The US Food and Drug Administration (FDA) has approved Exelixis’ Cabometyx (cabozantinib) for the treatment of patients with previously treated radioactive iodine-refractory differentiated thyroid cancer (DTC).

DTC is usually treated with surgery, followed by the removal of the remaining thyroid tissues with radioiodine. However, approximately 5% to 15% of cases are resistant to radioiodine treatment, with these patients carrying a life expectancy of only three to five years from the time metastatic lesions are detected.

Previously, Exelixis announced that a clinical trial evaluating Cabometyx in this tough-to-treat population met one of the two primary endpoints of significant improvement versus placebo in progression-free survival (PFS).

At a median follow-up of 10.1 months, Cabometyx reduced the risk of disease progression or death versus placebo in the intent-to-treat population.

The median PFS, as assessed by the blinded independent radiology committee (BIRC), was 11.0 months for patients treated with Cabometyx compared with 1.9 months for patients treated with placebo.

“Given the urgent need for new treatments for differentiated thyroid cancer, I’m encouraged to see that cabozantinib benefited patients in COSMIC-311 both at a longer follow-up and across prior therapy subgroups,” said Jaume Capdevila, medical oncologist at Vall d'Hebron University Hospital and Vall d'Hebron Institute of Oncology (VHIO), Barcelona, and a study investigator.

“These strong findings, which formed the basis for the recent US FDA approval, further support cabozantinib as an important new treatment option for patients with radioactive iodine-refractory differentiated thyroid cancer who previously had no standard of care following disease progression on anti-VEGFR therapy,” he added.