This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cytotoxic Anticancer Drugs, Subject name: Pharmacology
[{'content': 'All of the following drugs are used in the treatment of metastatic breast cancer except: \nSelect and explain. \nA. Ixabepilone, B. Abemaciclib, C. Ribociclib, D. Sunitinib', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ixabepilone is a semisynthetic epothilone B analog that functions as a microtubule inhibitor. it is approved for metastatic breast cancer in combination with the oral fluoropyrimidine capecitabine or as monotherapy. Abemaciclib & Ribociclib are cyclin dependent kinase inhibitors (CDKI) and are given orally in breast cancer. Sunitinibis a Tyrosine kinase inhibitor and is used mainly in GIST and RCC.', 'role': 'assistant'}]