Press release

Menlo Park, CA

First Clinical Data From Ongoing Orca-T Trial Shows Significantly Improved 12-Month Graft Versus Host Disease (GvHD)-Free and Relapse-Free Survival (GRFS) in Blood Cancer Patients Receiving a Hematopoietic Stem Cell Transplant (HSCT)

Early multicenter results indicate that Orca-T, a novel approach to HSCT, improves time-to-engraftment, markedly reduces the incidence and severity of GvHD, and significantly improved GRFS at 1 year

MENLO PARK, CA, December 6, 2020 
– Orca Bio, a clinical-stage biotechnology company developing high-precision cell therapies, today announced the first clinical data from its first-generation investigational therapy, Orca-T, in a phase I/II multicenter trial accepted for oral presentation at the 62nd American Society of Hematology Annual Meeting and Exposition.

The results from the single-arm, open-label trial showed that Orca-T (n=50) provided faster neutrophil (median: 12 days vs 14 days, P<0.0001) and platelet (median: 11 days vs 17 days, P<0.0001) engraftment, a decreased incidence of grade 2+ acute graft versus host disease (GvHD) (at 100 days: 10% vs 30%, P=0.005) and chronic GvHD (at 365 days: 3% vs 46%, P=0.0002), and significantly higher 1-year GvHD-free and Relapse-Free Survival (GRFS) (75% vs 31%, P=0.001) when compared to a cohort of patients who received a standard-of-care (SOC) hematopoietic stem cell transplant (HSCT) (n=144). The SOC comparator cohort was derived from contemporaneous patients treated at Stanford University with a conventional allograft.

As of the data cut-off, no patients who received Orca-T had suffered transplant-related mortality; this compares favorably to a SOC cohort (at 365 days: 0% vs 11%, P<0.04). Importantly, Orca-T demonstrated potent anti-leukemic activity in patients with active disease at transplant, suggesting that the decreased GvHD did not come at the expense of graft-versus-leukemia (GvL). While these early results of Orca-T demonstrate feasibility, more extensive studies are needed to characterize the safety and efficacy of the Orca-T approach.

The full presentation (not reviewed by ASH) by Everett Meyer, MD, PhD, Assistant Professor of Medicine, Blood and Marrow Transplantation at Stanford University is available on the

“For many patients with blood cancers, an HSCT is the best hope for a cure. However, despite progress in medical management, many patients still suffer from lethal complications of HSCT. Orca-T is an investigational new drug with the potential to dramatically reduce the complications of bone marrow transplants such as GvHD and bring curative outcomes to more patients,” said Scott McClellan MD, PhD, Senior Medical Director at Orca Bio.

Allogeneic HSCT replaces a patient’s diseased bone marrow with cells from a healthy donor. With certain kinds of blood cancer, these donor immune cells can also eliminate the cancer cells and provide a cure for the patient that is durable. However, the procedure carries serious risks, including graft failure, GvHD, and infection. Orca-T is an investigational cell therapy which is designed to prevent GvHD through the use of high-purity single cell sorted regulatory T cells that promote tolerance of the new immune system for the patient’s normal, healthy tissues.

The high-precision cellular products were successfully manufactured and scaled in a central facility and were delivered to patients at multiple clinical sites with a vein-to-vein time of less than 72 hours. Participating clinical sites include Stanford University; University of California, Davis; Oregon Health and Science University; University of Kansas Medical Center; Sarah Cannon Research Institute, TriStar Health Nashville; and the University of Texas MD Anderson Cancer Center.

“Orca-T is an investigational new drug with the potential to dramatically reduce the complications of bone marrow transplants such as GvHD and bring curative outcomes to more patients.”

Scott McClellan, MD, PhD

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 the standard of care. 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.


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