PURPOSE: Retrospective comparisons have suggested that adolescents or teenagers with acute lymphoblastic leukemia (ALL) benefit from pediatric rather than adult chemotherapy regimens. Thus, the aim of the present phase II study was to test a pediatric-inspired treatment, including intensified doses of nonmyelotoxic drugs, such as prednisone, vincristine, or L-asparaginase, in adult patients with ALL up to the age of 60 years. PATIENTS AND METHODS: Between 2003 and 2005, 225 adult patients (median age, 31 years; range, 15 to 60 years) with Philadelphia chromosome-negative ALL were enrolled onto the Group for Research on Adult Acute Lymphoblastic Leukemia 2003 protocol, which included several pediatric options. Some adult options, such as allogeneic stem-cell transplantation for patients with high-risk ALL, were nevertheless retained. RESULTS: were retrospectively compared with the historical France-Belgium Group for Lymphoblastic Acute Leukemia in Adults 94 (LALA-94) trial experience in 712 patients age 15 to 55 years. Results Complete remission rate was 93.5%. At 42 months, event-free survival (EFS) and overall survival (OS) rates were 55% (95% CI, 48% to 52%) and 60% (95% CI, 53% to 66%), respectively. Age remained an important bad prognostic factor, with 45 years of age as best cutoff. In older versus younger patients, there was a higher cumulative incidence of chemotherapy-related deaths (23% v 5%, respectively; P < .001) and deaths in first CR (22% v 5%, respectively; P < .001), whereas the incidence of relapse remained stable (30% v 32%, respectively). Complete remission rate (P = .02), EFS (P < .001), and OS (P < .001) compared favorably with the previous LALA-94 experience. CONCLUSION: These results suggest that pediatric-inspired therapy markedly improves the outcome of adult patients with ALL, at least until the age of 45 years.