Upfront DPD Deficiency Detection to Secure 5-FU Administration: Part 2- Application to Head-and-Neck Cancer Patients

Author(s): Manon Launay, Joseph Ciccolini*, Claire Fournel, Carmello Blanquicett, Charlotte Dupuis, Nicolas Fakhry, Florence Duffaud, Sebastien Salas, Bruno Lacarelle.

Journal Name: Clinical Cancer Drugs

Volume 4 , Issue 2 , 2017

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Abstract:

Background: Upfront screening for dihydropyrimidine dehydrogenase (DPD) deficiency in patients scheduled for 5-FU should help to reduce the risk of toxicities by preventive adaptive dosing. Our group has developed a simple functional testing categorizing patients upon their DPD status, i.e. extensive metabolizer (EM) or poor metabolizer (PM) patients, using UH2/U ratio measurement in plasma as a surrogate for DPD activity. 5-FU dosing can be next tailored according to DPD deficiency status.

Objectives: We present here an observational study of this strategy implemented in routine clinical practice when treating head-and-neck cancer patients.

Results: A total of 218 evaluable adult patients were treated with a 5-FU-regimen, with DPD-based adaptive dosing. Among them, 20 (9%) were identified as PM and received subsequently a 20-50% reduced dosing of 5-FU as compared with EM patients (2102 ±254 mg VS. 2577 ±353mg, p<0.001 ttest). Gender (Female) was associated with higher risk for being PM (p=0.01, Pearson's Chi squared test). Overall, early severe toxicities were seen only in 5% of patients, all being EM with standard dosing. Similarly, overall severe toxicities were observed in 12.8% of patients only, both figures being markedly lower than usually reported with standard 5-FU. Despite the average -20% reduction in 5- FU dosing between PM and EM patients, clinical efficacy was not statistically different between the two groups (p = 0.2774, chi-square test).

Conclusion: This study shows that 5-FU-related toxicities can be greatly reduced in routine clinical practice by the upfront detection of DPD deficient patients with simple adaptive dosing strategy.

Keywords: 5-FluoroUracil, head and neck cancer, dihydropyrimidine dehydrogenase, adaptive dosing, DPD deficiency, efficacy, toxicity.

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Article Details

VOLUME: 4
ISSUE: 2
Year: 2017
Page: [122 - 128]
Pages: 7
DOI: 10.2174/2212697X04666170817123425
Price: $58

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