NMDP and CIBMTR to Present New, Promising Stem Cell Transplantation Trial Data using Mismatched, Unrelated Donors at 2024 ASCO Annual Meeting

NMDP^SM, a global nonprofit leader in cell therapy, and the CIBMTR^® (Center for International Blood and Marrow Transplant Research^®), announced that interim results from the ACCESS trial will be presented as an oral abstract on Friday, May 31 at the American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Ill., demonstrating that adults with hematologic malignancies who received peripheral blood stem cell (PBSC) transplant from HLA-mismatched unrelated donors (MMUD) followed by post-transplant cyclophosphamide (PTCy) graft-versus-host-disease (GvHD) prophylaxis exhibited a 79% overall survival, with a significant 51% GvHD-free, relapse-free survival (GRFS) probability at one-year post transplant. Notably, ASCO also selected this abstract to be presented at its 2024 Best of ASCO program in July.

"We want more patients to survive and thrive ? results from ACCESS to-date have shown positive, significant transplant outcomes and good quality of life for patients," said Monzr M. Al Malki, M.D., Associate Professor, Department of Hematology & Hematopoietic Cell Transplantation, City of Hope; presenting author and ACCESS study co-chair. "These preliminary data provide strong support for inclusion of this novel treatment approach for patients receiving PBSC from partially matched, unrelated donors and advance current evidence demonstrating how more patients can benefit from the potentially curative therapeutic effects of transplant."

In addition to achieving very good OS and GRFS clinical endpoints, adult participants also exhibited low rates of severe acute and chronic GvHD, both at 9%. The NMDP-sponsored ACCESS trial, conducted through the CIBMTR ? a research collaboration between the Medical College of Wisconsin and NMDP ? enrolled 70 adult patients with blood cancers and disorders, including acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), and acute lymphoblastic leukemia (ALL), from 13 participating transplant centers, like City of Hope. All patients in this stratum received reduced intensity conditioning, most often fludarabine/melphalan (63%) or fludarabine/busulfan (20%), and PBSCs from donors matched at 5-7 of 8 HLA loci, predominantly at the 7/8 match level (67%). Notably, half of patients enrolled in the trial were people of color.

"Historically, barriers in access to transplant have been inhibited by two factors: the low availability of matched, related sibling donors; and the substantial variance of matched, unrelated donor availability on international registries, particularly for patients with diverse ancestry ? many of whom already face significant challenges," said study co-author Steven M. Devine, M.D., Chief Medical Officer, NMDP; Senior Scientific Director, CIBMTR. "Our research findings advance our ability to offer more options to patients without a fully matched donor, many of whom are ethnically diverse and have been underserved in receiving potentially life-saving cell therapy."

Addressing Equitable Care: NMDP-led Donor for All Research

Traditionally, finding an available matched, unrelated donor on international registries has been limited for patients with ethnically diverse ancestry ? from as low as 29% for Black or African American patients and 48% for Latino and Hispanic patients versus 79% for non-Hispanic Whites. NMDP's network of transplant centers, many of which participate in CIBMTR trials, are bringing new research to light that is challenging previously established stem cell transplantation science.

ACCESS builds upon findings from the first "Donor for All" trial, a groundbreaking NMDP-sponsored 15-MMUD study, which showed that PTCy was effective in decreasing risk for GvHD in adults with hematologic malignancies receiving bone marrow (BM) transplants from MMUD. Similar to ACCESS, 15-MMUD patients ? 48% of whom were ethnically diverse ? showed a one-year overall survival (OS) rate of 76% and exhibited a low rate of moderate / severe GvHD. Enrolling now, the OPTIMIZE trial is evaluating whether a reduced dose of PTCy will safely and effectively prevent GvHD while reducing infection risk in patients with hematologic malignancies receiving PBSC HCT from MMUDs. Finally, a recent observational study by the CIBMTR presented at the 2024 Tandem Meetings, reported no discernable differences in OS or GRFS for adult patients with hematologic malignancies using MMUD HCT at an 8/8 or 7/8 HLA match level using PTCy GvHD prophylaxis ? increasing the likelihood for patients of all ethnicities of finding a suitable donor to at least 84% and up to 99%.

"Our Donor for All research is the foundational future upon which we are building a new platform protocol using innovative strategies for preventing and treating GvHD, decreasing risk for post-transplant relapse of hematologic malignancies, and in the future, applying MMUD transplant to cure non-malignant conditions, such as sickle cell disease," said Dr. Devine. "Through CIBMTR, we are showing that science can solve the gap in equitable access to transplant, giving new hope to patients worldwide."

2024 ASCO Presentation Details

About CIBMTR^®

CIBMTR^® (Center for International Blood and Marrow Transplant Research^®) is a nonprofit research collaboration between NMDP^SM, in Minneapolis, and the Medical College of Wisconsin, in Milwaukee. CIBMTR collaborates with the global scientific community to increase survival and enrich quality of life for patients. CIBMTR facilitates critical observational and interventional research through scientific and statistical expertise, a large network of centers, and a unique database of long-term clinical data for more than 675,000 people who have received hematopoietic cell transplantation and other cellular therapies. Learn more at cibmtr.org.

About NMDP^SM

At NMDP^SM, we believe each of us holds the key to curing blood cancers and disorders. As a global nonprofit leader in cell therapy, NMDP creates essential connections between researchers and supporters to inspire action and accelerate innovation to find life-saving cures. With the help of blood stem cell donors from the world's most diverse registry and our extensive network of transplant partners, physicians and caregivers, we're expanding access to treatment so that every patient can receive their life-saving cell therapy. NMDP. Find cures. Save lives. Learn more at nmdp.org.