Pre-existing antibodies against polyethylene glycol reduce asparaginase activities on first administration of pegylated E. coli asparaginase in children with acute lymphocytic leukemia.

Antibodies against polyethylene glycol (PEG) in healthy subjects raise concerns about the efficacy of pegylated drugs. We evaluated the prevalence of antibodies against PEG among patients with acute lymphoblastic leukemia (ALL) prior to and/or immediately after their first dose of pegylated E.coli asparaginase (PEG-ASNase).