A 17-point absolute difference in leukemia relapse deserves attention—and close transplant scrutiny

Source: The Lancet Haematology, online/indexed in the October 29–31 retrieval window, November issue designation; eight-center Chinese phase 3 randomized trial in KMT2A-rearranged leukemia. PubMed · DOI 10.1016/S2352-3026(26)00250-400250-4). Evidence: randomized phase 3, relatively small molecularly selected population. Clinical state: transplant-specialist evaluation.

For a patient with a high-risk leukemia, transplant conditioning is an effort to destroy disease before donated immune cells establish themselves. In this study, 130 patients were randomized to conventional busulfan-cyclophosphamide conditioning or the same regimen preceded by decitabine. Median follow-up was 34.7 months. At two years, the cumulative incidence of relapse was 12% with decitabine conditioning versus 29% in the comparator group: an absolute difference of 17 percentage points, with hazard ratio 0.41 (95% CI 0.20–0.87; p=0.017).

There was no signal in the study that those gains required a major increase in some severe adverse-event categories: grade 3–5 infections were 42% versus 38%, acute graft-versus-host disease 35% versus 34%, and reported deaths attributed to adverse events 6% versus 8%. Yet the confidence interval around the relapse effect is wide, and two-year survival, nonrelapse mortality, transplant toxicity in other settings and longer follow-up remain important to examine in the full publication.

What this changes: The trial provides a potentially meaningful modification to a specific transplant regimen in a molecularly defined leukemia, not a general longevity or anticancer treatment. Its rationale should be assessed alongside real survival and quality-of-life outcomes.