Dihydropyrimidine Dehydrogenase Deficiency In Patients Research Articles

Consensus of experts from the Spanish Pharmacogenetics and Pharmacogenomics Society and the Spanish Society of Medical Oncology for the genotyping of DPYD in cancer patients who are candidates for treatment with fluoropyrimidines

5-Fluorouracil (5-FU) and oral fluoropyrimidines, such as capecitabine, are widely used in the treatment of cancer, especially gastrointestinal tumors and breast cancer, but their administration can produce serious and even lethal toxicity. This toxicity is often related to the partial or complete deficiency of the dihydropyrimidine dehydrogenase (DPD) enzyme, which causes a reduction in clearance and a longer half-life of 5-FU. It is advisable to determine if a DPD deficiency exists before administering these drugs by genotyping DPYD gene polymorphisms. The objective of this consensus of experts, in which representatives from the Spanish Pharmacogenetics and Pharmacogenomics Society and the Spanish Society of Medical Oncology participated, is to establish clear recommendations for the implementation of genotype and/or phenotype testing for DPD deficiency in patients who are candidates to receive fluoropyrimidines. The genotyping of DPYD previous to treatment classifies individuals as normal, intermediate, or poor metabolizers. Normal metabolizers do not require changes in the initial dose, intermediate metabolizers should start treatment with fluoropyrimidines at doses reduced to 50%, and poor metabolizers are contraindicated for fluoropyrimidines.

Dihydropyrimidine dehydrogenase deficiency in patients treated with 5FU or capecitabine based regimens: A single center experience from South India.

e15517 Background: DPYD deficiency is present in 3-5% of patients. The risk of treatment-related death in DPYD mutation carriers who receive fluoropyrimidine chemotherapy has been estimated at 3-10%. There is growing data in support of widespread screening for DPYD deficiency prior to fluoropyrimidine chemotherapy. The purpose of our study was to identify the prevalence of DPYD deficiency among patients receiving 5-fluorouracil (5FU) or capecitabine based combination chemotherapy, and to analyse the toxicity profile among the DPYD deficient group. Methods: The study involved patients who have received 5FU and capecitabine based chemotherapy for the treatment for gastrointestinal, breast and head and neck cancers between 2019-2020. Four DPYD variants were checked using real-time PCR based Genotyping assay. Three common DPYD variants recommended by the CPIC guidelines (IVS14+1 G>A (*2A), c.1679T>G (*13), c.2846A>T) and a common variant in Asian population (c.496A>G), based on previous studies, was included in our analysis. These variants were assessed prior to the initiation of the chemotherapy and dose was modified based on the activity score and the toxicity profile was assessed. Descriptive statistics was performed using SPSS version 20. Results: 375 patients were included in this analysis. The median age of the cohort was 61years (21-84 years). 51.3% were males and 49.7% females. Among the 375 patients, 47 patients had DPYD mutation (12.5%). The median age of the DPYD mutated patients were 68 years; 29 (61.7%) males and 18 (38.2%) females. 32 (68.8%) had deleterious mutation in DPYD variant c.496A>G (rs2297595) and 15 (31.9%) showed mutation IVS14+1 G>A (rs3918290). 35 out 47 patients had grade II-III toxicity even after dose reduction during the first cycle of chemotherapy. The commonly seen adverse events were hand and foot syndrome in 18 (38.3%), mucositis in 7 (14.9%), diarrrhoea in 15 (31.9%) and neutropenia in 25 (31.9%) patients. Four patients had febrile neutropenia. One patient experience myocardial infarction. There was no mortality. Chi square analysis showed DPYD mutation had significant association with presence of severe adverse reaction (74.5%, p-value. 0.002). Conclusions: Prevalence of DPYD mutation in our patients was 12.5%. They experienced more toxicities while receiving 5-FU/Capecitabine even after dose modification. c.496A>G (rs2297595) was the most common variant seen in our patients. Screening of patients for DPYD mutations prior to administration of 5-FU/capecitabine using pharmacogenetic methods may help identify those patients who are at risk for adverse effects, allowing a more individualized approach to their chemotherapy management. c.496A>G (rs2297595) variant should also be in included routinely in DPYD screening among South Asian population.

Dihydropyrimidine dehydrogenase deficiency in patients with severe toxicity after 5-fluorouracil: a retrospective single-center study.

