Allogenic hematopoietic stem-cell transplantation with reduced-intensity conditioning in patients with refractory and recurrent multiple myeloma: long-term follow-up.

Background: Allogeneic stem cell transplantation (SCT) with myeloablative conditioning is potentially curative therapy for myeloma, but is reportedly associated with a high risk of nonrecurrence mortality (NRM). Reduced-intensity conditioning (RIC) allows for the reduction of NRM, but the recurrence rate is increased. The role and timing of allogeneic SCT in the disease course remains controversial. To the authors' knowledge, there are limited data regarding the long-term outcome of RIC in the recurrent/refractory setting.

Methods: A retrospective analysis was conducted of SCT outcomes in 50 patients who received RIC for recurrent/refractory myeloma between the years 2001 and 2004. All patients were given fludarabine-melphalan based conditioning and stem cell grafts from a related (n=27) or unrelated donor (n=23).

Results: The median age was 53 years. Forty-seven patients failed a prior autologous SCT. Thirty patients were in disease remission at the time of SCT and 20 had stable or progressive disease. With a median follow-up of 6.4 years (range, 5-7.9 years), the overall and progression-free survival (PFS) rates were 34% and 26%, respectively. The NRM rate was 26%. Adverse prognostic factors for survival included SCT not in remission, long duration of disease (>5 years from diagnosis), and transplantation from a female donor to a male recipient. The 7-year PFS in 19 patients with none of these adverse prognostic factors was 47%. Chronic graft versus host disease and the achievement of complete remission after SCT were associated with improved outcome.

Conclusions: Allogeneic SCT can result in long-term PFS in a subset of myeloma patients who fail prior therapy and should be considered early after failure and after achieving remission.