Dr. Srour on Orca-Q Transplantation in Hematologic Malignancies

Samer A. Srour, MB ChB, MS, assistant professor, Department of Stem Cell Transplantation and Cellular Therapy, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, discusses findings with Orca-Q, an investigational therapy consisting of enriched CD34+ stem cells plus T-cell subsets, in patients with high-risk hematologic malignancies eligible for myeloablative conditioning and allogeneic stem cell transplant.

Encouraging interim findings from the first 26 patients treated in the expansion phase of this ongoing, phase 1, multicenter, first-in-human trial (NCT03802695) were presented at the 2023 Transplantation & Cellular Therapy Meetings, Srour says. Transplanting patients with stem cells from a mismatched unrelated or haploidentical donor presents risks for either graft failure, when patients’ bodies reject the graft, or graft-vs-host-disease (GVHD) after engraftment, when the donor cells reject the recipient, Srour explains.

In the 26 patients treated so far in this study, no patients had primary graft failure, Srour notes. At a median of 12 days, all patients had normal neutrophil engraftments, and at a median of 16 days, all patients had normal platelet engraftments, Srour emphasizes.

Additionally, this trial showed low incidences of GVHD, including both acute GVHD and chronic GVHD (cGVHD), Srour says. For example, at a median follow-up of 211 days, the investigators saw no cases of moderate or severe cGVHD, which is encouraging for patients who receive haploidentical transplant, around 24% to 33% of whom can present with cGVHD, even those who receive post-transplant cyclophosphamide, Srour explains. In this study, of the patients with over 3 months of follow-up, one patient had mild cGVHD, Srour notes.

This study also evaluated outcomes with GVHD-and–relapse-free survival (GRFS) at 1 year. At 1 year, 75% of patients were still alive without cancer or major complications such as GVHD, Srour emphasizes. This GRFS rate is favorable compared with those of historical controls, which tend to fall between 40% to 50%, Srour says. These are all positive outcomes for patients treated for high-risk hematologic malignancies, as the patients in this trial are living without disease and with good quality of life, Srour concludes.

Editor’s Note: This study is sponsored and funded by Orca Bio.