Background5-Fluorouracil (5-FU) is an agent frequently used in the treatment of solid cancers. A deficiency in the enzyme that catabolizes 5-FU leads to severe toxicity. The gene responsible for this enzyme is DPYD, located on chromosome 1q22. The most prevalent alteration described is DPYD*2A, which leads to a splicing defect and thus skipping of the translation of an entire exon. The objectives of this retrospective study were to describe the frequencies of DPYD gene mutations in a Belgian population and to correlate them with the grade of toxicity.MethodsThis was a retrospective, single-center study conducted at the University Hospitals Leuven, by reviewing a database of patients screened for DPYD gene mutations between May 2009 and June 2015 after prolonged grade 3-4 toxicity. Polymerase chain reaction sequencing of exons 2, 6, 10, 11, 13, 18, 19 and 22, and pyrosequencing of exon 14 were performed by an in-house laboratory.ResultsOf the 80 patients screened, 65 were heterozygous or compound heterozygous for DPYD and 3 had a homozygous mutation. The most prevalent mutation in our population was DPYD*9A.ConclusionsDespite previous reports, in our small retrospective study the most prevalent variation in patients with severe adverse events was DPYD*9A. As this variant has previously been reported to be benign, we suggest that screening for dihydropyrimidine dehydrogenase deficiency should be extended across multiple exons of the DPYD gene.

Response to Letter: Cost Implications of Reactive Versus Prospective Testing for Dihydropyrimidine Dehydrogenase Deficiency in Patients With Colorectal Cancer: A Single-Institution Experience.

Response to Letter: Cost Implications of Reactive Versus Prospective Testing for Dihydropyrimidine Dehydrogenase Deficiency in Patients With Colorectal Cancer: A Single-Institution Experience.

DPYD and Fluorouracil-Based Chemotherapy: Mini Review and Case Report.

5-Fluorouracil remains a foundational component of chemotherapy for solid tumour malignancies. While considered a generally safe and effective chemotherapeutic, 5-fluorouracil has demonstrated severe adverse event rates of up to 30%. Understanding the pharmacokinetics of 5-fluorouracil can improve the precision medicine approaches to this therapy. A single enzyme, dihydropyrimidine dehydrogenase (DPD), mediates 80% of 5-fluorouracil elimination, through hepatic metabolism. Importantly, it has been known for over 30-years that adverse events during 5-fluorouracil therapy are linked to high systemic exposure, and to those patients who exhibit DPD deficiency. To date, pre-treatment screening for DPD deficiency in patients with planned 5-fluorouracil-based therapy is not a standard of care. Here we provide a focused review of 5-fluorouracil metabolism, and the efforts to improve predictive dosing through screening for DPD deficiency. We also outline the history of key discoveries relating to DPD deficiency and include relevant information on the potential benefit of therapeutic drug monitoring of 5-fluorouracil. Finally, we present a brief case report that highlights a limitation of pharmacogenetics, where we carried out therapeutic drug monitoring of 5-fluorouracil in an orthotopic liver transplant recipient. This case supports the development of robust multimodality precision medicine services, capable of accommodating complex clinical dilemmas.

Cost Implications of Reactive Versus Prospective Testing for Dihydropyrimidine Dehydrogenase Deficiency in Patients With Colorectal Cancer: A Single-Institution Experience.

Background:Severe toxicity is experienced by a substantial minority of patients receiving fluoropyrimidine-based chemotherapy, with approximately 20% of these severe toxicities attributable to polymorphisms in the DPYD gene. The DPYD codes for the enzyme dihydropyrimidine dehydrogenase (DPD) important in the metabolism of fluoropyrimidine-based chemotherapy. We questioned whether prospective DPYD mutation analysis in all patients commencing such therapy would prove more cost-effective than reactive testing of patients experiencing severe toxicity.Methods:All patients experiencing severe toxicity from fluoropyrimidine-based chemotherapy for colorectal cancer in an Irish private hospital over a 3-year period were tested for 4 DPYD polymorphisms previously associated with toxicity. The costs associated with an index admission for toxicity in DPD-deficient patients were examined. A cost analysis was undertaken comparing the anticipated cost of implementing screening for DPYD mutations versus current usual care. One-way sensitivity analysis was conducted on known input variables. An alternative scenario analysis from the perspective of the Irish health-care payer (responsible for public hospitals) was also performed.Results:Of 134 patients commencing first-line fluoropyrimidine chemotherapy over 3 years, 30 (23%) patients developed grade 3/4 toxicity. Of these, 17% revealed heterozygote DPYD mutations. The cost of hospitalization for the DPYD-mutated patients was €232 061, while prospectively testing all 134 patients would have cost €23 718. Prospective testing would result in cost savings across all scenarios.Conclusions:The cost of hospital admission for severe chemotherapy-related toxicity is significantly higher than the cost of prospective DPYD testing of each patient commencing fluoropyrimidine chemotherapy.

