Effect of starting dose of regorafenib on overall survival of patients with metastatic colorectal cancer: a systematic review and meta-analysis

Aim. To conduct a systematic review and meta-analysis of studies on the effect of starting dose of regorafenib on overall survival (OS) of patients with chemorefractory metastatic colorectal cancer. Materials and methods. We searched for research data in the PubMed. The analysis included all publications till 08.20.2019 which compared OS depending on the starting dose of regorafenib (160 mg or less) in the 1st course of therapy. Meta-analysis was conducted using Review Manager Ver. 5.3. Results. Two studies demonstrated decreased OS at starting dose of less than 160 mg (A. Adenis et al., 2016: risk ratio - RR 1.26, 95% confidence interval - CI 1.01-1.56; A. Aljubran et al., 2019: RR 2.25, 95% CI 0.93-5.43). Two studies showed an improvement in OS with a starting dose of less than 160 mg in the 1st course (T. Bekaii-Saab et al., 2018: RR 0.72, 95% CI 0.47-1,11; J. Gotfrit et al., 2017: RR 0.46, 95% CI 0.17-1.22). In two other studies, there was no effect of a starting dose of regorafenib on OS (K. Yamaguchi et al., 2019: RR 0.95, 95% CI 0.82-1.1; G. Argiles et al., 2019: RR 0,86, 95% CI 0.65-1.13). The meta-analysis did not reveal the effect of starting dose of the drug on OS: RR 0.97, 95% CI 0.78-1.21; p=0.79; I2=64. Conclusions. Reducing the starting dose of regorafenib in the 1st course does not decrease OS and can be recommended for routine clinical practice.