? COSMIC-313 is the third phase 3 pivotal trial to investigate cabozantinib in combination with immune checkpoint inhibitors ?

ALAMEDA, Calif.--May 1, 2019-- Exelixis, Inc.(NASDAQ: EXEL) today announced that it is initiating COSMIC-313, a phase 3 pivotal trial of cabozantinib (CABOMETYX?) in combination with nivolumab (Opdivo?) and ipilimumab (Yervoy?) versus nivolumab and ipilimumab in patients with previously untreated advanced renal cell carcinoma (RCC) with intermediate- or poor-risk disease per the?International Metastatic Renal Cell Carcinoma Database Consortium. The primary endpoint of the trial is progression-free survival, and the secondary endpoints are overall survival and objective response rate. ?Clinical observations suggest cabozantinib promotes an immune-permissive environment, which could present an opportunity for additive or synergistic effects with immune checkpoint inhibitors,? said?Gisela Schwab, M.D., President, Product Development and Medical Affairs and Chief Medical Officer,?Exelixis. ?The mechanisms of action of single agent cabozantinib and the combination of nivolumab and ipilimumab are complementary, and each has demonstrated efficacy in advanced renal cell carcinoma. The further combination of these agents as a triplet regimen may offer promise to previously untreated patients with intermediate- or poor-risk disease, who are known to have poor treatment outcomes.? COSMIC-313 is a multicenter, randomized, double-blinded, controlled phase 3 pivotal trial that aims to enroll approximately 676 patients at 150 sites globally. Patients will be randomized 1:1 to the experimental arm of cabozantinib in combination with nivolumab and ipilimumab and to the control arm of nivolumab and ipilimumab in combination with matched placebo. Design of this phase 3 pivotal trial was informed by results from the ongoing phase 1b study of cabozantinib plus nivolumab with or without ipilimumab in patients with previously treated advanced genitourinary cancers, including RCC. The phase 1b trial is being conducted by the?U.S. National Cancer Institute?and includes centers from its Experimental Therapeutics Clinical Trials Network. Bristol-Myers Squibb?is providing nivolumab and ipilimumab for use in this trial. Please see Important Safety Information below and full U.S. prescribing information at?https://cabometyx.com/downloads/CABOMETYXUSPI.pdf. About RCC The American Cancer Society?s 2019 statistics cite kidney cancer as among the top ten most commonly diagnosed forms of cancer among both men and women in the U.S.¹?Clear cell RCC is the most common type of kidney cancer in adults.²?If detected in its early stages, the five-year survival rate for RCC is high; for patients with advanced or late-stage metastatic RCC, however, the five-year survival rate is only 12 percent, with no identified cure for the disease.¹?Approximately 32,000 patients in the U.S. and 70,000 globally require treatment, and an estimated 15,000 patients in the U.S. each year are in need of a first-line treatment for advanced kidney cancer.³ The majority of clear cell RCC tumors have lower than normal levels of a protein called von Hippel-Lindau, which leads to higher levels of MET, AXL and VEGF.^4,5?These proteins promote tumor angiogenesis (blood vessel growth), growth, invasiveness and metastasis.^6,7,8,9?MET and AXL may provide escape pathways that drive resistance to VEGF receptor inhibitors.^5,6 About CABOMETYX^??(cabozantinib) In the U.S., CABOMETYX tablets are approved for the treatment of patients with advanced RCC and for the treatment of patients with hepatocellular carcinoma (HCC) who have been previously treated with sorafenib. CABOMETYX tablets have also received regulatory approvals in the?European Union?and additional countries and regions worldwide. In 2016,?Exelixis?granted?Ipsen?exclusive rights for the commercialization and further clinical development of cabozantinib outside of?the United States?and?Japan. In 2017,?Exelixis?granted exclusive rights to?Takeda Pharmaceutical Company Limited?for the commercialization and further clinical development of cabozantinib for all future indications in?Japan. The combination of CABOMETYX with nivolumab and ipilimumab is not indicated for previously untreated advanced RCC. U.S. Important Safety Information

• Hemorrhage:?Severe and fatal hemorrhages occurred with CABOMETYX. The incidence of Grade 3 to 5 hemorrhagic events was 5% in CABOMETYX patients. Discontinue CABOMETYX for Grade 3 or 4 hemorrhage. Do not administer CABOMETYX to patients who have a recent history of hemorrhage, including hemoptysis, hematemesis, or melena.
