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Albitar O, Harun SN, Sheikh Ghadzi SM. Semi-physiological Pharmacokinetic Model of Clozapine and Norclozapine in Healthy, Non-smoking Volunteers: The Impact of Race and Genetics. CNS Drugs 2024; 38:571-581. [PMID: 38836990 DOI: 10.1007/s40263-024-01092-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/17/2024] [Indexed: 06/06/2024]
Abstract
BACKGROUND AND OBJECTIVES: Clozapine is the medication of choice for treatment-resistant schizophrenia. However, it has a complex metabolism and unexplained interindividual variability. The current work aims to develop a pharmacokinetic model of clozapine and norclozapine in non-smokers and assess the impact of demographic and genetic predictors. METHODS Healthy volunteers were recruited in a population pharmacokinetic study. Blood samples were collected at 30 min and 1, 2, 3, 5 and 8 h following a single flat dose of clozapine (12.5 mg). The clozapine and norclozapine concentrations were measured via high-performance liquid chromatography-ultraviolet method. A semi-physiological pharmacokinetic model of clozapine and norclozapine was developed using nonlinear mixed-effects modeling. Clinical and genetic predictors were evaluated, including CYP1A2 (rs762551) and ABCB1 (rs2032582), using restriction fragment length polymorphism. RESULTS A total of 270 samples were collected from 33 participants. The data were best described using a two-compartment model for clozapine and a two-compartment model for norclozapine with first-order absorption and elimination and pre-systemic metabolism. The estimated (relative standard error) clearance of clozapine and norclozapine were 27 L h-1 (31.5 %) and 19.6 L h-1 (30%), respectively. Clozapine clearance was lower in sub-Saharan Africans (n = 4) and higher in Caucasians (n = 9) than Asians (n = 20). Participants with CYP1A2 (rs762551) (n = 18) and ABCB1 (rs2032582) (n = 12) mutant alleles had lower clozapine clearance in the univariate analysis. CONCLUSIONS This is the first study to develop a semi-physiological pharmacokinetic model of clozapine and norclozapine accounting for the pre-systemic metabolism. Asians required lower doses of clozapine as compared with Caucasians, while clozapine pharmacokinetics in sub-Saharan Africans should be further investigated in larger trials.
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Affiliation(s)
- Orwa Albitar
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, USM, 11800, Gelugor, Penang, Malaysia
- Roche Pharma Research and Early Development, Basel, Switzerland
| | - Sabariah Noor Harun
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, USM, 11800, Gelugor, Penang, Malaysia
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Hart XM, Gründer G, Ansermot N, Conca A, Corruble E, Crettol S, Cumming P, Hefner G, Frajerman A, Howes O, Jukic M, Kim E, Kim S, Manisalco I, Moriguchi S, Müller DJ, Nakajima S, Osugo M, Paulzen M, Ruhe HG, Scherf-Clavel M, Schoretsanitis G, Serretti A, Spina E, Spigset O, Steimer W, Süzen HS, Uchida H, Unterecker S, Vandenberghe F, Verstuyft C, Zernig G, Hiemke C, Eap CB. Optimisation of pharmacotherapy in psychiatry through therapeutic drug monitoring, molecular brain imaging and pharmacogenetic tests: focus on antipsychotics. World J Biol Psychiatry 2024:1-123. [PMID: 38913780 DOI: 10.1080/15622975.2024.2366235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 06/06/2024] [Indexed: 06/26/2024]
Abstract
BACKGROUND For psychotic disorders (i.e. schizophrenia), pharmacotherapy plays a key role in controlling acute and long-term symptoms. To find the optimal individual dose and dosage strategy, specialized tools are used. Three tools have been proven useful to personalize drug treatments: therapeutic drug monitoring (TDM) of drug levels, pharmacogenetic testing (PG), and molecular neuroimaging. METHODS In these Guidelines, we provide an in-depth review of pharmacokinetics, pharmacodynamics, and pharmacogenetics for 50 antipsychotics. Over 30 international experts in psychiatry selected studies that have measured drug concentrations in the blood (TDM), gene polymorphisms of enzymes involved in drug metabolism, or receptor/transporter occupancies in the brain (positron emission tomography (PET)). RESULTS Study results strongly support the use of TDM and the cytochrome P450 (CYP) genotyping and/or phenotyping to guide drug therapies. Evidence-based target ranges are available for titrating drug doses that are often supported by PET findings. CONCLUSION All three tools discussed in these Guidelines are essential for drug treatment. TDM goes well beyond typical indications such as unclear compliance and polypharmacy. Despite its enormous potential to optimize treatment effects, minimize side effects and ultimately reduce the global burden of diseases, personalized drug treatment has not yet become the standard of care in psychiatry.
