e14079 Background: Liver metastases develop in half of colorectal cancer (CRC) cases and once metastatic, ~90% die due to their consequences. We are evaluating the aggressive management of liver metastases through the incorporation of selective internal radiation therapy (SIRT) using Yttrium-90 (Y-90) radioactive microspheres after evidence of progressive disease following 1st-line FOLFOX ± bevacizumab. Optimal timing for microsphere treatment relative to chemotherapy is not clearly established. Methods: Subjects with predominant hepatic metastatic CRC despite 1st-line FOLFOX based therapy ± bevacizumab are eligible. Interventional radiology and nuclear medicine assess the liver lesions and the subject receives SIRT followed by 2nd-line FOLFIRI 4-6 weeks after the final SIRT. Results: To date, 9 metastatic CRC subjects have been treated and 10 subjects enrolled (goal 30 subjects). One subject was withdrawn due to progressive lung metastases. 4 of 9 subjects (45%) achieved PFS at 6 mos and average TTP is 7 months(0.7-21.3 mos). Overall treatment has been well tolerated, except one possible study related SAE of liver failure. The OS endpoint has not been achieved. Conclusions: Historically, 2nd-line FOLFIRI has achieved a 2.5 mos median PFS. Our preliminary results of 9 subjects with metastatic CRC show a PFS up to 21.3 monthsand 45% PFS at 6 mos. These encouraging results demonstrate the utility of an innovative direct approach to metastatic CRC after failure of 1st-line combination chemotherapy. Based on our promising preliminary results, our aim is to enroll 30-35 metastatic CRC patients. [Table: see text]
