SAN FRANCISCO, Nov. 05, 2026 (GLOBE NEWSWIRE) — Ossium Health, a bioengineering company that built the world’s first bank of organ donor-derived bone marrow, today announced that four abstracts have been selected for presentation at the 68th American Society of Hematology (ASH) Annual Meeting and Exposition, taking place December 12–15, 2026, at the Ernest N. Morial Convention Center in New Orleans, Louisiana.
The featured oral presentation shares Day 180 and Day 365 outcomes from Ossium’s HOPE I Program in patients with acute myeloid leukemia (AML) who received transplants using Ossium’s cryopreserved deceased donor bone marrow. Four of the five evaluable patients received grafts matched at only 4 of 8 HLA alleles. All patients engrafted, and none relapsed or experienced graft failure. Three poster presentations cover emergency rescue transplants, the design of the 300-patient PRESERVE II study, and findings from preclinical research that suggest a biological explanation for the rapid engraftment observed clinically.
“Our organ donor-derived bone marrow is consistently enabling successful unrelated donor transplants even with highly mismatched grafts,” said Kevin Caldwell, CEO, Co-Founder & President of Ossium Health. “We look forward to presenting these updated clinical results along with new preclinical data on a biological mechanism that may help explain the remarkable results we’ve seen.”
Oral presentation: one-year HOPE I data in highly mismatched transplants
In the HOPE I Program, four of the five patients who reached Day 180 (80%) received bone marrow matched at only 4 of 8 alleles, while the fifth received a 6 of 8 match. Despite these mismatches, outcomes were consistently positive:
- Engraftment: 100% of patients achieved neutrophil engraftment, at a median of Day 16 (range: Days 14–20). All patients also achieved platelet engraftment, at a median of Day 21.
- Chimerism: All five patients showed 100% donor chimerism at Days 30 and 60, meaning their blood was produced entirely by the donor marrow.
- Durability: No relapses and no graft failures occurred through Day 180 or Day 365.
- Safety: No serious adverse events were attributed to the Ossium product, and no grade 4 acute graft-versus-host disease (GVHD) occurred. Four patients had grade 1–2 acute GVHD and one had grade 3 . Chronic GVHD in three patients resolved with treatment.
- Survival: Overall survival was 100% at Day 180. One patient died on Day 282 from an influenza-related infection.
Poster presentations
Emergency rescue transplants. A multicenter case series describes four AML patients at three U.S. transplant centers whose planned living donor became unavailable. In two cases, this happened during conditioning, and in one case on the day of transplant. Each patient instead received a transplant with an HLA-mismatched (4/8 to 6/8) Ossium HPC, Marrow graft. All four successfully engrafted at a median of Day 16, and all remain alive with no relapse, graft failure, or chronic GVHD to date.
PRESERVE II study design. PRESERVE II (NCT07710781) is a 300-patient, multicenter study of patients with hematologic malignancies. It compares Ossium’s cryopreserved deceased donor bone marrow with two living donor options: haploidentical related donors and mismatched unrelated donors.
Possible biological mechanism for rapid engraftment with deceased donor marrow. Preclinical research conducted by Ossium and the University of Kansas Medical Center examined the short burst of the signaling protein interleukin-6 (IL-6) that follows brain death. In laboratory studies, a brief, low-dose IL-6 pulse doubled the proportion of the most primitive blood stem cells and helped them survive stress. These findings suggest a possible biological explanation for the rapid engraftment seen in Ossium’s clinical studies.
Presentation details
The ASH abstracts are now available at www.hematology.org. Details of Ossium’s presentations follow:
Oral Session: 721. Allogeneic Transplantation: Conditioning Regimens, Engraftment, and Acute Toxicities: Hemoglobinopathies, Fungus, and Deceased Donor HPCs, Oh My!
Title: Cryopreserved whole bone marrow from deceased donors expands the donor pool in HLA-mismatched allogeneic transplantation: Day 180 and Day 365 update from the HOPE I program
Publication Number: 632
Presenter: Jeremy Pantin, MD, Clinical Director, Adult Transplant and Cellular Therapy Program, Sarah Cannon TriStar Centennial Medical Center
Date and Time: December 13, 2026 at 12:00 PM – 1:30 PM CST
Location: Ernest N. Morial Convention Center – Rooms 243-245
Poster Session: 721. Allogeneic Transplantation: Conditioning Regimens, Engraftment, and Acute Toxicities: Poster II
Title: Cryopreserved deceased donor bone marrow as an emergency rescue allograft following unexpected donor unavailability: A multicenter case series
Publication Number: 4220
Date and Time: December 13, 2026 at 6:00 PM – 8:00 PM CST
Location: Ernest N. Morial Convention Center – Hall F
Poster Session: 721. Allogeneic Transplantation: Conditioning Regimens, Engraftment, and Acute Toxicities: Poster III
Title: Trial in progress: A multicenter, multiple-arm, open-label study of cryopreserved deceased donor bone marrow and living-donor transplantation (PRESERVE II)
Publication Number: 5974
Date and Time: December 14, 2026 at 6:00 PM – 8:00 PM CST
Location: Ernest N. Morial Convention Center – Hall F
Poster Session: 701. Experimental Transplantation: Basic and Translational: Poster III
Title: A brief pulse of interleukin-6, such as occurs following brain death, enhances fitness of primitive bone marrow hematopoietic stem cells for transplantation
Publication Number: 5855
Date and Time: December 14, 2026 at 6:00 PM – 8:00 PM CST
Location: Ernest N. Morial Convention Center – Hall F
Ossium will also exhibit at Booth #904, where attendees can explore more about Ossium’s organ donor-derived bone marrow.
About Ossium Health
Ossium Health is a bioengineering company that leverages its proprietary organ donor bone marrow banking platform to develop stem cell therapies for patients with life-threatening hematologic conditions and musculoskeletal defects. Founded in 2016, the company is led by Kevin Caldwell, CEO, Co-Founder & President, and Erik Woods, Chief Science Officer, Co-Founder & Executive Vice President. Ossium’s manufacturing facility is registered with the FDA and its laboratory is certified under the Clinical Laboratory Improvement Amendments (CLIA). For more information, visit ossiumhealth.com or follow the company on LinkedIn and X.
Media Contact
Jane Griffin
Ossium Health
415-513-5535
press@ossiumhealth.com
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