Are CYP1A2*1F and *1C associated with clozapine tolerability?: a preliminary investigation

Clozapine's multiple cellular mechanisms: What do we know after more than fifty years? A systematic review and critical assessment of translational mechanisms relevant for innovative strategies in treatment-resistant schizophrenia

Almost fifty years after its first introduction into clinical care, clozapine remains the only evidence-based pharmacological option for treatment-resistant schizophrenia (TRS), which affects approximately 30% of patients with schizophrenia. Despite the long-time experience with clozapine, the specific mechanism of action (MOA) responsible for its superior efficacy among antipsychotics is still elusive, both at the receptor and intracellular signaling level. This systematic review is aimed at critically assessing the role and specific relevance of clozapine's multimodal actions, dissecting those mechanisms that under a translational perspective could shed light on molecular targets worth to be considered for further innovative antipsychotic development. In vivo and in vitro preclinical findings, supported by innovative techniques and methods, together with pharmacogenomic and in vivo functional studies, point to multiple and possibly overlapping MOAs. To better explore this crucial issue, the specific affinity for 5-HT₂R, D1R, α_2c, and muscarinic receptors, the relatively low occupancy at dopamine D2R, the interaction with receptor dimers, as well as the potential confounder effects resulting in biased ligand action, and lastly, the role of the moiety responsible for lipophilic and alkaline features of clozapine are highlighted. Finally, the role of transcription and protein changes at the synaptic level, and the possibility that clozapine can directly impact synaptic architecture are addressed. Although clozapine's exact MOAs that contribute to its unique efficacy and some of its severe adverse effects have not been fully understood, relevant information can be gleaned from recent mechanistic understandings that may help design much needed additional therapeutic strategies for TRS.

Effect of quetiapine on inflammation and immunity: a systematic review

INTRODUCTION

Knowledge about the neurobiology of psychiatric disorders is increasing in the last decades and evidence from literature suggests a central role for immuno-inflammatory mechanisms in these illnesses. The antipsychotic quetiapine acts on dopamine and serotonin signalling and well-established evidence demonstrates that these neurotransmitters can modulate immune functions in healthy and diseased conditions. Starting from this perspective, in the last few decades, a number of studies attempted to identify quetiapine effects on immune functions in order to highlight a possible additional effect of this drug in psychotic diseases, although no conclusive results were obtained.

METHODS

We critically reviewed preclinical and clinical studies evaluating quetiapine effects on immune systems, suggesting strategies for future work in this field.

RESULTS

Computerised search, in PubMed and Embase databases, was performed in March 2020: 120 studies were identified but only 29 relevant papers were selected for detailed review.

CONCLUSION

Despite some interesting preliminary findings about anti-inflammatory effects of quetiapine, mainly supported by preclinical studies, it is possible to conclude further studies are needed to investigate the immunomodulatory effects of this drug and achieve a better understanding of its relevance on clinical outcomes to finally identify new therapeutic approaches in psychiatric treatment.KeypointsMounting evidence points to a role for immuno-inflammatory mechanisms in psychiatric disorders.Quetiapine (QUE) acts on catecholamine (dopamine and norepinephrine) and serotonin signalling.The immunomodulatory effects of catecholamines are well established.Treatment with QUE in psychiatric disorders could leverage immunomodulatory effects.QUE unclear role in immune function modulation suggests future work.

Long Acting Injectables and their Correlation with Subjectivity in Schizophrenia Spectrum Disorder

Nowadays, mental illness can no longer be considered as a mere list of symptoms corresponding to localized brain dysfunctions but rather as a disturbance of the patient's subjectivity. Thus, a solid, qualitative study of patients' subjectivity could represent a useful tool in the complex evaluation of efficacy of pharmacotherapy in schizophrenic persons. In this perspective, authors performed a phenomenological oriented investigation on 49 patients, diagnosed with schizophrenia spectrum disorder, who were receiving long-acting injectable (LAI) antipsychotic therapy. From data analysis, authors found a positive correlation between general psychopathology and the use of LAI antipsychotic therapies. The present study highlighted the necessity of a careful investigation of patients' subjectivity in a phenomenological way as an irreducible part of both psychopathological and psychopharmacological matters.

Twenty years of Lithium pharmacogenetics: A systematic review

Lithium is among the best proven treatments for patients diagnosed with Bipolar Disorder, however response to Lithium appears to be considerably variable among individuals and it has been suggested that this inconstancy in Lithium response could be genetically determined. Starting from this perspective, in the last few decades, a number of pharmacogenetic studies have attempted to identify genetic variants, which might be associated with response to Lithium in bipolar patients, in order to develop a pharmacogenetics test to tailor treatment on patients, identifying who will benefit the most from therapy with Lithium. Within this context, authors have critically reviewed pharmacogenetic studies of Lithium response in bipolar disorder, suggesting strategies for future work in this field. Computerized searches of PubMed and Embase databases, for studies published between 1998 and January 2018, was performed: 1162 studies were identified but only 37 relevant papers were selected for detailed review. Despite some interesting preliminary findings, the pharmacogenetics of Lithium and the development of a specific pharmacogenetics test in bipolar disorder appears to be a field still in its infancy, even though the advent of genome-wide association studies holds particular promise for future studies, which should include larger samples.

