Delayed stem cell transplantation for the management of relapsed or refractory multiple myeloma

The optimal timing of stem cell transplantation for multiple myeloma is controversial. Late stem cell collection is undesirable because of the inability to mobilize stem cells. We report on 64 recipients of stem cells collected within 1 year after diagnosis, none of whom had transplantation in plateau phase of their disease. Patients seen within 12 months after diagnosis received four cycles of standard vincristine, doxorubicin, and dexamethasone (VAD) chemotherapy and then had stem cells mobilized. Patients were then placed on maintenance vincristine, BCNU, melphalan, cyclophosphamide, and prednisone or melphalan and prednisone chemotherapy for 12 cycles. At the sign of first progression, transplantation occurred. Fourteen patients were refractory to VAD chemotherapy, 20 relapsed on maintenance chemotherapy, and 30 relapsed off chemotherapy. The time to platelet engraftment was not affected by the duration of stem cell cryopreservation or extent of chemotherapy exposure after mobilization. The complete response rate was 34%. The actuarial median survival from initial diagnosis, from transplant day 0, and post-transplant progression-free survival was 51, 20 and 11.4 months, respectively. The patient status at transplantation and percentage of plasma cells circulating in the blood at apheresis influenced post-transplant survival; circulating plasma cells, status at transplantation and plasma cell labeling index influenced progression-free survival. Response duration was shorter in patients relapsing on chemotherapy.