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Affiliation(s)
- X M Hart
- Central Institute of Mental Health, Department of Molecular Neuroimaging, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - G Gründer
- Central Institute of Mental Health, Department of Molecular Neuroimaging, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
- German Center for Mental Health (DZPG), partner site Mannheim - Heidelberg - Ulm
| | - N Ansermot
- Unit of Pharmacogenetics and Clinical Psychopharmacology, Center for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital, Prilly, Switzerland
| | - A Conca
- Dipartimento di Psichiatria, Comprensorio Sanitario di Bolzano, Bolzano, Italy
| | - E Corruble
- Université Paris-Saclay, AP-HP, Service Hospitalo-Universitaire de Psychiatrie, Hôpital de Bicêtre
- Equipe MOODS, Inserm U1018, CESP (Centre de Recherche en Epidémiologie et Sante des Populations), Le Kremlin-Bicêtre, France
| | - S Crettol
- Unit of Pharmacogenetics and Clinical Psychopharmacology, Centre for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital and University of Lausanne, Prilly, Switzerland
| | - P Cumming
- Department of Nuclear Medicine, Bern University Hospital, Bern, Switzerland
- School of Psychology and Counseling, Queensland University of Technology, Brisbane, Australia
| | - G Hefner
- Vitos Clinic for Forensic Psychiatry, Forensic Psychiatry, Eltville, Germany
| | - A Frajerman
- Université Paris-Saclay, AP-HP, Service Hospitalo-Universitaire de Psychiatrie, Hôpital de Bicêtre
- Equipe MOODS, Inserm U1018, CESP (Centre de Recherche en Epidémiologie et Sante des Populations), Le Kremlin-Bicêtre, France
| | - O Howes
- Department of Psychosis Studies, IoPPN, King's College London, De Crespigny Park, London, SE5 8AF, UK
- Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - M Jukic
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia and Pharmacogenetics Section, Department of Physiology and Pharmacology, Karolinska Institutet, Solna, Sweden
| | - E Kim
- Department of Psychiatry, Seoul National University College of Medicine, Republic of Korea
| | - S Kim
- Department of Neuropsychiatry, Seoul National University Bundang Hospital, Republic of Korea
| | - I Manisalco
- Dipartimento di Psichiatria, Comprensorio Sanitario di Bolzano, Bolzano, Italy
| | - S Moriguchi
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - D J Müller
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Würzburg, Würzburg, Germany
- Pharmacogenetics Research Clinic, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada, and Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - S Nakajima
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - M Osugo
- Department of Psychosis Studies, IoPPN, King's College London, De Crespigny Park, London, SE5 8AF, UK
- Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - M Paulzen
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University
- JARA - Translational Brain Medicine, Aachen, Germany; Alexianer Center for Mental Health, Aachen, Germany
| | - H G Ruhe
- Department of psychiatry, Radboudumc, Nijmegen, Netherlands; Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, Netherlands
| | - M Scherf-Clavel
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Würzburg, Würzburg, Germany
| | - G Schoretsanitis
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, 8032 Zurich, Switzerland
| | - A Serretti
- Department of Medicine and Surgery, Kore University of Enna, Italy
| | - E Spina
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - O Spigset
- Department of Clinical Pharmacology, St. Olav University Hospital, Trondheim, Norway, and Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - W Steimer
- Institute of Clinical Chemistry and Pathobiochemistry, Technical University Munich, Munich, Germany
| | - H S Süzen
- Department of Pharmaceutic Toxicology, Faculty of Pharmacy, Ankara University, Ankara, Turkey
| | - H Uchida
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - S Unterecker
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Würzburg, Würzburg, Germany
| | - F Vandenberghe
- Unit of Pharmacogenetics and Clinical Psychopharmacology, Centre for Psychiatric Neuroscience, Department of Psychiatry, Lausanne University Hospital, Prilly, Switzerland
| | - C Verstuyft
- Department of Molecular Genetics, Pharmacogenetics and Hormonology Bicêtre University Hospital Paris-Saclay, Assistance Publique-Hôpitaux de Paris, Le Kremlin Bicêtre, F-94275, France
- CESP, MOODS Team, INSERM UMR 1018, Medicine Faculty, Paris-Saclay University, Le Kremlin Bicêtre, France
| | - G Zernig
- Department of Pharmacology, Medical University Innsbruck; Private Practice for Psychotherapy and Court-Certified Witness, Hall in Tirol, Austria
| | - C Hiemke
- Department of Psychiatry and Psychotherapy and Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center of Mainz, Germany
| | - C B Eap
- Unit of Pharmacogenetics and Clinical Psychopharmacology, Department of Psychiatry, Centre for Psychiatric Neuroscience, Lausanne University Hospital, University of Lausanne, 1008 Prilly, Switzerland
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland
- Center for Research and Innovation in Clinical Pharmaceutical Sciences, University of Lausanne, Lausanne, Switzerland
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, University of Lausanne, Lausanne, Switzerland
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Panić B, Jovanović M, Lukić V, Vučićević K, Miljković B, Milovanović S. Association of clozapine and norclozapine levels with patient and therapy characteristics-focus on interaction with valproic acid. Eur J Clin Pharmacol 2023; 79:1557-1564. [PMID: 37733278 DOI: 10.1007/s00228-023-03569-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 09/15/2023] [Indexed: 09/22/2023]
Abstract
PURPOSE The goal of the study was to examine clozapine (CLZ) and norclozapine (NCLZ) therapeutic drug monitoring (TDM) data and associated sources of pharmacokinetic variability, particularly the impact of valproic acid (VPA) use. METHODS This study included 126 patients with psychiatric disorders on mono- or co-therapy with CLZ. Patients' data during routine TDM were collected retrospectively from clinical records. The descriptive and statistical analysis was computed using IBM SPSS Statistics software (version 22, NY, USA). Multiple linear regression, based on the last observations, was used to assess correlation between demographic characteristics, life habits and co-therapy with dose-corrected serum levels (C/D) of CLZ and NCLZ, as well as CLZ/NCLZ. RESULTS A total of 295 CLZ concentrations were measured in 126 patients, with a mean of 275.5 ± 174.4 µg/L, while 124 NCLZ concentrations were determined in 74 patients, with a mean of 194.6 ± 149.8 µg/L. A statistically significant effect on ln-transformed CLZ C/D was confirmed for sex and smoking, whereas sex, smoking and VPA therapy were associated with ln-transformed NCLZ C/D. According to the final models, lower values of NCLZ C/D for about 45.9% can be expected in patients receiving VPA. Concomitant use of VPA was the only factor detected to contribute in CLZ/NCLZ variability. CONCLUSION The results of this study may help clinicians interpret TDM data and optimize CLZ dosing regimens, especially in patients concomitantly treated with VPA. Our results show that VPA primarily decreases NCLZ levels, while alteration of the parent drug is not statistically significant.
