Orca-T: Precision Allograft Demonstrates Promising GVHD Prevention

By Patrick Daly - Last Updated: October 14, 2022

Researchers evaluated the safety and efficacy of Orca-T in patients undergoing allogeneic hematopoietic stem-cell transplantation (allo-HSCT) with myeloablative conditioning. Orca-T is an investigational precision-engineered allograft that uses donor regulatory T cells to improve alloreactive immune response control. According to the lead author, Everett Meyer, MD, PhD, results from phase I and II trials supported that Orca-T may improve graft-versus-host disease (GVHD) outcomes.

The study, published in Clinical Lymphoma, Myeloma & Leukemia, included 41 and 97 patients from a single-center phase I/II study and a multicenter phase Ib study, respectively, who received Orca-T for hematological malignancies.

Orca-T Production and Chronic GVHD Results

Orca-T grafts were produced from granulocyte, colony-stimulating, factor-mobilized peripheral blood from matched related donors (n=72), matched unrelated donors (n=62), or mismatched unrelated donors (MMUD; n=4).

GVHD prophylaxis was tacrolimus (n=127), sirolimus (n=7), and tacrolimus plus mycophenolate in MMUD transplants (n=4). The authors noted that overall time from donor to recipient centers was less than 60 hours for all patients.

After Orca-T treatment, the rate of grade III or higher acute GVHD in the first 180 days was 4%, and the 1-year rate of moderate-to-severe chronic GVHD was 5%. The authors described both rates as low. Orca-T also had a nonrelapse mortality rate of 4%, a GVHD-free relapse-free survival (GRFS) rate of 71%, and an overall survival rate of 90% through 1 year.

Overall, Dr. Meyer and colleagues suggested that Orca-T yielded “a reduction in [chronic] GVHD, improved GRFS, and low toxicity relative to historic data.” They noted that a phase III trial comparing Orca-T with standard of care is currently recruiting.

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