Asenapine, iloperidone and lurasidone: critical appraisal of the most recently approved pharmacotherapies for schizophrenia in adults

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.

The atypical neuroleptics iloperidone and lurasidone inhibit human cytochrome P450 enzymes in vitro. Evaluation of potential metabolic interactions

Background

The present study aimed at examining the inhibitory effect of two atypical neuroleptics iloperidone and lurasidone on the main human cytochrome P450 (CYP) enzymes in pooled human liver microsomes and cDNA-expressed CYP enzymes (supersomes).

Methods

The activity of these enzymes was determined by the following CYP-specific reactions: caffeine 3-N-demethylation/CYP1A2, diclofenac 4′-hydroxylation/CYP2C9, perazine N-demethylation/CYP2C19, bufuralol 1′-hydroxylation/CYP2D6 and testosterone 6β-hydroxylation/CYP3A4, respectively, using HPLC.

Results

Iloperidone inhibited the activity of CYP3A4 via a noncompetitive mechanism (K_i = 0.38 and 0.3 µM in liver microsomes and supersomes, respectively) and CYP2D6 via a competitive mechanism (K_i = 2.9 and 10 µM in microsomes and supersomes). Moreover, iloperidone attenuated the activity of CYP1A2 (K_i = 45 and 31 µM in microsomes and supersomes) and CYP2C19 via a mixed mechanism (K_i = 6.5 and 32 µM in microsomes and supersomes) but did not affect CYP2C9. Lurasidone moderately inhibited CYP1A2 (K_i = 12.6 and 15.5 µM in microsomes and supersomes), CYP2C9 (K_i = 18 and 3.5 µM in microsomes and supersomes) and CYP2C19 via a mixed mechanism (K_i = 18 and 18.4 µM in microsomes and supersomes), and CYP3A4 via a competitive mechanism (K_i = 29.4 and 9.1 µM in microsomes and supersomes). Moreover, lurasidone competitively, though weakly diminished the CYP2D6 activity (K_i = 37.5 and 85 µM in microsomes and supersomes).

Conclusion

The examined neuroleptics showed inhibitory effects on different CYP enzymes. The obtained results indicate that metabolic/pharmacokinetic interactions with iloperidone (involving mainly CYP3A4 and CYP2D6) and possibly with lurasidone (involving CYP1A2, CYP2C9 or CYP2C19) may occur during combined therapy.

Immunoendocrine Peripheral Effects Induced by Atypical Antipsychotics

Atypical antipsychotics (AAP) or second-generation antipsychotics are the clinical option for schizophrenia treatment during acute psychoses, but they are also indicated for maintenance during lifetime, even though they are being used for other psychiatric conditions in clinical practice such as affective disorders and autism spectrum disorder, among others. These drugs are differentiated from typical antipsychotics based on their clinical profile and are a better choice because they cause fewer side effects regarding extrapyramidal symptoms (EPS). Even though they provide clear therapeutic benefits, AAP induce peripheral effects that trigger phenotypic, functional, and systemic changes outside the Central Nervous System (CNS). Metabolic disease is frequently associated with AAP and significantly impacts the patient's quality of life. However, other peripheral changes of clinical relevance are present during AAP treatment, such as alterations in the immune and endocrine systems as well as the intestinal microbiome. These less studied alterations also have a significant impact in the patient's health status. This manuscript aims to revise the peripheral immunological, endocrine, and intestinal microbiome changes induced by AAP consumption recommended in the clinical guidelines for schizophrenia and other psychiatric disorders.

A Review of the Pharmacological and Clinical Profile of Newer Atypical Antipsychotics as Treatments for Bipolar Disorder: Considerations for Use in Older Patients

