Allogeneic Hematopoietic Cell Transplantation in the Elderly Results in Similar Survival with Matched Related or Unrelated and Haploidentical Donors: A Report from the Société Francophone De Greffe De Moelle Et De Thérapie Cellulaire (SFGM-TC)

Introduction

Higher patient age is no longer considered to be a barrier for allogeneic hematopoietic cell transplantation (HCT). We sought to study the impact of different types of donors on the outcomes of HCT in subjects aged 65 years (y) or more, and to evaluate the determinants of these outcomes.

Methods

SFGM-TC registry data on first HCTs performed between January 2013 and July 2021 in patients aged 65 y or more, with myeloablative or reduced-intensity conditioning, and a 10/10 human leukocyte antigen (HLA) matched sibling donor (MSD), matched unrelated donor (MUD) or haploidentical donor (HAP) were analyzed. Main exclusion criteria were: MSD/MUD-HCT performed without anti-T lymphocyte globulin (ATG), and HAP-HCT performed without post-transplant cyclophosphamide (PTCY). Univariate analyses according to donor type, as well as multivariable analyses were performed.

Results

A total of 1176 patients met the eligibility criteria (215 MSD, 721 MUD, 240 HAP). Median follow-up was 2.8 y. In univariate analysis, there was no difference between donor types in terms of 3-y overall survival (OS: MSD 50%, MUD 49%, HAP 49%, p=0.52), progression-free survival (PFS: MSD 41%, MUD 45%, HAP 44%, p=0.51) and graft-versus-host disease-free, relapse-free survival (GRFS: MSD 34%, MUD 32%, HAP 35%, p=0.67). With MSD, the cumulative incidence of progression at 3 y was significantly higher at 47% (MUD 29%, HAP 29%, p<0.001), and non-relapse mortality (NRM) significantly lower at 12% (MUD 26%, HAP 27%, p<0.001). These MSD results were confirmed in multivariable analysis. Incidence of acute graft-versus-host disease (GVHD) at 180 days was lower with MSD: grades II-IV 21% (MUD 35%, HAP 38%, p<0.001) and grade III-IV 8% (MUD 13%, HAP 15%, p=0.05). Incidence of chronic GVHD at 2 y was comparable between MSD, MUD and HAP transplants: moderate to severe 14%, 18% and 15%, respectively, and severe 5%, 6% and 5%, respectively.

Conclusions

In patients aged 65 y or more, MSD/MUD HCT performed with ATG and HAP HCT performed with PTCY yielded similar survival outcomes. MSD HCT is associated with a lower acute GVHD and NRM but a higher relapse risk. Reducing the toxicity of MUD and HAP HCT may yield better results than with MSD HCT in this population.

_{Acknowledgements: Nicole Raus, Data manager coordinator, SFGM-TC. Viviane Fossat, Secretary, SFGM-TC.}