A French prospective pilot study for identifying dihydropyrimidine dehydrogenase (DPD) deficiency in breast cancer patients (pts) receiving capecitabine (cap)
e13519 Background: For fluoropyrimidines, and especially cap, Health Authorities point out that DPD deficiency confers a significant risk of major toxicity (tox). Identification of at-risk pts is thus relevant. This multicentric prospective study of the French GPCO group (Groupe de Pharmacologie Clinique Oncologique, Unicancer) evaluated the sensitivity, specificity and predictive values of DPD phenotyping and genotyping for predicting severe cap-related tox in metastatic breast cancer pts. Methods: 303 pts were included (15 institutions), 88% received cap as monotherapy, 28% were treated as first line (mean dose at 1st cycle 1957 mg/m2/d). Pre-treatment dihydrouracil (UH2) and uracil (U) …
Artificial increase of uracilemia during fluoropyrimidine treatment can lead to DPD deficiency misinterpretation
Each year in France, >75 000 patients receive fluoropyrimidines, including 5-fluorouracil (5-FU) and its oral prodrug capecitabine (Xeloda), to treat digestive, breast and head and neck cancers.1 Among them, ∼20% will experience severe hematological and digestive toxicities and <2% will have a fatal outcome in the first two cycles. A part of these toxicities may result from a deficiency in dihydropyrimidine dehydrogenase (DPD) which catabolizes the endogenous uracil (U) into dihydrouracil (UH2) as well as 5-FU. In 2018, French Health Authorities [Haute Autorité de Santé (HAS) and Institut National du Cancer, (INCa)] recommended the evaluation of the enzymatic activity of DPD by measuring th…