Efficacy analysis of regorafenib combined with PD-1 inhibitors in elderly patients with metastatic colorectal cancer.
Authors: Chen Beibei , Zhao Huichen , Huang Jinxi , Lv Huifang , Xu Weifeng , Nie Caiyun , Wang Jianzheng , Zhao Jing , He Yunduan , Wang Saiqi , Chen Xiaobing 
Published: January 2022

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Background: Recently, an increasing number of patients (pts) with advanced colorectal cancer tend to receive regorafenib plus PD-1 inhibitors. However, there is a lack of information regarding real world effects of this therapeutic strategy, especially in elderly Chinese pts. We aimed to investigate the treatment patterns, clinical outcomes and prognostic factors of regorafenib plus PD-1 inhibitors therapy to Chinese elderly pts with advanced colorectal cancer. Methods: Retrospective analysis of a cohort of pts with advanced colorectal cancer received treatment of regorafenib combined with PD-1 inhibitors enrolled in our institution between January 2019 and January 2021. Among them, pts with 60 years or older were included in our final analysis. Overall survival (OS) and progression free survival (PFS) were estimated by Kaplan Meier curves, and other endpoints included objective response rate, prognostic factors. Results: At a median follow-up of 16.2 months, a total of 24 pts were enrolled in a real-world dataset from Henan Cancer Hospital. The median age was 68 years; 62.5% were female. The median OS and PFS were 15.03 months (95% CI 7.0-23.0) and 4.0 months (95% CI 1.8-6.2), respectively. 2/24 partial responses (PR) observed (ORR = 8.3%); Stable disease (SD) was obtained in 15/24. Disease control rate (PR plus SD) was therefore obtained in 17/24 (70.8%). When compared with PFS and OS in different initial daily doses group of regorafenib (such as ≤80, 120 or 160 mg), we concluded that there were no significantly difference between these groups. And similar results were found in final daily doses groups. However, it showed a trend toward better PFS in pts with ≥120 mg final daily doses group compared to <120 mg group (median PFS was 3.5 months in <120mg group versus 10.0 months in ≥120mg group). Median OS of pts for male gender demonstrated increasing trends compared with those female gender (20.2 months in males versus 13.2 months in females). Pts with previous treated with regorafenib had longer median OS than those without it (20.2 months versus 13.2 months). There were no obvious correlation for survival between pts only had liver metastasis and lung metastasis (P>0.05). No significant associations for survival could be seen in other tumor sites, K-RAS status, any kind of PD-1 inhibitors and whether previously treated with bevacizumab (P>0.05). Conclusions: This real-world dataset confirms that Chinese elderly pts with advanced colorectal cancer also can benefit from treatment of regorafenib combined with PD-1 inhibitors, similarly with this combination therapy strategies in all age pts. Furthermore, a longer survival time were obtained in pts with prior treated with regorafenib. The result also suggests that pts with ≥120mg final daily doses group had better PFS. However, further larger cohorts research should investigate whether the PFS advantage in high dose group could eventually lead to improved OS outcomes.