MEPACT, also known by its generic name mifamurtide, is a type of immunotherapy medication primarily used in the treatment of osteosarcoma, a form of bone cancer, particularly in children and young adults following the removal of the tumor by surgery. Mifamurtide works by stimulating the body's immune system to attack cancer cells, helping to reduce the risk of the cancer returning. It is often used in combination with other chemotherapy drugs to enhance its effectiveness. MEPACT is administered through an infusion into a vein (intravenously), and its use is associated with a range of potential side effects, which can include flu-like symptoms, fatigue, nausea, and others. The introduction of MEPACT into the treatment regimen for osteosarcoma represents a significant advancement in the fight against this challenging disease, offering hope for improved outcomes in affected patients.