Background and objective: In the treatment of leukemia by stem cell transplantation, the immunological effects of allogeneic T-lymphocytes presumably play a greater part than high-dosage total-body irradiation (TBI) and chemotherapy. Using this immunological effect, attempts are currently being made to reduce the dosage of pre-treatment that is toxic to stem cell, such as TBI, thereby making transplantation available for a larger group of patients at high risk for transplantation. This study presents preliminary results of three current studies of this approach.
Patients and methods: Elderly patients with chronic myeloid leukemia (CML) have an increased transplantation risk. They were conditioned with TBI that was reduced stepwise (n = 27). Patients with advanced and refractory myeloid leukemia were treated with chemotherapy and dose-reduced TBI (FLAMSA protocol; n = 54). In patients with multiple myeloma, autologous transplantation with high-dose chemotherapy preceded allogeneic transplantation possible after dose-reduced conditioning (Tandem protocol; n = 6).
Results: All three protocols of TBI gave results that were not worse than those of previous studies. Relapse ocurred not more frequently in patients with CML. In patients with high-risk AML the FLAMSA protocol gave better results. Autologous-allogeneic tandem transplantation was well tolerated and led to a good response in all patients.
Conclusion: Allogeneic transplantation after dose-reduced conditioning opens up new possibilities with respect to widening indications for transplantation and improving results in hematological diseases with previously unsatisfactory treatment.