This study sought to quantify in vitro antiproliferative effects of
pamidronate in feline
cancer cells and assess feasibility of use of
pamidronate in cats by assessing short-term toxicity and dosing schedule in cats with bone-invasive
cancer. A retrospective pilot study included eight cats with bone invasive
cancer treated with intravenous
pamidronate. In vitro,
pamidronate reduced proliferation in feline
cancer cells (P < 0.05). One cat treated with
pamidronate in combination with
chemotherapy and two cats treated with
pamidronate as a single agent after failing prior
therapy had subjective clinically stable disease; median progression free interval in these cats from initial
pamidronate treatment was 81 days. Three cats developed
azotemia while undergoing various treatment modalities including nonsteroidal anti-inflammatory drugs and
pamidronate. Median overall survival was 116.5 days for all cats and 170 days for cats with
oral squamous cell carcinoma. Median progression free survival was 55 days for all cats and 71 days for cats with
oral squamous cell carcinoma.
Pamidronate therapy appears feasible for administration in
cancer bearing cats with aggressive bone lesions in the dose range of 1-2 mg/kg every 21-28 days for multiple treatments. No acute or short-term toxicity was directly attributable to
pamidronate.