Press release

MENLO PARK, CA, February 16, 2023 – Orca Bio, a late-stage biotechnology company developing high-precision cell therapies for the treatment of cancer, genetic blood disorders and autoimmune diseases, today announced data from the company’s investigational high-precision cell therapy programs, Orca-T and Orca-Q, were presented in three oral presentations at the 2023 Transplantation & Cellular Therapy Meetings of ASTCT and CIBMTR.

Positive data on Orca-T was presented from the single-center Phase 2 and multi-center Phase 1b trials of patients with acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), myelodysplastic syndromes (MDS) and other hematological malignancies. Outcomes with Orca-T appeared to be further enhanced in patients who received a conditioning regimen of busulfan, fludarabine and thiotepa (BFT). At 12 months, the 71 patients in the Orca-T BFT subgroup reported no non-relapse mortality (0%), and high rates of relapse-free survival (87%), graft-versus-host disease-free, relapse-free survival (GRFS) (81%) and overall survival (94%). These data were previously presented at the 64th American Society of Hematology (ASH) Annual Meeting in December 2022.

In a second oral presentation, new data highlighted how expanding the donor pool may help address disparities in access to transplant. Today, approximately 70% of blood cancer patients do not have access to a fully matched related donor, and the likelihood of a patient finding a matched unrelated donor in the U.S. is as low as 29% for some ethnic backgrounds. While the use of human leukocyte antigen (HLA) mismatched donors has increased access to treatment for these patients undergoing allogeneic hematopoietic stem cell transplant (alloHSCT), clinical outcomes have also been associated with significantly worse overall survival, disease-free survival, treatment-related mortality and acute graft versus host disease (aGvHD). In a small cohort (n=8), Orca-T demonstrated promising results in patients with HLA mismatched (7/8) donors, including no cases of severe GvHD or non-relapse mortality and 100% overall survival to date. While this early data is encouraging, more studies of Orca-T in this patient population are ongoing and will provide additional clinical data in this setting.

"As we continue to enroll patients in our pivotal Phase 3 trial of Orca-T, we are extremely encouraged by its continued potential to improve relapse-free and overall survival rates,” said Ivan Dimov, Ph.D., co-founder and chief executive officer of Orca Bio. “Beyond its promise to enhance outcomes and reduce deadly, transplant-related risks, this early evidence that Orca-T may improve clinical outcomes in patients who can’t find a fully matched donor is an important step toward our ultimate goal of offering a safe and effective treatment to all patients who may benefit.”

Orca Bio also presented findings from a Phase 1 multi-center trial of its second investigational cell therapy, Orca-Q, showing that patients with haploidentical – or half-matched – allogeneic hematopoietic stem cell donors, experienced no moderate-to-severe chronic GvHD (0%) and an improved GRFS rate (75%). Orca-Q is a proprietary composition of enriched CD34+ stem cells combined with specific T cell subsets derived from haploidentical donors. Unlike standard of care haploidentical alloHSCT, Orca-Q does not require post-transplant cyclophosphamide (PTCy). These data were also previously presented at the ASH Annual Meeting.

“A haploidentical stem cell transplant is currently the only curative treatment option available for the majority of blood cancer patients who lack a matched donor, but providers often find themselves balancing the risk of relapse and the risk of debilitating side effects like GvHD, infections and other toxicities,” said Samer Srour, M.D., Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas MD Anderson Cancer Center. “These interim findings show patients treated with Orca-Q experienced improved outcomes with significantly fewer transplant-related toxicities, suggesting this novel cell therapy could help to address this critical unmet medical need.”

Links to the abstracts follow:

Oral Presentation Title: Precision-Engineered Cell Therapy Orca-T Demonstrates High Relapse-Free Survival at 1 Year While Reducing Graft-Versus-Host Disease and Toxicity

Oral Presentation Title: Orca-T, a High-Precision Cell Therapy, for the Treatment of Hematologic Malignancies in Patients with 7/8 Mismatch Donors

Oral Presentation Title: Orca-Q Demonstrates Favorable GvHD-and-Relapse-Free Survival with Haploidentical Donors without Post-Transplant Cyclophosphamide

Poster Presentation Title: Estimating the Current and Future Costs and Health Outcomes of Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation (Allo-HCT)