A Critical Evaluation of Pharmacogenetic Information in Package Inserts for Selected Drugs Marketed in India and Its Comparison With US FDA-Approved Package Inserts

Our objective was to compare the pharmacogenetic information provided in the package inserts (PIs) of 7 drugs marketed in the United States and India, namely, abacavir, capecitabine, carbamazepine, clopidogrel, irinotecan, valproic acid, and warfarin. We evaluated the pharmacogenetic information provided in Indian PIs for the highest level where it was included, robustness and completeness, clinical validity, and clinical utility and compared it with corresponding data of US PIs. Pharmacogenetic studies carried out in India were identified using PubMed. Pharmacogenetic information was provided in Indian PIs of all the drugs except irinotecan. It appeared in the same section as in US PIs for abacavir, capecitabine, carbamazepine (HLA-*3101), valproic acid (urea cycle disorders), and warfarin (protein C and protein S), whereas it appeared at lower levels for other drug-gene combinations. The robustness of pharmacogenetic testing was graded convincing for abacavir, adequate for carbamazepine and clopidogrel, and incomplete for the remaining drugs, and only abacavir and clopidogrel PIs provided full details of supporting studies. These details, when provided in the Indian PIs were identical to those in the US PIs. The Indian PIs did not provide data on Indian patients, although published studies are available. Both US and Indian PIs lacked critical information on the clinical validity and utility of pharmacogenetic testing. The pharmacogenetic information should provide country/ethnicity-specific data so that they are useful to clinicians. Where data are not available, the prevalence of genetic variation in the population of a country needs to be determined and should then be translated to the PIs.