Thiotepa and fractionated TBI conditioning prior to allogeneic stem cell transplantation for advanced hematologic malignancies: a phase II single institution trial: Conditioning Regimens

Relapse of hematologic malignancies after allogeneic stem cell transplantation remains a common problem, in particular for patients who have advanced disease at the time of transplantation. Thiotepa has excellent antileukemic and immunosuppressive activity, and could therefore be a useful drug in the conditioning regimen for patients with advanced hematologic neoplasms. We retrospectively analyzed toxicity, engraftment and survival data of 41 patients who received a conditioning regimen of thiotepa (600 mg/m 2 ) and hyperfractionated TBI (10 Gy) prior to matched related ( n =25) or matched unrelated ( n =16) allogeneic stem cell transplantation. The mean age at transplantation was 37.8 years (range 20–59), all but five patients had advanced hematologic malignancies at the time of transplantation. GVHD prophylaxis was with standard cyclosporine and methotrexate. Engraftment was excellent, but the regimen was associated with a high incidence of grade III renal (41%) and hepatic (15%) toxicity, and high transplant-related mortality (44% at day +90). The 3-year event-free survival was 13% and overall survival 14%. We conclude that this regimen requires modification to reduce toxicity.