Graft-versus-host disease after an outpatient peripheral blood hematopoietic cell transplant using reduced-intensity conditioning: a single-center LATAM experience.

Background: HLA compatibility predicts allogeneic hematopoietic cell transplant (allo-HCT) and graft-versus-host disease (GvHD) outcomes. There is insufficient information regarding GvHD outcomes for outpatient HLA-identical and haploidentical-HCT employing reduced-intensity conditioning (RIC).

Research design and methods: We compare GvHD outcomes between donor types and report risk factors associated with GvHD. Stem cell source was T-cell replete peripheral blood. GvHD prophylaxis was post-transplant cyclophosphamide (PT-CY), mycophenolic acid, and calcineurin inhibitors for haploidentical (n = 107) and oral cyclosporine (CsA) plus methotrexate i.v. for HLA-identical (n = 89) recipients.

Results: One hundred and ninety-six HCT transplant patients were included. aGvHD and cGvHD frequency were similar between HCT types. aGvHD severity was comparable, but severe cGvHD was less frequent in the haploidentical group (p = .011). One-hundred-day cumulative incidence (CI) of aGvHD for haploidentical and HLA-identical was 31% and 33% (p = .84); 2-year CI of cGvHD was 32% and 38% (p = .6), respectively. Haploidentical recipients had less steroid-refractory cGvHD (p = .043). Patients with cGvHD had less 2-year relapse (p = .003); both aGvHD and cGvHD conferred higher OS (p = .010 and p = .001), respectively. Male sex was protective for steroid-refractory cGvHD (p = .028).

Conclusions: Acute and chronic GvHD rates were comparable between HLA-identical and haploidentical transplant groups. cGvHD severity was lower in the haploidentical group.