Review Question - QID 108720

A 50-year-old male presents to his dermatologist complaining of a spot on his upper back. He reports that he first noticed the spot 8 months ago after his wife pointed it out while they were swimming. The spot has been gradually enlarging since then. He denies pain, itching, or burning associated with the spot. He is otherwise healthy and takes no medication. He has been swimming regularly since he was a teenager but says that he does not regularly use sunscreen. An image of the skin lesion is shown in Figure A. Subsequent workup reveals lymph node metastases. He is started on a medication that specifically targets the protein mutation most commonly associated with this lesion. Which of the following medications was most likely used in this patient?