Pharmacogenetics and Metabolism from Science to Implementation in Clinical Practice: The Example of Dihydropyrimidine Dehydrogenase

Fluoropyrimidines are widely used in the treatment of solid tumors and remain the backbone of many combination chemotherapy regimens. Despite their clinical benefit, they are associated with frequent gastrointestinal and hematological toxicities, which often lead to treatment discontinuation. Fluoropyrimidines undergo complex anabolic and catabolic biotransformation. Enzymes involved in this pathway include dihydropyrimidine dehydrogenase (DPD), which breaks down 5-FU and its prodrugs. Candidate gene approaches have demonstrated associations between 5-FU treatment outcomes and germline polymorphisms in DPD. The aim of this review is to report and discuss the latest results on fluoropyrimidine pharmacogenetics. Literature from PubMed databases and bibliography from retrieved publications have been analyzed according to terms such DPD, DPYD, fluoropyrimdines, polymorphisms, toxicity, pharmacogenetics. To date, many sequence variations have been identified within DPYD gene, although the majority of these have no functional consequences on enzymatic activity. Nowadays, there is a general agreement on the clinical significance of the importance of DPD deficiency in patients who suffer from severe, life-threatening drug toxicity although preemptive testing is not applied to all patients. Considering the published literature, clinicians are strongly encouraged to consider testing for DPD poor metabolizer variants as a rational pre-treatment screening for patients candidate to a fluoropyrimidine-based regimens, in order to prevent toxicities and personalise treatments.

DPD deficiency in patients treated with fluorouracil

In The Lancet Oncology, Didier Meulendijks and colleagues report the findings from their meta-analysis of eight studies of DPYD genetic variants as predictors of fluoropyrimidine-induced severe toxicity. 1 Meulendjiks D Henricks LM Sonke GS et al. Clinical relevance of DPYD variants c.1679T>G, c.1236G>A/HapB3, and c.1601G>A as predictors of severe fluoropyrimidine-associated toxicity: a systematic review and meta-analysis of individual patient data. Lancet Oncol. 2015; (published online Oct 23.)http://dx.doi.org/10.1016/S1470-2045(15)00286-7 Google Scholar In Meulendijks and colleagues' meta-analysis of 7365 patients, DPYD c.1679T>G and c.1236G>A/HapB3 were significantly associated with fluoropyrimidine-associated toxicity (adjusted relative risk 4·40, 95% CI 2·08–9·30, p<0·0001; and 1·59, 1·29–1·97, p<0·0001, respectively). The investigators noted consistent associations of c.1679T>G and c.1236G>A/HapB3 with gastrointestinal and haematological toxicities, but not with hand-foot syndrome. Dihydropyrimidine dehydrogenase (DPD) deficiency is a pharmacogenetic syndrome resulting in an inability or impaired ability in some patients to detoxify fluorouracil in the liver. Consequently, DPD-deficient patients will have life-threatening toxicities with standard doses of fluorouracil. Clinical relevance of DPYD variants c.1679T>G, c.1236G>A/HapB3, and c.1601G>A as predictors of severe fluoropyrimidine-associated toxicity: a systematic review and meta-analysis of individual patient dataDPYD variants c.1679T>G and c.1236G>A/HapB3 are clinically relevant predictors of fluoropyrimidine-associated toxicity. Upfront screening for these variants, in addition to the established variants DPYD*2A and c.2846A>T, is recommended to improve the safety of patients with cancer treated with fluoropyrimidines. Full-Text PDF

Neuropathies associated with oxaliplatin therapy

Neuropathies associated with oxaliplatin therapy

Intragenic deletions and a deep intronic mutation affecting pre-mRNA splicing in the dihydropyrimidine dehydrogenase gene as novel mechanisms causing 5-fluorouracil toxicity

Dihydropyrimidine dehydrogenase (DPD) is the initial enzyme acting in the catabolism of the widely used antineoplastic agent 5-fluorouracil (5FU). DPD deficiency is known to cause a potentially lethal toxicity following administration of 5FU. Here, we report novel genetic mechanisms underlying DPD deficiency in patients presenting with grade III/IV 5FU-associated toxicity. In one patient a genomic DPYD deletion of exons 21–23 was observed. In five patients a deep intronic mutation c.1129–5923C>G was identified creating a cryptic splice donor site. As a consequence, a 44 bp fragment corresponding to nucleotides c.1129–5967 to c.1129–5924 of intron 10 was inserted in the mature DPD mRNA. The deleterious c.1129–5923C>G mutation proved to be in cis with three intronic polymorphisms (c.483 + 18G>A, c.959–51T>G, c.680 + 139G>A) and the synonymous mutation c.1236G>A of a previously identified haplotype. Retrospective analysis of 203 cancer patients showed that the c.1129–5923C>G mutation was significantly enriched in patients with severe 5FU-associated toxicity (9.1%) compared to patients without toxicity (2.2%). In addition, a high prevalence was observed for the c.1129–5923C>G mutation in the normal Dutch (2.6%) and German (3.3%) population. Our study demonstrates that a genomic deletion affecting DPYD and a deep intronic mutation affecting pre-mRNA splicing can cause severe 5FU-associated toxicity. We conclude that screening for DPD deficiency should include a search for genomic rearrangements and aberrant splicing.Electronic supplementary materialThe online version of this article (doi:10.1007/s00439-010-0879-3) contains supplementary material, which is available to authorized users.