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Affiliation(s)
- Bojana Panić
- Department of Pharmacokinetics and Clinical Pharmacy, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221, Belgrade, Serbia
| | - Marija Jovanović
- Department of Pharmacokinetics and Clinical Pharmacy, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221, Belgrade, Serbia.
| | - Vera Lukić
- Institute of Forensic Medicine "Milovan Milovanović", Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Katarina Vučićević
- Department of Pharmacokinetics and Clinical Pharmacy, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221, Belgrade, Serbia
| | - Branislava Miljković
- Department of Pharmacokinetics and Clinical Pharmacy, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11221, Belgrade, Serbia
| | - Srđan Milovanović
- Faculty of Medicine, University of Belgrade, Belgrade, Serbia
- Clinic for Psychiatry, University Clinical Center of Serbia, Belgrade, Serbia
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Genetic determinants associated with response to clozapine in schizophrenia: an umbrella review. Psychiatr Genet 2022; 32:163-170. [PMID: 35855515 DOI: 10.1097/ypg.0000000000000320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Clozapine response varies widely from person to person, which may be due to inter-individual genetic variability. This umbrella review aims to summarize the current evidence on associations between pharmacodynamic genes and response to clozapine treatment. METHODS Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis methodology, a systematic literature search was conducted in the PubMed and EMBASE databases from inception to November 2021 to identify systematic reviews and meta-analyses of studies that examined genetic determinants of clozapine response. The quality of the reviews was assessed with the AMSTAR-2 tool. RESULTS From a total of 128 records, 10 studies representing nine systematic reviews and one meta-analysis met our inclusion criteria. The overall quality of the included studies was poor. All systematic reviews concluded that the results of primary studies were largely negative or conflicting. Most evidence was found for an association with clozapine response and rs6313 and rs6314 within HTR2A and rs1062613 within HTR3A in the serotonergic system. CONCLUSIONS Conclusive evidence for associations between genetic variants and clozapine response is still lacking. Hypothesis-generating genetic studies in large, well-characterized study populations are urgently needed to obtain more consistent and clinically informative results. Future studies may also include multi-omics approaches to identify novel genetic determinants associated with clozapine response.
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Pandey A, Kalita KN. Treatment-resistant schizophrenia: How far have we traveled? Front Psychiatry 2022; 13:994425. [PMID: 36111312 PMCID: PMC9468267 DOI: 10.3389/fpsyt.2022.994425] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
Treatment-resistant schizophrenia is a lack of adequate response to antipsychotic medications resulting in incomplete functional and social recovery from the illness. Different definitions have been proposed for clinical practice and research work. Antipsychotics that are used in the management of schizophrenia mainly act on multiple dopaminergic pathways which are implicated in the development of symptoms of schizophrenia. Newer antipsychotics also are implicated to affect the serotonergic pathways. Clozapine is the only evidence-based treatment available for the management of treatment-resistant cases. Neurobiologically, there is a considerable overlap between treatment-resistant and treatment-responsive cases. The factors that are implicated in the evolution of treatment resistance are still not conclusive. These make the management of such patients a challenge. However, certain peculiarities of treatment-resistant schizophrenia have been identified which can guide us in the early identification and precise treatment of the treatment-resistant cases.
