Stem-cell transplantation for chronic lymphocytic leukemia: the 1999 perspective

The use of myeloablative intensive therapy followed by autologous or allogeneic stem-cell transplantation (SCT) for treatment of chronic lymphocytic leukemia (CLL) has largely increased over the last years.

The present overview updates the available clinical results and discusses important aspects of SCT in patients with CLL including the type of SCT (autologous vs. allogeneic), myeloablative regimens, purging, the predictive value of molecular monitoring of residual disease, and prognostic factors for the outcome of transplant approaches.

With appropriate supportive care, autologous SCT is safe and can induce long-lasting clinical and molecular remissions, which may improve the prognosis of patients with CLL. Feasibiliy and efficacy of autologous SCT appears to be best early during the course of the disease, but it is still unclear if autotransplantation can cure the disease even in this favorable subgroup. The role of purging is still unclear. The better disease control observed after allografting appears to be due to graft-versus-leukemia activity and may allow cure in at least a subset of poor-risk patients. Due to the extraordinarily high treatment-related mortality, however, the outcome after allogeneic SCT is still inferior to that after autologous SCT.

Autologous transplantation is a valuable treatment option for younger patients with early or sensitive poor-risk CLL. Selected patients with advanced poor-risk disease and low probability of successful auto-SCT should be considered for allografting. However, it must be kept in mind that both autologous and allogeneic stem-cell transplantation are still experimental procedures and clinical trials further elucidating their value in the treatment of patients with CLL are warranted.