Emzumab 150 mg Emzumab 150 mg contains Trastuzumab 150 mg, a monoclonal antibody used to treat HER2-positive cancers. It works by specifically targeting the HER2 protein found on certain cancer cells, helping slow their growth and enabling the immune system to destroy them. Emzumab is commonly prescribed for HER2-positive breast cancer and HER2-positive metastatic gastric or gastroesophageal junction cancer. It is administered by intravenous infusion under the supervision of an experienced healthcare professional.