Patients with anti–asparaginase antibodies had higher dexamethasone clearance. Patients who tested positive for anti–asparaginase antibodies had (A) higher dexamethasone clearance and (B) lower dexamethasone exposure (AUC). The level of anti–asparaginase antibodies over time (AUC) was correlated directly with dexamethasone clearance (C) and inversely with dexamethasone plasma exposure (D).