• Perforations and Fistulas:?GastrointestinaI (GI) perforations, including fatal cases, occurred in 1% of CABOMETYX patients. Fistulas, including fatal cases, occurred in 1% of CABOMETYX patients. Monitor patients for signs and symptoms of perforations and fistulas, including abscess and sepsis. Discontinue CABOMETYX in patients who experience a fistula that cannot be appropriately managed or a GI perforation.
• Thrombotic Events:?CABOMETYX increased the risk of thrombotic events. Venous thromboembolism occurred in 7% (including 4% pulmonary embolism) and arterial thromboembolism in 2% of CABOMETYX patients. Fatal thrombotic events occurred in CABOMETYX patients. Discontinue CABOMETYX in patients who develop an acute myocardial infarction or serious arterial or venous thromboembolic event requiring medical intervention.
• Hypertension and Hypertensive Crisis:?CABOMETYX can cause hypertension, including hypertensive crisis. Hypertension occurred in 36% (17% Grade 3 and <1% Grade 4) of CABOMETYX patients. Do not initiate CABOMETYX in patients with uncontrolled hypertension. Monitor blood pressure regularly during CABOMETYX treatment. Withhold CABOMETYX for hypertension that is not adequately controlled with medical management; when controlled, resume at a reduced dose. Discontinue CABOMETYX for severe hypertension that cannot be controlled with anti-hypertensive therapy or for hypertensive crisis.
• Diarrhea:?Diarrhea occurred in 63% of CABOMETYX patients. Grade 3 diarrhea occurred in 11% of CABOMETYX patients. Withhold CABOMETYX until improvement to Grade 1 and resume at a reduced dose for intolerable Grade 2 diarrhea, Grade 3 diarrhea that cannot be managed with standard antidiarrheal treatments, or Grade 4 diarrhea.
• Palmar-Plantar Erythrodysesthesia (PPE):?PPE occurred in 44% of CABOMETYX patients. Grade 3 PPE occurred in 13% of CABOMETYX patients. Withhold CABOMETYX until improvement to Grade 1 and resume at a reduced dose for intolerable Grade 2 PPE or Grade 3 PPE.
• Proteinuria:?Proteinuria occurred in 7% of CABOMETYX patients. Monitor urine protein regularly during CABOMETYX treatment. Discontinue CABOMETYX in patients who develop nephrotic syndrome.
• Osteonecrosis of the Jaw (ONJ):?ONJ occurred in <1% of CABOMETYX patients. ONJ can manifest as jaw pain, osteomyelitis, osteitis, bone erosion, tooth or periodontal infection, toothache, gingival ulceration or erosion, persistent jaw pain, or slow healing of the mouth or jaw after dental surgery. Perform an oral examination prior to CABOMETYX initiation and periodically during treatment. Advise patients regarding good oral hygiene practices. Withhold CABOMETYX for at least 28 days prior to scheduled dental surgery or invasive dental procedures. Withhold CABOMETYX for development of ONJ until complete resolution.
• Wound Complications:?Wound complications were reported with CABOMETYX. Stop CABOMETYX at least 28 days prior to scheduled surgery. Resume CABOMETYX after surgery based on clinical judgment of adequate wound healing. Withhold CABOMETYX in patients with dehiscence or wound healing complications requiring medical intervention.
• Reversible Posterior Leukoencephalopathy Syndrome (RPLS):?RPLS, a syndrome of subcortical vasogenic edema diagnosed by characteristic finding on MRI, can occur with CABOMETYX. Evaluate for RPLS in patients presenting with seizures, headache, visual disturbances, confusion, or altered mental function. Discontinue CABOMETYX in patients who develop RPLS.
• Embryo-Fetal Toxicity:?CABOMETYX can cause fetal harm. Advise pregnant women and females of reproductive potential of the potential risk to a fetus. Verify the pregnancy status of females of reproductive potential prior to initiating CABOMETYX and advise them to use effective contraception during treatment and for 4 months after the last dose.
• Adverse Reactions:?The most commonly reported (=25%) adverse reactions are: diarrhea, fatigue, decreased appetite, PPE, nausea, hypertension, and vomiting.