Bipolar disorder prevalence rates vary in the older adult population (defined as age ≥ 65 years), ranging from 1% in community dwellers to as high as 8-10% in hospital inpatients. Although older agents, including lithium and valproic acid, offer significant antimanic efficacy, as supported by a recent randomized controlled trial (RCT), there is growing interest in using atypical antipsychotics to treat bipolar disorder in older adults. Newer atypical antipsychotics are of interest based on their tolerability and efficacy in the general adult bipolar population. The aim of this review was to systematically examine efficacy and tolerability of newer atypical antipsychotics for older adult bipolar disorder (OABD). We conducted a systematic search utilizing the MEDLINE, EMBASE, PsycINFO and Cochrane Library electronic databases, with the aim of identifying all RCTs comparing newer atypical antipsychotics approved by the US FDA since 2002 (including brexpiprazole, cariprazine, lurasidone, iloperidone, asenapine, paliperidone, and aripiprazole) with placebo or another comparator, in the treatment of any phase of bipolar disorder (including mania, depression or mixed episodes while used as an acute or maintenance treatment) in older adults (> 65 years). We found no RCT data on any of the examined agents. Hence, we changed our search criteria to include studies with a lower age cut-off (≥ 55 years), as well as the inclusion of post hoc studies. Two post hoc studies on lurasidone suggest its reasonable safety and efficacy profile in the acute and maintenance treatment of OABD; however, there are no pharmacoeconomic data on the use of lurasidone in the treatment of OABD. Research data from open-label studies on oral asenapine and aripiprazole as add-on therapy suggest that these two agents are adequately tolerated and improved symptoms of depression and mania in OABD; hence, there is an urgent need to conduct RCTs on these two agents. Lastly, we found no studies for the treatment of OABD with brexpiprazole, cariprazine, iloperidone, or paliperidone.

Design, Optimization, and Evaluation of Lurasidone Hydrochloride Nanocrystals

The present investigation was carried out to design, optimize, and evaluate lurasidone hydrochloride nanocrystals for improving its solubility and dissolution characteristics. Nanocrystals were prepared by media milling technique using zirconium oxide beads with 0.1 mm diameter. Various stabilizers, viz. poloxamer 188, PVP K30, SLS, HPMC E15, and PVP S 630 D, were evaluated to stabilize the nanocrystals. The Pareto chart obtained through Plackett-Burman screening design revealed that HPMC E 15 showed the highest standardized effect (p value <0.05) on percent dissolution efficiency at 2 min. In subsequent studies, a 3(2) factorial design was employed to quantify the effect of two independent variables, namely amount of stabilizer and milling time on predetermined response variables mean particle size, saturation solubility, and percent dissolution efficiency at 2 min. Statistical analysis of the factorial design revealed that all predetermined response variables were significantly dependent (p value <0.05) on the independent variables. The observed response of the optimized batch prepared as per the desirability function was in close agreement with predicted response, and mathematical model generated was validated. The optimized batch was lyophilized, and X-ray powder diffraction studies indicated that there was no substantial change in crystallinity of the drug. The optimized formulation showed mean particle size of 228 nm and released almost all the drug within first 5 min. Since the crystallinity of the drug is maintained, improvement in saturation solubility and dissolution efficiency could be attributed to decrease in mean particle size of the drug.

Detecting and Managing Adverse Effects of Antipsychotic Medications: Current State of Play

Antipsychotics are some of the most frequently prescribed medications not only for psychotic disorders and symptoms but also for a wide range of on-label and off-label indications. Because second-generation antipsychotics have largely replaced first-generation antipsychotics as first-line options due to their substantially decreased risk of extrapyramidal side effects, attention has shifted to other clinically concerning adverse events associated with antipsychotic therapy. The focus of this article is to update the nonextrapyramidal side effects associated with second-generation antipsychotics. Issues surrounding diagnosis and monitoring as well as clinical management are addressed.

Adverse events and treatment failure leading to discontinuation of recently approved antipsychotic drugs in schizophrenia: A network meta-analysis

Objective:We aimed to gather evidence of the discontinuation rates owing to adverse events or treatment failure for four recently approved antipsychotics (asenapine, blonanserin, iloperidone, and lurasidone).Methods: A systematic review followed by pairwise meta-analysis and mixed treatment comparison meta analysis(MTC) was performed, including randomized controlled trials (RCTs) that compared the use of the above-mentioned drugs versus placebo in patients with schizophrenia. An electronic search was conducted in PubMed, Scopus, Science Direct, Scielo, the Cochrane Library, and International Pharmaceutical Abstracts(January 2015). The included trials were at least single blinded. The main outcome measures extracted were discontinuation owing to adverse events and discontinuation owing to treatment failure.Results: Fifteen RCTs were identified (n = 5400 participants) and 13 of them were amenable for use in our meta-analyses. No significant differences were observed between any of the four drugs and placebo as regards discontinuation owing to adverse events, whether in pairwise meta-analysis or in MTC. All drugs presented a better profile than placebo on discontinuation owing to treatment failure, both in pairwise meta-analysis and MTC. Asenapine was found to be the best therapy in terms of tolerability owing to failure,while lurasidone was the worst treatment in terms of adverse events. The evidence around blonanserin is weak.Conclusion: MTCs allowed the creation of two different rank orders of these four antipsychotic drugs in two outcome measures. This evidence-generating method allows direct and indirect comparisons, supporting approval and pricing decisions when lacking sufficient, direct, head-to-head trials.

