Use of cis-bis-neodecanoato-trans-R,R-1, 2-diaminocyclohexane platinum (II), a liposomal cisplatin analogue, in cats with oral squamous cell carcinoma

Objective: To determine clinical response and toxic effects of cis-bis- neodecanoato-trans-R,R-1,2-diaminocyclohexane platinum (II) (L-NDDP) administered IV at escalating doses to cats with oral squamous cell carcinoma (SCC). Animals: 18 cats with oral SCC. Procedure: Cats that failed to respond to conventional treatment or had nonresectable tumors were included. Data included a CBC, serum biochemical analyses, urinalysis, cytologic examination of a fine-needle aspirate of enlarged lymph nodes, and thoracic and oral radiographs for clinical staging. A starting dose (75 to 100 mg/m² of L- NDDP) was administered IV. At 21-day intervals, subsequent doses increased by the rate of 5 or 10 mg/m². Response was evaluated every 21 days by tumor measurement and thoracic radiography. Quality of life was assessed by owners, using a performance status questionnaire. Results: On average, cats received 2 treatments. Toxicoses included an intermittent, acute anaphylactoid- parasympathomimetic reaction, lethargy or sedation (≤ 24 hours), inappetence or signs of depression (≤ 72 hours), mild to moderate increase in hepatic enzyme activity, and melena. Pulmonary, renal, or hematopoietic abnormalities were not evident. Performance status surveys indicated normal behavior and grooming or decreased activity and self-care (19/20 assessments), ate well with or without assistance (15/20), and did not lose weight (15/20). Median survival time was 59.8 days (mean, 54.1 days). Conclusions and Clinical Relevance: L-NDDP was ineffective for treatment of cats with oral SCC. None of the cats had a complete or partial remission. Acute toxicoses and poor therapeutic response limit therapeutic usefulness of L-NDDP in cats, unless dosage, frequency, and administration procedures can be improved.