High-dose therapy and autologous stem cell transplantation for multiple myeloma poorly responsive to initial therapy

Autologous stem cell transplant (SCT) improves survival in multiple myeloma (MM) and remains the standard of care for eligible patients. Nearly a third of patients with newly diagnosed MM fail initial therapy aimed at reducing tumor burden preceding SCT (primary refractory). It is unclear if an initial response is important for successful SCT. We evaluated our experience with SCT in 50 patients with primary refractory MM and compared it to 101 patients with chemosensitive disease receiving SCT. The study cohort had a median age of 56 years (range 29-72) consisting of 87 males (58%). A total of 46 patients (92%) in the refractory group and 100 (99%) in the chemosensitive group had a response to transplant (50% or greater reduction in the M-protein). In all, 10 refractory patients (20%) and 35 (35%) in the chemosensitive group achieved a CR (P=0.06). The 1-year estimated progression-free survival from the time of transplant for the refractory group was 70% compared to 83% for the chemosensitive group (P=0.65). The lack of response to initial induction therapy does not appear to preclude a good response to SCT. We recommend that patients with primary refractory MM be offered early SCT.