by BW723c86 decreased escitalopram-induced inhibition of 5-HT reuptake, which was reversed by a 5-HT_2B receptor antagonist. Altogether, these results put into evidence the possibility that 5-HT_2B receptor blockade contributes to the therapeutic effect of aripiprazole addition to SSRIs in depression.

Targeting Serotonin 5-HT2A Receptors to Better Treat Schizophrenia: Rationale and Current Approaches

Schizophrenia is a major mental illness associated with profound disability. Current treatments for schizophrenia (antipsychotics) all have a similar mechanism of action and are primarily dopamine type 2 receptor (D₂R) antagonists. Antipsychotics are not fully effective for the majority of schizophrenia patients, suggesting the need for alternative approaches. The primary focus of this review is to assess the evidence for the role of the serotonin type 2A receptor (5-HT_2AR) in schizophrenia. Topics include an overview of 5-HT_2AR physiology and pathophysiology in schizophrenia, 5-HT_2AR interaction with other neurotransmitter systems, including the glutamatergic system, a review of the 5-HT_2AR/d-lysergic acid diethylamide (LSD) model of schizophrenia, a contrast of the 5-HT_2AR and glutamatergic models of schizophrenia, and finally, a review of Food and Drug Administration (FDA)-approved and investigational 5-HT_2AR-modulating compounds. Recent studies with lumeteperone, pimavanserin, and roluperidone are highlighted.

The Effects of Antipsychotics on the Synaptic Plasticity Gene Homer1a Depend on a Combination of Their Receptor Profile, Dose, Duration of Treatment, and Brain Regions Targeted

Background: Antipsychotic agents modulate key molecules of the postsynaptic density (PSD), including the Homer1a gene, implicated in dendritic spine architecture. How the antipsychotic receptor profile, dose, and duration of administration may influence synaptic plasticity and the Homer1a pattern of expression is yet to be determined. Methods: In situ hybridization for Homer1a was performed on rat tissue sections from cortical and striatal regions of interest (ROI) after acute or chronic administration of three antipsychotics with divergent receptor profile: Haloperidol, asenapine, and olanzapine. Univariate and multivariate analyses of the effects of topography, treatment, dose, and duration of antipsychotic administration were performed. Results: All acute treatment regimens were found to induce a consistently higher expression of Homer1a compared to chronic ones. Haloperidol increased Homer1a expression compared to olanzapine in striatum at the acute time-point. A dose effect was also observed for acute administration of haloperidol. Conclusions: Biological effects of antipsychotics on Homer1a varied strongly depending on the combination of their receptor profile, dose, duration of administration, and throughout the different brain regions. These molecular data may have translational valence and may reflect behavioral sensitization/tolerance phenomena observed with prolonged antipsychotics.

Recent advances in the development of asenapine formulations

INTRODUCTION

Asenapine maleate (AM) is an atypical antipsychotic agent, that has been widely prescribed for the management of schizoaffective disorders. However, the bioavailability of AM is extremely poor due to the extensive first-pass metabolism. With the advancement in pharmaceutical technologies, significant strides have been made to create novel formulations to address the bioavailability problem of AM.

AREAS COVERED

This review article provides an insight into all the formulation approaches undertaken by researchers to increase the bioavailability of AM encompassing the works utilizing ultrasound mediated transdermal delivery, nose to brain delivery, intestinal lymphatic system targeting, in situ implants, etc. All the patents associated with AM formulation have also been discussed and summarized.

EXPERT OPINION

Numerous studies have been carried out on AM formulations over the recent years, many of these studies have shown significant improvement in bioavailability. We have also mentioned the unexplored domains which can be exploited for further enhancing the bioavailability of AM. Nonetheless, most of these studies are still limited to the research laboratory level and face multiple hurdles before making into the market. Attaining controllability and reproducibility for the production of novel formulations is needed to enable its transition from bench to bedside.

