Exelixis announced results from the STELLAR-001 trial, a Phase 1b/2 study evaluating zanzalintinib, alone or combined with atezolizumab, in patients with previously treated metastatic colorectal cancer (CRC). The combination therapy showed numerically improved progression-free survival (PFS) and overall survival (OS) compared to zanzalintinib alone. This is particularly notable in a subgroup of patients without liver metastases, where the combination demonstrated a substantial PFS improvement.
These findings are important because they suggest a potential new treatment option for metastatic CRC, a disease with limited effective therapies, especially for patients who have progressed after multiple prior treatments. The improved outcomes observed in patients without liver metastases are particularly encouraging, as this subgroup often has a poorer prognosis. This also highlights the potential for personalized treatment strategies based on specific patient characteristics.
The STELLAR-001 trial randomized 107 patients to receive either zanzalintinib alone or in combination with atezolizumab. In the overall population, the median PFS was 3.0 months with zanzalintinib and 4.0 months with the combination. In patients without liver metastases, the median PFS was significantly longer at 8.2 months with the combination versus 3.3 months with zanzalintinib alone. While the OS data showed numerical improvement with the combination therapy, the results were not statistically significant. Safety profiles were generally manageable, with comparable rates of grade 3/4 treatment-related adverse events in both treatment arms.
The results from STELLAR-001 support the ongoing Phase 3 STELLAR-303 trial, which is comparing zanzalintinib plus atezolizumab to regorafenib in metastatic CRC. Data from STELLAR-303 are expected in the second half of 2025 and will be crucial to determine if the combination therapy translates into a clinically meaningful benefit for patients with this challenging cancer. The findings from STELLAR-303 could potentially reshape the treatment landscape for metastatic CRC, offering a new therapeutic option with improved efficacy.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
