MTHFR c.665C>T guided fluoropyrimidine therapy in cancer: gender-dependent effect on dose requirements

Gender oncology: recommendations and consensus of the Italian Association of Medical Oncology (AIOM)

BACKGROUND

Following the development of gender medicine in the past 20 years, more recently in the field of oncology an increasing amount of evidence suggests gender differences in the epidemiology of cancers, as well as in the response and toxicity associated with therapies. In a gender approach, critical issues related to sexual and gender minority (SGM) populations must also be considered.

MATERIALS AND METHODS

A working group of opinion leaders approved by the Italian Association of Medical Oncology (AIOM) has been set up with the aim of drafting a shared document on gender oncology. Through the 'consensus conference' method of the RAND/University of California Los Angeles (UCLA) variant, the members of the group evaluated statements partly from the scientific literature and partly produced by the experts themselves [good practice points (GPPs)], on the following topics: (i) Healthcare organisation, (ii) Therapy, (iii) Host factors, (iv) Cancer biology, and (v) Communication and social interventions. Finally, in support of each specific topic, they considered it appropriate to present some successful case studies.

RESULTS

A total of 42 articles met the inclusion criteria, from which 50 recommendations were extracted. Panel participants were given the opportunity to propose additional evidence from studies not included in the research results, from which 32 statements were extracted, and to make recommendations not derived from literature such as GPPs, four of which have been developed. After an evaluation of relevance by the panel, it was found that 81 recommendations scored >7, while 3 scored between 4 and 6.9, and 2 scored below 4.

CONCLUSIONS

This consensus and the document compiled thereafter represent an attempt to evaluate the available scientific evidence on the theme of gender oncology and to suggest standard criteria both for scientific research and for the care of patients in clinical practice that should take gender into account.

MIR27A rs895819 TC genotype increases risk of fluoropyrimidine-induced severe toxicity independently of DPYD variations

Aim: MicroRNA 27a (miR-27a) regulates post-transcriptionally DPD activity. We have analyzed the association of MIR27A rs895819T>C variation, that modulates miR-27a expression, with fluropyrimidine-induced toxicity. Materials & methods: MIR27A rs895819T>C genotyping was conducted by TaqMan® allelic discrimination assay in 313 FP-treated cancer patients. Results: In overdominance (TC vs TT + CC), TC genotype was associated with grade 3-4 toxicity (p = 0.002), any grade toxicity (p = 0.052), and delayed drug administration or therapy discontinuation (p = 0.038). Odds of grade 3-4 toxicity were increased by both DPYD deficiency (OR: 8.923; p = 0.006) and MIR27A rs895819 TC genotype (OR: 3.865; p = 0.002). Conclusion: MIR27A rs895819 TC genotype is an independent risk factor for fluoropyrimidine-associated toxicity in the Greek population. Thus, MIR27A rs895819TC patients can be closely monitored for fluoropyrimidine-induced severe toxicity.

Implementing pharmacogenetic testing in fluoropyrimidine-treated cancer patients: DPYD genotyping to guide chemotherapy dosing in Greece

Introduction: Dihydropyrimidine dehydrogenase (DPD), encoded by DPYD gene, is the rate-limiting enzyme responsible for fluoropyrimidine (FP) catabolism. DPYD gene variants seriously affect DPD activity and are well validated predictors of FP-associated toxicity. DPYD variants rs3918290, rs55886062, rs67376798, and rs75017182 are currently included in FP genetic-based dosing guidelines and are recommended for genotyping by the European Medicines Agency (EMA) before treatment initiation. In Greece, however, no data exist on DPYD genotyping. The aim of the present study was to analyze prevalence of DPYD rs3918290, rs55886062, rs67376798, rs75017182, and, additionally, rs1801160 variants, and assess their association with FP-induced toxicity in Greek cancer patients. Methods: Study group consisted of 313 FP-treated cancer patients. DPYD genotyping was conducted on QuantStudio ™ 12K Flex Real-Time PCR System (ThermoFisher Scientific) using the TaqMan® assays C__30633851_20 (rs3918290), C__11985548_10 (rs55886062), C__27530948_10 (rs67376798), C_104846637_10 (rs75017182) and C__11372171_10 (rs1801160). Results: Any grade toxicity (1-4) was recorded in 208 patients (66.5%). Out of them, 25 patients (12%) experienced grade 3-4 toxicity. DPYD EMA recommended variants were detected in 9 patients (2.9%), all experiencing toxicity (p = 0.031, 100% specificity). This frequency was found increased in grade 3-4 toxicity cases (12%, p = 0.004, 97.9% specificity). DPYD deficiency increased the odds of grade 3-4 toxicity (OR: 6.493, p = 0.014) and of grade 1-4 gastrointestinal (OR: 13.990, p = 0.014), neurological (OR: 4.134, p = 0.040) and nutrition/metabolism (OR: 4.821, p = 0.035) toxicities. FP dose intensity was significantly reduced in DPYD deficient patients (β = -0.060, p <0.001). DPYD rs1801160 variant was not associated with FP-induced toxicity or dose intensity. Triple interaction of DPYD*TYMS*MTHFR was associated with grade 3-4 toxicity (OR: 3.725, p = 0.007). Conclusion: Our findings confirm the clinical validity of DPYD reduced function alleles as risk factors for development of FP-associated toxicity in the Greek population. Pre-treatment DPYD genotyping should be implemented in clinical practice and guide FP dosing. DPYD*gene interactions merit further investigation as to their potential to increase the prognostic value of DPYD genotyping and improve safety of FP-based chemotherapy.

