Exelixis, Inc. announced final results from the phase 3 COSMIC-311 pivotal trial of CABOMETYX® (cabozantinib) in patients with previously treated radioactive iodine-refractory differentiated thyroid cancer (DTC). Following a previous announcement that the trial met one of the two primary endpoints of significant improvement versus placebo in progression-free survival (PFS) assessed by blinded independent radiology committee (BIRC; p<0.0001), the results of the final analysis are being presented during the Mini Oral Session – NETs and Endocrine Tumours at 5:30 p.m. CEST on September 20 at the 2021 European Society of Medical Oncology (ESMO) Congress (LBA67). At a median follow-up of 10.1 months, the significant improvement in PFS with CABOMETYX was maintained, with consistent benefit in subgroups based on prior treatment. At a median follow-up of 10.1 months, CABOMETYX reduced the risk of disease progression or death versus placebo (hazard ratio [HR]: 0.22; 96% confidence interval [CI]: 0.15–0.32) in the intent-to-treat (ITT) population. Median PFS as assessed by BIRC was 11.0 months for patients treated with CABOMETYX (n=170) compared with 1.9 months for patients treated with placebo (n=88). Subgroup analyses demonstrated that CABOMETYX improved PFS versus placebo irrespective of prior exposure to lenvatinib and/or sorafenib: Prior sorafenib/no lenvatinib: median PFS was 16.6 months for patients treated with CABOMETYX (n=63) compared with 3.2 months for placebo (n=33) (HR: 0.13; 95% CI: 0.06–0.26). Prior lenvatinib/no sorafenib: median PFS was 5.8 months for patients treated with CABOMETYX (n=68) compared with 1.9 months for placebo (n=34) (HR: 0.28; 95% CI: 0.16–0.48). Prior sorafenib and lenvatinib: median PFS was 7.6 months for patients treated with CABOMETYX (n=39) compared with 1.9 months for placebo (n=21) (HR: 0.27; 95% CI: 0.13–0.54).