Exelixis, Inc. (NASDAQ:EXEL) today announced results from the final analysis of the dual primary endpoint of overall survival (OS) in the subset of patients without active liver metastases (non-liver metastases, NLM) in the phase 3 STELLAR-303 pivotal trial evaluating zanzalintinib in combination with atezolizumab (Tecentriq®) versus regorafenib in previously treated non-microsatellite instability (MSI)-high metastatic colorectal cancer (mCRC). The results showed a non-statistically significant trend in OS favoring the combination in the NLM subpopulation (stratified hazard ratio: 0.83; 95% confidence interval: 0.66–1.05; P=0.1185), with median OS values of 15.9 months with zanzalintinib in combination with atezolizumab, and 12.7 months with regorafenib.

The safety profile of zanzalintinib in combination with atezolizumab in the NLM subgroup was consistent with that previously reported in the intention-to-treat (ITT) population, and no new safety signals were identified.

Exelixis previously announced that STELLAR-303 met its other dual primary endpoint, demonstrating a statistically significant improvement in OS in the ITT population, which included all randomized patients regardless of the presence of active liver metastases. Detailed results demonstrating the statistically significant improvement in OS in the ITT population were presented at the 2025 European Society for Medical Oncology Congress and published in The Lancet.