Phase I, Pharmacokinetic and Biological Correlative Study of OSI-7904L, a Novel Liposomal Thymidylate Synthase Inhibitor, and Cisplatin in Patients with Solid Tumors

Purpose:To evaluate the safety and describe the pharmacokinetic profile of OSI-7904L, a novel liposomal thymidylate synthase inhibitor, in combination with cisplatin (CDDP) in adults with advanced solid tumors. Experimental Design: CDDP was administered as a 2-h intravenous infusion followed by OSI-7904L intravenously over 30 min, both given every 3 weeks. Doses of each drug were escalated in separate cohorts of patients. Five dose levels of CDDP/OSI-7904L were explored: 60/6, 60/9, 60/12, 60/7.5, and 75/7.5 mg/m(2). Pharmacokinetic samples, baseline plasma homocysteine, and genotype polymorphisms were evaluated. Results: Twenty-seven patients were treated with 101 total courses of CDDP/OSI-7904L. Dose-limiting toxicity was observed in 2 patients in the CDDP/OSI-7904L 60/12 mg/m(2) cohort. One patient experienced rash, stomatitis, dehydration, renal failure, hyperbilirubinemia, and fatal neutropenic sepsis, whereas the other patient experienced grade 3 nausea, vomiting, and ileus. Therefore, the CDDP/OSI-7904L 60/9 mg/m(2) cohort was expanded, with 2 of 6 patients reporting significant fatigue. Other toxicities were mild or moderate. Intermediate dose levels of 60/7.5 and 75/7.5 mg/m(2) were evaluated, and the latter was identified as the recommended dose for phase 11 studies. No major pharmacokinetic interactions between CDDP and OSI-7904L were observed. Three patients had partial responses (gastric adenocarcinoma and heavily pretreated breast cancer). There was no significant relationship between baseline homocysteine and toxicity. Conclusions: The recommended doses for CDDP and OSI-7904L administered once every 3 weeks are 75 and 7.5 mg/m(2), respectively. Pharmacokinetic interaction between the agents was not apparent. Preliminary clinical activity was observed in breast and gastric cancer.