Posttreatment nadir M-protein level is a stronger discriminator of survival following plateau attainment than is percent reduction in M-protein in patients with IgG myeloma

We conducted a retrospective study of patients with I-G or IgA myeloma who attained plateau to evaluate the relationships between survival and posttre atment nadir M-protein levels and between survival and the response to trea tment evaluated by the percent reduction in M-protein. Of the 127 patients comprising 92 IgG and 35 IgA myeloma patients with disease stages II or III , 51 (40.2%) attained plateau. For IgG myeloma patients who attained platea u, survival time was not affected by the percent reduction in M-protein (me dian survival, 59.5 months for responding patients versus 54.4 months for n onresponding patients, P = .6910). Posttreatment nadir M-protein level, how ever, did affect survival time (median survival, 61.2 months for < 3000 mg/ dL versus 25.7 months for > 3000 mg/dL, P = .0439). These findings suggest that the posttreatment nadir M-protein level is a stronger discriminator of survival following plateau attainment than the percent reduction of M-prot ein in patients with IgG myeloma. (C) 2001 The Japanese Society of Hematolo gy.