NMDP ACCESS Trial Shows 80%+ Survival with Mismatched Donor Transplants, Expanding Access for Blood Cancer Patients
核心洞察
The Phase II ACCESS trial demonstrated that patients receiving blood stem cell transplants from mismatched unrelated donors achieved over 80% one-year survival rates, with 86% survival for <7/8 mismatches and 79% for 7/8 mismatches.
The study evaluated 268 adult patients with common blood cancers receiving 4/8 to 7/8 HLA-mismatched peripheral blood stem cell grafts with post-transplant cyclophosphamide, challenging traditional requirements for exact donor matching.
Results show that 99% of patients with common blood cancers can now find a suitable donor, with the median number of available donors increasing from two at 7/8 match level to 83 at 6/8 level.
The Phase II ACCESS trial has demonstrated that patients receiving blood stem cell transplants from mismatched unrelated donors can achieve survival outcomes comparable to those from more closely matched donors, potentially revolutionizing access to life-saving transplants for blood cancer patients. Results presented at the 67th American Society of Hematology (ASH) Annual Meeting show that one-year overall survival exceeded 80% across all mismatch levels, with 86% survival for <7/8 mismatches and 79% for 7/8 mismatches.
Breaking Traditional Transplant Barriers
The NMDP (搜索)-sponsored ACCESS study (NCT04904588) evaluated 268 adult patients with common blood cancers who received 4/8 to 7/8 HLA-mismatched unrelated donor peripheral blood stem cell grafts with post-transplant cyclophosphamide (PTCy). This represents the first study to evaluate PTCy-based regimens in patients receiving peripheral blood stem cell transplants from unrelated donors with as few as 4/8 HLA matches.
"We are fundamentally changing what's possible in transplant medicine and creating a new standard of care for curing common blood cancers," said Steven M. Devine, M.D., chief medical officer at NMDP (搜索) and executive lead at CIBMTR (搜索). "For the first time, we have clear evidence that patients can safely receive a range of mismatched unrelated donor grafts and achieve survival outcomes on par with those from fully matched donors—this is a giant leap forward for transplant science and medicine."
Addressing Historical Disparities in Donor Access
The findings are particularly significant for patients of diverse ancestry, who have historically faced lower chances of finding suitable donors. In the ACCESS trial, 61% of participants in the <7/8 cohort self-identified as other than non-Hispanic White. The study results show that virtually every patient searching international registries now has a greater than 99% likelihood of identifying a suitable blood stem cell donor.
An additional CIBMTR (搜索) analysis demonstrated the profound impact of broadening acceptable match levels. For patients highly unlikely to find an 8/8 match, allowing a <7/8 match offers significantly more potential donors. Among the 62% of ethnically diverse patients included in the five-year analysis, the median number of available donors increased dramatically from two at the 7/8 level to 83 at the 6/8 level.
Comparable Safety and Efficacy Outcomes
The trial demonstrated favorable safety profiles across both cohorts. Non-relapse mortality rates were 13.7% for 7/8 matches and 8.4% for <7/8 matches. Relapse rates were 17.1% for 7/8 matches and 22.8% for <7/8 matches. Moderate-to-severe chronic graft-versus-host disease (GVHD) rates were 11.3% for 7/8 matches and 7.7% for <7/8 matches, regardless of conditioning regimen.
"These results challenge long-held assumptions about the risks of HLA mismatching and demonstrate that PTCy-based regimens can safely extend donor eligibility to nearly all patients in need of transplant, including those from varied backgrounds who are most in need of a suitably matched donor," said Antonio Jimenez-Jimenez, M.D., associate professor of medicine in the division of Transplantation & Cellular Therapy at Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine.
Expanding the Donor for All Initiative
The ACCESS trial is part of NMDP (搜索)'s broader Donor for All initiative, which unites clinical research, data science and operational innovation to close access gaps for patients, especially those of diverse ancestry. Additional trials in this initiative include OPTIMIZE (NCT06001385) and ACCELERATE (NCT06859424).
Results from the reduced-intensity conditioning cohort of ACCESS showed one-year overall survival at 79.6% with relatively low rates of non-relapse mortality (12.5%), chronic GVHD (15.6%) and severe GVHD (3.7%) across HLA match levels. The ACCESS PRO study examining patient-reported outcomes found that quality-of-life scores, physical function and fatigue returned to or exceeded baseline levels one year after transplant, with results comparable to population norms.
Implications for Clinical Practice
The findings suggest a paradigm shift in transplant medicine, where exact donor-patient genetic matching may no longer be essential for preventing life-threatening complications. With donor matching becoming less restrictive, clinicians can now prioritize other factors such as donor age and cell quality to optimize outcomes and further individualize transplant care.
The research builds on NMDP (搜索)'s previous work published in the Journal of Clinical Oncology in June, which demonstrated that patients receiving <7/8 matched grafts achieved outcomes comparable to or exceeding historical 8/8 benchmarks of 75% survival. International registries now total more than 42 million potential donors and more than 760,000 cord blood units, providing an extensive pool for patient matching.
ASH selected the ACCESS abstract for presentation at its 2026 Highlights of ASH program in January, underscoring the significance of these findings for the transplant community.