The Role of Gender Pharmacogenetics in the Personalization of Drug Treatment

The use of pharmacogenetic guidelines in personalizing treatments has shown the potential to reduce interindividual variability in drug response by enabling genotype-matched dosing and drug selection. However, other important factors, such as patient gender, may interact strongly with pharmacogenetics in determining the individual profile of toxicity and efficacy but are still rarely considered when planning pharmacological treatment. The literature indicates that males and females respond differently to drugs, with women being at higher risk for toxicity and having different plasma exposure to drugs at standard doses. Recent studies have shown that pharmacogenetic variants may have different predictive value in different sexes, as in the case of treatment with opioids, angiotensin-converting enzyme inhibitors, or proton pump inhibitors. Of particular interest is the case of treatment with fluoropyrimidines for cancer. A significant increase in toxicity has been described in female patients, with a more pronounced effect of specific DPYD and TYMS polymorphisms also noted. This manuscript reviews the major findings in the field of sex-specific pharmacogenomics. SIGNIFICANCE STATEMENT: Interindividual variability in drug response is an emerging issue in pharmacology. The genetic profile of patients, as well as their gender, may play a role in the identification of patients more exposed to the risk of adverse drug reactions or poor efficacy. This article reviews the current state of research on the interaction between gender and pharmacogenetics in addressing interindividual variability.

Pharmacogenomic-guided dosing of fluoropyrimidines beyond DPYD: time for a polygenic algorithm?

Fluoropyrimidines are chemotherapeutic agents widely used for the treatment of various solid tumors. Commonly prescribed FPs include 5-fluorouracil (5-FU) and its oral prodrugs capecitabine (CAP) and tegafur. Bioconversion of 5-FU prodrugs to 5-FU and subsequent metabolic activation of 5-FU are required for the formation of fluorodeoxyuridine triphosphate (FdUTP) and fluorouridine triphosphate, the active nucleotides through which 5-FU exerts its antimetabolite actions. A significant proportion of FP-treated patients develop severe or life-threatening, even fatal, toxicity. It is well known that FP-induced toxicity is governed by genetic factors, with dihydropyrimidine dehydrogenase (DPYD), the rate limiting enzyme in 5-FU catabolism, being currently the cornerstone of FP pharmacogenomics. DPYD-based dosing guidelines exist to guide FP chemotherapy suggesting significant dose reductions in DPYD defective patients. Accumulated evidence shows that additional variations in other genes implicated in FP pharmacokinetics and pharmacodynamics increase risk for FP toxicity, therefore taking into account more gene variations in FP dosing guidelines holds promise to improve FP pharmacotherapy. In this review we describe the current knowledge on pharmacogenomics of FP-related genes, beyond DPYD, focusing on FP toxicity risk and genetic effects on FP dose reductions. We propose that in the future, FP dosing guidelines may be expanded to include a broader ethnicity-based genetic panel as well as gene*gene and gender*gene interactions towards safer FP prescription.

Capecitabine-induced hand-foot syndrome: A pharmacogenetic study beyond DPYD

AIM OF THE STUDY

Occurrence of hand-foot syndrome (HFS) during capecitabine treatment often results in treatment interruptions (26 %) or treatment discontinuation (17 %), and can severely decrease quality of life. In this study, we investigated whether single nucleotide polymorphisms (SNPs) in genes involved in capecitabine metabolism - other than DPYD - are associated with an increased risk for capecitabine-induced HFS.

METHODS

Patients treated with capecitabine according to standard of care were enrolled after providing written informed consent for genotyping purposes. Prospectively collected blood samples were used to extract genomic DNA, which was subsequently genotyped for SNPs in CES1, CES2 and CDA. SNPs and clinical baseline factors that were univariably associated with HFS with P ≤ 0.10, were tested in a multivariable model using logistic regression.

RESULTS

Of the 446 patients eligible for analysis, 146 (32.7 %) developed HFS, of whom 77 patients (17.3 %) experienced HFS ≥ grade 2. In the multivariable model, CES1 1165-33 C>A (rs2244613, minor allele frequency 19 %) and CDA 266 + 242 A>G (rs10916825, minor allele frequency 35 %) variant allele carriers were at higher risk of HFS ≥ grade 2 (OR 1.888; 95 %CI 1.075-3.315; P = 0.027 and OR 1.865; 95 %CI 1.087-3.200; P = 0.024, respectively).

CONCLUSIONS

We showed that CES1 1165-33 C>A and CDA 266 + 242 A>G are significantly associated with HFS grade 2 and grade 3 in patients treated with capecitabine. Prospective studies should assess whether this increased risk can be mitigated in carriers of these SNPs, when pre-emptive genotyping is being followed by dose adjustment or by alternative treatment by a fluoropyrimidine that is not substrate to CES1, such as S1.