The cumulative incidence of graft-versus-host disease (GVHD) was higher in patients who received a low CD3-positive T-cell dose during peripheral blood stem-cell product allogeneic transplantation than in those who received a higher dose of CD3-positive cells, according to research presented at the Tenth Annual Meeting of the Society of Hematologic Oncology (SOHO).
“The outcome of allogeneic [hematopoietic stem-cell transplantation] relies on both disease-related factors and transplant-related factors, including the conditioning regimen and immunotherapy exploiting the graft-versus-tumor effect,” the study’s authors wrote. “CD3+ T-cells are the main player in the [graft-versus-tumor] process, but an increased dose of these cells results in an increased risk of acute [GVHD]. We aimed to study whether the T-cell dose of allogeneic peripheral blood stem-cell product influences transplantation outcomes in our patient population.”
Rawan Mustafa, MD, of the King Hussein Cancer Center in Amman, Jordan, and colleagues conducted the study and presented its results at the SOHO meeting.
The researchers performed a retrospective chart review of adults diagnosed with acute myeloid leukemia, acute lymphoblastic leukemia, or myelodysplastic syndrome who underwent mismatched peripheral blood stem-cell product allogeneic transplantation. The study included 35 patients who received transplants between January 2010 and December 2020 from haploidentical donors, single-antigen mismatched related donors, or 2-allele mismatched related donors. Patients were grouped by their dose of CD3-positive T-cells, low (n=18) or high (n=17).
The mean CD3-positive T-cell dose was 13.7×107/kg (range, 2.8-19.7) in the low-dose CD3 group, and the mean dose was 29.7×107/kg (range, 19.8-93.1) in the high-dose CD3 group.
The cumulative incidences of acute GVHD and chronic GVHD were higher in the low-dose CD3 group (60% and 64%, respectively) than in the high-dose CD3 group (40% and 35%, respectively).
However, the 1-year and 2-year overall survival (OS) rates were higher in the low-dose CD3 group (66.7% and 66.7%, respectively) than in the high-dose CD3 group (52.9% and 33.1%, respectively). For the entire cohort, the 1-year OS was 60.9%, while the 2-year OS was 49.6%.
“Although the study showed a trend toward better OS in the low CD3+ dose group, the difference was not statistically significant,” Dr. Mustafa and colleagues concluded.
Mustafa R, Al-Rimawi D, Sarhan D, et al. Impact of T-cell dose on outcome of T cell–replete HLA-mismatched allogeneic peripheral blood stem cell transplantation. Poster CT-098. Presented at the Tenth Annual Meeting of the Society of Hematologic Oncology; September 28-October 1, 2022; Houston, TX.