Nausea and vomiting during post-transplantation cyclophosphamide administration

Post-transplantation cyclophosphamide (PTCy) is a new method to prevent graft-versus-host disease after allogeneic hematopoietic cell transplantation. Although the use of dexamethasone is recommended as prophylaxis against chemotherapy-induced nausea and vomiting (CINV) for patients who receive high-dose cyclophosphamide, corticosteroids cannot be used during PTCy administration to exploit depletion of alloreactive T cells. Thus, CINV may not be adequately controlled in this situation. We retrospectively examined antiemetic efficacy of the combination of a 5-hydroxytryptamine-3 receptor antagonist (5-HT₃ RA) and a NK₁ receptor antagonist (NK₁ RA) in 36 patients who received PTCy, and compared this efficacy with that of the same combination together with dexamethasone in 27 patients conditioned with cyclophosphamide and total body irradiation (CY/TBI). The proportion of patients who had no vomiting during the acute phase of PTCy administration was 81%, and was lower than 100% in the CY/TBI group (p = 0.02). Our results suggest that prevention of CINV using 5-HT₃ RA and NK₁ RA during PTCy administration is suboptimal and that addition of antiemetic is necessary in patients who receive PTCy.

Secure multiparty computation for privacy-preserving drug discovery

Motivation

Quantitative structure–activity relationship (QSAR) and drug–target interaction (DTI) prediction are both commonly used in drug discovery. Collaboration among pharmaceutical institutions can lead to better performance in both QSAR and DTI prediction. However, the drug-related data privacy and intellectual property issues have become a noticeable hindrance for inter-institutional collaboration in drug discovery.

Results

We have developed two novel algorithms under secure multiparty computation (MPC), including QSARMPC and DTIMPC, which enable pharmaceutical institutions to achieve high-quality collaboration to advance drug discovery without divulging private drug-related information. QSARMPC, a neural network model under MPC, displays good scalability and performance and is feasible for privacy-preserving collaboration on large-scale QSAR prediction. DTIMPC integrates drug-related heterogeneous network data and accurately predicts novel DTIs, while keeping the drug information confidential. Under several experimental settings that reflect the situations in real drug discovery scenarios, we have demonstrated that DTIMPC possesses significant performance improvement over the baseline methods, generates novel DTI predictions with supporting evidence from the literature and shows the feasible scalability to handle growing DTI data. All these results indicate that QSARMPC and DTIMPC can provide practically useful tools for advancing privacy-preserving drug discovery.

Availability and implementation

The source codes of QSARMPC and DTIMPC are available on the GitHub: https://github.com/rongma6/QSARMPC_DTIMPC.git.

Supplementary information

Supplementary data are available at Bioinformatics online.

Transdermal Asenapine in Schizophrenia: A Systematic Review

BACKGROUND

Asenapine is a novel antipsychotic that has demonstrated efficacy in controlling psychosis in schizophrenia and mania in bipolar illness. It must be administered as a sublingual formulation because it is nearly completely metabolized in the first pass through the liver. Recently, a transdermal formulation of asenapine has been approved for schizophrenia by the Food and Drug Administration.

METHODS

A systematic review of transdermal asenapine was done utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) model.

DISCUSSION

There are several formulations of transdermal asenapine but only Secuado^® has been approved for clinical use. Total bioavailability is 35%. Peak plasma concentration (Cmax) is 4 ng/mL and occurs within 1 hr (Tmax); elimination half-life (t_1/2) is 24 hrs (range 13.4 to 39.2 h). Asenapine is highly bound (95%) to albumin and α₁-acid glycoprotein. It has a unique receptor profile in which it functions as an antagonist at multiple receptors with affinity that is higher than D₂ (K_i = 1.3) including D₃, D₄, 5HT_2A, 5HT_2C, 5HT_2B, 5HT₇, 5HT₆, H₁, and α2. This profile suggests that asenapine may be of particular value off label for bipolar depression, anxiety, and aggression. Transdermal asenapine was only tested in one randomized, placebo-controlled study of acute psychosis in schizophrenia. It was superior to placebo at week 6 with nearly one-third of patients experiencing >30% improvement in total PANSS score which translates in a number needed to treat (NNT) of 9.