FDA Approves Tregzi as First Regulatory T Cell Therapy for Chronic GVHD Prevention

The U.S. Food and Drug Administration (FDA) has approved Tregzi, the first regulatory T (Treg) cell-based immunotherapy developed to improve chronic graft-versus-host disease (GVHD)-free survival in adults with high-risk blood cancers undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT).

Tregzi is a donor-derived cellular therapy designed to reduce the risk of chronic GVHD, a serious condition in which donor immune cells attack the recipient's healthy tissues after transplantation. 

The treatment is administered following chemotherapy and before stem cell transplantation to help rebuild the immune system while preserving its ability to fight cancer.

The therapy consists of three cell components: purified hematopoietic stem and progenitor cells (HSPCs), regulatory T (Treg) cells and conventional T (Tcon) cells. 

These are collected from the peripheral blood of an 8/8 HLA-matched related or unrelated donor. The combination is intended to promote immune tolerance and support healthy immune recovery after transplantation.

The approval was based on results from the Phase III PRECISION-T clinical trial involving 187 adults with blood cancers, including acute leukaemia and myelodysplastic syndrome.

At one year, 78% of patients receiving Tregzi remained free from moderate or severe chronic GVHD or death, compared with 38.4% of patients receiving a standard transplant. 

Serious chronic GVHD occurred in 12.6% of Tregzi-treated patients versus 44% in the standard treatment group. The therapy demonstrated a safety profile consistent with stem cell transplantation, with infections being the most commonly reported adverse event.