Acute lymphoblastic leukemia relapsing after first-line pediatric-inspired therapy: a retrospective GRAALL study

The outcome of adult patients with Philadelphia chromosome-negative acute lymphoblastic leukemia (Ph - ALL) relapsing after pediatric-inspired front-line therapy is ill known. Here 229 relapsing Ph - ALL younger adults (18-63 years) treated within the Group for Research on Adult Acute Lymphoblastic Leukemia (GRAALL)-2003/-2005 trials were considered. Salvage regimens consisted of potentially curative therapies in 194 cases, low-intensity therapies in 21, allogeneic stem cell transplant (allo-SCT) in 6 and best supportive care in 8. Overall, 77 patients received allo-SCT after relapse. The median follow-up was 3.1 years. A second complete remission (CR2) was achieved in 121 patients (53%). In multivariate analysis, only younger age <45 years (P = 0.008) and CR1 duration >= 18 months (P = 0.009) predicted CR2. Overall survival (OS) at 2 and 5 years was 19.3% (14-24%) and 13.3% (8-18%), respectively. In CR2 patients, disease-free survival (DFS) at 2 and 5 years was 29.0% (21-38%) and 25% (17-33%). In multivariate analysis, CR1 duration >= 18 months and allo-SCT after relapse were associated with longer DFS (P<0.009 and P = 0.004, respectively) and longer OS (P = 0.004 and P<0.0001, respectively). In conclusion, although younger adults relapsing after pediatric-inspired ALL therapies retain a poor outcome, some of them may be cured if CR1 duration >= 18 months and if allo-SCT can be performed in CR2. New therapies are definitely needed for these patients.