Asparaginase activity monitoring and management of asparaginase hypersensitivity reactions in Canada

Pegaspargase can cause anti-asparaginase antibody formation, which can decrease its effectiveness without causing any clinically apparent reaction (silent inactivation). When a patient has silent inactivation, a switch to Erwinia anti-asparaginase is warranted, but there is currently a global shortage of Erwinia. The only way to identify silent inactivation is to measure an asparaginase level. However, routine asparaginase level monitoring is not currently standard of care at all Canadian centers. This study aims to identify variations in practice regarding asparaginase level monitoring and Erwinia use.A 21-item survey was developed using OPINIO software and distributed to all Pediatric Hematology-Oncologists in Canada from February to October 2020.Respondents represented 15 hospitals across each region of Canada (response rate = 52%). Only 39.2% of respondents reported routinely measuring asparaginase levels, yet 53% of respondents have modified therapy from pegaspargase to Erwinia in up to half of their patients. The most common reason for not measuring asparaginase levels was not knowing how to use levels clinically (25.5%). There was variation in the timing of levels and their target.We identified substantial variation in asparaginase activity monitoring practices across Canada. Therefore, future research should aim to develop a national practice guideline on asparaginase activity monitoring.