The efficacy of regorafenib combined with PD-1/PD-L1 inhibitor in advanced or metastatic colorectal cancer: A single arm meta-analysis

Background: Regorafenib alone has shown limited efficacy in some cases of colorectal cancer (CRC), while the use of programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) inhibitors is becoming increasingly common in cancer treatment. Previous studies have indicated significant benefits of combining regorafenib with PD-1/PD-L1 inhibitors in patients with advanced or metastatic CRC. This study aimed to evaluate the efficacy and outcomes of combining regorafenib with PD-1/PD-L1 inhibitors in patients with advanced or metastatic CRC. Methods: We systematically retrieved clinical trials from PubMed and Embase up to August 1, 2023. The quality of eligible clinical trials was assessed using the methodological index for non-randomized studies and the JBI critical appraisal checklist for case eeries. Efficacy metrics, such as objective response rate (ORR), disease control rate (DCR), median progression-free survival (mPFS), and median overall survival, were analyzed using STATA version 15.1, with results presented as 95% confidence intervals. Heterogeneity was assessed using the chi-square Q test and I ² statistic, with I ² > 50% indicating high heterogeneity, which was addressed using a random effects model. Results: Fourteen studies were included in this meta-analysis. The pooled ORR, DCR, and mPFS were 7%, 54%, and 2.99 months, respectively. Subgroup analysis revealed that for patients with liver metastasis (LM), the pooled ORR was 6%, DCR was 47%, and mPFS was 1.99 months. In contrast, for patients without LM, the pooled ORR was 21%, DCR was 61%, and mPFS was 3.48 months. Conclusion: These results indicate that combination therapy is more effective in patients without LM than in those with LM. This suggests that regorafenib plus PD-1/PD-L1 inhibitors may be a more suitable option for patients without liver metastases.