Resilience and recovery style: a retrospective study on associations among personal resources, symptoms, neurocognition, quality of life and psychosocial functioning in psychotic patients

Background: Personal resources have been identified as important factors in predicting patient healing or symptoms control in schizophrenia. This observational retrospective study aims to explore the influence of resilience and recovery style on the modalities of clinical presentation of the disease, as well as individual functioning and quality of life. Methods: Participants were patients affected by schizophrenia spectrum disorders assessed at different mental health facilities. The rating scales considered are the following: Resilience Scale 10-items (RS); Recovery Style Questionnaire (RSQ); Montreal Cognitive Assessment (MoCA); Schizophrenia Quality of Life Scale (SQLS); Life Skills Profile (LSP); Positive and Negative Syndrome Scale (PANSS). Results: Forty-four patients fulfilled the inclusion criteria. The mean age was 46 years; the average length of the history of the disease at recruitment was 23 years with an average age at first episode of psychosis (FEP) of 23 years. General psychopathology, neurocognition, and integration recovery style can predict psychosocial functioning and explain ~54% of the LSP variance; RS total score and PANSS general psychopathology score can predict and explain ~29% of the LSP variance. A negative association between PANSS general psychopathology and LSP total score supports the need to reduce first the symptomatology, and then successfully apply other types of interventions. A strong positive association between neurocognition and life functioning was detected, showing that deficits in neurocognition have proved to be important predictors of the functional outcome. Integration was also proven to be significantly associated with a good functional outcome. Psychotic symptoms turn out to be a negative predictive factor, whereas resilience can be hypothesized as a protective factor. Conclusions: Resilience and recovery style "integration" can be considered as two complementary predictive resources for a good outcome; this result supports the need to set up personalized treatments, based on the characteristics of the patients.

Pharmacogenetic Testing in Acute and Chronic Pain: A Preliminary Study

Background and Objectives: Pain is one of the most common symptoms that weighs on life’s quality and health expenditure. In a reality where increasingly personalized therapies are needed, the early use of genetic tests that highlights the individual response to analgesic drugs could be a valuable help in clinical practice. The aim of this preliminary study is to observe if the therapy set to 5 patients suffering of chronic or acute pain is concordant to the Pharmacogenetic test (PGT) results. Materials and Methods: This preliminary study compares the genetic results of pharmacological effectiveness and tolerability analyzed by the genetic test Neurofarmagen Analgesia^®, with the results obtained in clinical practice of 5 patients suffering from acute and chronic pain. Results: Regarding the genetic results of the 5 samples analyzed, 2 reports were found to be completely comparable with the evidences of the clinical practice, while in 3 reports the profile of tolerability and effectiveness were partially discordant. Conclusion: In light of the data not completely overlapping with results observed in clinical practice, further studies would be appropriate in order to acquire more information on the use of Neurofarmagen in routine clinical settings.

Pharmacogenetic Tests in Reducing Accesses to Emergency Services and Days of Hospitalization in Bipolar Disorder: A 2-Year Mirror Analysis

Despite the enormous costs associated to mood disorders', few studies evaluate potential cost saving from the use of pharmacogenetic tests (PGT). This study compares 12 months before the execution of the PGT versus 12 months after, in terms of number and days of hospitalization and accesses to emergency services, in a sample of 30 patients affected by bipolar disorder. Secondarily, the study gives an economic value to the data based on the diagnosis-related group (DRG). Patients included in the study were required to be aged ≥18 years, sign an informed consent, have a score of Clinical Global Impression item Severity (CGIs) ≥3, and have a discordant therapy compared to the PGT in the 12 months preceding it and a therapy consistent with it for the following 12 months. Cost saving has been evaluated by paired t-tests in a mirror analysis. Statistically significant differences in all the comparisons (p < 0.0001) emerged. Important cost saving emerged after the use of PGT (€148,920 the first year versus €39,048 the following year). Despite the small sample size and lack of a control group in this study, the potential role of PGT in cost saving for the treatment of bipolar disorder treatment emerged. To confirm this result, larger and clinical trials are needed.

