OBJECTIVETo study the distribution of different genotypes of CYP2C19 in multiple myeloma (MM), and investigate the effect of its polymorphism on efficacy of thalidomide-based regimens for the treatment of MM and discuss the role of antiangiogenesis in MM.

METHODSThe CYP2C19 genotype of 92 patients with multiple myeloma was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The incidence of poor metabolizer (PM) in MM was compared with that in healthy Chinese people. After they were treated with thalidomide-based regimens, the response rate was compared between extensive metabolizers (EMs) and PMs.

RESULTSOf 92 patients, 18 (19.5%) were PMs, which was comparable to that in healthy ones. The response rates in EMs and PMs were 62.6% and 33.3%, respectively (P < 0.05). When patients were grouped by treatment regimens, the response rate in EMs was significantly higher than that in PMs (60.8% vs. 27.3%) for the thalidomide-dexamethasone group, and similar results were observed for the thalidomide-chemotherapy group (65.2% vs. 42.7%) though there was no statistical difference (P > 0.05).

CONCLUSIONCYP2C19 genotype has no difference between MM patients and healthy person, but exhibits an effect on the treatment efficacy of thalidomide for MM. The lower response rate observed in PMs is possibly due to the reduced activity to inhibit angiogenesis by thalidomide.