The approval of Tregzi—the first regulatory greenlight for Orca Bio—was based on a Phase 3 study in which patients on the therapy were twice as likely to survive without cancer relapse and without chronic GVHD compared with conventional allogeneic transplant.
The FDA has greenlit Orca Bio’s allogeneic T cell–based immunotherapy to reduce graft-versus-host disease in patients being treated for blood cancers. Tregzi marks the first approval of a cell therapy using regulatory T cells, according to the biotech.
Tregzi is also Orca’s first approved therapy, “validating the company’s high-precision platform and the potential of its pipeline,” the California-based company said in a Tuesday press release.
“Today’s approval marks a defining moment for Orca Bio and for the future of allogeneic transplant, which has long offered curative potential, but also carries significant risks like graft versus host disease,” Orca CEO and co-founder Nate Fernhoff told BioSpace in a Tuesday statement. Tregzi, which uses hematopoietic stem and progenitor cells (HSPCs) to reconstitute the immune system and highly purified regulatory T cells (Tregs) to suppress GVHD, “was developed to build on the foundation of transplant – applying precision science to improve how it is manufactured and delivered,” Fernhoff added.
GVHD is a severe complication that can occur after a stem cell or bone marrow treatment. It arises when donor immune cells attack the recipient’s body, leading to inflammation and tissue damage.
“For patients with blood cancers who need stem cell transplantation, chronic graft-versus-host disease has long been one of the most feared and difficult-to-prevent complications,” Karim Mikhail, acting director of the FDA’s Center for Biologics Evaluation and Research, said in a prepared statement on Tuesday. “Today’s approval offers a genuine new approach that can help reconstitute the immune system while substantially reducing that risk and reflects the promise of what cellular therapy can deliver for patients.”
The FDA nod for Tregzi is based on the results of Orca’s Precision-T Phase 3 study, which tested the therapy in 187 patients with acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), myelodysplastic syndrome (MDS) and mixed-phenotype acute leukemia. The patients were randomly assigned to receive either Tregzi plus single-agent tacrolimus (TAC) or a conventional allogeneic hematopoietic stem cell transplant (alloHSCT) plus TAC/methotrexate.
Patients on Orca’s therapy saw “significantly higher rates of chronic GVHD-free survival,” according to the FDA’s release, with 78% of patients achieving this outcome compared to 38.4% of those who underwent a standard transplant. GVHD-free and relapse-free survival was more than double for patients given Tregzi, while overall survival was 94% with Tregzi and 83% with alloHSCT.
Tregzi’s safety profile was also strong, with side effects “generally consistent with those expected in patients undergoing stem cell transplantation,” according to the FDA.
Robert Negrin, professor of medicine, blood and marrow transplantation at Stanford Medicine, in a prepared statement called Tregzi’s approval “a defining moment for the transplant community.”
