Half-matched family donors led to 96 percent survival in a small aplastic anemia study

Johns Hopkins researchers reported that a bone marrow transplant using a half-matched family donor, prepared with lower doses of chemotherapy and radiation and followed by the drug cyclophosphamide, kept 22 of 23 young patients alive. Johns Hopkins Medicine described the results on October 21, 2026. The paper was published August 3 in Blood Advances. Severe aplastic anemia is a rare failure of the bone marrow to make enough red cells, white cells, and platelets. A transplant can replace the damaged blood-forming cells. Only about 25 to 30 percent of patients have a fully matched sibling, and a matched unrelated donor can be harder to find for people who are underrepresented in registries.

The team reviewed 31 patients, ages 2 to 20, transplanted at Johns Hopkins from 2014 through 2024. Twenty-three received the reduced-intensity approach with post-transplant cyclophosphamide. Twenty-one of those grafts came from half-matched relatives, and two from fully matched siblings. Twenty-two of the 23 survived, which is the 96 percent figure. All 14 whose disease had come back or had not fully responded to earlier treatment survived, as did eight of nine who had not been treated before. Eight other patients, given a different matched-sibling regimen, also survived. At one year, survivors on the newer approach had at least 95 percent donor-derived blood cells, and every survivor was off transfusions at last follow-up. Serious graft-versus-host disease was uncommon, and 95 percent of survivors no longer needed immune-suppressing medicine at one year. Some patients had kidney problems or changes in reproductive hormones.

The authors say the study was small and that longer follow-up is needed before late effects are fully known. The 96 percent is survival in this group of 23. It is not a promise for every child with the disease, and it is not a comparison that proves the approach is better than every other transplant.