Hematopoietic Stem‐Cell Transplantation for B‐Cell Chronic Lymphocytic Leukemia: Current Status

Although B-cell chronic lymphocytic leukemia CLL) is incurable with standard therapies, important progress has been made in the treatment of this disease. New treatment modalities result in a high proportion of complete responses and a longer disease-free interval, but unfortunately not in a longer survival. Given these facts, as well as the increasing proportion of patients being diagnosed at a younger age, hematopoietic stem-cell transplants are being frequently offered to individuals with CLL. Candidates to be enrolled in transplant trials can be identified on the basis of a number of reliable prognostic factors. However, the role of transplants in the management of CLL patients has not been established in controlled trials. Therefore, such procedures should still be considered experimental in CLL. In the autologous transplantation setting, the mortality associated with the procedure is usually lower than 10% and the status of the disease at the time of transplantation is the most important factor for survival. However, survival plots do not show a plateau and there is a constant pattern of relapses about 50% at 4 years post-transplant), suggesting that autotransplants do not cure CLL. Allogeneic transplants result in a transplant-related mortality ranging from 25% to 50%. In contrast with autologous transplants, however, in most series there is a survival plateau of about 40%; this is probably due, at least in part, to a graft-vs.-CLL effect. As with autologous transplants, the absence of minimal residual disease after transplantation is associated with a longer disease-free interval. The use of nonmyeloablative regimens in allogeneic transplants is appealing, because they could contribute to a decrease in the transplant-related mortality and to an increase in the age limit of transplantable patients. Hopefully, ongoing prospective studies will help to clarify the many issues still pending on the role of transplants in patients suffering from CLL.