New advances in DPYD genotype and risk of severe toxicity under capecitabine.

Marie-Christine Étienne-Grimaldi ,Philippe Follana,Jacques Bonneterre,Fabienne Thomas,Henri Roché,Xavier Pivot,Laurence Llorca,Gilles Romieu,Emmanuel Chamorey,Jean-Pierre Desvignes,Christophe Ferrand,Judith Meijer,Jean-Christophe Boyer,Thomas Bachelot,Alexandre Evrard,Gérard Milano,Litaty Mbatchi,David Salgado,M Mousseau ,Étienne Chatelut ,André B P Kuilenburg ,Frédèric Pinguet ,Christine Bobin‐Dubigeon ,Anthony Gonçalvès ,Véronique Dièras ,V Servent ,Jean‐Louis Merlin ,Rémy Largillier ,L Chaigneau ,Nadine Dohollou ,Christophe Béroud ,Y Château ,Jean-­Marc Ferrero

doi:10.1371/journal.pone.0175998

Abstract

BackgroundDeficiency in dihydropyrimidine dehydrogenase (DPD) enzyme is the main cause of severe and lethal fluoropyrimidine-related toxicity. Various approaches have been developed for DPD-deficiency screening, including DPYD genotyping and phenotyping. The goal of this prospective observational study was to perform exhaustive exome DPYD sequencing and to examine relationships between DPYD variants and toxicity in advanced breast cancer patients receiving capecitabine.MethodsTwo-hundred forty-three patients were analysed (88.5% capecitabine monotherapy). Grade 3 and grade 4 capecitabine-related digestive and/or neurologic and/or hemato-toxicities were observed in 10.3% and 2.1% of patients, respectively. DPYD exome, along with flanking intronic regions 3’UTR and 5’UTR, were sequenced on MiSeq Illumina. DPD phenotype was assessed by pre-treatment plasma uracil (U) and dihydrouracil (UH2) measurement.ResultsAmong the 48 SNPs identified, 19 were located in coding regions, including 3 novel variations, each observed in a single patient (among which, F100L and A26T, both pathogenic in silico). Combined analysis of deleterious variants *2A, I560S (*13) and D949V showed significant association with grade 3–4 toxicity (sensitivity 16.7%, positive predictive value (PPV) 71.4%, relative risk (RR) 6.7, p<0.001) but not with grade 4 toxicity. Considering additional deleterious coding variants D342G, S492L, R592W and F100L increased the sensitivity to 26.7% for grade 3–4 toxicity (PPV 72.7%, RR 7.6, p<0.001), and was significantly associated with grade 4 toxicity (sensitivity 60%, PPV 27.3%, RR 31.4, p = 0.001), suggesting the clinical relevance of extended targeted DPYD genotyping. As compared to extended genotype, combining genotyping (7 variants) and phenotyping (U>16 ng/ml) did not substantially increase the sensitivity, while impairing PPV and RR.ConclusionsExploring an extended set of deleterious DPYD variants improves the performance of DPYD genotyping for predicting both grade 3–4 and grade 4 toxicities (digestive and/or neurologic and/or hematotoxicities) related to capecitabine, as compared to conventional genotyping restricted to consensual variants *2A, *13 and D949V.

Highlights

Since its launch in 1998, the 5FU oral prodrug capecitabine has gradually become a major drug and is currently considered as a standard of care for advanced breast cancer
Exploring an extended set of deleterious DPYD variants improves the performance of DPYD genotyping for predicting both grade 3–4 and grade 4 toxicities related to capecitabine, as compared to conventional genotyping restricted to consensual variants *2A, *13 and D949V
Most 5FU is deactivated into fluorodihydrouracil by ubiquitous dihydropyrimidine dehydrogenase (DPD), the rate-limiting enzyme of 5FU catabolism, expressed in various human tissues as well as in human cancer cells [1,2]

Summary

Introduction

Since its launch in 1998, the 5FU oral prodrug capecitabine has gradually become a major drug and is currently considered as a standard of care for advanced breast cancer. DPD deficiency may be considered as the major cause of capecitabine toxicity, and more generally fluoropyrimidine-related toxicity risk [3,4,5,6]. Breast cancer treatment with capecitabine is concerned since PBMC-DPD activity has been shown to be lower in women as compared to men [7], in line with the observation that women are prone to suffer from fluoropyrimidine toxicity [8]. Deficiency in dihydropyrimidine dehydrogenase (DPD) enzyme is the main cause of severe and lethal fluoropyrimidine-related toxicity. Various approaches have been developed for DPD-deficiency screening, including DPYD genotyping and phenotyping The goal of this prospective observational study was to perform exhaustive exome DPYD sequencing and to examine relationships between DPYD variants and toxicity in advanced breast cancer patients receiving capecitabine

Objectives

Methods

Conclusion