Similar Outcomes for Haplo-, Sibling-Matched Transplant for Lymphoma

Similar survival outcomes were seen in lymphoma patients who underwent related donor haploidentical hematopoietic cell transplantation (Haplo-HCT) using post-transplantation cyclophosphamide (PT-Cy) and those patients who underwent HLA-matched sibling donor transplant (MSD-HCT), according to the results of a study published in the Journal of Clinical Oncology.

In addition, patients who received Haplo-HCT had significantly lower rates of chronic graft-vs-host disease (GVHD) at 1 year.

“Reduced-intensity/nonmyeloablative conditioning followed by Haplo-HCT with PT-Cy should be considered an acceptable option for patients with lymphoma without MSDs,” wrote researchers led by Nilanjan Ghosh, MD, PhD, of Levine Cancer Institute of the Carolinas Healthcare System in Charlotte, North Carolina. “As such, this strategy can broaden the timely applicability of allogeneic (allo)-HCT without compromising efficacy and limit the racial barriers for receiving this potentially curative treatment option.”

According to the study, T-cell–replete allografts from haploidentical donors are associated with high rates of GVHD, nonrelapse mortality, and graft rejection. Recently, using new prophylactic approaches, including PT-Cy, clinicians have been able to reduce the morbidity associated with Haplo-HCT.

For this analysis, Ghosh and colleagues evaluated 987 adults with lymphoma taken from the Center for International Blood Marrow Transplant Research registry to compare outcomes after Haplo-HCT with PT-Cy (n = 180) and MSD-HCT (n = 807). Patients in the haploidentical group received GVHD prophylaxis with PT-Cy with or without a calcineurin inhibitor and mycophenolate. The MSD group received calcineurin inhibitor–based GVHD prophylaxis.

After a median follow-up of 3 years, the researchers observed similar rates of 28-day neutrophil recovery (95% vs 97%), but delayed 28-day platelet recovery in the haploidentical group (63% vs 91%; P = .001).

Although the cumulative incidence of acute GVHD at day 100 was similar between the two groups of patients, chronic GVHD at year 1 was significantly lower in patients who underwent Haplo-HCT with PT-Cy (12% vs 45%; P < .001). Multivariate analysis confirmed that patients who underwent Haplo-HCT had a lower risk for chronic GVHD (relative risk, 0.21 [95% CI, 0.14–0.31]; P < .001).

“Although it is plausible that the low chronic GVHD rates observed with Haplo-HCT are in part due to the frequent use of bone marrow as graft source in this cohort, it is important to point out that unlike myeloablative allografts, in the setting of reduced-intensity conditioning transplantation bone marrow grafts have not been consistently shown to be associated with reduced chronic GVHD risk,” the researchers wrote. “Effective depletion of alloreactive donor T cells by PT-Cy along with the use of bone marrow as the predominant graft source are likely major drivers of reduced chronic GVHD risk after Haplo-HCT in our study.”

The most common cause of death in the study was recurrent or progressive disease. The 3-year rates of nonrelapse mortality, relapse/progression, progression-free survival, and overall survival were all similar between the two groups.

“To date, no large prospective or registry data are available to suggest that alternative donor HCT for hematologic malignancies in general and lymphoma in particular could provide outcomes comparable to MSD-HCT,” the researchers wrote. “Additional analyses in collaboration with European Group for Blood and Marrow Transplantation are being planned to validate these results in a larger international patient cohort.”