A Desensitization Protocol in Children With L-Asparaginase Hypersensitivity

Background: L-asparaginase is effective in the treatment of malignant diseases, but it has been associated with hypersensitivity reactions in 5% to 45% of the patients. Purpose: To determine whether a desensitization protocol in children with native Escherichia coli L-asparaginase hypersensitivity allows subsequent safe administration of native E. coli L-asparaginase. Patients and Methods: A desensitization protocol was used in 9 children with leukemia (n = 8) or Langerhans cell histiocytosis (n = 1) and previous severe (n = 4) or mild/moderate (n = 5) L-asparaginase hypersensitivity. Dexamethasone (2 mg/kg intravenously) and pheniramine hydrogen maleate (1 mg/kg intravenously) were administered 1 hour before each of the following L-asparaginase administrations. Subsequently, 0.1%, 1%, 5%, 10%, and the remaining 84% of the total dose of L-asparaginase (10,000 IU/m(2)) were each prepared in 240 mL 0.9% saline and infused over 4 hours (20 h in total). Results: After desensitization, none of the patients had recurrence of hypersensitivity reactions during the subsequent 2 to 15 doses (median: 6 doses/patient; 68 doses in total) of native E. coli L-asparaginase. Conclusion: This desensitization protocol was safe and allows continued administration of native E. coli L-asparaginase administration.