- Trial Phase
- NDA filed / Under FDA Review (PDUFA Dec 3, 2026); Phase 3 completed (STELLAR-303); Phase 3 ongoing (STELLAR-311 NET); Ph
- Time to Market
- If approved, potential launch in late 2026 or early 2027 (PDUFA decision December 3, 2026); other indications (neuroendocrine tumors, NSCLC, prostate cancer) are in earlier-stage trials, likely years away.
- Why 7/10
- PDUFA target action date of December 3, 2026 for zanzalintinib + atezolizumab in previously treated metastatic colorectal cancer. This is the company's lead pipeline asset and a major potential growth driver beyond the Cabometyx franchise, but the June 2026 final analysis of STELLAR-303 missed one of its two dual primary endpoints, creating real FDA approval uncertainty. Exelixis also has established Cabometyx revenue (~$2.1B), so while this is a high-impact catalyst, it is not company-making-or-breaking.
Watch the PDUFA date (December 3, 2026) closely as the key binary. The STELLAR-303 split results (ITT positive, NLM subgroup negative) complicate FDA approval odds but analysts suggest approval is still possible given the positive ITT data. Monitor for an FDA Advisory Committee date and any additional communications from the FDA. Elevated short interest (~55-60% short ratio) suggests the market is skeptical, creating potential for a squeeze on positive news — but equally large downside if the FDA issues a CRL.
Price Chart
Executive Summary
Zanzalintinib (XL092) is Exelixis's next-generation tyrosine kinase inhibitor and the company's most important pipeline asset, developed as a successor to its blockbuster drug cabozantinib (Cabometyx). The NDA for zanzalintinib + atezolizumab in previously treated metastatic colorectal cancer was accepted by the FDA with a PDUFA date of December 3, 2026. The Phase 3 STELLAR-303 trial produced split results — statistically significant OS improvement in the full ITT population (HR 0.80, P=0.0045) but a non-significant trend in the pre-specified non-liver-metastases subgroup (HR 0.83, P=0.1185), creating real approval uncertainty. The company is also evaluating zanzalintinib across multiple other solid tumor types (neuroendocrine tumors, RCC, NSCLC, prostate cancer). Exelixis currently generates over $2B annually from Cabometyx, giving the stock a valuation floor, but zanzalintinib approval would unlock a substantial new growth vector. The stock trades near its 52-week high with the mean analyst target below the current price, elevated short interest, recent insider selling, and a downgrade from Truist — reflecting the market's skepticism about the split trial data.
How It Works
Zanzalintinib is an oral drug that blocks multiple growth-signaling proteins (VEGFR2, MET, AXL, MER) that cancers use to grow new blood vessels and spread. It is a next-generation successor to Exelixis's flagship drug Cabometyx, designed with better absorption and half-life. When combined with an immunotherapy (atezolizumab), it may also help the immune system better recognize and attack tumors.
Trial Status
Phase 3 STELLAR-303 in metastatic colorectal cancer met one of its dual primary endpoints (OS in ITT population: HR 0.80, P=0.0045) but missed the second (OS in NLM subgroup: HR 0.83, P=0.1185). NDA was accepted February 2026. Phase 3 STELLAR-311 (vs everolimus in neuroendocrine tumors) is ongoing. Plans for additional Phase 3 trials in squamous NSCLC and mCRPC in H2 2026.
The Two-Sided Case
Upcoming Catalysts
- PDUFA target action date December 3, 2026 — FDA decision on zanzalintinib + atezolizumab for metastatic CRC (potential approval or CRL).
- Possible FDA Advisory Committee meeting (if scheduled) ahead of the December 3 PDUFA date.
- Final OS data from STELLAR-311 Phase 3 trial of zanzalintinib vs everolimus in neuroendocrine tumors (NETs).
- Initiation of Phase 3 trials in squamous NSCLC and metastatic castration-resistant prostate cancer, planned for H2 2026.
- Upcoming medical conference presentations of detailed STELLAR-303 NLM subgroup analysis.
Source Filing
The SEC filing that triggered this drug report: