Serum asparaginase enzymatic activity. The results are from 19 patients who had 4 or more serum specimens after a single intravenous dose (2000 IU/m2) of pegaspargase over a period of 28 days. The results are depicted as the mean ± SD activity at the nearest time point to 7, 14, 21, and 28 days, respectively, after a single intravenous dose (2000/ IU/m2) of pegaspargase.