Phase II Trial of Tunlametinib in NRAS-Mutant Advanced Thyroid Cancer

This study is testing a targeted drug called tunlametinib in people with advanced thyroid cancer that has a specific NRAS gene mutation, to see if blocking this mutation pathway can shrink or control the cancer. **You may be eligible if...** - You are 18 or older with locally advanced or metastatic thyroid cancer confirmed by biopsy - Your tumor has an NRAS gene mutation confirmed by testing - Your cancer is iodine-refractory (radioactive iodine treatment no longer works), OR you have a type of thyroid cancer that doesn't absorb iodine (such as medullary or anaplastic thyroid cancer) - Surgery is no longer a curative option - Your organ function is adequate and you are in reasonably good health **You may NOT be eligible if...** - Your tumor does not have the NRAS mutation - You have received prior treatment specifically targeting RAS or MEK pathways - You have active brain metastases that are uncontrolled - You have uncontrolled heart conditions, active serious infections, or significant organ failure - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.