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Updated: Aug 11, 2026
Cytotoxic Efficacy of Photodynamic Therapy in Osteosarcoma Cells In Vitro
Published on: March 18, 2014
Phase I trial and pharmacokinetic analysis of ifosfamide in cats with sarcomas
Kenneth M Rassnick1, Antony S Moore, Nicole C Northrup
1Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Objective:
To determine the maximally tolerated dose (MTD) and dose-limiting toxicosis (DLT) of ifosfamide in tumor-bearing cats.
Animals:
38 cats with resected, recurrent, or metastatic sarcomas.
Procedure:
The starting dosage of ifosfamide was 400 mg/m(2) of body surface area, IV, and dosages were increased by 50 to 100 mg/m(2) in cohorts of 3 cats. To protect against urotoxicosis, mesna was administered at a dosage equal to 20% of the calculated ifosfamide dosage. Diuresis with saline (0.9% NaCl) solution before and after administration of ifosfamide was used to minimize nephrotoxicosis. Samples for pharmacokinetic analysis were obtained after the MTD was reached.
Results:
38 cats were entered into this phase I study and were administered a single dose of ifosfamide at various dosages. The MTD was 1,000 mg/m(2), and neutropenia was the DLT. Seven of 8 episodes of neutropenia were on day 7 after treatment, and 1 cat developed severe neutropenia on day 5. Adverse effects on the gastrointestinal tract were generally mild and self-limiting, the most common of which was nausea during ifosfamide infusion. One cat had signs consistent with a drug-induced hypersensitivity reaction. There were no episodes of hemorrhagic cystitis or nephrotoxicosis. Correlations between pharmacokinetic variables and ifosfamide-associated toxicoses were not found. Preliminary evidence of antitumor activity was observed in 6 of 27 cats with measurable tumors.
Conclusions And Clinical Relevance:
The dosage of ifosfamide recommended to treat tumor-bearing cats is 900 mg/m(2) every 3 weeks. This dosage should be used in phase II clinical trials.
