Second allogeneic bone marrow transplantation for post-transplant leukemia relapse: results of a survey of 66 cases in 24 Japanese institutes.

To assess the consequence of second BMT (BMT2) for leukemia relapse after allogeneic BMT, we analyzed the clinical course of 66 recipients who were treated by BMT2 in Japan. Diagnoses included 29 ANLL, 27 ALL, six CML and four MDS. Durations between the first BMT (BMT1) to relapse and BMT1 to BMT2 were 13.5 +/- 13.7 months and 17.4 +/- 13.9 months, respectively. Donors for BMT2 were replaced in 11 cases. Thirty-one patients were in CR (or CP) at BMT2. Earlier deaths were observed in those who received BMT2 within 12 months after BMT1, mostly caused by regimen-related toxicity and infections. Overall leukemia-free survival rate was 28% at 2 years and 16% at 4 years. Factors influencing the poor prognosis after BMT2 were early (<6 months) relapse, early (<12 months) BMT2, not in remission at BMT2, and ALL. Intensified conditioning did not affect either remission duration or LFS. Among the 39 cases observed for more than 100 days, 18 developed chronic GVHD (cGVHD) and showed longer remission duration than those without cGVHD. Our analysis indicates that BMT2 as treatment for leukemia relapse is effective in selected cases, and exploration of pre-BMT treatment and post-BMT immunotherapy is warranted.