Neoadjuvant mFOLFOXIRI with or without cadonilimab versus mFOLFOX6 in locally advanced colorectal cancer: A...

The efficacy of neoadjuvant chemotherapy combined with dual immune checkpoint blockade in proficient mismatch repair/microsatellite-stable (pMMR/MSS) locally advanced colorectal cancer (LACRC) remains uncertain.

In this open-label, randomized phase 2 trial (ClinicalTrials.gov: NCT05571644), eligible patients were randomly assigned (1:1:1) to receive 6 cycles of neoadjuvant mFOLFOXIRI plus cadonilimab, mFOLFOXIRI, or mFOLFOX6, followed by surgery and adjuvant chemotherapy. The primary endpoint was pathological complete response (pCR) in the intention-to-treat population. Secondary endpoints included major pathological response (MPR), safety, locoregional recurrence, disease-free survival, and overall survival.

Between July 2023 and August 2024, 123 patients were randomly assigned (41 per group). Neoadjuvant mFOLFOXIRI plus cadonilimab significantly improved pCR compared with mFOLFOX6 (26.8% versus 9.8%; odds ratio [OR], 3.4; 95% confidence interval [CI], 1.04 to 13.24; p = 0.046), whereas mFOLFOXIRI alone did not (14.6% versus 9.8%; OR, 1.6; 95% CI, 0.4 to 6.7; p = 0.50). MPR rates were 68.3%, 46.3%, and 43.9%, respectively, and were significantly higher with mFOLFOXIRI plus cadonilimab than with mFOLFOX6 (p = 0.026). Downstaging to ypStage 0-I occurred in 66%, 45%, and 41% of patients in the three groups, respectively, and was significantly higher in the mFOLFOXIRI plus cadonilimab group (p = 0.027). Grade ≥3 adverse events were manageable, with liver enzyme elevation and neutropenia being the most common.

Neoadjuvant mFOLFOXIRI plus cadonilimab significantly improved pCR compared with mFOLFOX6 in LACRC, with a manageable safety profile, supporting further investigation.

This work was funded by the National Science Fund for Distinguished Young Scholars (82425045) and the National Natural Science Foundation of China (82272800).