Understanding responder neurobiology in schizophrenia using a quantitative systems pharmacology model: application to iloperidone

The concept of targeted therapies remains a holy grail for the pharmaceutical drug industry for identifying responder populations or new drug targets. Here we provide quantitative systems pharmacology as an alternative to the more traditional approach of retrospective responder pharmacogenomics analysis and applied this to the case of iloperidone in schizophrenia. This approach implements the actual neurophysiological effect of genotypes in a computer-based biophysically realistic model of human neuronal circuits, is parameterized with human imaging and pathology, and is calibrated by clinical data. We keep the drug pharmacology constant, but allowed the biological model coupling values to fluctuate in a restricted range around their calibrated values, thereby simulating random genetic mutations and representing variability in patient response. Using hypothesis-free Design of Experiments methods the dopamine D4 R-AMPA (receptor-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor coupling in cortical neurons was found to drive the beneficial effect of iloperidone, likely corresponding to the rs2513265 upstream of the GRIA4 gene identified in a traditional pharmacogenomics analysis. The serotonin 5-HT3 receptor-mediated effect on interneuron gamma-aminobutyric acid conductance was identified as the process that moderately drove the differentiation of iloperidone versus ziprasidone. This paper suggests that reverse-engineered quantitative systems pharmacology is a powerful alternative tool to characterize the underlying neurobiology of a responder population and possibly identifying new targets.

Asenapine, blonanserin, iloperidone, lurasidone, and sertindole: distinctive clinical characteristics of 5 novel atypical antipsychotics

Schizophrenia is a serious, chronic, and devastating mental illness with a substantial impact on psychological, physical, social, and economical areas of an individual and society. To treat such critical mental illness, a number of first-generation (typical) and second-generation (atypical) antipsychotics are currently available in the market. Despite such treatment options, most of patients with schizophrenia have a poor treatment outcome and become treatment resistant, causing continual deterioration on positive, negative, and cognitive symptoms, resulting in impairment of socio-occupational functioning. Hence, additional novel antipsychotics with better efficacy, safety, and tolerability profiles are needed to enable clinicians to diversify treatment options to improve treatment of schizophrenia. Recently, the 3 antipsychotics, including iloperidone (2009), asenapine (2009), and lurasidone (2010), have been approved by the US Food and Drug Administration. Two other atypical antipsychotics, including sertindole and blonanserin, are approved and used outside the United States for treatment of schizophrenia. Sertindole, after it has been voluntarily suspended by the manufacturer in 1998 due to its potential risk in causing cardiovascular-related death, was relaunched to the European market in 2005. More recently, blonanserin was approved in Japan (2008) and in Korea (2009) for the management of schizophrenia. Individual antipsychotic may have differential pros and cons compared with other antipsychotic in terms of efficacy, safety, tolerability, restoration of functional capacity, and economic aspect reflecting relapse prevention. The purpose of this review was to provide distinctive clinical characteristics and up-to-date of clinical trial data of the 5 novel atypical antipsychotics for the management of schizophrenia, which may deliver clinicians better understanding in the use of such atypical antipsychotics for the treatment of schizophrenia in clinical practice.