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Affiliation(s)
- Ambu Pandey
- Department of Psychiatry, Maharshi Devraha Baba Autonomous State Medical College, Deoria, India
| | - Kamal Narayan Kalita
- Department of Psychiatry, Lokpriya Gopinath Bordoloi Regional Institute of Mental Health, Tezpur, India
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Review: Influence of the CYP450 Genetic Variation on the Treatment of Psychotic Disorders. J Clin Med 2021; 10:jcm10184275. [PMID: 34575384 PMCID: PMC8464829 DOI: 10.3390/jcm10184275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/11/2021] [Accepted: 09/15/2021] [Indexed: 12/12/2022] Open
Abstract
Second-generation antipsychotic metabolism is mainly carried out by the CYP450 superfamily, which is highly polymorphic. Therefore, knowing the influence of the different known CYP450 polymorphisms on antipsychotic plasmatic levels and, consequently, the biological effect could contribute to a deeper knowledge of interindividual antipsychotic treatment variability, prompting possible solutions. Considering this, this state of the art review aimed to summarize the current knowledge about the influence of the diverse characterized phenotypes on the metabolism of the most used second-generation antipsychotics. Forty studies describing different single nucleotide polymorphisms (SNPs) associated with the genes CYP1A2, CYP2D6, CYP3A4, CYP3A5, and ABCB1 and their influence on pharmacokinetics of olanzapine, clozapine, aripiprazole, risperidone, and quetiapine. Most of the authors concluded that although significant differences in the pharmacokinetic parameters between the different phenotypes could be observed, more thorough studies describing pharmacokinetic interactions and environmental conditions, among other variables, are needed to fully comprehend these pharmacogenetic interactions.
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John AP, Kecanovic A. Unusually high serum levels of clozapine associated with genetic polymorphism of CYP3A enzymes. Asian J Psychiatr 2021; 57:102126. [PMID: 32386926 DOI: 10.1016/j.ajp.2020.102126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/17/2020] [Accepted: 04/18/2020] [Indexed: 12/01/2022]
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Whiskey E, Romano G, Elliott M, Campbell M, Anandarajah C, Taylor D, Valsraj K. Possible pharmacogenetic factors in clozapine treatment failure: a case report. Ther Adv Psychopharmacol 2021; 11:20451253211030844. [PMID: 35211290 PMCID: PMC8862186 DOI: 10.1177/20451253211030844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/18/2021] [Indexed: 01/19/2023] Open
Abstract
There is still much to learn about the predictors of therapeutic response in psychiatry, but progress is gradually being made and precision psychiatry is an exciting and emerging subspeciality in this field. This is critically important in the treatment of refractory psychotic disorders, where clozapine is the only evidence-based treatment but only about half the patients experience an adequate response. In this case report, we explore the possible biological mechanisms underlying treatment failure and discuss possible ways of improving clinical outcomes. Further work is required to fully understand why some patients fail to respond to the most effective treatment in refractory schizophrenia. Therapeutic drug monitoring together with early pharmacogenetic testing may offer a path for some patients with refractory psychotic symptoms unresponsive to clozapine treatment.
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Affiliation(s)
- Eromona Whiskey
- Pharmacy Department, South London and Maudsley NHS Foundation Trust, Denmark Hill, London, SE5 8AZ, UK
| | | | | | | | | | - David Taylor
- Pharmacy Department, South London and Maudsley NHS Foundation Trust, London, UK
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Carvalho Henriques B, Yang EH, Lapetina D, Carr MS, Yavorskyy V, Hague J, Aitchison KJ. How Can Drug Metabolism and Transporter Genetics Inform Psychotropic Prescribing? Front Genet 2020; 11:491895. [PMID: 33363564 PMCID: PMC7753050 DOI: 10.3389/fgene.2020.491895] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 09/25/2020] [Indexed: 12/11/2022] Open
Abstract
Many genetic variants in drug metabolizing enzymes and transporters have been shown to be relevant for treating psychiatric disorders. Associations are strong enough to feature on drug labels and for prescribing guidelines based on such data. A range of commercial tests are available; however, there is variability in included genetic variants, methodology, and interpretation. We herein provide relevant background for understanding clinical associations with specific variants, other factors that are relevant to consider when interpreting such data (such as age, gender, drug-drug interactions), and summarize the data relevant to clinical utility of pharmacogenetic testing in psychiatry and the available prescribing guidelines. We also highlight areas for future research focus in this field.
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Affiliation(s)
| | - Esther H. Yang
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
| | - Diego Lapetina
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
| | - Michael S. Carr
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Vasyl Yavorskyy
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Joshua Hague
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
| | - Katherine J. Aitchison
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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Smith RL, O'Connell K, Athanasiu L, Djurovic S, Kringen MK, Andreassen OA, Molden E. Identification of a novel polymorphism associated with reduced clozapine concentration in schizophrenia patients-a genome-wide association study adjusting for smoking habits. Transl Psychiatry 2020; 10:198. [PMID: 32555152 PMCID: PMC7303159 DOI: 10.1038/s41398-020-00888-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 06/09/2020] [Accepted: 06/09/2020] [Indexed: 11/28/2022] Open
Abstract
Clozapine (CLZ) is the superior antipsychotic drug for treatment of schizophrenia, but exhibits an extensive interpatient pharmacokinetic variability. Here, we conducted a genome-wide association study (GWAS) of CLZ serum concentration adjusting for known smoking habits, which is a major nongenetic factor reducing CLZ levels. The study included 484 patients with 10,283 steady-state serum concentrations of CLZ and N-desmethylclozapine, prescribed dosing, co-medications and known smoking habits (n = 422; 9284 serum samples) from a therapeutic drug monitoring (TDM) service. The GWAS analyses were performed with and without smoking habits as covariate, where possible hits were assessed in relation to the target CLZ concentration range applied in the TDM service (300-2500 nmol/L). The smoking-independent analysis of N-desmethylclozapine serum concentration and the CLZ-to-N-desmethylclozapine ratio replicated the previously identified locus on chromosome 4. After adjusting for smoking habits in patients confirmed as 'smokers' (61%) or 'nonsmokers' (39%), a novel variant (rs28379954; minor T>C allele frequency 4.1%; 7.6% CT carriers in the population) within the gene encoding the nuclear factor 1 B-type (NFIB) was significantly associated with reduced CLZ serum concentration (p = 1.68 × 10-8, beta = -0.376; explained variance 7.63%). There was no significant association between rs28379954 and N-desmethylclozapine concentration in the GWAS analysis (p = 5.63 × 10-5). The fraction of CLZ TDM samples below 300 nmol/L was significantly higher in carriers vs. noncarriers of the rs28379954 minor C allele [12.0% (95% CI: 9.4-14.7) vs. 6.2% (95% CI: 5.7-6.8), p < 0.001]. We identified a novel variant in the NFIB gene associated with reduced CLZ levels and increased risk of subtherapeutic serum concentrations. This warrants testing of clinical relevance of screening for this gene variant, and also experimental studies to investigate the biological mechanisms of NFIB involvement in CLZ pharmacokinetics.
