Background: Sorafenib (BAY 43-9006), a multiple kinase inhibitor, has been shown to inhibit tumor growth and tumor angiogenesis by targeting Raf kinase, vascular endothelial growth factor receptor, and platelet-derived growth factor receptor. In phase I studies, sorafenib demonstrated single-agent activity in patients with advanced solid tumors and was successfully combined with oxaliplatin in preclinical studies. This phase I study investigated the safety, pharmacokinetics, and efficacy of sorafenib in combination with oxaliplatin.
Patients and methods: Twenty-seven patients with refractory solid tumors were enrolled in the initial dose-escalation part (cohorts 1, 2A, and 2B) and 10 additional patients with oxaliplatin-refractory colorectal cancer were subsequently enrolled in an extension part (cohort 3). Oxaliplatin 130 mg/m2 was given on day 1 of a 3-week cycle and oral sorafenib was administered continuously from day 4 of cycle 1 at 200 mg twice daily (cohort 1) or 400 mg twice daily (cohorts 2A, 2B, and 3).
Results: Adverse events were generally mild to moderate and the maximum tolerated dose was not reached. Common adverse events were diarrhea (52% of patients in the dose-escalation part and 20% in the extension part), sensory neuropathy (44% and 20%), and dermatologic toxicities (41% and 80%). No pharmacokinetic interaction between sorafenib and oxaliplatin was detectable. Two patients with gastric cancer had a partial response. Forty-three percent of patients in cohorts 1 and 2A/B and 78% of patients in cohort 3 exhibited stable disease for >or=10 weeks.
Conclusion: Continuous oral sorafenib 400 mg twice daily was safely combined with oxaliplatin without detectable drug interactions and showed preliminary antitumor activity in this phase I study. This dose is recommended for phase II studies.