The effects of novel and newly approved antipsychotics on serum prolactin levels: a comprehensive review

Since the 1970s, clinicians have increasingly become more familiar with hyperprolactinemia (HPRL) as a common adverse effect of antipsychotic medication, which remains the cornerstone of pharmacological treatment for patients with schizophrenia. Although treatment with second-generation antipsychotics (SGAs) as a group is, compared with use of the first-generation antipsychotics, associated with lower prolactin (PRL) plasma levels, the detailed effects on plasma PRL levels for each of these compounds in reports often remain incomplete or inaccurate. Moreover, at this moment, no review has been published about the effect of the newly approved antipsychotics asenapine, iloperidone and lurasidone on PRL levels. The objective of this review is to describe PRL physiology; PRL measurement; diagnosis, causes, consequences and mechanisms of HPRL; incidence figures of (new-onset) HPRL with SGAs and newly approved antipsychotics in adolescent and adult patients; and revisit lingering questions regarding this hormone. A literature search, using the MEDLINE database (1966-December 2013), was conducted to identify relevant publications to report on the state of the art of HPRL and to summarize the available evidence with respect to the propensity of the SGAs and the newly approved antipsychotics to elevate PRL levels. Our review shows that although HPRL usually is defined as a sustained level of PRL above the laboratory upper limit of normal, limit values show some degree of variability in clinical reports, making the interpretation and comparison of data across studies difficult. Moreover, many reports do not provide much or any data detailing the measurement of PRL. Although the highest rates of HPRL are consistently reported in association with amisulpride, risperidone and paliperidone, while aripiprazole and quetiapine have the most favorable profile with respect to this outcome, all SGAs can induce PRL elevations, especially at the beginning of treatment, and have the potential to cause new-onset HPRL. Considering the PRL-elevating propensity of the newly approved antipsychotics, evidence seems to indicate these agents have a PRL profile comparable to that of clozapine (asenapine and iloperidone), ziprasidone and olanzapine (lurasidone). PRL elevations with antipsychotic medication generally are dose dependant. However, antipsychotics having a high potential for PRL elevation (amisulpride, risperidone and paliperidone) can have a profound impact on PRL levels even at relatively low doses, while PRL levels with antipsychotics having a minimal effect on PRL, in most cases, can remain unchanged (quetiapine) or reduce (aripiprazole) over all dosages. Although tolerance and decreases in PRL values after long-term administration of PRL-elevating antipsychotics can occur, the elevations, in most cases, remain above the upper limit of normal. PRL profiles of antipsychotics in children and adolescents seem to be the same as in adults. The hyperprolactinemic effects of antipsychotic medication are mostly correlated with their affinity for dopamine D2 receptors at the level of the anterior pituitary lactotrophs (and probably other neurotransmitter mechanisms) and their blood-brain barrier penetrating capability. Even though antipsychotics are the most common cause of pharmacologically induced HPRL, recent research has shown that HPRL can be pre-existing in a substantial portion of antipsychotic-naïve patients with first-episode psychosis or at-risk mental state.

Second-generation and newly approved antipsychotics, serum prolactin levels and sexual dysfunctions: a critical literature review

INTRODUCTION

Using antipsychotic (AP) medication can increase prolactin (PRL) levels and place the patient at risk of sexual dysfunction (SD).

AREAS COVERED

The aim of this review is to describe the PRL propensity of the different second-generation and newly approved APs. It then considers the prevalence rates of SDs associated with these compounds in patients with schizophrenia and treatment strategies for the management of SDs and/or hyperprolactinemia (HPRL). Furthermore, we address the lingering question regarding the association between SDs and PRL.

EXPERT OPINION

SD (particularly long-term) data remain scarce for several APs. A wide variety of assessment techniques used in SD research make reliable comparisons between APs impossible. The majority of these reports do not equally allow us to distinguish between treatment (AP and co-medication)-emergent SDs and illness-related SDs. This makes it difficult to assess the degree to which these side effects are associated with 'PRL-raising' APs, and what part of this fraction is directly reducible to serum PRL levels. Also, few evidence-based treatment strategies for HPRL and associated side effects are available. Therefore, longer-term randomized controlled trials, using reliable and valid structured interviews or questionnaires, are necessary to establish the precise relationship between APs, PRL levels and SDs rates and develop valuable treatment options.

Clinically relevant interactions between newer antidepressants and second-generation antipsychotics

INTRODUCTION

Combinations of newer antidepressants and second-generation antipsychotics (SGAs) are frequently used by clinicians. Pharmacokinetic drug interaction (PK DI) and poorly understood pharmacodynamic (PD) drug interaction (PD DI) can occur between them.

AREAS COVERED

This paper comprehensively reviews PD DI and PK DI studies.

