Speed of transplant is more critical than match
Important Points
- Patients unlikely to have a fully matched donor should use alternates
For patients unlikely to have a fully matched donor, their team should quickly switch to searching for alternate (mismatched) donors
Results of a new study show transplant should not be delayed waiting for a fully matched donor.
BMT can cure some cancers and blood disorders. However, 2 out of 3 patients do not have a completely matched sibling who can donate to them.
In the past, BMT might be delayed for months during the search for a fully matched unrelated donor. Meanwhile, patients got sicker and needed more treatment.
After a new study, doctors say that no one should wait long for BMT. People who are very unlikely to have a matched donor should quickly get BMT from a mismatched donor. Newer approaches, such as using post-transplant cyclophosphamide, can prevent side effects from the mismatch.
The likelihood of having a fully matched donor depends on genetic markers called HLA, as well as ancestry.
About 1800 people volunteered in a recent clinical trial of donor selection. Everyone had aplastic anemia, leukemia, lymphoma, myelodysplastic syndrome, or sickle cell disease. Researchers used a tool to divide people into 3 groups, by patients’ likelihood of having a fully matched donor:
- Very likely
- Less likely
- Unlikely
Most patients who were unlikely to have a full match got BMT from a mismatched donor. The group that was very likely to have a fully matched donor and those very unlikely to find a fully matched donor took about the same time to get to transplant and had same likelihood to receive BMT.
About 2 years later, survival of the 3 groups of patients was not different.
Doctors said it is more important to have the transplant when you are ready for it than to wait for a fully matched donor.
Keep In Mind
Each person’s health is different. Ask your doctor about treatments.
This plain-language summary was written by Jennifer Motl at the Medical College of Wisconsin and reviewed by an author of the full article. © 2025 by CIBMTR, license CC BY-SA 4.0.
Learn More About
- Finding a blood stem cell donor at NMDP.org
- Clinical trials of mismatched BMT at CTsearchsupport.org
- More study summaries at CIBMTR.org
Source
Stephanie J Lee, Brent Logan, Mary M Horowitz, et al. Primary Results from BMT CTN 1702 - Clinical Transplant-related Long-term Outcomes of Alternative Donor Allogeneic Transplantation. Journal of Clinical Oncology. [Epub ahead of print] Epub 2025 Sept 18. doi:10.1200/JCO-25-00206.
Clinical Trial IDs
BMT CTN 1702; ClinicalTrials.gov NCT03904134
Sponsor
Blood and Marrow Transplant Clinical Trials Network® (BMT CTN®) thanks study participants. BMT CTN, funded by the National Heart, Lung, and Blood Institute and by the National Cancer Institute, is a collaborative effort of 19 core transplant centers/Consortia, The Emmes Company, and the Center for International Blood and Marrow Transplant Research (CIBMTR), which is a research collaboration of the Medical College of Wisconsin (MCW) and NMDP. You may contact CIBMTR, MCW, Clinical Cancer Center, 9200 W. Wisconsin Ave., Suite C5500, Milwaukee, WI 53226, 414-805-0700.
Learn more at BMTCTN.net