Objective—To determine the maximum tolerated
dose (MTD) of cisplatin administered with piroxicam,
the antitumor activity and toxicity of cisplatin combined
with piroxicam in dogs with oral malignant
melanoma (OMM) and oral squamous cell carcinoma
(SCC), and the effects of piroxicam on the pharmacokinetics
of cisplatin in dogs with tumors.
Design—Prospective nonrandomized clinical trial.
Procedure—Dogs were treated with a combination
of cisplatin (escalating dose with 6 hours of diuresis
with saline [0.9% NaCl] solution) and piroxicam
(0.3 mg/kg [0.14 mg/lb], PO, q 24 h). The initial cisplatin
dose (50 mg/m2) was increased by 5 mg/m2
until the MTD was reached. Tumor stage and size
were determined at 6-week intervals during treatment.
The pharmacokinetics of cisplatin were determined
in dogs receiving a combination of cisplatin
and piroxicam during the clinical trial and dogs that
were treated with cisplatin alone.
Results—11 dogs with OMM and 9 dogs with SCC
were included in the clinical trial. The MTD of cisplatin
when administered in combination with piroxicam
was 50 mg/m2. Tumor remission occurred in 5
of 9 dogs with SCC and 2 of 11 dogs with OMM.
The most common abnormality observed was renal
toxicosis. Clearance of cisplatin in dogs that were
treated with cisplatin alone was not significantly different
from that in dogs treated with a combination
of cisplatin and piroxicam.
Conclusions and Clinical Relevance—Cisplatin administered
in combination with piroxicam had antitumor
activity against OMM and SCC. The level of toxicity was
acceptable, although renal function must be monitored
carefully. ( J Am Vet Med Assoc 2004;224:388–394)