TAS-102 with or without bevacizumab in patients with chemorefractory metastatic colorectal cancer: an investigator-initiated, open-label, randomised, phase 2 trial.

Background: TAS-102 (trifluridine-tipiracil) has shown a significant overall survival benefit compared with placebo in patients with chemorefractory metastatic colorectal cancer. Inspired by the encouraging results of a small phase 1-2 study, C-TASK FORCE, which evaluated the combination of TAS-102 plus bevacizumab in patients with chemorefractory metastatic colorectal cancer, we aimed to compare the efficacy of TAS-102 plus bevacizumab versus TAS-102 monotherapy in patients receiving refractory therapy for metastatic colorectal cancer .

Methods: This investigator-initiated, open-label, randomised, phase 2 study enrolled patients (aged ≥18 years) with metastatic colorectal from four cancer centres in Denmark. The main inclusion criteria were histopathologically confirmed metastatic colorectal cancer refractory or intolerant to a fluoropyrimidine, irinotecan, oxaliplatin, and cetuximab or panitumumab (only for RAS wild-type), and WHO performance status of 0 or 1. Previous therapy with bevacizumab, aflibercept, ramucirumab, or regorafenib was allowed but not mandatory. Participants were enrolled and randomly assigned (1:1) in block sizes of two, four, or six by a web-based tool to receive oral TAS-102 (35 mg/m twice daily on days 1-5 and 8-12 every 28 days) alone or combined with intravenous bevacizumab (5 mg/kg on days 1 and 15) until progression, unacceptable toxicity, or patient decision to withdraw. Treatment assignment was not masked, and randomisation was stratified by institution and RAS mutation status. The primary endpoint was investigator-evaluated progression-free survival. All analyses were based on intention to treat. This trial is registered with EudraCT, 2016-005241-23.

Findings: From Aug 24, 2017, to Oct 31, 2018, 93 patients were enrolled and randomly assigned to TAS-102 (n=47) or TAS-102 plus bevacizumab (n=46). The clinical cut-off date was Feb 15, 2019, after a median follow-up of 10·0 months (IQR 6·8-14·0). Median progression-free survival was 2·6 months (95% CI 1·6-3·5) in the TAS-102 group versus 4·6 months (3·5-6·5) in the TAS-102 plus bevacizumab group (hazard ratio 0·45 [95% CI 0·29-0·72]; p=0·0015). The most frequent grade 3 or worse adverse event was neutropenia (18 [38%] of 47 in the TAS-102 monotherapy group vs 31 [67%] of 46 in the TAS-102 plus bevacizumab group). Serious adverse events were observed in 21 (45%) patients in the TAS-102 group and 19 (41%) in the TAS-102 plus bevacizumab group. No deaths were deemed treatment related.

Interpretation: In patients with chemorefractory metastatic colorectal cancer, TAS-102 plus bevacizumab, as compared with TAS-102 monotherapy, was associated with a significant and clinically relevant improvement in progression-free survival with tolerable toxicity. The combination of TAS-102 plus bevacizumab could be a new treatment option for patients with refractory metastatic colorectal cancer and could be a practice-changing development.

Funding: Servier.