FDA extends review of Exelixis colorectal cancer drug by three months

The U.S. FDA has extended its review of Exelixis' experimental colorectal cancer drug combination, zanzalintinib and Roche's Tecentriq, by three months to March 3, 2027. The delay, triggered by a major amendment classification of updated safety and efficacy data, caused Exelixis shares to slip 3.5% premarket. Despite mixed clinical trial results, analysts view the drug as a key growth driver to succeed Cabometyx and believe the risk of regulatory rejection remains low.

FDA review extension timeline

• ▪The U.S. Food and Drug Administration extended the review of Exelixis' experimental colorectal cancer drug combination by three months, setting a new decision deadline of March 3, 2027
• ▪The U.S. Food and Drug Administration classified Exelixis' submission of updated safety and efficacy data, which was sent in response to an information request, as a major amendment

Zanzalintinib combination therapy approval

• ▪Zanzalintinib is an oral drug belonging to the class of tyrosine kinase inhibitors that selectively inhibit protein kinases regulating cell growth
• ▪Exelixis is seeking approval for zanzalintinib in combination with Roche's immunotherapy Tecentriq to treat a subset of adult patients with previously treated metastatic colorectal cancer

Clinical trial efficacy data

• ▪In June 2026, the combination of zanzalintinib and Tecentriq failed to achieve statistical significance in a late-stage trial measuring overall survival in patients without active liver metastases
• ▪In a clinical trial reported in June 2025, the combination of zanzalintinib and Tecentriq showed statistically significant improvement in overall survival compared to Bayer's Stivarga in the intent-to-treat population

Analyst outlook on approval

• ▪William Blair analyst Andy Hsieh stated that while the three-month delay was surprising, the risk of rejection for Exelixis' drug combination remains low
• ▪William Blair analysts wrote in August 2026 that intent-to-treat patients represent the largest commercial opportunity within the target population for the zanzalintinib combination

Exelixis growth strategy expansion

• ▪Analysts view zanzalintinib as a key growth driver for Exelixis that could extend the company's cancer franchise beyond its older drug Cabometyx
• ▪Exelixis is studying the experimental drug zanzalintinib in other types of cancer beyond metastatic colorectal cancer