High-dose therapy/autologous stem cell transplantation in patients with chemosensitive multiple myeloma: predictors of complete remission.

High-dose therapy (HDT) followed by autologous stem cell support is widely used as intensification treatment in patients with multiple myeloma (MM) responsive to the initial chemotherapy. However, there is growing evidence that only the subset of patients who achieve complete remission (CR) actually benefit from this approach. The aim of this study was to identify pretransplant predictors of CR in responding myeloma patients intensified with HDT. A total of 59 patients with chemosensitive disease received myeloablative therapy. The intensification regimen consisted of MEL-200 (23), MEL-140/TBI 12 Gy (21) or busulfan-based regimens (15). Serum and urine negative immunofixation were required for CR. After HDT, the CR rate increased from 8 to 37%. For the overall series, the median event-free survival (EFS) and overall survival (OS) from the initiation of therapy were 41 and 68 months, respectively. Patients who achieved CR had an EFS (median 47 vs 36 months; P=0.023) as well as an OS (median not reached vs 60 months; P=0.006) significantly longer than those attaining a lower degree of response. Finally, the pretransplant features significantly associated to CR were a low M-protein size (serum </=10 g/l and urine <0.5 g/24 h) (P=0.0003) and a proportion of bone marrow plasma cells of </=5% (P=0.02).