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Affiliation(s)
| | - Kevin O'Connell
- CoE NORMENT, Division of Mental Health and Addiction, Oslo University Hospital, and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Lavinia Athanasiu
- CoE NORMENT, Division of Mental Health and Addiction, Oslo University Hospital, and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Srdjan Djurovic
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
- NORMENT, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Marianne Kristiansen Kringen
- Center for Psychopharmacology, Diakonhjemmet Hospital, Oslo, Norway
- Department of Life Sciences and Health, Oslo Metropolitan University, Oslo, Norway
| | - Ole A Andreassen
- CoE NORMENT, Division of Mental Health and Addiction, Oslo University Hospital, and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Espen Molden
- Center for Psychopharmacology, Diakonhjemmet Hospital, Oslo, Norway.
- Department of Pharmacy, Section for Pharmacology and Pharmaceutical Biosciences, University of Oslo, Oslo, Norway.
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Jovanović M, Vučićević K, Miljković B. Understanding variability in the pharmacokinetics of atypical antipsychotics - focus on clozapine, olanzapine and aripiprazole population models. Drug Metab Rev 2020; 52:1-18. [PMID: 32008418 DOI: 10.1080/03602532.2020.1717517] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Antipsychotic medicines are widely used for the management of psychotic symptoms regardless of the underlying diagnosis. Most atypical antipsychotics undergo extensive metabolism prior to excretion. Various factors may influence their pharmacokinetics, particularly elimination, leading to highly variable drug concentrations between individual patients following the same dosing regimen. Population pharmacokinetic approach, based on nonlinear mixed effects modeling, is a useful tool to identify covariates explaining pharmacokinetic variability, as well as to characterize and distinguish unexplained residual and between-subject (interindividual) variability. In addition, this approach allows the use of both sparsely and intensively sampled data. In this paper, we reviewed the pharmacokinetic characteristics of clozapine, olanzapine and aripiprazole, focusing on a population modeling approach. In particular, models based on a nonlinear mixed effects approach performed by NONMEM® software in order to identify and quantify sources of pharmacokinetic variability are presented. Population models were identified through systematic searches of PubMed and sixteen studies were selected. Some of the factors identified that significantly contribute to variability in elimination among clozapine, olanzapine, and aripiprazole are demographic characteristics, body weight, genetic polymorphism, smoking and in some cases drug interactions. Scientific research based on pharmacometric modeling is useful to further characterize sources of variability and their combined effect.
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Affiliation(s)
- Marija Jovanović
- Department of Pharmacokinetics and Clinical Pharmacy, University of Belgrade - Faculty of Pharmacy, Belgrade, Republic of Serbia
| | - Katarina Vučićević
- Department of Pharmacokinetics and Clinical Pharmacy, University of Belgrade - Faculty of Pharmacy, Belgrade, Republic of Serbia
| | - Branislava Miljković
- Department of Pharmacokinetics and Clinical Pharmacy, University of Belgrade - Faculty of Pharmacy, Belgrade, Republic of Serbia
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Population Pharmacokinetics of Clozapine: A Systematic Review. BIOMED RESEARCH INTERNATIONAL 2020; 2020:9872936. [PMID: 31998804 PMCID: PMC6970501 DOI: 10.1155/2020/9872936] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/10/2019] [Accepted: 12/19/2019] [Indexed: 12/19/2022]
Abstract
Background and Objective Clozapine is a second-generation antipsychotic drug that is considered the most effective treatment for refractory schizophrenia. Several clozapine population pharmacokinetic models have been introduced in the last decades. Thus, a systematic review was performed (i) to compare published pharmacokinetics models and (ii) to summarize and explore identified covariates influencing the clozapine pharmacokinetics models. Methods A search of publications for population pharmacokinetic analyses of clozapine either in healthy volunteers or patients from inception to April 2019 was conducted in PubMed and SCOPUS databases. Reviews, methodology articles, in vitro and animal studies, and noncompartmental analysis were excluded. Results Twelve studies were included in this review. Clozapine pharmacokinetics was described as one-compartment with first-order absorption and elimination in most of the studies. Significant interindividual variations of clozapine pharmacokinetic parameters were found in most of the included studies. Age, sex, smoking status, and cytochrome P450 1A2 were found to be the most common identified covariates affecting these parameters. External validation was only performed in one study to determine the predictive performance of the models. Conclusions Large pharmacokinetic variability remains despite the inclusion of several covariates. This can be improved by including other potential factors such as genetic polymorphisms, metabolic factors, and significant drug-drug interactions in a well-designed population pharmacokinetic model in the future, taking into account the incorporation of larger sample size and more stringent sampling strategy. External validation should also be performed to the previously published models to compare their predictive performances.
