Single Center Randomized Trial of T-reg graft alone versus T-reg graft Plus Tacrolimus for the Prevention of Acute GVHD. Blood advances Bader, C. S., Pavlova, A., Lowsky, R., Muffly, L., Shiraz, P., Arai, S., Johnston, L. J., Rezvani, A. R., Weng, W. K., Miklos, D. B., Frank, M. J., Tamaresis, J. S., Agrawal, V., Bharadwaj, S., Sidana, S., Shizuru, J. A., Fernhoff, N. B., Putnam, A., Killian, S., Xie, B. J., Negrin, R. S., Meyer, E. 2023


Allogeneic hematopoietic cell transplantation (HCT) is a curative therapy for hematological malignancies for which graft-versus-host disease (GVHD) remains a major complication. The use of donor T regulatory cells (Tregs) to prevent GVHD appears promising, including in our previous evaluation of an engineered graft product (T-reg graft) consisting of the timed, sequential infusion of CD34+ hematopoietic stem cells and high-purity Tregs followed by conventional T cells. However, whether immunosuppressive prophylaxis can be removed from this protocol remains unclear. We report the results of the first stage of an open-label single-center phase 2 study (NCT01660607) investigating T-reg graft in myeloablative HCT of HLA-matched and 9/10 matched recipients. Twenty-four patients were randomized to receive T-reg graft alone (n=12) or T-reg graft plus single-agent GVHD prophylaxis (n=12) to determine if T-reg graft alone was non-inferior in preventing acute GVHD. All patients developed full donor myeloid chimerism. Patients with T-reg graft alone versus with prophylaxis had an incidence of grade II-IV acute GVHD of 58% versus 8% (p=0.005) and grade III-IV of 17% versus 0% (p=0.149), respectively. The incidence of moderate to severe chronic GVHD was 28% in the T-reg graft alone arm versus 0% with prophylaxis (p=0.056). Among patients with T-reg graft and prophylaxis, CD4+ T cell:Treg ratios were reduced after transplantation, gene-expression profiles showed reduced CD4+ proliferation, and the achievement of full donor T cell chimerism was delayed. This study indicates that T-reg graft with single-agent tacrolimus is preferred to T-reg graft alone for the prevention of acute GVHD. Clinical Trial #: NCT01660607.

View details for DOI 10.1182/bloodadvances.2023011625

View details for PubMedID 38091578