• Strong CYP3A4 Inhibitors:?If coadministration with strong CYP3A4 inhibitors cannot be avoided, reduce the CABOMETYX dosage. Avoid grapefruit or grapefruit juice.
• Strong CYP3A4 Inducers:?If coadministration with strong CYP3A4 inducers cannot be avoided, increase the CABOMETYX dosage.?Avoid St.?John?s wort.
• Lactation:?Advise women not to breastfeed during CABOMETYX treatment and for 4 months after the final dose.
• Hepatic Impairment:?In patients with moderate hepatic impairment, reduce the CABOMETYX dosage. CABOMETYX is not recommended for use in patients with severe hepatic impairment.

Please see accompanying full Prescribing Informationhttps://cabometyx.com/downloads/CABOMETYXUSPI.pdf. About?Exelixis Founded in 1994,?Exelixis, Inc.?(Nasdaq: EXEL) is a commercially successful, oncology-focused biotechnology company that strives to accelerate the discovery, development and commercialization of new medicines for difficult-to-treat cancers. Following early work in model genetic systems, we established a broad drug discovery and development platform that has served as the foundation for our continued efforts to bring new cancer therapies to patients in need. Our discovery efforts have resulted in four marketed products, CABOMETYX^??(cabozantinib), COMETRIQ^??(cabozantinib), COTELLIC^??(cobimetinib) and MINNEBRO? (esaxerenone), and we have entered into partnerships with leading pharmaceutical companies to bring these important medicines to patients worldwide. Supported by revenues from our marketed products and collaborations, we are committed to prudently reinvesting in our business to maximize the potential of our pipeline. We are supplementing our existing therapeutic assets with targeted business development activities and internal drug discovery ? all to deliver the next generation of?Exelixis?medicines and help patients recover stronger and live longer.?Exelixis?is a member of Standard & Poor?s (S&P) MidCap 400 index, which measures the performance of profitable mid-sized companies. For more information about?Exelixis, please visit?www.exelixis.com, follow?@ExelixisInc?on Twitter or like?Exelixis, Inc.?on?Facebook. Forward-Looking Statements This press release contains forward-looking statements, including, without limitation, statements related to: the opportunity for the combination of cabozantinib with immune checkpoint inhibitors to produce additive or synergistic effects; the potential of the triplet combination of cabozantinib, nivolumab and ipilimumab to offer promise to previously untreated patients with intermediate- or poor-risk advanced RCC; and Exelixis? plans to reinvest in its business to maximize the potential of the company?s pipeline, including through targeted business development activities and internal drug discovery. Any statements that refer to expectations, projections or other characterizations of future events or circumstances are forward-looking statements and are based upon Exelixis? current plans, assumptions, beliefs, expectations, estimates and projections. Forward-looking statements involve risks and uncertainties. Actual results and the timing of events could differ materially from those anticipated in the forward-looking statements as a result of these risks and uncertainties, which include, without limitation: risks and uncertainties related to regulatory review and approval processes and Exelixis? compliance with applicable legal and regulatory requirements; the potential failure of the triplet combination of cabozantinib, nivolumab and ipilimumab to demonstrate safety and/or efficacy in COSMIC-313; uncertainties inherent in the product development process, including evolving regulatory requirements, slower than anticipated patient enrollment or inability to identify a sufficient number of clinical trial sites; the costs of conducting clinical trials, including the ability or willingness of Exelixis? collaboration partners to invest in the resources necessary to complete the trials; Exelixis? dependence on third-party vendors for the development, manufacture and supply of cabozantinib; Exelixis? ability to protect its intellectual property rights; market competition; changes in economic and business conditions; and other factors affecting?Exelixis?and its development programs discussed under the caption ?Risk Factors? in Exelixis? Annual Report on Form 10-K filed with the?Securities and Exchange Commission?(SEC) on?February 22, 2019, and in Exelixis? future filings with the?SEC, including, without limitation, Exelixis? Quarterly Report on Form 10-Q expected to be filed with the?SEC?on?May 1, 2019. All forward-looking statements in this press release are based on information available to?Exelixis?as of the date of this press release, and?Exelixis?undertakes no obligation to update or revise any forward-looking statements contained herein.