HLA-identical marrow transplantation during accelerated-phase chronic myelogenous leukemia: analysis of survival and remission duration

Results of HLA-identical allogeneic marrow transplantation were analyzed for 66 patients with accelerated-phase chronic myelogenous leukemia (CML). Multivariate proportional hazards regression models were used to determine disease-related and transplant-related factors associated with posttransplant mortality and relapse. The projected 5- year survival rate was estimated at 18% by the product-limit method. The major causes of death were interstitial pneumonia, infection, and relapse. Splenomegaly at initial diagnosis and longer time interval from diagnosis to transplant were associated with decreased overall survival and event-free survival. Sixteen patients have relapsed between 17 and 1,569 days (median, 486) posttransplant. The use of T- cell-depleted marrow and older age of the donor or recipient were associated with an increased probability of leukemic relapse. Ten of the 16 relapses occurred among the 15 patients who received T-cell- depleted marrow. The actuarial relapse risk 2.5 years posttransplant was 100% in patients administered T-cell-depleted marrow as compared with 25% in patients administered unmodified marrow. The data in this report emphasize the increased risks and relatively poor results that occur when marrow transplantation is deferred until after signs of acceleration appear. When compared with results for patients who received transplants during chronic phase, the poor results seen here in patients administered unmodified marrow stem primarily from increased transplant-related mortality rather than increased relapse risk. The strikingly increased relapse rate associated with the use of T-cell depletion would discourage its use for graft-v-host disease prevention in patients who receive transplants for CML.