Herramientas para un ajuste de dosis de tacrolimus más personalizado en el seguimiento de los pacientes con transplante renal. Fenotipo metabolizador según polimorfismos genéticos del CYP3A vs. el cociente concentración-dosis / Tools for a personalized tacrolimus dose adjustment in the follow-up of renal transplant recipients: Metabolizing phenotype according to CYP3A genetic polymorphisms versus concentration–dose ratio

Antecedentes y justificación: La estrategia de la aproximación concentración-dosis (C/D) y los distintos perfiles del tacrolimus (Tac), según los polimorfismos del citocromo P450 (CYPs) se centran en el metabolismo de Tac y se plantean como herramientas para el seguimiento de los pacientes trasplantados. El objetivo de este estudio es comparar la exposición al Tac analizado según ambas estrategias. Materiales y métodos: Se han incluido 425 pacientes trasplantados renales. El cálculo del cociente concentración Tac/dosis (C/D) permitió dividir la población en terciles y clasificar los pacientes según su tasa de metabolismo del Tac en tres grupos (rápida, intermedia y lenta). Con base en los polimorfismos del CYP3A4 y A5, los pacientes se agruparon en metabolizadores rápidos (portadores del CYP3A5*1 y CYP34A *1/*1), intermedios (CYP3A5*3/3 y CYP3A4*1/*1) y lentos (CYP3A5 *3/*3 y portadores del CYP3A4*22). Resultados: Al comparar los pacientes de cada grupo metabolizador según los dos criterios, coincidieron 47% (65/139) de los metabolizadores rápidos, 85% (125/146) de los intermedios y solo 12% (17/140) de los lentos. Se observaron concentraciones de Tac estadísticamente menores en los metabolizadores rápidos y concentraciones mayores en los lentos, comparándolos con el grupo intermedio según el cociente C/D o según polimorfismos. Los metabolizadores rápidos requirieron alrededor de 60% más de dosis de Tac que los intermedios a lo largo del seguimiento, mientras que los lentos aproximadamente 20% menos de dosis que los intermedios. Los metabolizadores rápidos clasificados por ambos criterios presentan un porcentaje mayor de veces con valores de concentración de Tac en sangre infraterapéuticos... (AU)

Background and justification: The strategy of the concentration–dose (C/D) approach and the different profiles of tacrolimus (Tac) according to the cytochrome P450 polymorphisms (CYPs) focus on the metabolism of Tac and are proposed as tools for the follow-up of transplant patients. The objective of this study is to analyse both strategies to confirm whether the stratification of patients according to the pharmacokinetic behaviour of C/D corresponds to the classification according to their CYP3A4/5 cluster metabolizer profile. Materials and methods: Four hundred and twenty-five kidney transplant patients who received Tac as immunosuppressive treatment have been included. The concentration/dose ratio (C/D) was used to divided patients in terciles and classify them according to their Tac metabolism rate (fast, intermediate, and slow). Based on CYP3A4 and A5 polymorphisms, patients were classified into three metabolizer groups: fast (CYP3A5*1 and CYP34A*1/*1 carriers), intermediate (CYP3A5*3/3 and CYP3A4*1/*1) and slow (CYP3A5*3/*3 and CYP3A4*22 carriers). Results: When comparing patients included in each metabolizer group according to C/D ratio, 47% (65/139) of the fast metabolizers, 85% (125/146) of the intermediate and only 12% (17/140) of the slow also fitted in the homonym genotype group. Statistically lower Tac concentrations were observed in the fast metabolizers group and higher Tac concentrations in the slow metabolizers when compared with the intermediate group both in C/D ratio and polymorphisms criteria. High metabolizers required approximately 60% more Tac doses than intermediates throughout follow-up, while poor metabolizers required approximately 20% fewer doses than intermediates. Fast metabolizers classified by both criteria presented a higher percentage of times with sub-therapeutic blood Tac concentration values... (AU)

Descripción de polimorfismos genéticos en CYP3A5 y MDR-1 y su impacto en el rechazo agudo clínico de pacientes trasplantados de hígado del Hospital San Vicente Fundación Rionegro / Description of genetic polymorphisms in CYP3A5 and MDR-1 and their impact on clinical acute rejection in liver transplant patients at Hospital San Vicente Fundación Rionegro

Introducción. El tacrolimus es un medicamento inmunosupresor ampliamente usado en trasplante hepático, que presenta una gran variabilidad interindividual la cual se considera asociada a la frecuencia de polimorfismos de CYP3A5 y MDR-1. El objetivo de este estudio fue evaluar la frecuencia de los polimorfismos rs776746, rs2032582 y rs1045642 y su asociación con rechazo clínico y toxicidad farmacológica. Métodos. Se incluyeron pacientes inmunosuprimidos con tacrolimus a quienes se les realizó trasplante hepático en el Hospital San Vicente Fundación Rionegro entre 2020 y 2022, con supervivencia mayor a un mes. Se evaluaron las variables clínicas, rechazo agudo y toxicidad farmacológica. Se secuenciaron los genes de estudio mediante PCR, comparando la expresión o no en cada uno de los pacientes. Resultados. Se identificaron 17 pacientes. El 43 % de los pacientes se clasificaron como CYP3A5*1/*1 y CYP3A5*1/*3, entre los cuales se encontró asociación con aumento en la tasa de rechazo agudo clínico, al comparar con los pacientes no expresivos (100 % vs. 44 %, p=0,05); no hubo diferencias en cuanto a la toxicidad farmacológica u otros desenlaces. Se encontró el polimorfismo rs2032582 en un 50 % y el rs1045642 en un 23,5 % de los pacientes, sin embargo, no se identificó asociación con rechazo u otros eventos clínicos. Conclusiones. Se encontró una asociación entre el genotipo CYP3A5*1/*1 y CYP3A5*1/*3 y la tasa de rechazo clínico. Sin embargo, se requiere una muestra más amplia para validar estos datos y plantear modelos de medicina personalizada.

