Impact of donor age and type on outcomes with allo-HSCT for AML in first remission

Allo-HSCT is a cornerstone treatment for AML in first remission. While matched sibling donors are preferred, many patients receive grafts from matched unrelated (MUD) or haploidentical (HAPLO) donors. Emerging evidence suggests donor age may be a more critical factor in transplant outcomes than donor type.¹ 

In a recent study published by Ye et al. in the American Journal of Hematology, the impact of donor age and type on outcomes in AML was evaluated.¹ The study analyzed 3,296 adult patients with AML who underwent allo-HSCT in first remission using either a younger HAPLO donor (aged 15–40 years; n = 2,127) or an older MUD (aged 40–65 years; n = 1,169) between 2010 and 2022, with the aim of optimizing donor selection for patients with AML undergoing allo-HSCT.¹

Key learnings

In patients who were considered “fit” (Karnofsky score ≥90), younger HAPLO donors were associated with higher 2-year OS (66.9% vs 63.8%) and LFS (62.3% vs 57%) compared with older MUDs.

The 2-year cumulative incidence of relapse was 20% in the younger HAPLO group vs 24.9% in the older MUD group, with multivariate analysis showing a 36% increased relapse risk for older MUDs in fit patients (p = 0.004).

Older MUDs were associated with significantly higher rates of chronic GvHD (HR = 1.28) and extensive chronic GvHD (HR = 1.83) than younger HAPLO donors were, regardless of patient Karnofsky score.

Older donor age was independently associated with higher NRM and poorer LFS and OS, particularly in patients with a Karnofsky score ≥90.

Among patients with a Karnofsky score <90, there were no survival benefits observed with younger HAPLO donors. Older MUDs resulted in a slight OS benefit (HR = 0.75; p = 0.046), potentially attributable to better tolerability of reduced-intensity conditioning.