Abatacept-based Graft-Versus-Host-Disease Prophylaxis in Haplo-identical
Hematopoietic Cell Transplant: Single Center Experience in a High-Risk
Cohort
Abstract
Post-transplant cyclophosphamide (PTCy) has become the most popular
approach in haplo-identical hematopoietic cell transplant (haplo-HCT).
Although there are reports of a small number of adult patients in the
literature who experienced graft failure and were re-transplanted with a
haploidentical donor with PTCy prophylaxis, there is still insufficient
guidance for patients with specific contraindications/complications to
cyclophosphamide and virtually no data in the pediatric setting.
Abatacept (Aba), a T cell co-stimulation blockade, has been shown in
previous studies to prevent severe acute graft-versus-host disease
(GVHD) with minimal toxicity and durable engraftment. We report the
efficacy of Aba-based GVHD prophylaxis in four pediatrics patients (ages
2-12 years) who received a haplo-HCT with peripheral blood stem cells
(PBSC). Three patients had previous transplants. One patient developed
acute GVHD of skin stage 3 and one patient had both stage 3 skin and
stage 1 GI acute GVHD. Two patients had mild chronic skin GVHD. All 4
patients are alive with full donor chimerism and without disease at 7-23
months follow up, weaning or off immunosuppressive agents with no
complications. Successful haplo-HCT utilizing an Aba- based regimen can
result in reliable engraftment and acceptable GVHD. However, our small
sample size limits generalizability and encourages the consideration of
a larger prospective trial to validate these results in the haplo-HCT
setting.