Orca-T May Be “Important Step Forward” in Hematologic Malignancy Care

In October 2025, the FDA granted priority review to Orca-T as a treatment for patients with acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), and myelodysplastic syndrome (MDS) undergoing hematopoietic stem cell transplantation.¹ The agency is currently evaluating the biologics license application for Orca-T after extending its review period in light of newly submitted chemistry, manufacturing, and controls data.²

Ahead of the potential approval, CancerNetwork^® spoke with Wendy Stock, MD, about how the availability of Orca-T may transform the treatment paradigm across different hematologic malignancies. The conversation touched upon supporting efficacy and safety findings from the phase 3 Precision-T trial (NCT04013685), which included an improvement in graft-versus-host disease–free survival with Orca-T vs conventional transplantation strategies. Stock also discussed potential next steps for further improving transplantation outcomes in the field, as ongoing studies assessing preparative regimens and other strategies may yield additional progress.

Stock is the Anjuli Seth Nayak Professor of Medicine, cochair of the Leukemia Committee for the National Cancer Institute–supported Alliance for Clinical Trials in Oncology, and a coleader of the Clinical and Experimental Therapeutics Research Program at the University of Chicago Medicine Comprehensive Cancer Center.

CancerNetwork: What might the potential FDA approval of Orca-T mean for patients with different hematologic malignancies, including ALL, AML, and MDS?

Stock: The potential approval of [Orca-T] is quite exciting in the sense that it will hopefully allow patients to [experience] better outcomes after allogeneic transplant for these disorders. The hope is that the allogeneic transplant is a potentially curative procedure for these malignancies. Making it safer and potentially even more effective is something that we all strive for on a daily basis. This is an exciting possibility.

Mechanistically, what characteristics differentiate Orca-T from conventional therapeutic strategies in these hematologic malignancies?

Orca-T is a cellular therapy product. The goal of the Orca-T product is that [when] you’re infusing these regulatory T cells, [they] will modulate graft-vs-host disease and potentially allow for quicker immune reconstitution in patients undergoing allogeneic transplant. This is an approach that has never been used before in the setting of [allogeneic] transplant for the prevention of graft-vs-host disease. It’s quite exciting that this cellular component is added to the stem cell product to enrich it for regulatory T cells, which will modulate graft-vs-host disease.

What do findings from the phase 3 Precision-T trial show about the potential efficacy of Orca-T in these patient populations?

The study included all these types of patients undergoing allogeneic transplant. It was a randomized prospective trial—the best kind of design possible—and the results were quite clear in terms of benefit and the primary end points of the trial, which were a reduction in graft-versus-host disease. There were quite clearly different outcomes for the patients who received Orca-T than those who were in the control group. Interestingly, the other thing was that there was a hint, or a suggestion, that immune reconstitution was also improved, potentially resulting in better survival rates overall for these patients. [These are] quite exciting data.

How does the safety and tolerability of Orca-T compare with conventional transplantation strategies?

The safety data were very good. It did not seem to cause any kind of specific additional toxicity. Of course, if one can minimize the risk of acute graft-versus-host disease, where a lot more immune suppression is needed in that setting, and you reduce the toxicity of the transplant [and] reduce the risk of transplant-related, or treatment-related, infections and complications of the other immunosuppressive agents, which are much more toxic in terms of risk of infection and organ toxicity [like] nephrotoxicity, then you’ve done a huge service for these patients.

What are the next steps for research in AML, ALL, and/or MDS? What other anticipated developments in these disease types may impact the treatment paradigm?

This one is specifically a transplant regimen-related improvement, which is tremendous. One of the big challenges in the world of leukemia is having patients enter the transplant with the lowest disease burden possible. One of the big challenges now is improving transplant outcomes. We know patients who enter transplant in a molecularly deep remission are the ones who do the best, regardless of the transplant preparative regimen. [The other challenge is] potentially [developing] additional therapies that could be used after transplant to minimize the risk of relapse. There are other studies ongoing trying to improve preparative regimens. But this is potentially a huge step forward for all patients undergoing allogeneic transplant for the leukemias and myeloid-related malignancies like MDS and potentially even myeloproliferative neoplasms.

What do you hope others take away from this conversation?

This is another important step forward in making allogeneic transplant, which is still an incredibly important yet very fraught procedure to potentially cure these very high-risk leukemias, a safer and more effective process. Given the safety data, the efficacy data, and the promise of this approach for future generations of patients, while potentially even optimizing it more with even more cell-specific therapies, it is a great step forward.

References

1. Orca Bio announces FDA acceptance and priority review of the biologics license application (BLA) for Orca-T to treat hematological malignancies. News release. Orca Bio. October 6, 2025. Accessed April 16, 2026. https://tinyurl.com/urwb7244
2. Orca Bio announces FDA review extension of BLA for Orca-T for the treatment of hematologic malignancies. News release. Orca Bio. April 1, 2026. Accessed April 16, 2026. https://tinyurl.com/5atyjxbz