Comparison of allergic reactions to pegasparaginase given intravenously versus intramuscularly

Background Pegasparaginase (PEG) is important for treatment of Acute Lymphoblastic Leukemia (ALL). Despite conjugation to polyethylene glycol to reduce immunogenicity, allergic reactions still occur and may be severe. Traditionally, PEG is given via intramuscular (IM) injection but recent protocols have shown it can be safely given intravenously (IV), which may be preferred by patients. There is a potential concern that the IV route may result in more severe allergic reactions due to immediate exposure to reactive antibodies in the blood, which is delayed after IM administration. The purpose of our study is to compare the severity and incidence of allergic reactions with IV versus IM PEG. We are unaware of any prior studies examining this. Procedure We reviewed all patients with ALL diagnosed from 2005 to 2010 inclusive who received PEG and had an allergic reaction. Reactions were graded using both common toxicity criteria (CTC) 3.0 and 4.0. Results Allergic reactions were seen in 17 of 186 (9%) newly diagnosed patients receiving IM PEG and 4 of 11 (36%) receiving IV PEG; P?=?0.019. The severity of reaction was not increased with IV versus IM. Allergic reactions occurred more frequently in high-risk patients (14 of 85; 16%) versus standard risk (7 of 112; 6%), P?=?0.034. Conclusions There appears to be an increased incidence of allergic reactions in patients who receive IV PEG compared with IM although the severity is similar. In addition high-risk patients appear to have more allergic reactions than standard risk. Pediatr Blood Cancer 2012;59:436439. (c) 2011 Wiley Periodicals, Inc.