STELLAR-303: Breaking the immunotherapy wall in MSS colorectal cancer.
The phase 3 STELLAR-303 trial1 demonstrated a significant overall survival benefit of zanzalintinib plus atezolizumab over regorafenib in refractory microsatellite-stable (MSS) metastatic colorectal cancer, marking the first phase 3 success of an immunotherapy-based regimen in this population. These results may reshape treatment paradigms and renew interest in biomarker-guided immunotherapy for MSS disease.