Eltrombopag is well tolerated but provides no additional benefit in the treatment of canine primary immune-mediated thrombocytopenia.

Abstract

OBJECTIVE: To evaluate the efficacy and tolerability of eltrombopag in dogs diagnosed with primary immune-mediated thrombocytopenia (pITP). METHODS: Medical records from dogs diagnosed with pITP between January 2018 and March 2024 were retrospectively reviewed. Data collected included signalment, presenting signs, diagnostic findings, duration of hospitalization, time to platelet recovery (defined as days to achieve a platelet count ≥ 100,000/μL, with no evidence of bleeding), mortality, relapse incidence, transfusion requirements, and adverse events. Dogs were included if they received a combination of corticosteroids, vincristine, mycophenolate mofetil, and human immunoglobulin, with or without the addition of oral eltrombopag administered within 24 hours of diagnosis. Dogs were grouped on the basis of whether they did or did not receive eltrombopag (eltrombopag group vs control group), and results were compared between groups. RESULTS: 18 dogs met the inclusion criteria (control group, n = 13; eltrombopag group, 5). Median time to platelet recovery, hospitalization, transfusion needs, and mortality did not differ significantly between groups. Eltrombopag was well tolerated, and adverse events, primarily gastrointestinal, were less frequent in the eltrombopag group. CONCLUSIONS: Eltrombopag was well tolerated as part of a multimodal treatment protocol for pITP in dogs. However, it was not associated with improved platelet recovery, shorter hospitalization, or reduced mortality compared with standard therapy alone. CLINICAL RELEVANCE: This study provided evidence that eltrombopag may be safely incorporated into immunosuppressive regimens for canine pITP; however, its clinical benefit remains uncertain. Further research is required to determine its role in optimizing treatment for ITP in dogs.