Regorafenib (BAY 73-4506) in advanced colorectal cancer: a phase I study

BACKGROUND: In a phase I dose-escalation study, regorafenib demonstrated tolerability and antitumour activity in solid tumour patients. The study was expanded to focus on patients with metastatic colorectal cancer (CRC). METHODS: Patients received oral regorafenib 60–220 mg daily (160 mg daily in the extension cohort) in cycles of 21 days on, 7 days off treatment. Assessments included toxicity, response, pharmacokinetics and pharmacodynamics. RESULTS: Thirty-eight patients with heavily pretreated CRC (median 4 prior lines of therapy, range 0–7) were enrolled in the dose-escalation and extension phases; 26 patients received regorafenib 160 mg daily. Median treatment duration was 53 days (range 7–280 days). The most common treatment-related toxicities included hand–foot skin reaction, fatigue, voice change and rash. Twenty-seven patients were evaluable for response: 1 achieved partial response and 19 had stable disease. Median progression-free survival was 107 days (95% CI, 66–161). At steady state, regorafenib and its active metabolites had similar systemic exposure. Pharmacodynamic assessment indicated decreased tumour perfusion in most patients. CONCLUSION: Regorafenib showed tolerability and antitumour activity in patients with metastatic CRC. This expanded-cohort phase I study provided the foundation for further clinical trials of regorafenib in this patient population.