Dabrafenib and Lapatinib in Treating Patients With Refractory Thyroid Cancer That Cannot Be Removed by Surgery

This phase I trial studies the side effects and best dose of lapatinib when given together with dabrafenib in treating patients with thyroid cancer that cannot be removed by surgery and has not responded to previous treatment (refractory). Dabrafenib selectively binds to and blocks the activity of v-raf murine sarcoma viral oncogene homolog B (BRAF), which may block the growth of tumor cells which contain a mutated BRAF gene. Lapatinib reversibly blocks the process in which a phosphate group is added to a molecule (phosphorylation) of the epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (ErbB2), and the mitogen-activated protein kinase 3 (Erk-1) and mitogen-activated protein kinase 1(Erk-2) and protein kinase B (AKT) kinases. It also blocks cyclin D protein levels in human tumor cell lines. Dabrafenib and lapatinib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth.