To exclude the impact of OATP1B and CYP2C8 genetic polymorphisms on the response to repaglinide, 82 patients with T2DM (48 men and 34 women) with the same OATP1B1 521TT and CYP2C8*3 139 Arg genotypes but different KCNQ1 rs2237892 genotypes (44 patients with a CC genotype, 38 patients with a CT/TT genotype) were randomly selected to participate in the therapeutic efficacy study. This evidence concerns the gene CYP2C8 and type 2 diabetes mellitus.