Phase II study of S-1 combined with oxaliplatin as therapy for patients with metastatic biliary tract cancer: influence of the CYP2A6 polymorphism on pharmacokinetics and clinical activity.
Br J Cancer 2011;
104:605-12. [PMID:
21326246 PMCID:
PMC3049596 DOI:
10.1038/bjc.2011.17]
[Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background:
Advanced biliary cancer is often treated with fluoropyrimidine-based chemotherapy. In this study, we evaluated the efficacy and tolerability of a combination of S-1, an oral fluoropyrimidine prodrug, and oxaliplatin in patients with metastatic biliary cancer.
Methods:
Patients with histologically confirmed metastatic biliary cancer and no history of radiotherapy or chemotherapy were enrolled. Oxaliplatin was administered intravenously (130 mg m−2), followed by 14-day administration of oral S-1 (40 mg m−2 twice daily) with a subsequent 7-day rest period every 21 days. Pharmacokinetic analysis of S-1 was performed at cycle 1. Patients were genotyped for CYP2A6 polymorphisms (*1, *4, *7, *9 or *10), and pharmacokinetic and clinical parameters compared according to the CYP2A6 genotype.
Results:
In total, 49 patients were evaluated, who received a median of four cycles. The overall response rate was 24.5%. Median progression-free and overall survival was 3.7 and 8.7 months, respectively. The most common haematological grade 3 out of 4 toxicity was neutropenia (14%), while non-hematological grade 3 out of 4 toxicities included anorexia (14%), nausea (12%), asthenia (10%), vomiting (10%), and diarrhoea (4%). Biotransformation of S-1 (AUC0−24 h of 5-fluorouracil/AUC0−24 h of tegafur) was 1.85-fold higher for the *1/*1 group than for the other groups (90% confidence interval 1.37–2.49). Diarrhoea (P=0.0740), neutropenia (P=0.396), and clinical efficacy (response rate, P=0.583; PFS, P=0.916) were not significantly associated with CYP2A6 genotype, despite differences in 5-FU exposure.
Conclusion:
The combination of S-1 and oxaliplatin appears to be active and well tolerated in patients with metastatic biliary cancer, and thus is feasible as a therapeutic modality. CYP2A6 genotypes are associated with differences in the biotransformation of S-1. However, the impact of the CYP2A6 polymorphism on variations in clinical efficacy or toxicity requires further evaluation.
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