Trastuzumab Lyophilized Powder 440mg is a recombinant DNA-derived monoclonal antibody used primarily to treat HER2-positive breast cancer and HER2-positive gastric cancer. It works by selectively binding to HER2 receptors on cancer cells, blocking their growth signals and promoting immune system destruction of these cancer cells. This medication is supplied as a lyophilized powder that is reconstituted and given as an intravenous infusion, typically under strict medical supervision. Trastuzumab targets aggressive tumors characterized by overexpression of HER2, slowing tumor progression and improving patient outcomes. It is usually part of a comprehensive cancer treatment regimen.