Comparison of anaphylactic reactions to asparaginase derived from Escherichia coli and from Erwinia cultures.

A retrospective study was undertaken comparing the frequency and severity of anaphylactic reactions to E. coli-derived and Erwinia-derived asparaginase given intravenously on a weekly dosage schedule. Both drugs were found to produce life-threatening hypersensivity reactions with the chance of reaction per dose administered being almost identical--8% for each dose administered. Eleven of 31 patients (35%) experienced anaphylactic reactions, 9/27 (33%) with E. coli and 3/10 (30%) with Erwinia asparaginase, with one patient suffering anaphylaxis to both preparations. A marked increase in the percentage of patients having reactions occurred after the fourth dose of either preparation, with the incidence per dose increasing from 3.3% with the first dose to 32% on the fifth and subsequent doses. Rationale for an antibody-mediated allergic reaction is presented to explain the data.