The Role of Allogeneic Transplantation in the Treatment of Multiple Myeloma

In multiple myeloma (MM) attempts to improve upon the results of standard melphalanpredisone with other conventional dose drug combinations, have generally been unsuccessful, producing only minor improvements in response rate, with little effect on survival. The only treatment capable of producing a dramatic change in response and life expectancy is high-dose chemo-radiotherapy followed by stem cell transplantation. However, after autologous transplant relapse will almost inevitably occur, and freedom from recurrence curves show no plateau in most studies. Besides the resistance of the disease to chemotherapy, another possible explanation is tumor contamination of the graft. This is one major advantage of allogeneic transplantation over autologous, the other being an immune mediated mechanism of tumor suppression in part related to GVHD. Application of allogeneic transplantation to MM has met a number of obstacles, but is now entering a phase of reappraisal, due in part to a tendency to earlier transplantation, in part to the use of novel technologies such as allogeneic peripheral blood stem cells instead of marrow. The goal should be the reduction of transplant related deaths, to better exploit the higher eradication potential of allogeneic cell therapies. The most intriguing perspectives are those related to immune manipulation of recipient and/or donor.