Tregzi (Allogeneic Treg Therapy) — Drug Monograph
Brand names: Orca-T
Drug class: Other
Mechanism of Action
Tregzi (Orca-T) is an allogeneic cell therapy product composed of highly purified CD4+CD25+CD127lo regulatory T cells (Tregs) combined with conventional T cells (Tcons) derived from HLA-matched allogeneic donors. The product replaces the standard unmanipulated peripheral blood stem cell (PBSC) graft used in allogeneic hematopoietic stem cell transplantation (HSCT). Tregs suppress alloreactive conventional T cells by secreting immunosuppressive cytokines (IL-10, TGF-β) and through contact-dependent mechanisms, thereby preventing the pathological graft-versus-host immune response that…
FDA Indications
- Prevention of chronic graft-versus-host disease (cGVHD) in adults undergoing allogeneic hematopoietic stem cell transplantation (HSCT) from an HLA-matched related or unrelated donor (FDA accelerated approval June 2026; based on ORC-2 and ORC-3 clinical data)
Common Side Effects
- Infusion reactions (fever, chills, rigors)
- Cytopenias related to conditioning regimen
- Nausea and vomiting (conditioning-related)
- Mucositis (conditioning-related)
- Fatigue
- Hypertension (tacrolimus)
- Hypomagnesemia (tacrolimus)
- Acute GVHD (skin, GI, liver)
- Infections (bacterial, CMV, EBV)
Clinical Pearl
Tregzi (Orca-T) represents a paradigm shift from pharmacologic GVHD prophylaxis to a cellular immunoengineering approach. By infusing a defined Treg:Tcon ratio to replace the standard graft, it aims to reduce chronic GVHD incidence without sacrificing graft-versus-leukemia activity. Unlike other cell therapies, it is given within the transplant procedure itself. The critical distinction from other CAR-T products is that graft failure — not CRS — is the primary life-threatening risk. Sponsor…