U.S. FDA designation based on an interim analysis of the phase 3 COSMIC-311 pivotal trial, in which cabozantinib demonstrated significant improvement in progression-free survival –

Exelixis expects to submit supplementary New Drug Application in 2021 –

ALAMEDA, CA, USA I February 25, 2021 IExelixis, Inc. (NASDAQ: EXEL) today announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation to cabozantinib (CABOMETYX®) as a potential treatment for patients with differentiated thyroid cancer (DTC) that has progressed following prior therapy and who are radioactive iodine-refractory (if radioactive iodine is appropriate). The FDA’s Breakthrough Therapy Designation aims to expedite the development and review of drugs that are intended to treat serious or life-threatening diseases. To qualify for this designation, preliminary clinical evidence must indicate that the drug may demonstrate substantial improvement on at least one clinically significant endpoint over existing therapies.

“Receiving Breakthrough Therapy Designation is a testament to both the urgent need for effective treatments for patients with differentiated thyroid cancer who progressed after prior therapy and the promising data demonstrating cabozantinib significantly improved progression-free survival for these patients,” said Gisela Schwab, M.D., President, Product Development and Medical Affairs and Chief Medical Officer, Exelixis. “We look forward to submitting our regulatory application in 2021 and to working closely with the FDA during the review process, with the goal of bringing cabozantinib to this patient population with a high unmet medical need for whom there is currently no available standard of care.”

In December 2020, Exelixis announced that at a planned interim analysis, the phase 3 COSMIC-311 pivotal trial met the co-primary endpoint, demonstrating a significant reduction in the risk of disease progression or death of 78% with cabozantinib versus placebo (HR 0.22, 96% CI 0.13 – 0.36; p<0.0001) in patients with radioactive iodine-refractory differentiated thyroid cancer who have progressed after up to two prior VEGFR-targeted therapies. The safety profile was consistent with that previously observed for cabozantinib.

About COSMIC-311

COSMIC-311 is a multicenter, randomized, double-blind, placebo-controlled phase 3 pivotal trial that aimed to enroll approximately 300 patients at 150 sites globally. Patients were randomized in a 2:1 ratio to receive either cabozantinib 60 mg or placebo once daily. The co-primary endpoints are progression-free survival and objective response rate. More information about this trial is available at ClinicalTrials.gov.

About Differentiated Thyroid Cancer

Approximately 44,000 new cases of thyroid cancer will be diagnosed in the U.S. in 2021.1 Nearly three out of four of these cases will be in women, and the disease is more commonly diagnosed at a younger age compared to most other adult cancers.1 While cancerous thyroid tumors include differentiated, medullary and anaplastic forms, differentiated thyroid tumors make up about 90 percent of cases.1 These include papillary, follicular and Hürthle cell cancer.1 Differentiated thyroid cancer is typically treated with surgery followed by ablation of the remaining thyroid tissue with radioiodine, but approximately 5% to 15% of cases are resistant to radioiodine treatment. 2,3 For these patients, life expectancy is only three to six years from the time metastatic lesions are detected.4,5,6

About CABOMETYX® (cabozantinib)

In the U.S., CABOMETYX tablets are approved for the treatment of patients with advanced RCC; for the treatment of patients with HCC who have been previously treated with sorafenib; and for patients with advanced RCC as a first-line treatment in combination with nivolumab. 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. Exelixis holds the exclusive rights to develop and commercialize cabozantinib in the United States.

CABOMETYX is not indicated for radioiodine-refractory differentiated thyroid cancer.

Please see accompanying full Prescribing Information https://www.cabometyx.com/downloads/CABOMETYXUSPI.pdf.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.FDA.gov/medwatch or call 1-800-FDA-1088.

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 system genetics, 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 commercially available 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 the Standard & Poor’s (S&P) MidCap 400 index, which measures the performance of profitable mid-sized companies. In November 2020, the company was named to Fortune’s 100 Fastest-Growing Companies list for the first time, ranking 17th overall and the third-highest biopharmaceutical company. For more information about Exelixis, please visit www.exelixis.com, follow @ExelixisInc on Twitter or like Exelixis, Inc. on Facebook.

1 American Cancer Society. About Thyroid Cancer. Available at: https://www.cancer.org/cancer/thyroid-cancer/about.html. Accessed February 2021.

2 Cooper DS, et al. 2009. Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer: The American Thyroid Association (ATA) Guidelines Taskforce on Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid. 19:1167–1214.

3 Worden F. 2014. Treatment strategies for radioactive iodine-refractory differentiated thyroid cancer. Ther Adv Med Oncol. 6:267–279.

4 Xing M, Haugen BR, Schlumberger M. 2013. Progress in molecular-based management of differentiated thyroid cancer. Lancet. 381:1058–1069.

5 Pacini F, et al. 2012. Radioactive iodine-refractory differentiated thyroid cancer: unmet needs and future directions. Expert Rev Endocrinol Metab. 7:541–554.

6 Durante C, et al. 2006. Long-term outcome of 444 patients with distant metastases from papillary and follicular thyroid carcinoma: benefits and limits of radioiodine therapy. J Clin Endocrinol Metab. 91:2892–2899.

SOURCE: Exelixis