Addition of venetoclax to myeloablative conditioning regimens for allogeneic hematopoietic stem cell transplantation in high-risk AML

AbstractBackground Venetoclax monotherapy is an effective option for patients with acute myeloid leukemia (AML). Venetoclax has also been used in non-myeloablative conditioning allogeneic hematopoietic stem cell transplantation (allo-HSCT) for high-risk AML with a tolerable toxicity profile. However, the efficacy and safety of a venetoclax-containing myeloablative conditioning (MAC) allo-HSCT regimen for high-risk AML have not been evaluated.Objective To evaluate the safety and efficacy of a MAC regimen containing venetoclax for high-risk AML.Study design From 25 February 2021 to 4 September 2022, a total of 31 patients with high-risk AML who underwent allo-HSCT and a MAC regimen with venetoclax were analyzed.Results At the time of transplantation, 21 patients were in first complete remission (CR1), 4 were in a second complete remission (CR2), and 6 in non-remission (NR). Twenty-four patients (77.4%) were minimal residual disease (MRD)-positive before transplant. The FLT3-ITD gene mutation was present in 51.6% of patients. NUP98 rearrangement, MLL rearrangement or MLL-PTD and DEK::CAN fusion genes were found in 5 (16.1%), 7(22.6%) and 2 (6.5%) patients, respectively. Twenty-nine (93.6%) patients underwent haploidentical allo-HSCT. The median follow-up time was 278 days (range: 52–632 days). The 100-day cumulative incidence of grade 3 to 4 acute graft-versus-host disease (aGVHD) was 16.1% (95%CI, 7.2–36.0%). The 180-day cumulative incidence of moderate to severe chronic graft-versus-host disease (cGVHD) was 7.1% (95%CI, 1.9–26.9%). Cumulative incidence of 100-day cytomegalovirus (CMV) viraemia and 100-day Epstein-Barr virus (EBV) viraemia was 61.6% (95%CI, 46.5–81.4%) and 3.2% (95%CI, 0.4–22.2%), respectively. The 600-day overall survival (OS) and leukemia-free survival (LFS) were 80.9% (95%CI, 63.5–93.6%) and 81.3% (95%CI, 64.2–93.7%), respectively. The 600-day relapse incidence (RI) and non-relapse mortality (NRM) was 6.9% (95%CI, 1.8–26.3%) and 11.7% (95%CI, 3.9–35.0%).Conclusion Our study shows that the addition of venetoclax to a MAC allo-HSCT was feasible, safe and effective for high-risk AML patients.