FDA Approves Immunotherapy to Reduce Chronic GVHD in Patients With Blood Cancer Undergoing Stem Cell Transplantation

Clinical Summary:

• Based on results from the randomized phase 3 Precision-T trial, the FDA has approved Tregzi for use in matched donor hematopoietic stem cell transplantation in adults with hematologic malignancies. 
• In this multicenter study, Tregzi significantly improved chronic graft-versus-host disease–free survival and reduced the incidence of moderate-to-severe chronic graft-versus-host disease compared with standard unmanipulated allografts, while achieving successful hematopoietic engraftment in all evaluable patients. 
• This approval introduces a novel allogeneic regulatory T cell–based graft platform designed to improve long-term transplant outcomes while reducing chronic graft-versus-host disease.

On June 30, 2026, the US Food and Drug Administration (FDA) approved the first regulatory T cell–based immunotherapy (Tregzi; Orca Bio) for reducing chronic graft-versus-host disease (GVHD) in adult patients with blood cancers undergoing allogeneic hematopoietic stem cell transplantation (HSCT).

Tregzi is a donor-derived cellular immunotherapy composed of purified hematopoietic stem and progenitor cells (HSPCs), regulatory T cells (Treg), and conventional T cells (Tcon). Tregzi was approved for use with a myeloablative preparative regimen to achieve hematopoietic and immunologic reconstitution and improve chronic GVHD-free survival.

This approval was based on results from the phase 3 multicenter, open-label, randomized, controlled Precision-T trial which enrolled 187 adult patients with acute leukemias or myelodysplastic syndrome (MDS). Patients were randomized to receive Tregzi (n = 93) followed by single-agent tacrolimus for GVHD prophylaxis or an unmanipulated allograft (n = 94) followed by tacrolimus plus methotrexate. 

The primary efficacy end point was chronic GVHD-free survival (cGFS), which was defined as the time from HSCT to death from any cause or development of moderate-to-severe cGVHD, as determined by a blinded independent end point adjudication committee using National Institutes of Health consensus criteria. 

After a median follow-up of 8.48 months in the Tregzi arm and 9.03 months in the control arm, the median cGFS was not estimable (95% CI, not estimable to not estimable) with Tregzi compared with 7.3 months (95% CI, 6.3 to 15.5) in the control arm (hazard ratio [HR], 0.26; 95% CI, 0.14 to 0.47; P <.00001). The 12-month cumulative incidence of moderate-to-severe cGVHD was 12.6% (95% CI, 5.3 to 23.1) with Tregzi and 44% (95% CI, 31.3 to 56.1) with the unmanipulated allograft (HR, 0.19; 95% CI, 0.08 to 0.43; P = .00002). 

Among 88 evaluable patients, 100% treated with Tregzi achieved a neutrophil count of at least 500/mm³ within 28 days of infusion, and 60.2% of patients maintained neutrophil counts above 500/mm³ for 3 consecutive days, confirming neutrophil recovery.

The most common adverse reactions were mucositis, diarrhea, rash, viral infections, infections (pathogen unspecified), abdominal pain, vomiting, nausea, bacterial infections, hemorrhage, acute GVHD, edema, and fungal infections (≥20%). The prescribing information includes warnings and precautions for graft failure, GVHD, infusion reactions, secondary malignancies and malignancies of donor origin, and transmission of infectious agents.

Source:

US Food and Drug Administration. FDA approves allogeneic regulatory T cell-based immunotherapy with HSPC and T cells-vldq for use in matched donor hematopoietic stem cell transplantation for adults with hematologic malignancies. Accessed July 1, 2026. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-allogeneic-regulatory-t-cell-based-immunotherapy-hspc-and-t-cells-vldq-use-matched