Use of combinatorial pharmacogenomic guidance in treating psychiatric disorders

Aim: To evaluate payer costs associated with treating psychiatric disorders utilizing a combinatorial pharmacogenomics test versus treatment-as-usual (TAU). Patients & methods: Administrative claims data were analyzed from health plan members whose treatment was guided by GeneSight® Psychotropic testing (CPGx® cohort) and those who received TAU (TAU cohort). Reimbursed costs were calculated over the 12-month pre-index and post-index event periods. Results: 205 CPGx and 478 TAU members were included. Post-index cost savings (US$5505) drove a per-member-per-month savings of US$0.07. Disease-specific analyses resulted in similar savings. Conclusion: Use of CPGx yielded reduced spending for a commercial health plan across the patient population with psychiatric disorders, as well as among high-cost subpopulations.

The utility of pharmacogenetic testing to support the treatment of bipolar disorder

Background

Bipolar disorder (BD) is a frequent cause of disability, health care costs, and risk of suicide. Pharmacogenetic tests (PGTs) could help clinicians to identify those patients predisposed to the occurrence of adverse events (AEs) improving the understanding of the correlation between genetic variants and drug response.

Materials and methods

The study evaluated 30 patients affected by BD type I or II (according to Diagnostic and Statistical Manual of Mental Disorders, version 5) who underwent the PGT Neurofarmagen^® (AB-BIOTICS SA, Barcelona, Spain) between March 2016 and March 2017. The primary aim of this study was to identify if the treatment prescribed by the psychiatrists was consistent with the treatment suggested by the PGT at T0 (corresponding to the test report communication). As a secondary aim, we wanted to assess if clinicians had changed the treatment (in case of discordance) at T1 (3-month follow-up visit) according to the results of the PGT.

Results

At T0, only 4 patients (13%) had an optimal therapy in line with the PGT suggestions. At 3-month follow-up, 13 patients (40%) had received a change of therapy consistent to the test, showing a significant statistical improvement in the Clinical Global Impression item Severity (CGI-S) score over time compared to those not having changes consistent with the test. Regarding AEs, at baseline 9 out of 10 (90%) of the patients who received a therapy modification according to the test presented AEs, and a significant within-group reduction was observed after 3 months (p = 0.031).

Conclusion

Despite the small sample size, the study shows promising data about the usefulness of PGT to support clinicians in reaching a more effective and tolerated treatment in the routine approach of BD.

CYP1A2 polymorphism -1545C > T (rs2470890) is associated with increased side effects to clozapine

BACKGROUND

Cytochrome P450 1A2 gene (CYP1A2) polymorphisms have been suggested to be associated with increased side effects to antipsychotics. However, studies on this are scarce and have been conducted with either various antipsychotics or only in small samples of patients receiving clozapine. The aim of the present study was to test for an association between the CYP1A2 -1545C > T (rs2470890) polymorphism and side effects in a larger sample of patients during long-term clozapine treatment.

METHODS

A total of 237 patients receiving clozapine treatment completed the Liverpool University Neuroleptic Side-Effect Rating Scale (LUNSERS) assessing clozapine-induced side effects. Of these patients, 180 completed the questionnaire satisfactorily, agreed to provide a blood sample, and were successfully genotyped for the polymorphism.

RESULTS

The TT genotype of CYP1A2 polymorphism -1545C > T (rs2470890) was associated with significantly more severe side effects during clozapine treatment (p = 0.011). In a subanalysis, all seven types of side effects (sympathicotonia-tension; depression-anxiety; sedation; orthostatic hypotension; dermal side effects; urinary side effects; and sexual side effects) appeared numerically (but insignificantly) more severely among TT carriers. In addition, use of mood stabilizers was more common among patients with the TT genotype (OR = 2.63, p = 0.004).

CONCLUSIONS

This study has identified an association between the CYP1A2 polymorphism -1545C > T (rs2470890) and the occurrence of more severe clozapine side effects. However, these results should be regarded as tentative and more studies of larger sample sizes will be required to confirm the result.

The CYP1A2 -163C>A polymorphism is associated with clozapine-induced generalized tonic-clonic seizures in Brazilian schizophrenia patients

We evaluated two polymorphisms at CYP1A2 (*1C and *1F) in a sample of 108 European-derived patients with schizophrenia and their influence on the pro-convulsive effect of clozapine. We found the *1F/*1F genotype to be significantly associated with seizures, and no relationship was observed with combinations of *1F and *1C alleles.

Association between CYP1A2 polymorphisms and clozapine-induced adverse reactions in patients with schizophrenia

We investigated the relationships between common polymorphisms in CYP1A2 (CYP1A2(⁎)1C and (⁎)1F), CYP1A2-mRNA levels in circulating lymphocytes and clozapine(CLZ)-induced adverse drug reactions (ADRs) in 34 patients. Patients with ADRs had a higher frequency of CYP1A2 low activity allele combinations (8/12; 67%) and lower CYP1A2-mRNA levels than patients without ADRs (6/22; 27%, P=0.019).