This randomized phase III trial of 272 adults with myelodysplastic syndromes (MDS) and acute myelogenous leukemia (AML) found that patients with hematopoietic cell transplantation (HCT) comorbidity index scores ≤4 and with <5% marrow myeloblasts had better relapse-free survival (RFS) after HCT with myeloablative conditioning (MAC), than after reduced-intensity conditioning (RIC).
In this multi-center Blood and Marrow Transplant Clinical Trials Network (BMT CTN) trial, patients ages 18-65 years old were randomly assigned to receive MAC (n=135) or RIC (n=137) followed by HCT from HLA-matched related or unrelated donors. Although planned enrollment was 356 patients, accrual was stopped at 272 patients due to high relapse incidence in the RIC arm, compared to the MAC arm: 48.3% vs. 13.5%, respectively (p<0.001).
At 18 months, overall survival for patients was comparable in both arms: 67.7% for those in the RIC arm vs. 77.5% for those in the MAC arm (p=0.07). Transplant-related mortality with RIC was 4.4% vs. 15.8% with MAC (p=0.002). RFS was significantly higher at 67.8% in the MAC arm compared with 47.3% in the RIC arm (p<0.01), a 20% survival advantage for MAC recipients.
The researchers concluded that myeloablative regimens should be standard of care for those patients with MDS and AML healthy enough to receive them.