SummaryA retrospective analysis of children with first relapse of acute lymphoblastic leukaemia (ALL), treated on the UKALL R2 protocol at four different hospitals, between June 1995 and December 2002 was performed. Of the 150 children 139 (93%) achieved a second complete remission. The overall survival (OS) and event-free survival (EFS) for the whole group was 56% and 47% respectively. The duration of first complete remission and immunophenotype, but not sites of relapse, were predictive for survival. Using the Berlin-Frankfürt-Münster risk stratification for relapsed ALL, the OS and EFS for standard, intermediate (IR) and high risk (HR) groups were 92% and 92%, 64% and 51%, and 14% and 15%, respectively; P < 0AE0001 for both OS and EFS. In the IR group, those with a very early isolated central nervous system relapse also had a significantly worse outcome (P ¼ 0AE0001). Given the poor outcome of a second relapse, clear strategies are required to identify those in the IR group who will most benefit from stem cell transplantation (SCT). A higher proportion (16%) of induction failures in the HR group suggest the need for novel agents during this phase of treatment, but SCT was associated with a lower relapse rate and better outcome than those treated with chemotherapy alone.

Purpose Safe, effective treatments are needed for pediatric patients with chronic myeloid leukemia in chronic phase (CML-CP). Dasatinib is approved for treatment of adults and children with CML-CP. A phase I study determined suitable dosing for children with Philadelphia chromosome-positive (Ph+) leukemias. Methods CA180-226/NCT00777036 is a phase II, open-label, nonrandomized prospective trial of patients < 18 years of age receiving dasatinib. There are three cohorts: (1) imatinib-resistant/intolerant CML-CP, (2) imatinib-resistant/intolerant CML in accelerated/blast phase or Ph+ acute lymphoblastic leukemia (n = 17), and (3) newly diagnosed CML-CP treated with tablets or powder for oral suspension. Major cytogenetic response > 30% for imatinib-resistant/intolerant patients and complete cytogenetic response (CCyR) > 55% for newly diagnosed patients were of clinical interest. Results Of 113 patients with CML-CP, 14 (48%) who were imatinib-resistant/intolerant and 61 (73%) who were newly diagnosed remained on treatment at time of analysis. Major cytogenetic response > 30% was reached by 3 months in the imatinib-resistant/intolerant group and CCyR > 55% was reached by 6 months in the newly diagnosed CML-CP group. CCyR and major molecular response by 12 months, respectively, were 76% and 41% in the imatinib-resistant/intolerant group and 92% and 52% in newly diagnosed CML-CP group. Progression-free survival by 48 months was 78% and 93% in the imatinib-resistant/intolerant and newly diagnosed CML-CP groups, respectively. No dasatinib-related pleural or pericardial effusion, pulmonary edema, or pulmonary arterial hypertension were reported. Bone growth and development events were reported in 4% of patients. Conclusion In the largest prospective trial to date in children with CML-CP, we demonstrate that dasatinib is a safe, effective treatment of pediatric CML-CP. Target responses to first- or second-line dasatinib were met early, and deep molecular responses were observed. Safety of dasatinib in pediatric patients was similar to that observed in adults; however, no cases of pleural or pericardial effusion or pulmonary arterial hypertension were reported.

Dasatinib 60 mg/m(2) and 80 mg/m(2) once-daily dosing were selected for phase II studies in children with Ph-positive leukemias.