mFOLFOX6 + Bevacizumab + PD-1 Monoclonal Antibody Vs. mFOLFOX6 in Locally Advanced pMMR/MSS CRC

Neoadjuvant immunotherapy has shown promising therapeutic effects in mismatch repair-deficient or microsatellite instability-high (dMMR/MSI-H) colorectal cancer (CRC). However, for patients with mismatch repair-proficient or microsatellite stable (pMMR/MSS) CRC, the efficacy of PD-1 monoclonal antibody remains limited. Enhancing the efficacy of immunotherapy in pMMR/MSS CRC has become a key area of exploration. Additionally, for locally advanced (cT4NxM0) CRC patients, achieving R0 resection poses a significant challenge. Failure to achieve R0 resection often results in recurrence, severely impacting patient survival outcomes. Our previous phase II clinical study (BASKET Ⅱ) demonstrated that the neoadjuvant regimen of mFOLFOX6 combined with Bevacizumab and PD-1 monoclonal antibody significantly enhanced the immunotherapy sensitivity of locally advanced pMMR/MSS CRC, leading to improved pathological complete response (pCR) rates and higher R0 resection rates. This prospective, multicenter, randomized phase III trial aims to evaluate whether the neoadjuvant regimen of mFOLFOX6 + Bevacizumab + PD-1 monoclonal antibody can further improve pCR rate, enhance survival outcomes, and maintain an acceptable safety profile compared to mFOLFOX6 alone in pMMR/MSS locally advanced CRC patients.