Metronidazole as Preoperative Therapy in CRC / FusoMetro-001

Colorectal cancer (CRC) is among the most frequent tumor types and is a leading cause of cancer-related death worldwide. Surgery represents the first therapeutic option, whereas advanced cases are usually treated by established chemotherapy protocols, yet with variable response rates. Mechanisms underlying unresponsiveness are still largely unclear. Recently, the gut microbiota, consisting of trillions of microorganisms, which populate the gastrointestinal tract, has also been implicated in chemo-resistance. Defined bacterial species have been reported to be associated with CRC. In particular, Fusobacterium nucleatum (F.n.), a commensal bacterium of the oral cavity, is enriched in CRC tissues and its abundance appears to be associated with reduced patient survival. In experimental models F.n. promotes CRC cell proliferation and reduces tumor responsiveness to 5-fluorouracil (5-FU). Furthermore, it suppresses tumor infiltration by immune cells associated with improved prognosis. Administration of metronidazole effectively reduces F.n. load and overall tumor growth in animal models. However, its efficacy in reducing F.n. loads in human CRC has not been verified so far. The proposed proof-of concept trial aims at determining the effectiveness of metronidazole in decreasing the F.n. load in tissues and possibly on its detrimental effects on tumor cells and tumor microenvironment.