Introduction. Tacrolimus is an immunosuppressive drug widely used in liver transplantation, which presents great interindividual variability which is considered associated with the frequency of CYP3A5 and MDR-1 polymorphisms. The objective of this study was to evaluate the frequency of the rs776746, rs2032582 and rs1045642 polymorphisms and their association with clinical rejection and drug toxicity. Methods. Immunosuppressed patients with tacrolimus who underwent a liver transplant at the Hospital San Vicente Fundación Rionegro between 2020 and 2022 were included, with survival of more than one month. Clinical variables, acute rejection and pharmacological toxicity were evaluated. The study genes were sequenced by PCR, comparing their expression or not in each of the patients. Results. Seventeen patients were identified. 43% of the patients were classified as CYP3A5*1/*1 and CYP3A5*1/*3, among which an association was found with increased rates of clinical acute rejection when compared with non-expressive patients (100% vs. 44%, p=0.05). There were no differences in drug toxicity or other outcomes. The rs2032582 polymorphism was found in 50% and rs1045642 in 23.5% of patients; however, no association with rejection or other clinical events was identified. Conclusions. An association was found between the CYP3A5*1/*1 and CYP3A5*1/*3 genotype and the clinical rejection rate. However, a larger sample is required to validate these data and propose models of personalized medicine.

Exploring the impact of pharmacogenetics on personalized medicine: A systematic review.

INTRODUCTION: Pharmacogenetics evaluates how genetic variations influence drug responses. Nowadays, genetic tests have advanced, becoming more affordable, and its integration is supported by stronger clinical evidence. Guidelines such as those from CPIC (Clinical Pharmacogenetics Implementation Consortium) and resources like PharmGKB facilitate genotype-based prescribing; and organizations like the FDA promote genetic testing before initiating certain medications. Preventive pharmacogenetic panels seem promising, but further research on biomarkers and diverse populations is needed. The aim of this review is to analyze recent evidence on the genotype-drug response relationship to examine how the genetic profile of patients influences the clinical response to treatments, and analyze the areas of research that need further study to advance towards a genetic-based precision medicine. MATERIALS AND METHODS: A systematic search was conducted on PubMed to identify articles investigating the genotype-drug response relationship. The search strategy included terms such as "pharmacogenetics", "personalized treatment", "precision medicine", "dose adjustment", "individualizing dosing", "clinical routine", and "clinical practice." Clinical trials, observational studies, and meta-analyses published in English or Spanish between 2013 and 2023 were included. The initial search resulted in a total of 136 articles for analysis. RESULTS: 49 articles were included for the final analysis following review by 2 investigators. A relationship between genetic polymorphisms and drug response or toxicity was found for drugs such as opioids, GLP-1 agonists, tacrolimus, oral anticoagulants, antineoplastics, atypical antipsychotics, efavirenz, clopidogrel, lamotrigine, anti-TNFα agents, voriconazole, antidepressants, or statins. However, for drugs like metformin, quetiapine, irinotecan, bisoprolol, and anti-VEGF agents, no statistically significant association between genotype and response was found. CONCLUSION: The studies analyzed in this review suggest a strong correlation between genetic variability and individual drug responses, supporting the use of pharmacogenetics for treatment optimization. However, for certain drugs like metformin or quetiapine, the influence of genotype on their response remains unclear. More studies with larger sample sizes, greater ethnic diversity, and consideration of non-genetic factors are needed. The lack of standardization in analysis methods and accessibility to genetic testing are significant challenges in this field. As a conclusion, pharmacogenetics shows immense potential in personalized medicine, but further research is required.

Role of the IL8 rs4073 polymorphism in central nervous system toxicity in patients receiving multidrug-resistant tuberculosis treatment / Papel do polimorfismo rs4073 do gene IL8 na toxicidade do sistema nervoso central em pacientes em tratamento para tuberculose multirresistente

ABSTRACT Objective: To determine the role of the IL8 rs4073 polymorphism in predicting the risk of central nervous system (CNS) toxicity in patients receiving standard pharmacological treatment for multidrug-resistant tuberculosis (MDR-TB). Methods: A cohort of 85 consenting MDR-TB patients receiving treatment with second-line antituberculosis drugs had their blood samples amplified for the IL8 (rs4073) gene and genotyped. All patients were clinically screened for evidence of treatment toxicity and categorized accordingly. Crude and adjusted associations were assessed. Results: The chief complaints fell into the following categories: CNS toxicity; gastrointestinal toxicity; skin toxicity; and eye and ear toxicities. Symptoms of gastrointestinal toxicity were reported by 59% of the patients, and symptoms of CNS toxicity were reported by 42.7%. With regard to the genotypes of IL8 (rs4073), the following were identified: AA, in 64 of the study participants; AT, in 7; and TT, in 11. A significant association was found between the dominant model of inheritance and CNS toxicity for the crude model (p = 0.024; OR = 3.57; 95% CI, 1.18-10.76) and the adjusted model (p = 0.031; OR = 3.92; 95% CI, 1.13-13.58). The AT+TT genotype of IL8 (rs4073) showed a 3.92 times increased risk of CNS toxicity when compared with the AA genotype. Conclusions: The AT+TT genotype has a tendency to be associated with an increased risk of adverse clinical features during MDR-TB treatment.

RESUMO Objetivo: Determinar o papel do polimorfismo rs4073 do gene IL8 na previsão do risco de toxicidade do sistema nervoso central (SNC) em pacientes em tratamento farmacológico padrão para tuberculose multirresistente (TBMR). Métodos: Amostras de sangue de uma coorte de 85 pacientes com TBMR que assinaram um termo de consentimento livre e esclarecido e que estavam recebendo tratamento com medicamentos antituberculosos de segunda linha foram amplificadas para o gene IL8 (rs4073) e genotipadas. Todos os pacientes foram avaliados clinicamente quanto a evidências de toxicidade do tratamento e categorizados de acordo com os achados. Foram avaliadas as associações brutas e ajustadas. Resultados: As principais queixas enquadraram-se nas seguintes categorias: toxicidade do SNC; toxicidade gastrointestinal; toxicidade cutânea; e toxicidade ocular e ototoxicidade. Sintomas de toxicidade gastrointestinal foram relatados por 59% dos pacientes, e sintomas de toxicidade do SNC foram relatados por 42,7%. Foram identificados os seguintes genótipos de IL8 (rs4073): AA, em 64 dos participantes; AT, em 7; TT, em 11. Houve associação significativa entre o modelo dominante de herança e toxicidade do SNC no modelo bruto (p = 0,024; OR = 3,57; IC95%: 1,18-10,76) e no ajustado (p = 0,031; OR = 3,92; IC95%: 1,13-13,58). O genótipo AT+TT do gene IL8 (rs4073) apresentou risco 3,92 vezes maior de toxicidade do SNC que o genótipo AA. Conclusões: O genótipo AT+TT tende a se associar a um maior risco de características clínicas adversas durante o tratamento da TBMR.

