Conference Abstracts - Summit on Cancer Health Disparities (SCHD26)
Vol. 6, Issue Supplement 1, 2026 · S1-2
Older Donor Age is Not Associated with Inferior Survival in Contemporary Haploidentical Transplantation
Yosra Aljawai, MD,Denai Milton, MS,Richard Champlin, MD,Elizabeth Shpall, MD,Rohtesh Mehta, MD
Submission received: 2025-12-16 / Accepted: 2026-01-07 / Published: 2026-01-24
Abstract
Background
Data regarding the association of donor age with haploidentical (haplo) hematopoietic stem cell transplant (HCT) outcomes, an important donor source for ethnically diverse patients, has been inconsistent, particularly concerning a specific age cutoff. Most published studies on donor age in the haplo setting predated the advancement in cytomegalovirus (CMV) prophylaxis, improved graft-versus-host disease (GVHD) treatments, and maintenance therapy post-HCT.
Objective
Examine the role of donor age in a recent cohort of patients, from 2018-2024.
Methods
We included consecutive adult patients with hematologic malignancies who underwent their first haplo HCT (n=364) at MD Anderson Cancer Center. All patients received post-transplant cyclophosphamide (PTCy)-based GVHD prophylaxis.
Results
We categorized donor age into three groups (≤30 [n=155], 31-44 [n=139], and ≥45 years [n=70]). Compared to donor age ≤30 years, the hazards of overall mortality were 0.92 (95% CI 0.62-1.37, P = 0.69) for donor age 31-44 years and 1.19 (95% CI 0.78-1.81, P = 0.43) for donor age ≥45 years in multivariable analysis (MVA). Similar patterns emerged for PFS. Older donor age was associated with increased hazards of non-relapse mortality (NRM) in MVA: (31-44 years: hazard ratio [95% CI] 1.44 [0.84-2.45], P = 0.18) and (≥45 years: 1.52 [0.87-2.66], P = 0.14). Consequently, relapse rates were lower in these groups (31-44 years: 0.55 [0.33-0.93], P = 0.025) and (≥45 years: 0.70 [0.36-1.36], P = 0.29) compared to donors ≤30 years.
Older donors were associated with a significantly increased risk of grade III-IV acute GVHD (31-44 years: 3.77 [1.69-8.39], P = 0.001; ≥45 years: 3.83 [1.64-8.98], P = 0.002) compared to donors ≤30 years. The risk of chronic GVHD was also higher with older donors (31-44 years: 1.44 [0.84-2.45], P = 0.18; ≥45 years: 1.52 [0.87-2.66], P = 0.14) compared to younger donors.
We noted patient and disease-related factors significantly associated with OS in MVA; older patient age (≥ 65 years vs. < 50 years: 1.90 [1.22-2.98], P = 0.005) and a high/very high disease risk index (DRI) (1.89 [1.38-2.60], P < 0.001). DRI also influenced relapse rates with a 2.5-fold increased risk observed in patients with high/very high DRI (95% CI 1.63-3.90, P < 0.001).
Conclusion
Our study suggested that dichotomization of donor age did not reveal it to be a major selection factor. However, it remains to be assessed whether HLA factors play a more dominant role, if improved post-HCT strategies have altered the adverse effect of donor age in this population, or if dichotomization may present a limited methodology of modeling donor age, and novel approaches need to be adopted in this contemporary era. Despite the lack of survival differences, older donor age remains a significant predictor of severe acute GVHD risk.