Effective asparagine depletion with pegylated asparaginase results in improved outcomes in adult acute lymphoblastic leukemia: Cancer and Leukemia Group B Study 9511.

CALGB 9511 used pegaspargase (PEG-ASP) in lieu of the native enzyme. The aim was to compare differences in overall survival (OS) and disease-free survival (DFS) between patients who did and did not achieve asparagine depletion, defined by enzyme levels greater than 0.03 U/mL plasma for 14 consecutive days after at least 1 of 4 planned PEG-ASP administrations. Samples were available from 85 eligible patients. On univariate analyses, the 22 patients who did not achieve asparagine depletion had inferior OS (P = .002; hazard ratio [HR] = 2.37; 95% CI = 1.38-4.09) and DFS (P = .012; HR = 2.21; 95% CI = 1.19-4.13). After adjusting for age, performance status, leukocyte count, and karyotype in a proportional hazards model, both the OS and DFS HRs decreased to 1.8 (P = .056; 95% CI = 1.0-3.2 and P = .084; 95% CI = 0.9-3.6, respectively). We conclude that effective asparagine depletion with PEG-ASP is feasible as part of an intensive multiagent therapeutic regimen in adult acute lymphoblastic leukemia and appears associated with improved outcomes.

Duke Scholars

Author Joanne Kurtzberg Pediatrics, Transplant and Cellular Therapy