Long-term results of AIEOP-8805 protocol for acute B-cell lymphoblastic leukemia of childhood

BACKGROUND: Acute B-cell leukemia (B-ALL) is a rare form of pediatric leukemia characterized by a very high-proliferation index, rapid clinical progression, and a high frequency of central nervous system (CNS) involvement. Commonly, it is treated in the clinical trials for Burkitt lymphoma, of which it represents the leukemic counterpart. PROCEDURE: Children with B-ALL diagnosed between 1988 and 1999 were enrolled in the AIEOP-8805 protocol. Treatment included six high-dose chemotherapy courses. No prophylactic CNS irradiation was administered. RESULTS: Sixty-five consecutive patients were enrolled in the study. L3 morphology was observed in 57 of 65 patients (88%). Twenty-five children (38%) had tumor mass in addition to massive bone marrow infiltration; 11 children (17%) had CNS disease at diagnosis. Sixty-two patients obtained complete morphological remission of which 13 suffered a relapse, including 3 with initial CNS involvement. Ten-year overall survival and event-free survival were 77% and 75%, respectively. Neither relevant long-term toxicity nor second malignancies were observed. CONCLUSIONS: The AIEOP-8805 confirmed that short high-dose chemotherapy is highly effective for the treatment of B-ALL without significant long-term adverse sequelae. Therapy modifications to reduce relapse rate, such as the use of anti-CD20 monoclonal antibody and more effective CNS treatment, are being tested