February 2022 Project Summary/Abstract Asparaginase is MUMS Designated for the induction of remission in multicentric lymphoma in dogs. To date, toxicity data regarding the use of asparaginase in dogs has not been available. As part of the approval process for asparaginase as a new animal drug, a Target Animal Safety Study has been proposed to, and concurred with by, the Center for Veterinary Medicine of the Food and Drug Administration. The study involves the subcutaneous administration of asparaginase to thirty-two (16/sex) dogs, randomly assigned to 4 groups of 4/sex/group to determine the toxicity of asparaginase when given once weekly for 6 doses (Days 1, 8, 15, 22, 29 and 36) ranging from 0 IU/kg/dose (control animals), to 400, 800, or 1600 IU/kg/dose. Animals will be terminated and necropsied on Day 38. Local and systemic effects of asparaginase administration will be catalogued both in-life and at necropsy. In addition, because asparaginase is a heterologous protein (it is derived from E. coli), study animals will be observed each day of the study for signs of hypersensitivity reactions and blood samples will be collected throughout the study period from all study animals for subsequent determination of the presence of anti-drug antibodies if hypersensitivity reactions are detected by in-life observations or at necropsy. Ultimately, the data collected by this study will be presented, in summary fashion, in the Animal Safety portion of the approved product prescribing information for the benefit of prescribing veterinarians.