Treatment of acute lymphoblastic leukaemia. Comparison of immunotherapy (B.C.G.), intermittent methotrexate, and no therapy after a five-month intensive cytotoxic regimen ((Concord trial). Preliminary report to the Medical Research Council by the Leukaemia Committee and the Working Party on Leukaemia in Childhood.

One hundred and ninety-one cases of acute lymphoblastic leukaemia were entered in a trial in which, for five months, all received cytotoxic therapy with prednisolone, vincristine, mercaptopurine, L-asparaginase, and methotrexate (the latter in high dosage followed by folinic acid). Patients were then randomized to receive immunotherapy (B.C.G.), twice-weekly methotrexate, or no further treatment.One hundred and seventy-seven patients (93%) achieved full remission and at the time of analysis, 26 months from the beginning of the trial, 143 were still alive, including 70 in their first remission. Median "post-intensive" remission lengths were 17 weeks (no treatment), 27 weeks (B.C.G.), and 52 weeks (methotrexate). The prolongation of remission by methotrexate was most evident in those patients with low initial white cell counts. B.C.G. seemed to cause lymphocytosis but was without other conspicuous effect. The incidence of toxic reactions is reported, including an unusually low rate of anaphylaxis with L-asparaginase.These preliminary results are discussed and compared with those of similar trials.