Reshaping neuroimmunology: diagnosis and treatment in the era of precision medicine / Remodelando a neuroimunologia: diagnóstico e tratamento na era da medicina de precisão

Abstract Precision medicine has revolutionized the field of neuroimmunology, with innovative approaches that characterize diseases based on their biology, deeper understanding of the factors leading to heterogeneity within the same disease, development of targeted therapies, and strategies to tailor therapies to each patient. This review explores the impact of precision medicine on various neuroimmunological conditions, including multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), optic neuritis, autoimmune encephalitis, and immune-mediated neuropathies. We discuss advances in disease subtyping, recognition of novel entities, promising biomarkers, and the development of more selective monoclonal antibodies and cutting-edge synthetic cell-based immunotherapies in neuroimmunological disorders. In addition, we analyze the challenges related to affordability and equity in the implementation of these emerging technologies, especially in situations with limited resources.

Resumo A medicina de precisão está revolucionando o campo da neuroimunologia, com uma abordagem inovadora caracterizada pela classificação de doenças com base em sua biologia, compreensão mais profunda dos fatores que levam à heterogeneidade dentro da mesma doença, desenvolvimento de terapias com alvos específicos e estratégias para adaptar as terapias a cada paciente. Esta revisão explora o impacto da medicina de precisão em várias condições neuroimunológicas, incluindo esclerose múltipla (EM), distúrbio do espectro da neuromielite óptica (NMOSD), doença associada ao anticorpo anti-glicoproteína da mielina do oligodendrócito (MOGAD), neurites ópticas, encefalites autoimunes e neuropatias imunomediadas. Discutimos avanços na subclassificação de doenças, reconhecimento de novas entidades, biomarcadores promissores e desenvolvimento de anticorpos monoclonais mais seletivos e imunoterapias de ponta baseadas em células sintéticas para as condições acima. Além disso, analisamos os desafios relacionados com acessibilidade e equidade na implementação dessas tecnologias emergentes, especialmente em ambientes com recursos limitados.

Impact of the homozygous mutation in Nudix hydrolase 15 on myelosuppression with 6-mercaptopurine in a European girl with acute lymphoblastic leukemia: A case report / Impacto de la mutación homocigota en Nudix hidrolasa 15 sobre la mielosupresión con 6-mercaptopurina en una niña europea con leucemia linfoblástica aguda: A propósito de un caso

Una paciente pediátrica de 6 años, diagnosticada de leucemia linfoblástica aguda (LLA) de riesgo intermedio, presenta milotoxicidad grave y múltiples infecciones durante la fase de inducción IB del tratamiento con 6-mercaptopurina (6-MP). En las siguientes fases del protocolo de tratamiento, que incluía también 6-MP, la paciente continúa mostrando aplasia de médula ósea y neutropenia, requiriendo numerosos ajustes de dosis e interrupciones. La dosis recomendada de 6-MP se reduce entonces al 5 %. El análisis farmacogenético, realizado en la fase de inducción IB, detectó tres polimorfismos de nucleótido único (SNPs) en el gen que codifica para la enzima tiopurina S-metiltransferasa (TPMT), observándose un fenotipo de metabolizador normal para esta enzima. Como consecuencia, se requirió de un segundo análisis farmacogenético más completo, que reveló polimorfismos patológicos en el gen de la hidrolasa Nudix 15 (NUDT15), explicaría la mielotoxicidad observada en esta paciente. Por ello, un análisis farmacogenético completo debería llevarse a cabo con anterioridad al inicio de 6-MP y de manera rutinaria en la práctica clínica, para conseguir prevenir los efectos adversos graves y/o el fracaso terapéutico. (AU)

A 6-year-old girl diagnosed with intermediate-risk acute lymphoblastic leukemia (ALL) presented with severe my-elotoxicity and multiple infections during phase IB induction treatment with 6-mercaptopurine (6-MP). In the sub-sequent treatment phases, which included 6-MP, the patient continued to show bone marrow aplasia and neu-tropenia, necessitating numerous dose adjustments and interruptions. The recommended dose was eventually reduced to 5 %. A pharmacogenetic analysis, conducted in induction phase IB, detected three single-nucleotide polymorphisms (SNPs) of the thiopurine S-methyltransferase (TPMT) gene, and the phenotype of a normal metab-olizer was observed. As a result of a second pharmacogenetic analysis, pathological polymorphisms were revealed in Nudix hydrolase 15 (NUDT15), which may explain the patient’s myelotoxicity. Hence, a pharmacogenetic analysis performed in advance would have been able to prevent her from suffering severe toxicity and/or treatment failure. (AU)

Polimorfismo de proteína 5, 10-metilentetrahidrofolatoreductasa en población venezolana / Polymorphisms proteína 5, 10-metilentetrahidrofolatoreductasa in venezuelan people

El folato es un miembro del grupo de la vitamina B y está relacionado con enfermedades crónicas como anemia megaloblástica, enfermedad cardiovascular, cáncer, disfunción cognitiva y riesgo de defectos del tubo neural. La proteína 5,10-metilentetrahidrofolato reductasa (MTHFR) juega un papel clave en el metabolismo del folato mediante la síntesis de nucleótidos y reacciones de metilación. El gen MTHFR se encuentra en el cromosoma 1 (1p36.3), y se han descrito dos alelos comunes, el alelo C677T (termolábil) y el alelo A1298C.El objetivo de este estudio es evaluar la distribución de los polimorfismos genéticos en MTHFR C677T y A1298C en la población venezolana. METODOS: estudio de tipo transversal, descriptivo, experimental y correlacional Las muestras de sangre se colectaron en 314 donantes no emparentados y sanos de la población. Los polimorfismos de un solo nucleótido(SNP) MTHFR 677C>T y 1298A>C se analizaron mediante polimorfismo de longitud de fragmento de restricción de reacción en cadena de polimerasa (PCR-RFLP). El desequilibrio de ligamiento (LD) entre pares de SNP se calculó mediante la prueba X. usando Prism 5 (GraphPad software, Inc). RESULTADOS: Encontramos mayor frecuencia genotípica de heterocigotos para el polimorfismo MTHFR C677T en la población general venezolana, con excepción del grupo caucásico. El polimorfismo MTHFR A1298C en el 70%de la población de estudio es homocigoto de tipo salvaje, encontrándose una baja frecuencia de homocigoto mutado. CONCLUSIONES: Se encontraron diferencias significativas entre grupos étnicos, destacando la importancia del genotipado racial de estos polimorfismos en la población venezolana(AU)

