Abstract
BACKGROUND: Colorectal cancer (CRC) is among the most prevalent and deadly cancers globally, particularly in China. Treatment challenges remain in advanced and metastatic cases, especially in third- and fourth-line settings. The combination of targeted therapies with immune checkpoint inhibitors (ICIs) has shown potential in addressing the limitations of single-agent treatments. AIM: To evaluate the efficacy and safety of targeted therapy (TT) alone and in combination with ICIs for metastatic CRC (mCRC). METHODS: A multicenter retrospective observational study was conducted to evaluate the efficacy and safety of TT alone and in combination with ICIs for mCRC. A total of 99 patients treated with regorafenib or fruquintinib, with or without ICIs, were enrolled. Propensity score matching (PSM) and inverse probability weighting (IPW) were employed to balance baseline characteristics. The primary endpoint was progression-free survival (PFS), while overall survival (OS) and safety were secondary. RESULTS: Patients who received combined therapy showed significantly longer median PFS rates compared to those who underwent TT in all analyses (original: 6.0 vs 3.4 months, P < 0.01; PSM: 6.15 vs 4.25 months, P < 0.05; IPW: 5.6 vs 3.3 months, P < 0.01). Although the median OS showed a trend toward improvement in the combination group, the difference was insignificant. Cox regression analysis revealed that combining TT with ICIs significantly reduced the risk of disease progression (hazard ratio = 0.38, P < 0.001). Adverse events (AEs) were generally manageable with both regimens, while serious AEs (grade 3-4) were primarily hypertension, fatigue, and reduced platelet counts. All AEs were controlled effectively by symptomatic treatment or discontinuation of the drug, and no treatment-related deaths were observed. CONCLUSION: The combination of TT with ICIs offers a significant advantage in terms of PFS for patients with advanced mCRC, accompanied by a favorable safety profile. These findings underscore the benefits of combination therapy in this setting, warranting further investigation in larger prospective clinical trials.