COSMIC-311, the phase III pivotal trial evaluating Cabometyx (cabozantinib) versus placebo in patients with radioiodine-refractory differentiated thyroid cancer who have progressed after up to two prior vascular endothelial growth factor receptor-targeted therapies, met the co-primary endpoint of demonstrating significant improvement in progression-free survival.
Cabometyx is sponsored by Exelixis.
Cabometyx reduced the risk of disease progression or death by 78% with a hazard ratio of 0.22 (96% CI 0.13 – 0.36; p<0.0001) at this planned interim analysis. The safety profile was consistent with that previously observed for Cabometyx.
Given these results, the independent data monitoring committee for the study recommended to stop enrollment and unblind sites and patients. Exelixis intends to discuss the study results, proposed changes to the study conduct, as well as plans for a regulatory filing with FDA in the near term.
COSMIC-311 is a multicenter, randomized, double-blind, placebo-controlled phase III 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. Detailed results will be submitted for presentation at a future medical conference.
