Background: Patients with metastatic colorectal cancer (mCRC) with progressive disease on/after or who are intolerant to fluoropyrimidines, oxaliplatin, irinotecan, anti-angiogenic and anti-EGFR therapies have limited therapeutic options and a dismal prognosis, with a median survival below 6 months. Recently, Trifluridin/Tipiracil (TAS102) significantly improved survival in patients with refractory mCRC and ramucirumab has been approved in combination with FOLFIRI for the treatment of patients with mCRC after prior FOLFOX/bevacizumab first line therapy. Previous studies on both components provide a strong rationale to conduct a randomized study evaluating the efficacy and safety of ramucirumab in combination with TAS102 in patients with refractory mCRC to improve efficacy and prevent resistance. Methods: This is an interventional, randomized, open label, multicenter, phase IIb study in patients with advanced mCRC. Eligible patients will be randomized 1:1 and receive either ramucirumab and TAS102 (ramucirumab 8 mg/kg on d1+15, q4w and TAS102 35 mg/m² on d1-5 and d8-12, q4w) or TAS102 alone. Primary endpoint is overall survival as assessed by the Kaplan-Meier method, assuming a 6 months survival probability of 70% with ramucirumab in combination with TAS102 and 58% with TAS102 alone. Treatment groups are compared using the log-rank test. A total of 144 patients will be enrolled at 30 sites (1-sided alpha 0.10, power 0.80). Main secondary endpoints are overall response rate, disease control rate, progression free survival and quality of life. In addition, a large comprehensive translational research program will be conducted to identify novel predictive and prognostic biomarkers. The study started in December 2018. By February 2019, a total of 3 patients have been enrolled. Clinical trial information: NCT03520946