New, Affirming Hematopoietic Cell Transplant Results Highlight Approaches to Increase Patient Access at 2025 Tandem Meetings

Eighty-four percent overall survival at one year exceeds primary endpoint; results reaffirm the safety, efficacy and feasibility of using HLA-mismatched unrelated donors (MMUD) for all patients, regardless of conditioning approach

Additional oral presentation highlights imperatives for improving clinical trial support and participation for patients and caregivers

MINNEAPOLIS, February 15, 2025 — NMDP^SM, a global nonprofit leader in cell therapy, will present new, interim data from its prospective, multi-center phase II ACCESS trial that exceeded the primary endpoint of overall survival (OS) at one year [84% v. 75%] for adult patients with hematologic malignancies receiving mobilized peripheral blood stem cells (PBSC) from HLA-mismatched unrelated donors (MMUD) (abstract #84)—as well as findings identifying support infrastructure to increase participation and access for ethnically-diverse patients. Conducted through CIBMTR® (Center for International Blood and Marrow Transplant Research®)—a research collaboration between the Medical College of Wisconsin® and NMDP—this industry-advancing research, among others, will be presented on Friday, Feb. 14 and Saturday, Feb. 15 at the 2025 Tandem Meetings in Honolulu, Hawaii.

"Our ACCESS trial and other research are advancing not only critical transplantation evidence, these data are also uncovering insights on how we continually serve comprehensive, unmet patient needs that impact outcomes—embodying our research mission to find a donor for all patients in need," study co-author Steven Devine, MD, chief medical officer, NMDP, and senior scientific director, CIBMTR, said.

The ACCESS trial is the second in a series of NMDP-sponsored Donor for All prospective trials, and builds upon evidence from the groundbreaking 15-MMUD study,1 which showed that using a post-transplant cyclophosphamide (PTCy)-based approach was effective in preventing life-threatening graft-versus-host disease (GVHD) resulting in favorable outcomes in adults with hematologic malignancies receiving bone marrow transplants from MMUDs. These trials examine how MMUD transplants can improve access and outcomes for patients without fully matched donors, which have traditionally shown worse outcomes. Ethnically diverse patients are disproportionally impacted, as these historical barriers have prevented them from successfully achieving transplant.

Interim results from the ACCESS trial sought to determine whether OS in adult patients receiving myeloablative conditioning (MAC) followed by PBSC grafts from MMUD, which account for roughly 80% of all grafts facilitated through NMDP, would be comparable to 15-MMUD results that used bone marrow. One-year OS post-transplant was 84% versus 72% in 15-MMUD, and one-year GVHD-free, relapse-free survival was 48% versus 38%—reinforcing the safety, efficacy and feasibility of MMUD transplant for patients receiving PBSC as a graft source.

This cohort included 75 patients averaging 46 years old with most receiving transplant to treat acute leukemia. Enrolled at 18 U.S. transplant centers, patients were transplanted with donors matched at 4-7/8 HLA-loci (HLA -A, -B, -C, and -DRB1), with the majority matched at 7/8 (69%). Notably, 71% of patients enrolled were of ethnically diverse ancestry.

"These are excellent results, reaffirming conclusions from previous studies and underscore the strong evidence base behind using MMUD to expand patient access to life-saving therapy," said Monzr M. Al Malki, MD, associate professor, Department of Hematology & Hematopoietic Cell Transplantation, City of Hope; presenting author and ACCESS study co-chair. "The research suggests that even with a 5/8 match, overall survival is strong, which would open the door to transplant for thousands of patients without a fully matched donor available."

Researchers will also present insights from an analysis of the 268 adult patients participating in the MAC and reduced intensity conditioning (RIC)2 cohorts of ACCESS, who collectively achieved a 79% OS (abstract #65). Approximately half (51%) were ethnically diverse and were younger [averaging 55.5 years old], reporting lower educational attainment, higher financial toxicity and social vulnerability index compared to non-Hispanic White patients. Sixty percent (162/268) of all patients received support services, 56% (90/162) of whom reported ethnically diverse ancestry and most frequently received patient navigation and financial assistance to access and achieve transplant.

"Understanding key patient characteristics and the structural barriers they face is imperative to determining essential support systems to continually serve all patients in need," said Jeffery Auletta, MD, chief scientific director, CIBMTR; senior vice president of health equity, NMDP and study author. "The road from diagnosis to receiving and recovering from transplant is arduous for patients, families and caregivers—addressing and alleviating the burdens associated with a blood cancer diagnosis, particularly for ethnically diverse patients, can help improve patient outcomes."

• Title: Post-Transplant Cyclophosphamide-Based Graft-Versus-Host Disease Prophylaxis Following Mismatched Unrelated Donor Peripheral Blood Stem Cell Transplantation Using Myeloablative Conditioning—Results from the NMDP ACCESS Trial
• Presenting author: Monzr Al-Malki, MD
• Session type and title: Oral Abstract; Session K - Conditioning & Graft Sources
• Abstract number: 84
• Date & time: Saturday, Feb. 15, 11:45 a.m.–noon HST
• Location: Ballroom B, Hawai’i Convention Center (HCC)

• Title: Addressing Patient Representation in Hematopoietic Cell Transplant Clinical Trials: Insights Gained Through the ACCESS Trial
• Presenting author: Jeffery J. Auletta, MD
• Session type and title: Oral Abstract; Session H - Diversity and Graft Sources
• Abstract number: 65
• Date & time: Friday, Feb. 14; 4:15–4:30 p.m. HST
• Location: Ballroom B (HCC)

• Title: HCT Donor Options for Patients without Matched Donors—Impact of Patient HLA and Genetic Ancestry in the NMDP-Sponsored, CIBMTR-Led ACCESS Trial
• Presenting author: Abeer Madbouly, PhD
• Session type and title: Poster; Poster Session: Graft Sources (related, matched and mismatched unrelated, haplo, autologous, cord blood, bone marrow and peripheral blood)
• Abstract number: 356
• Date & time: Thursday, Feb. 13, 6:45–7:45 p.m. HST
• Location: Exhibit Hall 3 (HCC)

• Title: Performing Mismatched Unrelated Donor Transplants: Attitudes, Barriers and Facilitators
• Presenting author: Anna DeSalvo, MS
• Session type and title: Poster; Poster Session: Graft Sources (related, matched and mismatched unrelated, haplo, autologous, cord blood, bone marrow and peripheral blood)
• Abstract number: 367
• Date & time: Thursday, Feb. 13; 6:45–7:45 p.m. HST
• Location: Exhibit Hall 3 (HCC) 

CIBMTR® (Center for International Blood and Marrow Transplant Research®) is a nonprofit research collaboration between NMDPSM, in Minneapolis, and the Medical College of Wisconsin (MCW), 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 680,000 people who have received hematopoietic cell transplantation and other cellular therapies. Learn more at cibmtr.org.

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.

Jess Ayers
media@nmdp.org