Role of treatment intensification in infants with acute lymphoblastic leukemia: results of two consecutive AIEOP studies.

Fifty-two infants with acute lymphoblastic leukemia (ALL) enrolled in the AIEOP ALL-91 and ALL-95 studies were treated with the intermediate or high risk protocols according to their presenting features and early response to treatment. The 5-year event-free survival was 33.3% (95% CI 12.1-54.5), 53.5% (95% CI 35.7-71.3) and 45.0% (95% CI 31.3-58.7) in the ALL-91 and ALL-95 studies and in the overall cohort, respectively. In the ALL-95 high-risk group (BFM therapy intensified by three blocks and double protocol II) nine of 17 patients treated with chemotherapy only and three of four transplanted patients were alive and in complete remission. The corresponding figures for patients treated in the ALL-91 high-risk protocol (reduced induction and nine blocks) were one of seven patients treated with chemotherapy only and none of two who were transplanted.