Phase II Trial of Moderate Dose Omega-3 Acid Ethyl Esters for Colorectal Cancer Prevention in Patients with Lynch Syndrome (COLYNE).

TPS209 Background: Lynch syndrome (LS) is the most common inherited colorectal cancer (CRC) syndrome and is responsible for about 3% of newly diagnosed CRC. It is caused by germline mutations in one of the DNA mismatch repair (MMR) genes, and patients with LS carry a lifetime risk of CRC ranging between 10% and 70%. The role of inflammation in driving this malignant transformation is now well established and retrospective studies have revealed a potential chemo-preventative role for omega-3 (ω-3) polyunsaturated fatty acids (PUFAs), possibly via inhibition of inflammatory pathways associated with the development of defective MMR CRC tumors. While patients with LS have the highest risk of developing CRC, the majority of chemoprevention trials are focused on sporadic CRC. Effective interventions to reduce the risk of developing CRC in this population are limited to close surveillance and surgical prophylaxis. There is an unmet need for safe, effective, and non-invasive chemo-preventive interventions in patients with LS. Methods: This pilot study is a single-arm, open-label, phase 2 clinical trial of omega-3 acid ethyl esters (generic Lovasa; 2 grams orally once daily) for adult patients (≥ 18 years of age) with confirmed LS (based on germline testing of the MMR genes panel: MLH1, MSH2, MSHS6, PMS2 or deletion in EPCAM gene). Patients who are not candidate for elective endoscopy and/or with prior history of right sided or pan-colectomy are excluded. Thirty-four patients are expected to enroll, with a primary objective to determine the feasibility (defined as 80% retention rate) of 12 months of treatment with 2 grams capsules of omega-3 acid ethyl esters daily. Secondary endpoints include safety and tolerability of the intervention. Correlative aims include pre and post treatment assessment of colon mucosal tissue proliferation (right sided colon specimens will be evaluated for markers of proliferation (Ki-67) and apoptosis (Caspase-3)), the effect of omega-3 acid ethyl esters on inflammatory markers in serum, urine and feces (PGE-2, COX-2, β-catenin levels, and EPA:AA ratios), and gene expression related to proliferation, apoptosis and cell survival in colon tissue (NF-κB/Wnt pathways). The impact of omega-3 acid ethyl esters on intestinal microbiota will also be assessed (16S rRNA-based profiling). Correlative Colon tissue, serum, urine and feces samples are collected at baseline and at 12 months. The study is actively enrolling with 20 patients enrolled at the time of submission. Clinical trial information: NCT03831698.