Exelixis leans on zanzalintinib as cabozantinib nears patent expiry

US biotech group Exelixis (NASDAQ: EXEL) has taken a major step forward in its cancer drug pipeline, reporting positive Phase III trial results in June for its experimental therapy zanzalintinib (XL092). When used in combination with Roche’s (SWX: ROG) immunotherapy Tecentriq (atezolizumab), the drug significantly improved overall survival in patients with advanced colorectal cancer, outperforming Bayer’s (FWB: BAYN) Stivarga in the same setting.

Pending regulatory approval, Zanzalintinib is projected to generate $14 million in risk-adjusted sales from colorectal cancer in 2025, according to Visible Alpha consensus, with analysts assigning a 61% probability of approval in this indication. Broader commercial potential lies ahead, with peak global risk-adjusted sales estimated at $518 million by 2035.

The drug is also being tested across other cancers, including renal cell carcinoma and castration-resistant prostate cancer. However, development for head and neck squamous cell carcinoma has been discontinued after zanzalintinib failed to meet its primary endpoint in a Phase II study, a setback that has weighed on Exelixis’s shares.

If successful across indications, zanzalintinib could reach blockbuster status with risk-adjusted global sales of $1 billion by 2031 and peak sales of $1.6 billion by 2035.

Exelixis is hoping the drug will succeed cabozantinib —its current blockbuster sold under the brand names Cabometyx and Cometriq —which generated $1.8 billion in 2024. Sales are projected to rise to $2.2 billion in 2025 and peak at $2.8 billion by 2029, before generic competition begins to erode revenues following patent expiry in 2026. Analysts expect Exelixis’s top line to begin declining from 2030, exposing a gap that zanzalintinib alone is unlikely to close.