Abstract
BACKGROUND: Regorafenib (R) and fruquintinib (F) are the standard third-line regimens for colorectal cancer (CRC) according to the National Comprehensive Cancer Network guidelines, but both have limited efficacy. Several phase 2 trials have indicated that R or F combined with immune checkpoint inhibitors can reverse immunosuppression and achieve promising efficacy for microsatellite stable or proficient mismatch repair (MSS/pMMR) CRC. Due to the lack of studies comparing the efficacy between F, R, F plus programmed death-1 (PD-1) inhibitor, and R plus PD-1 inhibitors (RP), it is still unclear whether the combination therapy is more effective than monotherapy. AIM: To provide critical evidence for selecting the appropriate drugs for MSS/pMMR metastatic CRC (mCRC) patients in clinical practice. METHODS: A total of 2639 CRC patients were enrolled from January 2018 to September 2022 in our hospital, and 313 MSS/pMMR mCRC patients were finally included. RESULTS: A total of 313 eligible patients were divided into F (n = 70), R (n = 67), F plus PD-1 inhibitor (FP) (n = 95) and RP (n = 81) groups. The key clinical characteristics were well balanced among the groups. The median progression-free survival (PFS) of the F, R, FP, and RP groups was 3.5 months, 3.6 months, 4.9 months, and 3.0 months, respectively. The median overall survival (OS) was 14.6 months, 15.7 months, 16.7 months, and 14.1 months. The FP regimen had an improved disease control rate (DCR) (P = 0.044) and 6-month PFS (P = 0.014) and exhibited a better trend in PFS (P = 0.057) compared with F, and it was also significantly better in PFS than RP (P = 0.030). RP did not confer a significant survival benefit; instead, the R group had a trend toward greater benefit with OS (P = 0.080) compared with RP. No significant differences were observed between the R and F groups in PFS or OS (P > 0.05). CONCLUSION: FP is superior to F in achieving 6-month PFS and DCR, while RP is not better than R. FP has an improved PFS and 6-month PFS compared with RP, but F and R had similar clinical efficacy. Therefore, FP may be a highly promising strategy in the treatment of MSS/pMMR mCRC.