Folate is a member of the vitamin B and it has also been indicated that may be related to chronic diseases such as megaloblastic anemia, cardiovascular disease, cognitive dysfunction and risk of neural tube. Methylenetetrahydro folatereductase (MTHFR) is a key enzyme of folate pathway by nucleotide synthesis and methylation reactions. Several polymorphisms were reported in MTHFR gene but C677Tand A1298 polymorphism are most studied and these have been reported to be risk factor for several diseases/disorders. The present study was designed to determine the frequency of MTHFR polymorphisms in Venezuelan healthy population. METHODS: The blood samples were collected from 314 unrelated and healthy donors from population. Both the MTHFR 677C>T and 1298A>C single nucleotide polymorphisms (SNPs) were analyzed by Polymerase chainreaction-restriction fragment length polymorphism (PCR-RFLP). Linkage disequilibrium (LD) between pair of SNPs was calculated through the .. test using Prism 5 (GraphPad sftoware, Inc). RESULTS: We find higher genotypic frequency of heterozygotes for the MTHFR C677T polymorphism in the Venezuelan general population, with the exception of the Caucasian group. MTHFR A1298C polymorphism in 70%of the study population is homozygous wild type, finding alow frequency of homozygous mutated. CONCLUSIONS: Significant differences between ethnic groups were found,highlighting the importance of racial genotyping of these polymorphisms in the Venezuelan population(AU)

Variantes genéticas y actividad enzimática de la citidin desaminasa: relación con la toxicidad a la capecitabina y recomendación de ajuste de las dosis / Genetic variants and enzyme activity in citidin deaminase: Relationship with capecitabine toxicity and recommendation for dose adjustment

Objetivo: la capecitabina es un fármaco antineoplásico utilizado en el tratamiento del cáncer de mama y de colon que puede dar lugar a una toxicidad grave, llegando a ser mortal en algunos pacientes. La variabilidad interindividual de esta toxicidad es debida en gran medida a las variaciones genéticas en los genes diana y las enzimas de metabolismo de este fármaco, como la timidilato sintasa y la dihidropirimidina deshidrogenasa. La enzima citidin desaminasa (CDA), imprescindible en la activación de la capecitabina, también presenta diversas variantes asociadas con un mayor riesgo de toxicidad al tratamiento, aunque su papel como biomarcador aún no está claramente definido. Por ello, nuestro objetivo principal es estudiar la asociación entre la presencia de las variantes genéticas en el gen CDA, su actividad enzimática y el desarrollo de la toxicidad grave en los pacientes tratados con capecitabina, cuya dosis inicial se haya ajustado con base en el perfil genético del gen de la dihidropirimidina deshidrogenasa (DPYD). Método: estudio de cohortes observacional multicéntrico prospectivo, centrado en el análisis de la asociación genotipo-fenotipo de la enzima CDA. Tras la fase experimental, se desarrollará un algoritmo que permita determinar el ajuste necesario de las dosis para disminuir el riesgo de toxicidad del tratamiento en función del genotipo CDA, elaborando una guía clínica para la dosificación de la capecitabina en función de las variantes genéticas en DPYD y CDA. Con base en esta guía, se creará una herramienta bioinformática que genere el informe farmacoterapéutico de manera automática, facilitando la implementación del consejo farmacogenético en la práctica clínica. Esta herramienta proporcionará un gran respaldo en la toma de decisiones farmacoterapéuticas basadas en el perfil genético del paciente, incorporando la medicina de precisión en la rutina clínica. ... (AU)

Objective: Capecitabine, an antineoplastic drug used in the treatment of breast and colon cancer, can cause severe, even fatal toxicity in some patients. The interindividual variability of this toxicity is largely due to genetic variations in target genes and enzymes of metabolism of this drug, such as thymidylate synthase and dihydropyrimidine dehydrogenase. The enzyme cytidine deaminase (CDA), involved in the activation of capecitabine, also has several variants associated with an increased risk of toxicity to treatment, although its role as a biomarker is not yet clearly defined.Therefore, our main objective is to study the association between the presence of genetic variants in CDA gen, CDA enzymatic activity and the development of severe toxicity in patients treated with capecitabine whose initial dose was adjusted based on the genetic profile of the dihydropyrimidine dehydrogenase gen (DPYD). Method: Prospective multicenter observational cohort study, focused on the analysis of the genotype-phenotype association of the CDA enzyme.After the experimental phase, an algorithm will be developed to determine the dose adjustment needed to reduce the risk of treatment toxicity according to CDA genotype, developing a clinical guide for capecitabine dosing according to genetic variants in DPYD and CDA. Based on this guide, a Bioinformatics Tool will be created to generate the pharmacotherapeutic report automatically, facilitating the implementation of pharmacogenetic advice in clinical practice. This tool will be a great support in making pharmacotherapeutic decisions based on the patient's genetic profile, incorporating precision medicine into clinical routine. Once the usefulness of this tool has been validated, it will be offered free of charge to facilitate the implementation of pharmacogenetics in hospital centers and equitably benefit all patients on capecitabine treatment. (AU)

[Translated article] Genetic variants and enzyme activity in citidin deaminase: Relationship with capecitabine toxicity and recommendation for dose adjustment.

OBJECTIVE: Capecitabine, an antineoplastic drug used in the treatment of breast and colon cancer, can cause severe, even fatal toxicity in some patients. The interindividual variability of this toxicity is largely due to genetic variations in target genes and enzymes of metabolism of this drug, such as Thymidylate Synthase (TS) and Dihydropyrimidine Dehydrogenase (DPD). The enzyme Cytidine Deaminase (CDA), involved in the activation of capecitabine, also has several variants associated with an increased risk of toxicity to treatment, although its role as a biomarker is not yet clearly defined. Therefore, our main objective is to study the association between the presence of genetic variants in CDA gen, CDA enzymatic activity and the development of severe toxicity in patients treated with capecitabine whose initial dose was adjusted based on the genetic profile of the DPD gen (DPYD). METHOD: Prospective multicenter observational cohort study, focused on the analysis of the genotype-phenotype association of the CDA enzyme. After the experimental phase, an algorithm will be developed to determine the dose adjustment needed to reduce the risk of treatment toxicity according to CDA genotype, developing a Clinical Guide for capecitabine dosing according to genetic variants in DPYD and CDA. Based on this guide, a Bioinformatics Tool will be created to generate the pharmacotherapeutic report automatically, facilitating the implementation of pharmacogenetic advice in clinical practice. This tool will be a great support in making pharmacotherapeutic decisions based on the patient's genetic profile, incorporating precision medicine into clinical routine. Once the usefulness of this tool has been validated, it will be offered free of charge to facilitate the implementation of pharmacogenetics in hospital centers and equitably benefit all patients on capecitabine treatment.

