Safety and efficacy of thiotepa-based conditioning for allogeneic transplantation in AML: A survey from the ALWP of the EBMT

This study evaluated the safety and efficacy of thiotepa-based regimens before allogeneic stem cell transplantation in 310 adult patients with AML. Disease status at the time of transplantation was CR1 in 50%, CR2+ in 23.5% and advanced disease in 26.5%. Transplantation was performed from haploidentical (35%), matched sibling (27%), unrelated (20%) or cord blood (18%) donors. As for safety: mucositis occurred in 46.8% of the patients and the cumulative incidence (CI) of sinusoidal obstruction syndrome was 4.0%. With a median follow-up of 37 months, the CI of acute GvHD grade>II was 26.5%, whereas CI of chronic GvHD was 28.1% at 3 years. CI for non-relapse mortality at 3 years was 38.4%, 49.7% and 45.4% for patients in CR1, CR2+ and advanced disease, respectively (P=0.10). Relapse incidence at 3 years was 20.2, 30.7 and 40.6% in these three respective groups (P=0.002). CI for 3-year leukemia-free survival and overall survival were 41.4% and 45.6% (CR1), 19.6% and 27.7% (CR2+), and 13.9% and 13.6% (advanced disease), respectively (P<10-4 for both). Our data suggest that thiotepa-based conditioning therapy in AML is feasible, effective and safe, as investigated for sinusoidal obstruction syndrome and mucositis.