EFS by randomized treatment.

(A) Event-free survival (EFS) by randomized steroid. The 6-year EFS ± standard error is 85% ± 2% in patients randomized to dexamethasone and 77% ± 2% in patients randomized to prednisone (P = .002). (B) Event-free survival (EFS) by 6-mercaptopurine route randomization during consolidation. The 6-year EFS ± standard error is 82% ± 2% in patients randomized to daily oral (PO) 6-mercaptopurine and 80% ± 2% in patients randomized to weekly intravenous (IV) 6-mercaptopurine in consolidation (P = .2). All patients received oral 6-mercaptopurine during maintenance.