EXPERT OPINION

More PK DI studies are needed to better establish dose correction factors after adding fluoxetine and paroxetine to aripiprazole, iloperidone and risperidone. Further PK DI studies and case reports are also needed to better establish the need for dose correction factors after adding i) fluoxetine to clozapine, lurasidone, quetiapine and olanzapine; ii) paroxetine to olanzapine; iii) fluvoxamine to asenapine, aripiprazole, iloperidone, lurasidone, olanzapine, quetiapine and risperidone; iv) high sertraline doses to aripiprazole, clozapine, iloperidone and risperidone: v) bupropion and duloxetine to aripiprazole, clozapine, iloperidone and risperidone; and vi) asenapine to paroxetine and venlafaxine. Possible beneficial PD DI effects occur after adding SGAs to newer antidepressants for treatment-resistant major depressive and obsessive-compulsive disorders. The lack of studies combining newer antidepressants and SGAs in psychotic depression is worrisome. PD DIs between newer antidepressants and SGAs may be more likely for mirtazapine and bupropion. Adding selective serotonin reuptake inhibitors and SGAs may increase QTc interval and may very rarely contribute to torsades de pointes.

Long-term efficacy and safety of iloperidone: an update

Schizophrenia is a devastating neuropsychiatric disease with a worldwide prevalence of approximately 0.5%-1%. Since many patients do not achieve adequate symptom relief from available agents, alternate pharmacotherapeutic approaches are needed. In this context, iloperidone was recently approved by the US Food and Drug Administration for the treatment of schizophrenia. This paper first reviews its pharmacodynamic and pharmacokinetic profiles, emphasizing their clinical relevance. Next, it summarizes the literature on its acute and maintenance efficacy, safety, and tolerability. It then considers pharmacogenetic data which may help to predict response and risk of cardiac arrhythmias with this agent. Finally, it critically positions iloperidone relative to other first- and second-generation antipsychotics.

Dynamics of drug evaluation: Formulary placement of antipsychotics

Formulary management for psychotropic medications can be more difficult compared to other medication classes, as the same medications can produce significantly different results in individual patients. This article reviews various factors which should be examined when deciding which antipsychotics to include on a formulary.

Strategies for prevention and management of second generation antipsychotic-induced metabolic side effects

Preventing, minimizing and managing risks associated with second generation antipsychotic (SGA) use in patients with schizophrenia and other psychotic disorders is a priority for clinicians working with this population. Among these risks is metabolic syndrome. As this population exhibits increased rates of obesity, diabetes and atherogenic dyslipidemia compared to the general population, metabolic syndrome deserves serious consideration in patient care planning for managing risks. This article comprehensively reviews different strategies and recommendations for prevention and/or management of metabolic abnormalities associated with the use of SGAs. Baseline screening and follow-up metabolic monitoring as well as education and counseling on risk for SGA-induced weight gain and other metabolic abnormalities, physical activity and healthy diet for weight maintenance/loss should be promoted shortly after initiation of SGAs. In select patients, the clinician can consider simplifying the antipsychotic treatment regimen by switching to an agent with a lower propensity of metabolic side effects or possibly adding metformin for weight loss and glucose metabolism regulation in those experiencing a first episode of schizophrenia. Future research should focus on combinations of interventions and treatment modalities and exploration of novel interventions.

Antipsychotic treatments; focus on lurasidone

The introduction of atypical antipsychotic drugs (AAPDs), or second-generation antipsychotics, with clozapine as the prototype, has largely changed the clinicians' attitudes toward the treatment of mental illnesses including, but not limited to schizophrenia. Initially, there was optimism that AAPDs would be superior over typical antipsychotic drugs (TAPDs), or first-generation antipsychotic drugs, in terms of efficacy in various phenomenological aspects, including cognitive impairment, and less likelihood of causing adverse events. However, these views have been partly challenged by results from recent meta-analysis studies. Specifically, cardio-metabolic side effects of AAPDs, in spite of a relative paucity of extrapyramidal symptoms, may sometimes limit the use of these agents. Accordingly, attempts have been made to develop newer compounds, e.g., lurasidone, with the aim of increasing efficacy and tolerability. Further investigations are warranted to determine if a larger proportion of patients will be benefitted by treatment with AAPDs compared to TAPDs in terms of remission and recovery.