Phase I study of ursodeoxycholic acid in combination with 5-fluorouracil, leucovorin, oxaliplatin, and bevacizumab for metastatic colorectal cancer.

Abstract

569 Background: Emerging data links cancer growth with aberrant metabolism. These findings suggest that treatment directed against CRC metabolism may improve survival outcomes. Bile acids are involved in the metabolism of cholesterol and glucose. The bile acid, ursodeoxycholic acid (UDCA), protects against intestinal polyp development in animal and human studies. UDCA effects may be mediated through the nuclear receptor, farnesoid X receptor (FXR), since bile acids are the receptor’s endogenous ligands. FXR is a tumor suppressor in mouse models and a prognostic biomarker in patients with CRC. Bile acid activation of FXR in mouse models suppresses intestinal tumorigenesis. We sought to determine dose and safety of UDCA when added to standard therapy for mCRC. Methods: Patients with mCRC were accrued to an institutionally approved Phase I study. At the end of a 7-day run-in period of oral UDCA, standard doses of 5-fluorouracil, leucovorin, oxaliplatin, and bevacizumab were added. UDCA doses were escalated using a 3+3 design to determine MTD. The use of a run-in period allowed for correlative studies to identify serum biomarkers of FXR activation. Results: 11 patients were treated on three dose levels (250, 500, and 750 mg/day in divided doses). Patients were treated on protocol for a median time of 6 months with a median follow-up of 15 months. Patients were taken off protocol for progression of disease (n = 7); for declining performance status (n = 1); for toxicity (n=1); for patient refusal (n= 1). One patient remains on protocol at this time. No Grade 4 or higher toxicity was identified. Grade 3 toxicities were recorded in 5 patients; the majority was hematologic. Oral glucose tolerance tests, serum glucose and insulin levels, and serum FGF-19 were determined before and after UDCA treatment. Conclusions: UDCA, given with standard chemotherapy and biologic treatment, is safe and well tolerated in patients with mCRC. Further studies are needed to determine the efficacy of targeting FXR and cancer metabolism in mCRC. Supported by a grant from The Phase One Foundation. Clinical trial information: NCT00873275.