Update of St Jude Study XI for childhood acute lymphoblastic leukemia.

We treated 358 children with non-B-cell acute lymphoblastic leukemia with intensive multiagent chemotherapy (St. Jude Study XI) in a risk-directed study which used very intensive induction and consolidation therapy followed by continuation treatment comprised of rotating drug pairs given for the entire duration of therapy (except for a third of lower-risk patients). CNS irradiation was reserved for a subset of patients at higher risk of treatment failure. All patients received triple intrathecal chemotherapy (hydrocortisone, ara-C, methotrexate) for prevention of CNS leukemia. At a median follow-up of almost 5 years (all patients are off therapy for 8 months or more), the estimated 5-year event-free survival rate is 72% +/- 4%. The isolated CNS relapse rate is 5% and there has been only a single testicular relapse. The high incidence of secondary acute myeloid leukemia which we previously associated with use of epipodophyllotoxins were highly associated with a single treatment regimen featuring 6 consecutive weeks of epipodophyllotoxin therapy. Study XI was significantly more effective than all previous St. Jude Total Therapy studies (especially for higher risk patients), could be delivered mostly in the outpatient setting, and, except for a single regimen, was largely free of serious side effects.