Influence of ABCB1 genetic polymorphisms on the antiemetic response to ondansetron-based medication for cisplatin-based chemotherapy in South Indian cancer patients in a tertiary care hospital

Genetic variations in the receptor, metabolizing enzymes and transporters may explain a part of the variation in anti-emetic response to ondansetron among cancer patients. This study assesses the role of ABCB1 genetic polymorphisms in the anti-emetic efficacy of ondansetron-based medication for cisplatin-based chemotherapy in South Indian cancer patients.The frequencies of common ABCB1 polymorphisms (rs1045642; C>T, rs1128503; C>T and rs2032582; G>T/A) were studied in 234 South Indian cancer patients receiving cisplatin-based chemotherapy. Comparison of nausea and vomiting with respect to number of episodes and severity by Visual Analogue Scale (VAS), and Common Terminology Criteria for Adverse Events version 4.0 (CTCAEv4.0) was made across genotype groups of each polymorphism.TT genotype carriers of all three polymorphisms had significantly lesser incidence of nausea and vomiting when compared to other genotypes of the respective polymorphisms during 2-24 hours and on days 2-5. Median VAS score for nausea and vomiting was also lower for TT genotype carriers at each time point except for nausea on days 2-5 (p=0.057) of C3435T. As per CTCAEv4.0, TT genotype carriers had less severe grade at each time point except for days 2-5 nausea (p=0.278) and vomiting (p=0.219) of C3435T and nausea on days 2-5 (p=0.068) of G2677T/A: TT genotype of ABCB1 genetic polymorphisms was associated with anti-emetic response to ondansetron-based medication in the population studied. Hence, genotyping for ABCB1 polymorphisms may be used as a tool to predict response to ondansetron.