Press release

Menlo Park, CA

December 10, 2022

Orca Bio Presents Data Demonstrating its Lead Investigational High-Precision Cell Therapy Orca-T Significantly Improved Relapse-Free Survival at 64th ASH Annual Meeting

Updated data from Phase 1b/2 trials include 151 patients with acute myeloid leukemia, acute lymphocytic leukemia, myelodysplastic syndromes and other hematologic malignancies

Relapse-free survival was 87% at one year in a group of 71 patients who received the preferred conditioning regimen being used in the Precision-T Phase 3 Study of Orca-T

Data also showed improved graft-versus-host disease-free, relapse-free survival rates and overall survival rates at one year with Orca-T compared to standard of care

Precision-T is ongoing and enrolling patients at transplant centers across the U.S.

MENLO PARK, CA, Dec. 10, 2022 – Orca Bio, a late-stage biotechnology company developing high-precision cell therapies for the treatment of cancer, genetic blood disorders and autoimmune diseases, today presented updated positive clinical data on its lead investigational cell therapy, Orca-T, during an oral presentation at the 64th American Society of Hematology (ASH) Annual Meeting.

The data demonstrated a significant improvement in relapse-free survival (RFS) at one year with 87% in 71 patients who received Orca-T and busulfan, fludarabine, and thiotepa (BFT) conditioning. BFT is the preferred conditioning regimen used in Precision-T, the ongoing Phase 3 pivotal study of Orca-T. Additionally, across all 151 patients, there was an increase in graft-versus-host disease, relapse-free survival (GRFS) rates and overall survival rates at one year with Orca-T compared to an independent cohort.

“Today, providers must balance treatment decisions with the goal of fighting cancer while minimizing toxicities. With a standard allogeneic transplant, highly myeloablative conditioning regimens can lead to reduced rates of patient relapse, but can also increase rates of non-relapse mortality,” said Everett Meyer, M.D., Ph.D., primary investigator. “It is encouraging to see that the use of Orca-T across multiple hematological malignancies resulted in a remarkable improvement in relapse-free and overall survival while lowering the rate of serious toxicities compared to standard of care allogeneic hematopoietic stem cell transplants.”

The results of the patient subgroup conditioned with BFT were presented today along with pooled results from the single-center Phase 2 and multi-center Phase 1b trials from 151 patients treated with Orca-T with acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), myelodysplastic syndromes (MDS) and other hematological malignancies. For comparison purposes, an independent Center for International Blood and Marrow Transplant Research (CIBMTR)-based cohort was identified consisting of patients with AML, ALL or MDS who received a standard of care allogeneic hematopoietic stem cell transplant.

Results demonstrated that patients conditioned with BFT and treated with Orca-T experienced:

  • 87% RFS at one year among all groups, including minimal residual disease positive acute leukemia patients.
  • 81% GRFS at one year.
  • 0% non-relapse mortality and only 5% moderate-to-severe chronic GvHD at one year.
  • 94% overall survival (OS) at one year.

In pooled results from all patients treated with Orca-T, patients experienced:

  • 70% GRFS at one year compared to 21% in the CIBMTR-based cohort.
  • 4% non-relapse mortality at one year compared to 10% in the CIBMTR-based cohort.

  • 88% OS at one year compared to 68% in the CIBMTR-based cohort.

Importantly, Orca-T was manufactured reliably and delivered with vein-to-vein times of 72 hours or less across the U.S.

“These relapse-free and overall survival rates from more than 150 patients treated with Orca-T are very encouraging, and we are extremely pleased to see the strong results of patients who were given the preferred conditioning regimen used in our pivotal Phase 3 trial,” said Ivan Dimov, Ph.D., co-founder and chief executive officer of Orca Bio. “These new data continue to reinforce the potential of this high-precision cell therapy to become a better treatment option for patients and transplant physicians. We remain laser-focused on advancing Orca-T through Precision-T and ultimately on delivering the therapy to more patients in need.”     

The full presentation is available on

About Orca-T

Orca-T is an investigational high-precision allogeneic cellular therapy consisting of infusions containing regulatory T-cells, conventional T-cells and CD34+ stem cells derived from peripheral blood from either related or unrelated matched donors. Orca-T has received Regenerative Medicine Advanced Therapy (RMAT) designation from the U.S. Food and Drug Administration and is being studied to treat multiple hematologic malignancies.

About Orca Bio

Orca Bio is a late-stage biotechnology company developing purified, high-precision cell therapies for the treatment of cancer, autoimmune diseases and genetic blood disorders. Our investigational therapies are designed to deliver better survival rates with dramatically fewer risks than standard allogeneic stem cell transplants, like graft versus host disease and other debilitating transplant-related toxicities. At Orca Bio, we hope to not only replace patients' blood and immune systems with healthy ones, but restore their quality of life. For more information, visit and follow Orca Bio on Twitter: @orcabio.


Corporate Communications

Investor Relations

Joshua Murray