Genetic variants and enzyme activity in citidin deaminase: Relationship with capecitabine toxicity and recommendation for dose adjustment. / Variantes genéticas y actividad enzimática de la citidin desaminasa: relación con la toxicidad a la capecitabina y recomendación de ajuste de las dosis.

OBJECTIVE: Capecitabine, an antineoplastic drug used in the treatment of breast and colon cancer, can cause severe, even fatal toxicity in some patients. The interindividual variability of this toxicity is largely due to genetic variations in target genes and enzymes of metabolism of this drug, such as thymidylate synthase and dihydropyrimidine dehydrogenase. The enzyme cytidine deaminase (CDA), involved in the activation of capecitabine, also has several variants associated with an increased risk of toxicity to treatment, although its role as a biomarker is not yet clearly defined. Therefore, our main objective is to study the association between the presence of genetic variants in CDA gen, CDA enzymatic activity and the development of severe toxicity in patients treated with capecitabine whose initial dose was adjusted based on the genetic profile of the dihydropyrimidine dehydrogenase gen (DPYD). METHOD: Prospective multicenter observational cohort study, focused on the analysis of the genotype-phenotype association of the CDA enzyme. After the experimental phase, an algorithm will be developed to determine the dose adjustment needed to reduce the risk of treatment toxicity according to CDA genotype, developing a clinical guide for capecitabine dosing according to genetic variants in DPYD and CDA. Based on this guide, a Bioinformatics Tool will be created to generate the pharmacotherapeutic report automatically, facilitating the implementation of pharmacogenetic advice in clinical practice. This tool will be a great support in making pharmacotherapeutic decisions based on the patient's genetic profile, incorporating precision medicine into clinical routine. Once the usefulness of this tool has been validated, it will be offered free of charge to facilitate the implementation of pharmacogenetics in hospital centers and equitably benefit all patients on capecitabine treatment.

Impact of pharmacogenetics on aspirin resistance: a systematic review / Impacto da farmacogenética na resistência à aspirina: uma revisão sistemática

Abstract Background Pharmacogenetics promises better control of diseases such as cardiovascular disease (CVD). Acetylsalicylic acid, aspirin, prevents the formation of an activating agent of platelet aggregation and vasoconstriction, and it is used to prevent CVD. Nevertheless, patients may have treatment failure due to genetic variants that modify the metabolism of the drug causing aspirin resistance (AR). Objectives To realize a systematic literature review to determine the impact of genetic variants on AR. Methods Articles published in the MEDLINE/PubMed, Cochrane, Scopus, LILACS, and SCIELO databases were systematically screened. A total of 290 articles were identified and 269 articles were excluded because they did not comply with the previously established inclusion criteria. A total of 20 case-control studies and 1 cohort was included. Results The genetic variants rs1126643 (ITGA2), rs3842787 (PTGS1), rs20417 (PTGS2), and rs5918 (ITGB3) were the most studied. As for relevance, of the 64 genetic variants evaluated by the articles, 14 had statistical significance (p< 0.05; 95% confidence interval [CI]) in at least one article. Among them, the following have had unanimous results: rs1371097 (P2RY1), rs1045642 (MDR1), rs1051931 and rs7756935 (PLA2G7), rs2071746 (HO1), rs1131882 and rs4523 (TBXA2R), rs434473 (ALOX12), rs9315042 (ALOX5AP), and rs662 (PON1), while these differ in real interference in AR: rs5918 (ITGB3), rs2243093 (GP1BA), rs1330344 (PTGS1), and rs20417 (PTGS2). As study limitations, we highlight the nonuniform methodologies of the analyzed articles and population differences. Conclusion It is noteworthy that pharmacogenetics is an expanding area. Therefore, further studies are needed to better understand the association between genetic variants and AR.

Resumo Antecedentes A farmacogenética promete melhorar o controle de doenças como as cardiovasculares. O ácido acetilsalicílico, a aspirina, previne a formação de um agente ativador da agregação plaquetária e vasoconstrição e é usado na prevenção de tais doenças. No entanto, os pacientes podem ter falha no tratamento devido a variantes genéticas que modificam o metabolismo da droga causando resistência à aspirina (RA). Objetivos Realizar uma revisão sistemática da literatura para determinar o impacto das variantes genéticas na resistência à aspirina. Métodos Artigos publicados nos bancos de dados MEDLINE/PubMed, Cochrane, Scopus, LILACS e SCIELO foram sistematicamente selecionados. Foram identificados 290 artigos e, destes, 269 artigos foram excluídos por não atenderem aos critérios de inclusão previamente estabelecidos. Um total de 20 estudos caso-controles e 1 coorte foi incluído. Resultados As variantes genéticas rs1126643 (ITGA2), rs3842787 (PTGS1), rs20417 (PTGS2) e rs5918 (ITGB3) foram as mais estudadas. Quanto à relevância, das 64 variantes genéticas avaliadas pelos artigos, 14 tiveram significância estatística (p< 0,05; intervalo de confiança [IC] de 95%) em pelo menos um artigo. Entre eles, os seguintes tiveram resultados unânimes: rs1371097 (P2RY1), rs1045642 (MDR1), rs1051931 e rs7756935 (PLA2G7), rs2071746 (HO1), rs1131882 e rs4523 (TBXA2R), rs434473 (ALOX12), rs9315042 (ALOX5AP) e rs662 (PON1), enquanto estes diferiram na interferência real na RA: rs5918 (ITGB3), rs2243093 (GP1BA), rs1330344 (PTGS1) e rs20417 (PTGS2). Como limitações do estudo, destacam-se as metodologias não uniformes dos artigos analisados e as diferenças populacionais. Conclusão Vale ressaltar que a farmacogenética é uma área em expansão. Portanto, mais estudos são necessários para entender melhor a associação entre variantes genéticas e RA.

