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Assessing HLA-mismatched unrelated donor hematopoietic cell transplantation with post-transplantation cyclophosphamide

February 25 2021

MINNEAPOLIS, Minn., February 25—The National Marrow Donor Program® (NMDP)/Be The Match® announced plans to launch the ACCESS clinical trial titled “A Multicenter Phase II Trial of HLA-Mismatched Unrelated Donor Hematopoietic Cell Transplantation with Post-Transplantation Cyclophosphamide for Patients with Hematologic Malignancies.”  

ACCESS will assess whether transplantation of a peripheral blood stem cell (PBSC) or bone marrow (BM) product from a human leukocyte antigen (HLA)-mismatched, unrelated donor (MMUD) using post-transplant cyclophosphamide (PTCy) based graft-versus-host disease (GVHD) prophylaxis will be safe and feasible and result in a high likelihood of overall survival at one year after hematopoietic cell transplant (HCT). 

ACCESS will have three patient groups—two adult and one pediatric—totaling as many as 180 patients. Patients eligible for ACCESS are those who do not have an available HLA matched sibling or unrelated donor and will receive a MMUD PBSC or BM (pediatric group only) product at one of the approximately 40 participating transplant centers. The study is expected to span three years—two years of enrollment and one year of follow-up.

The ACCESS trial is a follow-up study to the recently completed NMDP/Be The Match-sponsored prospective multicenter Phase II study, called 15-MMUD, that assessed MMUD transplantation using PTCy with bone marrow grafts. That trial successfully met all of the study objectives, with high rates of overall survival and engraftment coupled with a low incidence of severe acute GVHD. Almost 50% of the patients enrolled in that trial were racial/ethnic minorities who did not have an available well-matched donor in the family or on the registry. Many of these patients would likely not have had a transplant were it not for the availability of the clinical trial.  

The ACCESS trial will greatly expand the reach of this approach because the clear majority of allogeneic transplants for adult patients use PBSC grafts. The ACCESS protocol also will explore the safety and efficacy of MMUD BM in pediatric patients with hematological malignancies who lack well matched family and unrelated donor options. The ACCESS trial is another step toward the NMDP/Be The Match goal of democratizing cell therapy and ensuring that access to a suitable donor is no longer a barrier to transplant. 

“Our success with the 15-MMUD study provides compelling evidence that a treatment approach using mismatched unrelated donors is a strong option for patients who don’t have an HLA matched, unrelated donor—most of whom are from diverse racial or ethnic backgrounds,” says Steven Devine, MD, NMDP protocol chair for the ACCESS trial and Chief Medical Officer at Be The Match. “Our efforts aim to achieve a likelihood of a donor match for close to 100% of patients—unprecedented access to a quality donor for everyone.” 

Transplant is a well-established potentially curative therapy for hematological diseases, and the best outcomes are seen in the setting of a well-matched family or unrelated donor.  

“Unfortunately, only 30% of patients will have a well-matched family donor, and only 19-75% a well-matched unrelated donor,” says Bronwen Shaw, protocol officer, Center for International Blood and Marrow Transplant Research® (CIBMTR®). “There is no doubt that patients from racial/ethnic minorities are disproportionately disadvantaged in transplant medicine. This creates a critical need to develop strategies for safe, effective transplant using mismatched donors to expand access to this potentially curative therapy to all patients in need.” 

"The use of PTCy in mismatched unrelated donor transplantation effectively expands transplant access to racial and ethnic minorities. Serving a large population of Hispanic patients, access to this platform allows our program to identify a suitable donor for every patient we evaluate" says Antonio Martin Jiménez Jiménez, MD, Network transplant center chair, University of Miami, Sylvester Comprehensive Cancer Center. 

The NMDP/Be The Match mission is to save lives through cellular therapy. As the global leader in providing a cure to patients with life-threatening blood and marrow cancers like leukemia, lymphoma and other diseases, we manage the world’s largest registry of potential blood stem cell donors and cord blood units. We work with a global network to connect patients to their donor match for a life-saving transplant. Through Be the Match BioTherapies®, we partner with cell and gene therapy companies to support the development and delivery of new therapies. And, we conduct research through our research program, CIBMTR®, (Center for International Blood and Marrow Transplant Research®), in collaboration with Medical College of Wisconsin. 

About Be The Match®

For people with life-threatening blood cancers—like leukemia and lymphoma—or other diseases, a cure exists. Be The Match connects patients with their donor match for a life-saving marrow or umbilical cord blood transplant. People can contribute to the cure as a member of the Be The Match Registry®, financial contributor or volunteer. Be The Match provides patients and their families one-on-one support, education, and guidance before, during and after transplant.

Be The Match is operated by the National Marrow Donor Program® (NMDP), a nonprofit organization that matches patients with donors, educates health care professionals and conducts research through its research program, CIBMTR® (Center for International Blood and Marrow Transplant Research®), so more lives can be saved. To learn more about the cure, visit or call 1 (800) MARROW-2.