Exelixis' Cabometyx scores backing from Ipsen in thyroid cancer, with full data release set for ASCO

Exelixis' flagship oncology drug Cabometyx has attracted a pharma partner to take it into a new type of cancer thanks to promising results in a pivotal trial.

In a late-stage trial in patients with a form of thyroid cancer, Cabometyx posted promising results, executives say, prompting French pharma Ipsen to step in and help get the drug across the finish line with global regulators. 

Ipsen has exercised its option to collaborate with Exelixis on Cabometyx’s pivotal phase 3 clinical trial, known as COSMIC-311, studying the medicine in patients with radioiodine-resistant differentiated thyroid cancer who have progressed after prior treatment with vascular endothelial growth factor receptor (VEGFR)-targeted therapies. 

Ipsen is anteing up in the thyroid cancer use thanks to “promising and clinically meaningful results” in the trial, Howard Mayer, Ipsen's R&D head, said in a statement.

In late December, Exelixis said interim results from COSMIC-311 showed the tyrosine kinase inhibitor reduced the risk of disease progression or death by 78%, meeting its co-primary endpoint of progression-free survival. For the study, investigators enrolled approximately 300 patients at 150 sites globally. Patients received either cabozantinib or placebo once daily. 

After the interim results, the FDA awarded the drug a breakthrough therapy designation in February. Now, Exelixis and Ipsen plan to present detailed results from the phase 3 trial at the ASCO Annual Meeting, taking place beginning on June 4. Ipsen will have access to its full set of results, which it will use for potential future regulatory submissions.

The company previously had a partnership with Exelixis to commercialize Cabometyx—authorized in over 50 countries for the treatment of kidney cancer—outside the U.S. and Japan. 

RELATED: With 2-year data, the jury's still out on the kidney cancer race between Opdivo-Cabometyx and Keytruda-Inlyta

Roughly 44,000 new cases of thyroid cancer will be diagnosed in the U.S. this year, Exelixis says. Differentiated thyroid tumors make up most of all thyroid cancers and are usually treated with surgery, followed by treatment with radioiodine.

But roughly 5% to 15% of those tumors are resistant to the treatment, leaving patients with few treatment options to improve life expectancy, Exelixis says. 

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Aside from its Ipsen collab, Exelis has partnerships on its cancer medicines with Bristol Myers Squibb and Roche.

Earlier this year, the FDA authorized Cabometyx in combination with Bristol Myers Squibb’s Opdivo for the treatment of patients with advanced renal cell carcinoma, setting up a showdown between that combo and the Merck and Pfizer’s cocktail of Keytruda and Inlyta. In previously untreated kidney cancer, the Opdivo-Cabometyx combo slashed the risk of death by 34% compared with Pfizer’s older drug Sutent.