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Rodrigues-Silva C, Semedo AT, Neri HFDS, Vianello RP, Galaviz-Hernández C, Sosa-Macías M, de Brito RB, Ghedini PC. The CYP2C19*2 and CYP2C19*17 Polymorphisms Influence Responses to Clozapine for the Treatment of Schizophrenia. Neuropsychiatr Dis Treat 2020; 16:427-432. [PMID: 32103962 PMCID: PMC7023876 DOI: 10.2147/ndt.s228103] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 12/21/2019] [Indexed: 02/03/2023] Open
Abstract
INTRODUCTION Clozapine (CLZ) is the gold standard drug for treatment-refractory schizophrenia (TRS). However, approximately 30% of patients partially respond to CLZ, defining this subset with super refractory schizophrenia (SRS). Alterations in enzyme activity may affect CLZ responses; the CYP3A4, CYP1A2 and CYP2C19 genes are primarily responsible for CLZ metabolism. OBJECTIVE The aim of this study was to assess if CYP2C19 variants were associated with TRS or SRS. METHODS CYP2C19*2 loss-of-function and CYP2C19*17 gain-of-function polymorphism genotype testing were performed in 108 individuals undergoing pharmacological treatment for TRS or SRS. DNA was extracted and polymorphisms were analyzed by polymerase chain reaction (PCR) and sequencing. RESULTS CYP2C19*17 had positive correlations with SRS and lower Brief Psychiatric Rating Scale (BPRS) scores for TRS. In addition, CYP2C19*2 was associated with lower CLZ dosages for TRS. CONCLUSION These results show that CYP2C19*2 and CYP2C19*17 polymorphisms influence CLZ responses during schizophrenia treatment.
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Affiliation(s)
- Christielly Rodrigues-Silva
- Department of Pharmacology, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | - Agostinho Tavares Semedo
- Department of Pharmacology, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
| | | | | | | | - Martha Sosa-Macías
- Instituto Politécnico Nacional, Academia de Genómica, CIIDIR-Durango, Durango, México
| | - Rodrigo Bernini de Brito
- Department of Pharmacology, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil.,Brain Institute Medical Clinic, Bueno Medical Center Building, Goiânia, GO, Brazil
| | - Paulo César Ghedini
- Department of Pharmacology, Institute of Biological Sciences, Federal University of Goiás, Goiânia, GO, Brazil
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Pardiñas AF, Nalmpanti M, Pocklington AJ, Legge SE, Medway C, King A, Jansen J, Helthuis M, Zammit S, MacCabe J, Owen MJ, O'Donovan MC, Walters JTR. Pharmacogenomic Variants and Drug Interactions Identified Through the Genetic Analysis of Clozapine Metabolism. Am J Psychiatry 2019; 176:477-486. [PMID: 30922102 DOI: 10.1176/appi.ajp.2019.18050589] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Clozapine is the only effective medication for treatment-resistant schizophrenia, but its worldwide use is still limited because of its complex titration protocols. While the discovery of pharmacogenomic variants of clozapine metabolism may improve clinical management, no robust findings have yet been reported. This study is the first to adopt the framework of genome-wide association studies (GWASs) to discover genetic markers of clozapine plasma concentrations in a large sample of patients with treatment-resistant schizophrenia. METHODS The authors used mixed-model regression to combine data from multiple assays of clozapine metabolite plasma concentrations from a clozapine monitoring service and carried out a genome-wide analysis of clozapine, norclozapine, and their ratio on 10,353 assays from 2,989 individuals. These analyses were adjusted for demographic factors known to influence clozapine metabolism, although it was not possible to adjust for all potential mediators given the available data. GWAS results were used to pinpoint specific enzymes and metabolic pathways and compounds that might interact with clozapine pharmacokinetics. RESULTS The authors identified four distinct genome-wide significant loci that harbor common variants affecting the metabolism of clozapine or its metabolites. Detailed examination pointed to coding and regulatory variants at several CYP* and UGT* genes as well as corroborative evidence for interactions between the metabolism of clozapine, coffee, and tobacco. Individual effects of single single-nucleotide polymorphisms (SNPs) fine-mapped from these loci were large, such as the minor allele of rs2472297, which was associated with a reduction in clozapine concentrations roughly equivalent to a decrease of 50 mg/day in clozapine dosage. On their own, these single SNPs explained from 1.15% to 9.48% of the variance in the plasma concentration data. CONCLUSIONS Common genetic variants with large effects on clozapine metabolism exist and can be found via genome-wide approaches. Their identification opens the way for clinical studies assessing the use of pharmacogenomics in the clinical management of patients with treatment-resistant schizophrenia.
