Though post-transplant cyclophosphamide (PTCy) is widely regarded as the best option for graft-versus-host disease (GVHD) prophylaxis for patients undergoing allogeneic stem-cell transplantation (allo-SCT), little is known about its safety for patients older than 70 years.
To determine the safety of PTCy in this group of patients, researchers from Banner MD Anderson Cancer Center, Gilbert, Arizona, analyzed the results of 46 patients over 70 years old (median age 72 years) who received allo-SCT with PTCy-based GVHD prophylaxis.
All patients received reduced-intensity melphalan-based conditioning and additional prophylaxis, including sirolimus (7 patients), tacrolimus/sirolimus (26 patients), and tacrolimus/sirolimus/T-cell antibody (13 patients). Donor sources included matched unrelated donors, haploidentical donors, and matched/mismatched related donors.
In addition, all patients achieved successful engraftment, and neutrophil engraftment occurred at 21 days (median). At 1 year post-transplant, 32.8% had acute GVHD, with no cases of grade IV acute GVHD, and 20.3% had chronic GVHD.
At day 100, non-relapse mortality was 6.6%, which increased to 34% at 1 year. Overall survival (OS) and GVHD-free, relapse-free survival (GRFS) for the total cohort at 1 year was 60% and 39.4%, respectively. At 3 years, OS and GRFS decreased to 43.7% and 27.3%, respectively. The 1 year OS numbers were higher when observing only the patients who received haploidentical SCT, reaching 87%.
Upon further analysis, the researchers found that patients with a lower Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI) and a low/intermediate Disease Risk Index (DRI) had favorable 1 and 3-year survival rates. Those with an HCT-CI of 0-3 had an OS of 72.8% and 54.8% at 1 and 3 years, respectively. Those with a low/intermediate DRI had an OS of 59.7% and 48.4% at the same time points.
Though the study authors emphasized the need for larger datasets, they concluded that allo-SCT “can be safely performed in elderly patients over age 70 years with PTCy-based GVHD prophylaxis with low NRM, good control of GVHD and acceptable survival.”
Nath R, Kodali M, Kamal A, et al. Post-Transplant Cyclophosphamide (PTCy) Based Graft Versus Host Disease (GVHD) Prophylaxis is Safe and Effective in Elderly Patients over Age 70 Years Undergoing Allogeneic (Allo) Stem Cell Transplantation (SCT). Abstract CT-637. Presented at the 11th Annual Meeting of the Society of Hematologic Oncology; September 6-9, 2023; Houston, Texas.