Zanzalintinib

STELLAR-303 was open-label and required ECOG performance status 0–1. Its protocol excluded prior regorafenib, trifluridine/tipiracil, and PD-1/PD-L1-targeting checkpoint inhibitors, limiting direct applicability to participants already exposed to these treatments. The earlier published protocol described a different endpoint hierarchy from the dual-primary-endpoint framework reported with the pivotal results, so its statistical plan should not be treated as the final analysis plan. The reported progression-free-survival difference was qualified by hierarchical testing, and the later final overall-survival analysis without active liver metastases was not statistically significant. The randomized comparison evaluates the combination against regorafenib, not the independent contribution of each combination component.

The colorectal expansion cohort enrolled 107 participants, including 53 assigned to zanzalintinib alone and 54 assigned to zanzalintinib plus atezolizumab. Eligibility required RAS wild-type disease and ECOG performance status 0–1. The subgroup without liver metastases contained 17 participants in each group. The company-reported overall-survival hazard ratio was 0.89 with a 95% confidence interval of 0.56–1.42; the corresponding subgroup interval was 0.27–2.04. These small cohorts and intervals crossing 1 limit conclusions about a survival difference. The comparison against zanzalintinib monotherapy does not establish comparative effectiveness against an approved later-line regimen.

The reported zanzalintinib plus nivolumab cohort included 19 participants with multiple solid-tumor types; colorectal cancer accounted for 26%. The reported absence of responses and disease-control rate of 42% are cohort-level findings, not colorectal-specific efficacy estimates. The open-label phase 1b design and safety-focused primary endpoint do not provide a randomized comparative estimate of benefit in metastatic colorectal cancer.