Comparison of allogeneic transplant versus chemotherapy for relapsed childhood acute lymphoblastic leukaemia in the MRC UKALL R1 trial

Background: Although reinduction rates are good for children with relapsed acute lymphoblastic leukaemia there is no consensus on whether bone marrow transplantation (BMT) is the most effective treatment to prolong second rem ission. Patients and methods: Analyses comparing the outcome of related donor allog eneic BMT (related allograft) with chemotherapy are unreliable because of s election biases. To avoid these biases, the MRC UKALL R1 trial was analysed by HLA-matched donor availability. Results: No significant difference in outcome was found between the donor a nd no donor groups. The donor group had a non-significant eight-year event- free survival (EFS) advantage of 8% (95% confidence interval = -9%-24%) ove r the no donor group. Patients with a first remission less than two years a ppeared to benefit most from having a donor, although the effect was only m arginally significantly different from patients with longer first remission . Analysis by treatment received gave similar results, with BMT patients ha ving a 5% (P = 0.8) eight-year EFS advantage over patients who received che motherapy. Conclusions: Related allograft was not found to be significantly better tha n chemotherapy, but there was the possibility of a moderate EFS benefit wit h related allograft, especially in patients with a short first remission.