New York, May 20, 2026, 13:04 (EDT)
- Exelixis shares were up roughly 2.5% Wednesday afternoon, beating the iShares Nasdaq Biotechnology ETF. The stock still trailed the SPDR S&P Biotech ETF.
- Exelixis said Merck agreed to provide Keytruda Qlex for its upcoming STELLAR-316 Phase 3 trial in colorectal cancer.
- Investors are watching the FDA’s December 3 target date for another zanzalintinib filing and Exelixis’ $750 million buyback plan.
Exelixis shares climbed Wednesday after the company announced a new Merck partnership, putting its next cancer drug program further into late-stage trials.
Shares traded 2.5% higher at $49.89 in the afternoon, putting the Alameda, California-based company’s market cap near $13.3 billion. Biotech stocks were strong, with the iShares Nasdaq Biotechnology ETF up 1.8% and the SPDR S&P Biotech ETF up 3.8%.
Exelixis is under pressure to prove it can grow past Cabometyx, its top cancer drug, as it keeps shareholders interested with buybacks and coming regulatory news. Up next for the company is zanzalintinib, an oral kinase inhibitor, or a drug that blocks enzymes helping cancer cells multiply.
Exelixis said Tuesday Merck will provide Keytruda Qlex, a subcutaneous version of its anti-PD-1 drug, for the STELLAR-316 trial. The phase 3 study is set to test the therapy in patients with resected stage II/III colorectal cancer, aiming for data that could back regulatory approval.
Exelixis, Inc. said it will run a study of zanzalintinib in MRD-positive patients, either alone or with Keytruda Qlex. MRD means bits of cancer DNA can still be found after treatment, even if scans look clear. The trial’s main endpoint is disease-free survival – tracking how long patients stay free of cancer.
Exelixis’ R&D chief Dana T. Aftab called the Merck deal “continued progress” for zanzalintinib, saying the goal is to “prevent or delay metastatic progression.” The company plans to begin the STELLAR-316 study in mid-2026. Exelixis, Inc.
Merck’s deal follows Exelixis’ January move to work with Natera. The companies will use Natera’s Signatera test to select MRD-positive patients for the study. John Simmons of Natera said the test might find “high-risk patients earlier.” Aftab said that if the trial works, zanzalintinib could be the first MRD-guided treatment for these patients. Natera Investor Relations
There’s competition at play, but not as simple as one company against another. Merck is delivering the immunotherapy in this trial, Natera has the test, and Exelixis runs the study. In another colorectal cancer project, Exelixis’ zanzalintinib and Roche’s atezolizumab were put up against Bayer’s regorafenib in the phase 3 STELLAR-303 trial.
The earlier filing is still a near-term driver. Exelixis said the FDA has accepted its new drug application for zanzalintinib plus atezolizumab in previously treated metastatic colorectal cancer, with a target action date of December 3, 2026. Exelixis also said its 2026 revenue outlook does not factor in any sales from a potential approval.
Exelixis shares are getting a lift after its latest results. The company posted first-quarter revenue of $610.8 million, up from $555.4 million in the same period last year. The U.S. cabozantinib business brought in net product revenue of $555.0 million. Exelixis reported non-GAAP earnings of 87 cents per diluted share; these adjusted numbers back out items like stock-based comp.
Exelixis is leaning into buybacks. A May 5 filing showed the board approved up to $750 million more for share repurchases through December 31, 2027. The company has already retired 86.8 million shares since March 2023.
CFO Christopher Senner sold 34,901 shares at a weighted average of $50 on May 18, according to a Form 4 filed Tuesday. The sale came after a tax-withholding trade connected to restricted units. After selling, Senner held 952,317 shares directly.
But the risk is clear. STELLAR-316 hasn’t begun. Late-stage cancer trials can fail, and there’s no guarantee the FDA will approve zanzalintinib in December. Exelixis has flagged that trial timelines, safety issues, partner execution and new rivals—including generics to its current drugs—could change what it expects.
