CNS Pharmacology USMLE Step 1 Practice Question

A 55-year-old woman presents to her oncologist for follow-up after being diagnosed with invasive ductal carcinoma of the right breast six months ago. Immunohistochemical staining of the tumor biopsy demonstrated 3+ overexpression of a transmembrane receptor tyrosine kinase encoded by the HER2 proto-oncogene, with fluorescence in situ hybridization confirming gene amplification. Her estrogen and progesterone receptor staining was negative. She completed lumpectomy and adjuvant chemotherapy with docetaxel and carboplatin, and was subsequently started on a targeted monoclonal antibody directed against the extracellular domain of this receptor. Her baseline echocardiogram showed a left ventricular ejection fraction of 62%. During routine follow-up visits, repeat echocardiography is performed every three months to monitor for possible reversible, non-dose-dependent cardiotoxicity. Which of the following drugs was most likely prescribed?