Lapatinib (INN), used in the form of lapatinib ditosylate (USAN) (trade names Tykerb and Tyverb) is an orally active drug for breast cancer and other solid tumours. It is a dual tyrosine kinase inhibitor which interrupts the HER2/neu and epidermal growth factor receptor (EGFR) pathways....Wikipedia

Manufacturer's Website: Tykerb                                                                                                                                   Average retail cost: $1,350/month

Trastuzumab emtansine also known as ado-trastuzumab emtansine and sold under the trade name Kadcyla, is an antibody-drug conjugate consisting of the monoclonal antibody trastuzumab (Herceptin) linked to the cytotoxic agent emtansine (DM1). Trastuzumab alone stops growth of cancer cells by binding to the HER2/neu receptor, whereas DM1 enters cells and destroys them by binding to tubulin....Wikipedia

Manufacturer's Website: Kadcyla                                                                                                                                  Average retail cost: $3,000/month

Trastuzumab, sold under the brand name Herceptin among others, is a monoclonal antibody used to treat breast cancer. Specifically it is used for breast cancer that is HER2 receptor positive. It may be used by itself or together with other chemotherapy medication. Trastuzumab is given by slow injection into a vein and injection just under the skin. Trastuzumab was approved for medical use in the United States in 1998. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system....Wikipedia

Manufacturer's Website: Herceptin                                                                                                                         Average retail cost: $4,600/month

Pertuzumab (also called 2C4, trade name Perjeta) is a monoclonal antibody used in combination with trastuzumab and docetaxel for the treatment of metastatic HER2-positive breast cancer; it also used in the same combination as a neoadjuvant in early HER2-positive breast cancer...Wikipedia

Manufacturer's Website: Perjeta                                                                                                                                    Average retail cost: $4,800/vial

NERLYNX is a kinase inhibitor indicated for the extended adjuvant treatment of adult patients with early-stage HER2‑overexpressed/amplified breast cancer, to follow adjuvant trastuzumab-based therapy.

Manufacturer's Website: Nerlynx                                                                                                                                 Average retail cost: $5,700/month

Pertuzumab/trastuzumab/hyaluronidase, sold under the brand name Phesgo, is a fixed-dose combination medication to treat adults with HER2-positive breast cancer that has spread to other parts of the body, and for treatment of adults with early HER2-positive breast cancer. It contains pertuzumab, trastuzumab, and hyaluronidase–zzxf. It is injected under the skin via subcutaneous injection in the thigh... Wikipedia

Manufacturer's Website: Phesgo                                                                                                                             Average retail cost: $8,700/month