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Affiliation(s)
- Antonio F Pardiñas
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
| | - Mariana Nalmpanti
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
| | - Andrew J Pocklington
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
| | - Sophie E Legge
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
| | - Christopher Medway
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
| | - Adrian King
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
| | - John Jansen
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
| | - Marinka Helthuis
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
| | - Stanley Zammit
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
| | - James MacCabe
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
| | - Michael J Owen
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
| | - Michael C O'Donovan
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
| | - James T R Walters
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, Wales (Pardiñas, Nalmpanti, Pocklington, Legge, Medway, Zammit, Owen, O'Donovan, Walters); Magna Laboratories, Ross-on-Wye, U.K. (King); Leyden Delta, Nijmegen, the Netherlands (Jansen, Helthuis); the Centre for Academic Mental Health, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, U.K. (Zammit); the National Institute for Health Research, Biomedical Research Centre, University of Bristol, Bristol, U.K. (Zammit); and the Department of Psychosis Studies, Institute of Psychiatry, Psychology, and Neuroscience, King's College London (MacCabe)
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Legge SE, Walters JT. Genetics of clozapine-associated neutropenia: recent advances, challenges and future perspective. Pharmacogenomics 2019; 20:279-290. [PMID: 30767710 PMCID: PMC6563116 DOI: 10.2217/pgs-2018-0188] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Clozapine is the only effective antipsychotic for treatment-resistant schizophrenia but remains widely under prescribed, at least in part due to its potential to cause agranulocytosis and neutropenia. In this article, we provide an overview of the current understanding of the genetics of clozapine-associated agranulocytosis and neutropenia. We now know that the genetic etiology of clozapine-associated neutropenia is complex and is likely to involve variants from several genes including HLA-DQB1, HLA-B and SLCO1B3/SLCO1B7. We describe recent findings relating to the Duffy-null genotype and its association with benign neutropenia in individuals with African ancestry. Further advances will come from sequencing studies, large, cross-population studies and in understanding the molecular mechanisms underlying these associations.
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Affiliation(s)
- Sophie E Legge
- MRC Centre for Neuropsychiatric Genetics & Genomics, Division of Psychological Medicine & Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
| | - James Tr Walters
- MRC Centre for Neuropsychiatric Genetics & Genomics, Division of Psychological Medicine & Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, CF24 4HQ, UK
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Na Takuathung M, Hanprasertpong N, Teekachunhatean S, Koonrungsesomboon N. Impact of CYP1A2 genetic polymorphisms on pharmacokinetics of antipsychotic drugs: a systematic review and meta-analysis. Acta Psychiatr Scand 2019; 139:15-25. [PMID: 30112761 DOI: 10.1111/acps.12947] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/16/2018] [Indexed: 12/23/2022]
Abstract
OBJECTIVE To determine the impact of CYP1A2 genetic polymorphisms on the pharmacokinetics of CYP1A2-metabolized antipsychotic drugs in humans by means of systematic review and meta-analysis. METHOD A systematic search was conducted in PubMed and Scopus databases as of June 26, 2018. Studies reporting the pharmacokinetic parameters of CYP1A2-metabolized antipsychotic drugs in individuals who were genotyped for CYP1A2 genetic polymorphisms were retrieved. Pharmacokinetic parameters of individuals who have mutant alleles of a CYP1A2 genetic polymorphism were compared with the wild-type individuals. Pooled-effect estimates, presented as standardized mean difference, were calculated by means of the fixed-effect or random-effects model, as appropriate. RESULTS Ten studies involving 872 clozapine users, seven studies involving 712 olanzapine users, and two studies involving 141 haloperidol users were included. All but one study reported no associations between any CYP1A2 genetic polymorphisms and the pharmacokinetics of CYP1A2-metabolized antipsychotic drugs. The pooled-effect estimates through meta-analyses of seven studies demonstrated no significant associations between the -163C>A or -2467delT polymorphism and clozapine or olanzapine concentrations in the blood. CONCLUSIONS This study suggests that CYP1A2 genetic polymorphisms have no significant impact on the pharmacokinetics of CYP1A2-metabolized antipsychotic drugs. CYP1A2 genotyping may have no clinical implications for personalized dosing of CYP1A2-metabolized antipsychotic drugs.
