Exelixis Expands Colorectal Cancer Trials with Merck Collaboration

Exelixis (EXEL) announced a new collaboration with Merck (MRK) for the STELLAR-316 phase 3 colorectal cancer trial, utilizing circulating tumor DNA (MRD)-guided patient enrollment. The announcement coincides with extensive presentations at the American Society of Clinical Oncology (ASCO) Annual Meeting in May 2026, featuring new data on CABOMETYX and pivotal trials of zanzalintinib across multiple hard-to-treat cancers.

Collaboration and Trial Details

The STELLAR-316 trial combines zanzalintinib with a Merck immunotherapy, focusing on patients with detectable residual disease after surgery. This marks the first time Exelixis uses MRD guidance in a phase 3 trial, reflecting a shift toward precision medicine.

Additionally, Exelixis will present data from the STELLAR-303 trial and other studies of zanzalintinib in renal cell carcinoma, hepatocellular carcinoma, and other cancers at ASCO.

Context

This expansion represents a key step for Exelixis to reduce its reliance on CABOMETYX, which generates the majority of its revenue. The broader zanzalintinib program aims to diversify the company's pipeline and increase its presence in the growing oncology market.

What This Means for Investors

While quarterly financial results have not been announced, this collaboration strengthens Exelixis' position in oncology. Investors should monitor the trial results to be presented at ASCO, as they could impact the stock's trajectory.