Polymorphisms of CYP2C19 gene are associated with the efficacy of thalidomide based regimens in multiple myeloma.

In this study, CYP2C19 genotypes were tested by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method in 92 patients with multiple myeloma (MM). Sixty-two patients were treated with thalidomide plus dexamethasone (Thal+Dex) and 30 with thalidomide combined with chemotherapy (Thal+CC). The overall response rate of extensive metabolizers (EMs) was statistically higher than that of poor metabolizers (PMs) (62.6% vs. 33.3%, p < 0.05). Similar results were also observed in the Thal+Dex cohort. For the first time, our primary data suggested that the polymorphisms of CYP2C19 gene are associated with the efficacy of thalidomide based regimens in MM.