Cabozantinib is a medicine that blocks certain proteins that cancel cells need to grow. This may help slow or stop cancer and blood vessels that feed the tumor. Dabrafenib blocks a protein called B-raf, which some cancer cells use to grow, especially if they have a mutated BRAF gene. Trametinib blocks proteins called MEK 1 and 2, which help control cell growth. By blocking these proteins, it may help slow down cancer cell growth. If you join this study, you will be put into one of two groups by chance. One group will take dabrafenib twice a day and trametinib once a day. The other group will take cabozantinib once a day. Both study medicines are taken by mouth as a pill. Everyone will take their study medicine until their cancer gets worse or the side effects become too severe. If your cancer gets worse, you may switch to the other treatment group. During the study, you will have physical exams, CT and MRI scans, and blood tests to check your health and safety. Most of these tests are part of regular medical care you would get even if you were not in the study. You will also fill out surveys about your energy, pain, side effects, and quality of life at 5 different times. These surveys will take about 20 to 30 minutes to finish. You will have 5 visits in the first 16 weeks, and then one visit every 3 months for 2 years. Your doctor and study team will check on you while you are taking the study drugs. After you finish treatment, your doctor will keep checking you for side effects and your overall health every 6 months for up to 5 years. You and your insurance will need to pay for the costs of the medical you get as part of the study. You will not be paid for being part of the study.

Who can Participate

You may be able to join this study if you are 18 or older, have differentiated thyroid cancer with BRAF V600E mutation, have already been treated with Iodine-131 or were told you cannot receive it, are taking thyroxine suppression therapy, and have been treated with either lenvatinib or sorafenib before. You cannot join if you have already taken cabozantinib or any other treatment that targets BRAF for thyroid cancer. Your doctor or study team member will explain all the study requirements. You can also find more information about the study on ClinicalTrials.gov.

Study ID

More information available at ClinicalTrials.gov: NCT06475989