A Systematic Review and Meta-analysis of Retrospective Series of Regorafenib for Treatment of Metastatic Colorectal Cancer

Background: Metastatic colorectal cancer is a common disease encountered in oncology practice and treatment options beyond fluoropyrimidines, irinotecan, oxaliplatin and monoclonal antibodies against epidermal growth factor receptor and vascular endothelium growth factor (VEGF) are limited. Regorafenib, a new drug that targets tyrosine kinases such as VEGF receptor as well as others, has been added recently to the armamentarium for metastatic colorectal cancer. This report analyzes the published experience with this drug in clinical practice outside of clinical trials.

Materials and methods: A literature search of major databases was performed for the identification of studies of regorafenib in metastatic colorectal cancer. Studies retained for further analysis were in English or French, describing 20 or more patients treated with regorafenib monotherapy and not part of a phase I, II or III trial. Results of the pooled analysis of retrospective studies were compared with results of the published phase III trials and a phase IIIb prospective study.

Results: Twelve publications including a total of 702 patients were included in the meta-analysis. Summary response rate was 2% [95% confidence interval (CI) =0.8-3.2%] and the disease control rate 38.14% (95% CI=32.35-43.93%). Summary survival rates were 3.34 months (95% CI=2.71-3.97 months) for progression-free and 7.27 months (95% CI=6.23-8.3 months) for overall survival. These were similar to the phase III and IIIb studies. Most common adverse effects were also consistent with those of the published phase III experience.

Conclusion: This systematic review and meta-analysis confirmed a moderate efficacy of regorafenib in later-stage metastatic colorectal cancer in the everyday clinical practice setting outside of clinical trials. Future identification of biomarkers may aid in further tailoring of this treatment in order to obtain maximum clinical benefit.