Farmacogenética y respuesta analgésica: hacia una medicina personalizada con análisis de las diferencias por sexo / Pharmacogenetics in analgesic response: towards a sex-differences personalized medicine

El dolor crónico supone una epidemia silenciosa que afecta a 1 de cada 5 personas adultas en Europa. Este hecho convive con el abuso que realizan algunos pacientes de los medicamentos analgésicos, circunstancia que está limitando su prescripción en el dolor crónico no oncológico. El reto sería poder seleccionar las personas que, a priori, tendrían una mejor respuesta analgésica en base a una serie de condicionamientos intrínsecos. La presente revisión analiza las diferencias en base al sexo y a la presencia de ciertas variantes en los genes que codifican el receptor opioide mu (OPRM1), la enzima metabolizadora del citocromo CYP2D6 y la catecol-O-metiltransferasa (COMT) que degrada catecolaminas. El objetivo es suministrar potenciales elementos explicativos que puedan orientar al profesional clínico en la selección de una analgesia más personalizada.(AU)

Chronic pain is a silent epidemic, affecting 1 in 5 adults in Europe. This fact coexists with the abuse of analgesic drugs by some patients, a circumstance that is limiting their prescription in chronic non-cancer pain. The challenge would be to be able to select the people who, a priori, would have a better analgesic response based on a series of intrinsic conditions. This review analyzes the differences based on sex and the presence of certain variants in the genes that encode the mu opioid receptor (OPRM1), the cytochrome metabolizing enzyme CYP2D6 and the catechol-O-methyltransferase (COMT) that degrades catecholamines. The objective is to provide potentially explanatory elements that can guide the clinical professional in the selection of a more personalized analgesia.(AU)

Genetic testing for cannabinoid use / Testes genéticos para uso de canabinoides

ABSTRACT BACKGROUND AND OBJECTIVES: Cannabis is the most popular and consumed illicit drug in the world, it has about 540 bioactive phytocannabinoids, including tetrahydrocarbinol (THC) and cannabidiol (CBD). The therapeutic potential of phytocannabinoids has been the subject of many studies in recent decades for many medical situations, including the management of chronic pain. The advent of pharmacogenetics currently allows the indication of the Cannabis dose to be evaluated individually. The objective of this work was to carry out a survey of the literature on the medicinal use of Cannabis and the application of pharmacogenetics in this therapy. CONTENTS: THC and CBD phytocannabinoids are the most abundant and researched. In the endocannabinoid system there are compounds similar to phytocannabinoids, cell receptors and metabolism enzymes. All these molecules are secreted from genes, which may have individual genetic polymorphisms that determine the modulation of the endocannabinoid system, and consequently impact the patients' therapeutic response. CONCLUSION: The existence of genetic tests for the prior assessment of the patients genetic profile in order to avoid side effects and to have more assertiveness in the indication of the cannabis product is an important tool to increase adherence to cannabis treatment.

RESUMO JUSTIFICATIVA E OBJETIVOS: A cannabis é a droga ilícita mais popular e consumida no mundo, possuindo cerca de 540 fitocanabinoides bioativos, entre eles o tetra-hidrocarbinol (THC) e o canabidiol (CBD). O potencial terapêutico dos fitocanabinoides tem sido alvo de muitos estudos nas últimas décadas para muitas situações médicas, incluindo o manejo da dor crônica. O advento da farmacogenética permite que atualmente a indicação da dose de cannabis seja avaliada individualmente. O objetivo deste estudo foi realizar um levantamento da literatura sobre o uso medicinal da cannabis e a aplicação da farmacogenética nessa terapia. CONTEÚDO: Os fitocanabinoides THC e CBD são os mais abundantes e pesquisados. No sistema endocanabinoide, existem compostos similares aos fitocanabinoides, receptores celulares e enzimas de metabolismo. Todas essas moléculas são secretadas a partir de genes que podem possuir polimorfismos genéticos individuais determinantes para a modulação do sistema endocanabinoide e, consequentemente, impactam a resposta terapêutica do paciente. CONCLUSÃO: A existência de testes genéticos para avaliação prévia do perfil genético do paciente a fim de evitar efeitos colaterais e ter mais assertividade na indicação do produto de cannabis é uma importante ferramenta para aumentar a aderência ao tratamento com cannabis.

Bioética e medicina personalizada no envelhecimento: explorando complexidades / Bioethics and concierge medicine in aging: exploring complexities / Bioética y medicina personalizada en el envejecimiento: explorar las complejidades

Resumo A medicina personalizada surgiu como uma abordagem promissora para fornecer tratamentos exclusivos e personalizados para doenças usando ferramentas genômicas. No campo dos estudos do envelhecimento, a medicina personalizada tem grande potencial para transformar o tratamento e a prevenção de doenças associadas à idade e relacionadas à nutrigenômica e à farmacogenômica. No entanto, o uso de dados genômicos na medicina personalizada levanta preocupações bioéticas significativas, incluindo questões como privacidade, consentimento, equidade e potencial uso indevido de dados genômicos para fins discriminatórios. Portanto, é crucial considerar cuidadosamente os aspectos biomédicos, sociais e éticos da medicina personalizada no contexto de condições relacionadas à idade. Esta revisão tem o objetivo de explorar os principais aspectos da medicina personalizada concernentes a doenças relacionadas à idade nos dados farmacogenômicos e nutrigenômicos, abordando as preocupações bioéticas envolvidas no uso desses dados.

Abstract Concierge medicine emerged as a promising approach to offer exclusive and personalized treatments using genomic tools. In aging studies, concierge medicine has the potential to transform the treatment and prevention of age-associated and related diseases through pharmacogenetics and nutrigenomics; however, its use of genomic data raises important bioethical concerns, including privacy, consent, equity issues and potential misuse of these data for discriminatory purposes. Hence, careful consideration should be given to the biomedical, social, and ethical aspects of concierge medicine in aging contexts. Our review explores the main aspects of age-related pharmacogenetics and nutrigenomics data in concierge medicine, discussing the bioethical concerns involved in its use.

Resumen La medicina personalizada surgió como un enfoque prometedor con el fin de proporcionar tratamientos únicos y personalizados a enfermedades utilizando herramientas genómicas. En los estudios de envejecimiento, la medicina personalizada puede transformar el tratamiento y la prevención de enfermedades asociadas a la edad y relacionadas con la nutrigenómica y la farmacogenómica. Sin embargo, el uso de datos genómicos en medicina personalizada plantea importantes preocupaciones bioéticas, incluidos temas como la privacidad, el consentimiento, la equidad y el posible uso indebido de los datos genómicos con fines discriminatorios. Así, es fundamental ponderar cuidadosamente los aspectos biomédicos, sociales y éticos de la medicina personalizada en el contexto de las afecciones relacionadas con la edad. Esta revisión pretende explorar los principales aspectos de la medicina personalizada sobre las enfermedades relacionadas con la edad en los datos farmacogenómicos y nutrigenómicos al abordar las preocupaciones bioéticas involucradas en el uso de estos datos.

