Background: Colorectal cancer is the fourth most commonly diagnosed cancer and the second leading cause of cancer death. Liver metastases develop in half of all the colorectal cancer (CRC) cases and cause death in ∼90% of patients. We are evaluating the treatment of liver metastases through the incorporation of selective internal radiation therapy (SIRT) using Yttrium-90 radioactive microspheres for subjects with liver progressive disease following failure of first-line FOLFOX (± bevacizumab). We are presenting our preliminary data for the phase II study evaluating the tumor response rates, PFS, and long-term safety and toxicity to SIRT following FOLFOX (± bevacizumab) prior to FOLFIRI. Methods: Subjects with predominantly hepatic metastatic CRC whose disease progressed on first-line FOLFOX (± bevacizumab) based therapy are eligible. Interventional radiology and nuclear medicine assess the liver lesions and the subject receives their SIRT treatment(s) followed by second-line FOLFIRI based therapy 4-6 weeks after the final SIRT treatment. Optimal timing for microsphere treatment relative to chemotherapy is not clearly established. Results: To date, 9 metastatic CRC subjects have been treated and 11 subjects enrolled (goal 30 subjects). One subject was withdrawn due to progressive lung metastases. Four of 8 subjects (50%) achieved PFS at 6 months and average TTP is 6.7 months (0.7-17.3 months). Overall treatment has been well tolerated, but one possible study related SAE of liver failure occurred (Subject 8). The OS endpoint has not been achieved. Conclusions: Historically, second-line FOLFIRI has achieved a 2.5 months median PFS. In 8 subjects with predominant liver metastatic CRC, we have observed 50% PFS at 6 months. These encouraging results demonstrate the utility of an innovative direct approach to metastatic CRC after failure of first-line combination chemotherapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3692. doi:1538-7445.AM2012-3692