Exelixis’s son of Cabometyx disappoints again

Exelixis’s Cabometyx successor zanzalintinib has had its ups and downs, and the group disclosed another setback in its second-quarter results release on Monday. Exelixis has discontinued the Stellar-305 phase 2/3 trial in first-line head and neck cancer, citing emerging phase 2 data as well as “emerging competition [and] other potentially larger commercial opportunities”. Meanwhile, the Stellar-304 study, in first-line non-clear cell renal cancer, has been delayed: results are now expected in the first half of 2026, from the second half of 2025 previously. Exelixis says it will announce an “additional wave” of zanzalintinib pivotal trials in the coming months, including combo studies alongside Merck & Co’s HIF2α inhibitor Welireg that are due to start “towards the end of 2025”. A phase 1/2 trial of the combo was recently listed on clinicaltrials.gov. In better zanzalintinib news, Exelixis last month toplined a win in the Stellar-303 colorectal cancer study, but there are questions about whether the project, alongside Tecentriq, works in patients with liver metastases. Nevertheless, the company plans a filing here “as quickly as possible”. Cabometyx sold $1.8bn in 2024, but is set to come off patent in 2030; Exelixis hopes that zanzalintinib could make $5bn by 2033.

Ongoing phase 3 zanzalintinib studies

Note: *phase 2/3 trial. Source: OncologyPipeline & company release.