Farmacogenética en el cáncer de mama: implicaciones de los genes del citocromo p450 en la supervivencia libre de la enfermedad en las mujeres jóvenes / Pharmacogenetics in breast cancer: Implications of cytochrome p450 genes in disease-free survival in young women

Las mujeres jóvenes (≤40 años) con cáncer de mama suelen tener un peor pronóstico que las mujeres posmenopáusicas, con repercusiones reproductivas y familiares importantes. El tratamiento quimioterapéutico, así como la hormonoterapia, pueden mejorar el pronóstico y la supervivencia libre de enfermedad (SLE); sin embargo, la capacidad individual de metabolizar los fármacos puede modificar la respuesta al tratamiento. Las diferencias interpersonales de esta capacidad tienen una explicación en las variaciones de los genes que codifican las enzimas que metabolizan los quimioterapéuticos y las hormonas endógenas y exógenas. Los genes del citocromo P450 (CYP450), CYP3A4, CYP2B6, CYP2D6 y CYP2C19, están involucrados en el metabolismo de los estrógenos y la ciclofosfamida, los taxanos y el tamoxifeno. La presente revisión expone la evidencia científica del efecto de los polimorfismos funcionales de estos genes sobre la SLE, y sus implicaciones, en las mujeres jóvenes con cáncer de mama. (AU)

Breast cancer prognosis tends to be worse in young women (≤40 years) than in postmenopausal women, with significant reproductive and family repercussions. Both chemotherapy and hormonal therapy can improve prognosis and disease-free survival but treatment response may be influenced by the individual's ability to metabolize drugs. Individual differences in metabolic ability can be explained by variations in the genes encoding the enzymes that metabolize chemotherapeutic agents and hormones. The cytochrome P450 genes CYP3A4, CYP2B6, CYP2D6 and CYP2C19 are involved in the metabolism of estrogen, cyclophosphamide, taxanes, and tamoxifen. This review discusses the scientific evidence of the effect of functional polymorphisms in these genes on disease-free survival and overall survival and its implications for young women with breast cancer. (AU)

Revisión bibliográfica de las actuaciones llevadas a cabo en materia de farmacogenética en farmacia comunitaria en distintos países / Bibliographic review of pharmacogenetic actions carried out in community pharmacy in different countries

JUSTIFICACIÓN: la farmacogenética se ha implementado principalmente para la dosificación de medicamentos en el ámbito hospitalario. Sin embargo, en los últimos 10 años ha tomado relevancia en el entorno de la farmacia comunitaria, especialmente en otros países europeos, EEUU y Canadá. Para plantear los futuros pasos a nivel nacional, se hace interesante conocer la situación en materia de investigación farmacogenética en farmacia comunitaria en estos países.OBJETIVO: conocer el tipo de estudios de investigación sobre farmacogenética en farmacia comunitaria desarrollados en distintos países.MATERIAL Y MÉTODOS: se realizó una revisión bibliográfica con el motor de búsqueda Pubmed, en la mayor base de datos de acceso libre de artículos científicos: Medline. Para encontrar los artículos de nuestro interés, es decir, que trataran de trabajos de investigación relacionados con la farmacogenética y que se hubieran llevado a cabo en farmacia comunitaria, se utilizaron los siguientes términos de búsqueda: pharmacogenetics; pharmacogenomics; community pharmacy; pilot study; service implementation; y testing. Las publicaciones identificadas se agruparon por temática relacionada en base a las similitudes metodológicas que presentaron.RESULTADOS: se identificaron 29 publicaciones relevantes para la revisión. De estas publicaciones, el 34,5 % se habían publicado entre los años 2020 y 2021. Además, el 65,5 % de ellas se basaban en trabajos realizados en farmacias comunitarias de EEUU y el 3,5 % en farmacias comunitarias españolas. Las temáticas de dichas publicaciones se agruparon de la siguiente forma: encuestas a farmacéuticos (37,9 %), ajustes de tratamientos guiados por test farmacogenéticos (34,5 %), entrevistas a pacientes (6,9 %), comparación de la implantación del servicio de farmacogenética y el servicio de farmacogenética junto con el manejo del tratamiento médico (6,9 %) y otros variados (13,8 %). (AU)

Evidencia farmacogenética disponible de los subgrupos terapéuticos más consumidos en España / Available pharmacogenetic evidence on the most widely used therapeutic subgroups in Spain

JUSTIFICACIÓN: la variabilidad interindividual en la respuesta a los medicamentos depende de muchos factores, entre los que se encuentra el perfil genético. Polimorfismos en los genes que codifican proteínas implicadas en la farmacocinética y farmacodinámica de los medicamentos pueden modificar su efecto, dando lugar a una respuesta pobre y por lo tanto un tratamiento inefectivo, o una respuesta exagerada lo que conlleva un riesgo alto de toxicidad. La presencia de polimorfismos en genes de transportadores, enzimas metabolizadoras o receptores podría implicar la necesidad o recomendación de un ajuste de dosis, sustitución y/o retirada de los medicamentos. Debido a esto, conocer qué evidencia existe en relación a la farmacogenética de los medicamentos de mayor consumo es de gran interés para los farmacéuticos comunitarios.OBJETIVO: identificar los medicamentos más consumidos en España y determinar la evidencia científica existente en cuanto al efecto que la farmacogenética tiene en ellos.MATERIAL Y MÉTODOS: se identificaron los 15 grupos de medicamentos más consumidos en España (clasificados por subgrupo terapéutico, ACT4) en base al último informe anual disponible de la Prestación Farmacéutica en el Sistema Nacional de Salud (2019).Para cada medicamento de dichos grupos se realizó una búsqueda de la evidencia científica disponible, en materia de farmacogenética, en las Guías Clínicas del CPIC y el DPWG y las anotaciones registradas en la base de datos sobre farmacogenética PharmGKB.RESULTADOS: los 15 subgrupos terapéuticos más dispensados en farmacia comunitaria en España en el 2019 sumaron el 48 % de todos los medicamentos dispensados. De ellos, 8 subgrupos disponen de guías clínicas publicadas de dosificación basada en farmacogenética (Antiulcerosos: inhibidores de la bomba de protones; Hipolipemiantes: inhibidores de la HMG CoA reductasa; Inhibidores de la agregación plaquetaria, excluyendo heparina. (AU)

Pharmacogenetic studies in Alzheimer disease.

