Comparison of the effects of asparaginase administered subcutaneously versus intramuscularly for treatment of multicentric lymphoma in dogs receivingdoxorubicin

Objective-To determine the effectiveness and safely of asparaginase adminis tered SC versus IM for treatment of multicentric lymphoma in dogs receiving doxorubicin. Design-Prospective study. Animals-49 dogs with multicentric lymphoma. Procedure-Dogs were treated with doxorubicin every 3 weeks, for a total of 5 treatments, and were given 3 weekly treatments of asparaginase, SC or IM. Using high-performance liquid chromatography, mean plasma asparagine, aspa rtic acid, glutamine, and glutamic acid concentrations were determined in d ogs before and during treatment with asparaginase (10,000 U/m(2) of body su rface area, once a week for 3 weeks). Asparaginase was administered SC in 2 3 dogs and IM in 26 dogs. Variables evaluated included time to response to chemotherapy, remission and survival times, and clinical and serum biochemi cal indicators of toxicoses. Results-Using the World Health Organization's staging system for lymphoma, 30 dogs were in clinical stage III and 19 were in clinical stage IV. One we ek after asparaginase treatment, plasma asparagine concentrations were low and plasma aspartic acid, glutamine, and glutamic acid concentrations were high. Differences in plasma amino acid concentrations were not found betwee n SC and IM groups. For dogs in clinical stage IV, IM administration of asp araginase significantly decreased the number of days to complete remission, compared with SC administration (8 vs 17 days, respectively). For dogs in clinical stage III, IM administration favorably increased the duration of f irst remission (191 vs 103 days) and survival time (289 vs 209 days). Overa ll, dogs treated IM had a faster response to chemotherapy (9 vs 15 days), a longer remission (191 vs 109 days), and a longer survival time (286 vs 198 days), compared with all dogs treated SC. Asparaginase toxicoses were not observed regardless of the route of administration. Clinical Implications-For dogs with multicentric lymphoma that are receivin g doxorubicin, IM treatment with asparaginase is more effective than SC tre atment.