IM02 - Evaluation for Anti-Erythrocyte and Anti-Platelet Antibodies in Healthy Dogs Administered Lokivetmab

Abstract: Background - Lokivetmab (Cytopoint^®) is an anti-IL-31 monoclonal antibody used for management of canine allergic pruritis. IL-31 is a cytokine shown to activate the neuronal signaling pathway associated with itch in dogs. Multiple publications confer the efficacy and safety of lokivetmab for allergic disease when given at recommended dosages. However, there have been anecdotal concerns that lokivetmab could trigger an immune-mediated response leading to immune-mediated hemolytic anemia (IMHA) or immune thrombocytopenia (ITP). No study to date has evaluated for the development of antibodies against erythrocytes or platelets when using this drug.

Hypothesis/Objectives - Determine if anti-erythrocyte antibodies (AEA) or anti-platelet antibodies (APA) develop following a standard dose therapy of lokivetmab in healthy dogs. We hypothesized that the development of AEA or APA following a single-dose of lokivetmab would be rare and unlikely of clinical significance.

Animals - 8 healthy adult purpose-bred research beagles.

Methods - Prospective descriptive study. Whole blood samples were taken at baseline (day 0) prior to lokivetmab administration and on days 14 and 28 following lokivetmab administration. A CBC and AEA and APA direct flow cytometry assays were performed at all time points.

Results - No dogs exhibited anemia or thrombocytopenia and all were negative for AEA and APA at all measured time points.

Conclusions and clinical importance - There was no evidence of APA or AEA formation in healthy dogs administered lokivetmab at standard dosages. Future work includes a clinical trial for the evaluation of anemia, thrombocytopenia, AEA, and APA in client-owned allergic dogs receiving lokivetmab.