INTRODUCTION: Alzheimer disease (AD) is the most common cause of dementia and is considered one of the main causes of disability and dependence affecting quality of life in elderly people and their families. Current pharmacological treatment includes acetylcholinesterase inhibitors (donepezil, galantamine, rivastigmine) and memantine; however, only one-third of patients respond to treatment. Genetic factors have been shown to play a role in this inter-individual variability in drug response. DEVELOPMENT: We review pharmacogenetic reports of AD-modifying drugs, the pharmacogenetic biomarkers included, and the phenotypes evaluated. We also discuss relevant methodological considerations for the design of pharmacogenetic studies into AD. A total of 33 pharmacogenetic reports were found; the majority of these focused on the variability in response to and metabolism of donepezil. Most of the patients included were from Caucasian populations, although some studies also include Korean, Indian, and Brazilian patients. CYP2D6 and APOE are the most frequently studied biomarkers. The associations proposed are controversial. CONCLUSIONS: Potential pharmacogenetic biomarkers for AD have been identified; however, it is still necessary to conduct further research into other populations and to identify new biomarkers. This information could assist in predicting patient response to these drugs and contribute to better treatment decision-making in a context as complex as ageing.

Metodología de investigación en farmacogenética: estudios de casos y controles / Methodology for research in pharmacogenetics: Case-control studies

RESUMEN La farmacogenética estudia la asociación entre el fenotipo farmacológico de un individuo con su constitución genética, y el diseño de estudios de casos y controles es una metodología de uso frecuente. Este diseño consiste en que se analiza la frecuencia de las variantes genéticas en los casos, es decir, de los pacientes que presentan el fenotipo (desenlaces o resultados) comparado con los controles. Para obtener una calidad metodológica adecuada en este tipo de estudios es importante trabajar con fenotipos precisos, adecuada selección de los casos y controles y tamaño de la muestra; seleccionar una metodología adecuada para la identificación de variantes genéticas; y en el momento del análisis de resultados utilizar el Equilibrio de Hardy-Weinberg (EHW) e interpretar los resultados considerando la posibilidad de un fenómeno de fenoconversión.

ABSTRACT Pharmacogenetics studies the association between the pharmacological phenotype of an individual with his/her genetic constitution. Case-control studies is a commonly used methodology when performing pharmacogenetics research. This design analyses the frequency of genetic variants in cases; that is, of those patients who have a particular phenotype (outcomes or results) compared with controls. For obtaining adequate methodological quality in pharmacogenetic case-control studies, it is important to work with precise phenotypes, have adequate case and control selection and appropriate sample size; select an adequate methodology for the identification of genetic variants, analyze the results using Hardy-Weinberg Equilibrium (HWE); and interpret the results considering the possibility of a phenoconversion phenomenon.

Susceptibility to thiopurine toxicity by TPMT and NUDT15 variants in Colombian children with acute lymphoblastic leukemia / Asociación de variantes genéticas en TPMT y NUDT15 con los eventos de toxicidad durante la terapia de mantenimiento en niños colombianos con Leucemia Linfoide Aguda

Abstract Objective: This study aimed to correlate the genetic profile of the NUDT15 and TPMT genes with the side effects of the treatment of pediatric patients with acute lymphoid leukemia who were undergoing maintenance therapy at a tertiary care hospital in 2017. Methods: This was an analytical, longitudinal, observational study in which the genotypes of the genes of interest were determined by PCR allelic discrimination with TaqMan® probes in patients receiving chemotherapy during the maintenance phase in the Pediatric Hematology and Oncology Unit in 2017. Sociodemographic and clinical data corresponding to the first six months of their maintenance chemotherapy were collected, and the correlation between the genotypes obtained and the development of side effects during the maintenance phase of chemotherapy in these patients was evaluated. Results: Seventy pediatric patients were included in the study. Genetic analyses were carried out of these for NUDT15 and TPMT (rs1800462 and rs1800460) on 68 patients, while for the rs1142345 polymorphism, typing was achieved in 42 patients. 4/68 patients were heterozygous for NUDT15, and the same number of patients were heterozygous for rs1800462 and rs1142345, while for rs1800460, 6 heterozygous patients were identified. No statistically significant association was identified between the genetic variants and the outcomes of interest. Conclusion: Studies with a larger population size are needed and the evaluation of other genetic variants that may influence the development of side effects during maintenance chemotherapy.

Resumen Objetivo: la finalidad de este estudio fue evaluar las asociaciones entre los perfiles de los genes NUDT15 y TPMT con los efectos adversos del tratamiento de mantenimiento en pacientes pediátricos con Leucemia Linfoblástica Aguda atendidos en un hospital de referencia durante el 2017. Métodos: Este fue un estudio observacional analítico, de corte longitudinal en el que los genotipos de los genes de interés fueron determinados mediante PCR de discriminación alélica con sondas TaqMan® en pacientes que estaban recibiendo quimioterapia de mantenimiento en la Unidad de Oncohematología Pediátrica durante el 2017. Los datos clínicos y sociodemográficos correspondientes a los primeros 6 meses de sus tratamientos de mantenimiento fueron colectados, y se evaluó la correlación entre los genotipos identificados y el desarrollo de efectos secundarios en estos pacientes. Resultados: setenta pacientes fueron incluidos en el estudio, de estos, los análisis genéticos para NUDT15 y TPMT (rs1800462 and rs1800460) fueron realizados en 68 pacientes, en tanto que para el polimorfismo rs1142345 se logró la tipificación en 42 pacientes. 4/68 pacientes fueron heterocigotos para NUDT15 y el mismo número de pacientes fueron heterocigotos para rs1800462 and rs1142345, mientras que para rs1800460, 6 pacientes heterocigotos fueron identificados. No se identificaron asociaciones estadísticamente significantes entre las variants genéticas y los resultados clínicos de interés. Conclusiones: Estos hallazgos resaltan la importancia de realizar estudios de este tipo con un mayor número de sujetos de estudio, así como plantean la necesidad de evaluar otras variantes genéticas que podrían tener algún impacto en el desarrollo de efectos secundarios durante la quimioterapia de mantenimiento.