Second EBMT Workshop on reduced intensity allogeneic hemopoietic stem cell transplants (RI-HSCT)

A second meeting on reduced intensity allogeneic stem cell transplants (RI-HSCT) was convened in Zurich in February 2001 and focused on transplant-related mortality (TRM) and graft-versus-host disease (GVHD). Retrospective and prospective studies from the EBMT, national groups and single institutions included over 900 patients: the incidence of acute GVHD grade III-IV was 12% (1-17%), extensive chronic GVHD 42% (25-51%) and TRM 20% (14-38%). Conditioning regimens could be classified into four major groups based on (1) total body irradiation (TBI) 200 cGy, (2) busulfan 8 mg/kg, (3) thiotepa 10 mg/kg, and (4) melphalan 140 mg/ml: most of these regimens are given in association with fludarabine in different doses and use mobilized peripheral blood as a source of stem cells. The incidence of TRM is similar if not identical for all four regimens, whereas the risk of acute GVHD and chronic GVHD may vary with different protocols. Reduced intensity transplant programs are being explored in patients above the age of 60 and in patients with solid tumors: encouraging results are being recorded in individual patients. Overall these data confirm that allogeneic HSCT can be performed in elderly patients, although a TRM of approximately 15% must be expected and is age dependent. A high rate of extensive chronic GVHD is seen and should be followed carefully. The term mini-or micro-transplant is probably misleading and one should refer to this procedure as an allogeneic HSCT and further classify the intensity of the conditioning regimen.