The purpose of this study is to evaluate the safety and preliminary effectiveness of dabrafenib and lapatinib in patients with inoperable thyroid cancers that contain an abnormal (mutated) form of BRAF and cannot be cured with radioactive iodine therapy.
Dabrafenib works by blocking the activity of abnormal BRAF. Lapatinib blocks two targets in cells that fuel cancer growth when mutated: EGFR and HER2. Earlier studies have suggested that targeting BRAF was not enough to treat thyroid cancer successfully because EGFR and HER2 became more active. It is hoped that treating the cancer with both drugs can overcome this resistance.
Dabrafenib is approved by the U.S. Food and Drug Administration for treating melanoma and lapatinib is approved for advanced breast cancer, but their use in treating thyroid cancer is considered investigational. Both drugs are taken orally (by mouth).