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Affiliation(s)
- M Na Takuathung
- Department of Pharmacology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - N Hanprasertpong
- Department of Pharmacology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - S Teekachunhatean
- Department of Pharmacology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.,Center of Thai Traditional and Complementary Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - N Koonrungsesomboon
- Department of Pharmacology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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Abstract
PURPOSE OF REVIEW To examine recent literature regarding the pharmacogenomics of clozapine (CLZ) efficacy, pharmacokinetics, and agranulocytosis. RECENT FINDINGS Several genetic loci (FKBP5, NR3C1, BDNF, NTRK2) along the hypothalamic pituitary adrenal axis have been investigated as targets for CLZ response. Homozygous FKBP5-rs1360780, homozygous NTRK2-rs1778929, and homozygous NTRK2-rs10465180 conferred significant risks for CLZ nonresponse - 2.11x risk [95% confidence interval (CI) 1.22-3.64], 1.7x risk (95% CI 1.13-2.59), and 2.15x risk (95% CI 1.3-3.55), respectively. BDNF and NR3C1 had no significant associations with CLZ response. Candidate genes within neurotransmitter pathways continue to be explored including dopaminergic (DRD1-4, COMT) and glutamatergic pathways (GRIN2B, SLC1A2, SLC6A9, GRIA1, GAD1). Despite promising trending data, no significant associations between CLZ response and glutamatergic system variants have been found. Synergistic effect of catecholamine O-methyltransferase (COMT) Met and dopamine receptor-4 (DRD4) single 120 bp duplicate associated with improved CLZ response odds ratio (OR) 0.15 (95% CI 0.03-0.62) while COMT Val/Val confer a risk of CLZ nonresponse OR 4.34 (95% CI 0.98-23.9). Diagnostic performance testing continues through human leukocyte antigen (HLA) and other genetic loci but have yet to find statistically or clinically meaningful results. SUMMARY Current landscape of pharmacogenomic research in CLZ continues to be limited by small sample sizes and low power. However, many promising candidate genes have been discovered and should be further investigated with larger cohorts.
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Abstract
Schizophrenia is a devastating illness that affects up to 1% of the population; it is characterized by a combination of positive symptoms, negative symptoms, and cognitive impairment. Currently, treatment consists of one class of medications known as antipsychotics, which include typical (first-generation) and atypical (second-generation) agents. Unfortunately, antipsychotic medications have limited efficacy, with up to a third of patients lacking a full response. Clozapine, the first atypical antipsychotic developed, is the only medication shown to be superior to all other antipsychotics. However, owing to several life-threatening side effects and required enrollment in a registry with routine blood monitoring, clozapine is greatly underutilized in the US. Developing a medication as efficacious as clozapine with limited side effects would likely become the first-line therapy for schizophrenia and related disorders. In this review, we discuss the history of clozapine, landmark studies, and its clinical advantages and disadvantages. We further discuss the hypotheses for clozapine's superior efficacy based on neuroreceptor binding, and the limitations of a receptor-based approach to antipsychotic development. We highlight some of the advances from pharmacogenetic studies on clozapine and then focus on studies of clozapine using unbiased approaches such as pharmacogenomics and gene expression profiling. Finally, we examine how these approaches could provide insights into clozapine's mechanism of action and side-effect profile, and lead to novel and improved therapeutics.
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Affiliation(s)
- Frederick C Nucifora
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | | | - Brian J Lee
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Akira Sawa
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Trans-generation enrichment of clozapine-responsiveness trait in mice using a subchronic hypo-glutamatergic model of schizophrenia:A preliminary study. Behav Brain Res 2017; 323:141-145. [DOI: 10.1016/j.bbr.2017.01.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 01/25/2017] [Accepted: 01/27/2017] [Indexed: 11/19/2022]
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Lally J, Gaughran F, Timms P, Curran SR. Treatment-resistant schizophrenia: current insights on the pharmacogenomics of antipsychotics. Pharmgenomics Pers Med 2016; 9:117-129. [PMID: 27853387 PMCID: PMC5106233 DOI: 10.2147/pgpm.s115741] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Up to 30% of people with schizophrenia do not respond to two (or more) trials of dopaminergic antipsychotics. They are said to have treatment-resistant schizophrenia (TRS). Clozapine is still the only effective treatment for TRS, although it is underused in clinical practice. Initial use is delayed, it can be hard for patients to tolerate, and clinicians can be uncertain as to when to use it. What if, at the start of treatment, we could identify those patients likely to respond to clozapine - and those likely to suffer adverse effects? It is likely that clinicians would feel less inhibited about using it, allowing clozapine to be used earlier and more appropriately. Genetic testing holds out the tantalizing possibility of being able to do just this, and hence the vital importance of pharmacogenomic studies. These can potentially identify genetic markers for both tolerance of and vulnerability to clozapine. We aim to summarize progress so far, possible clinical applications, limitations to the evidence, and problems in applying these findings to the management of TRS. Pharmacogenomic studies of clozapine response and tolerability have produced conflicting results. These are due, at least in part, to significant differences in the patient groups studied. The use of clinical pharmacogenomic testing - to personalize clozapine treatment and identify patients at high risk of treatment failure or of adverse events - has moved closer over the last 20 years. However, to develop such testing that could be used clinically will require larger, multicenter, prospective studies.
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Affiliation(s)
- John Lally
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
- Department of Psychiatry, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
- National Psychosis Service
| | - Fiona Gaughran
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
- National Psychosis Service
| | - Philip Timms
- START Team, South London and Maudsley NHS Foundation Trust
- King’s College London
| | - Sarah R Curran
- King’s College London
- South West London and St George’s Mental Health NHS Foundation Trust
- St George’s University of London, London, UK
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