Relationship Between Age, Conditioning Intensity, and Outcome After Allografting in Adults Age ≥60 Years with AML

Abstract Methodological advancements now allow older adults with AML to receive allografts although conflicting data exist regarding relative outcomes across age groups and benefits of different conditioning intensities. We retrospectively analyzed 495 adults aged 60–64 (n = 184), 65–69 (n = 189), or ≥ 70 (n = 122) who underwent allogeneic HCT for AML in remission at our institution from 2006 to 2023. There were no significant differences in relapse or relapse-free survival (RFS) among the 3 age cohorts after multivariable adjustment. Patients aged ≥ 70 years had a higher risk of non-relapse mortality (NRM) than those aged ≥ 60–64 (P = 0.022) but their overall survival (OS) was only statistically non-significantly shorter (P = 0.11). There was an important interplay between age, conditioning intensity, and outcomes. Age ≥ 70 years was associated with a higher risk of relapse (hazard ratio [HR] = 3.47; P = 0.012) and NRM (HR = 3.88; P = 0.001) with reduced intensity conditioning (RIC), leading to shorter RFS (HR = 3.79; P < 0.001) and OS (HR = 3.46; P < 0.001), while no association was found with nonmyeloablative conditioning. Conversely, patients aged 60–64 and 65–69, not those aged ≥ 70, had a significantly lower risk of relapse with RIC, but NRM risk increased with age. Our findings support allogeneic HCT for adults with AML in remission even if aged beyond 70, especially with nonmyeloablative conditioning.