Evaluation of severe neutropenia and diarrhea in Asian cancer patients receiving UGT1A1 genotype-guided irinotecan dosing.

e13572 Background: Inactivation of SN-38, the active metabolite of irinotecan, occurs mainly via glucuronidation mediated by UDP glucuronosyltransferase (UGT) 1A1. The role of UGT1A1*6 and *28 polymorphisms in altering SN-38 disposition and increasing the risks of neutropenia and diarrhea has been reported in Asian cancer patients receiving standard-dose irinotecan. This study aimed to evaluate the incidence of severe neutropenia and diarrhea in Asian cancer patients treated with UGT1A1 genotype-guided doses of irinotecan. Methods: High Resolution Melting analysis was performed for the detection of UGT1A1*6 and *28 in 61 patients with advanced solid tumours prior to the initiation of irinotecan-based regimens. Irinotecan dose was administered according to their UGT1A1 genotypes and chemotherapy regimens. Incidence and severity of neutropenia and diarrhea were retrospectively evaluated over the entire duration of irinotecan therapy according to the National Cancer Institute Common Toxicity Criteria for Adv...