Tolerability and Adverse Event Profile of Fixed Dose Rate Gemcitabine in Dogs With Neoplasia

Fixed dose rate (FDR) gemcitabine offers pharmacokinetic advantages over bolus dosing, and there is evidence in human medicine that FDR gemcitabine is more effective than intravenous (IV) bolus. To date, literature describing gemcitabine use in dogs is limited to bolus administration. The goal of this study was to describe the tolerability and adverse event profile of a novel FDR gemcitabine protocol in tumour-bearing dogs. Thirty-nine dogs who received at least one infusion of FDR gemcitabine at 400 mg/m² IV over 2 h (3.3 mg/m²/min) were retrospectively evaluated. An average of 4 FDR gemcitabine doses (range, 1-15) were administered per dog. Sixteen dogs (41%) developed neutropenia (12 Grade 1, 1 Grade 2, 2 Grade 3, 1 Grade 4) and 5 dogs (13%) developed thrombocytopenia (3 Grade 1, 1 Grade 2, 1 Grade 3). Gastrointestinal adverse events were reported in 23 dogs (59%), and all were classified as Grade 1 or 2. Of the 35 dogs who had gross disease and adequate information available to assess response to treatment, 8 dogs (23%) achieved a partial response (PR), 11 dogs (31%) maintained stable disease (SD) and 16 dogs (46%) experienced disease progression. PR was documented in 5 out of 8 dogs (63%) with squamous cell carcinoma. This FDR gemcitabine protocol demonstrated manageable toxicity and a promising response rate in dogs. Further investigation is warranted to explore its potential role in treating canine tumours.