Background: Infants with acute lymphoblastic leukemia (ALL) present with aggressive disease and a poor prognosis. Early relapse within 6-9 months of diagnosis is common. Approximately 75% of infants have MLL-rearranged (MLL-R) ALL with event free survival (EFS) ranging from 20% to 30%. Children's Oncology Group (COG) P9407 used shortened (46 weeks), intensified therapy to address early relapse and poor EFS. Procedure: P9407 therapy was modified three times for induction toxicity resulting in three cohorts of therapy. One hundred forty-seven infants were enrolled in the third cohort. Results: We report an overall 5-year EFS and OS of 42.3±6% and 52.9±6.5% respectively. Poor prognostic factors included age ≤90 days at diagnosis, MLL-R ALL and white cell count ≥50,000/μl. For infants ≤90 days of age, the 5-year EFS was 15.5±10.1% and 48.5±6.7% for those >90 days (P<0.0001). Among infants >90 days of age, 5-year EFS rates were 43.8±8% for MLL-R versus 69.1±13.6% for MLL-germline ALL (P<0.0001). Conclusions: Age ≤90 days at diagnosis was the most important prognostic factor. Despite shortened therapy with early intensification, EFS remained less than 50% overall in MLL-R ALL.
- COG P9407
- Infant ALL
- Intensified therapy without SCT
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health