Mifamurtide (trade name Mepact, marketed by Takeda) is a drug against osteosarcoma, a kind of bone cancer mainly affecting children and young adults, which is lethal in over half of cases.

Mifamurtide is indicated for the treatment of high-grade, nonmetastasizing, resectable osteosarcoma following complete surgical removal in children, adolescents, and young adults, aged two to 30 years.

[4] The drug is used in combination with postoperative, multiagent chemotherapy to kill remaining cancer cells and improve a patient's chance of overall survival.

[2] In a phase-III clinical trial in about 800 newly diagnosed osteosarcoma patients, mifamurtide was combined with the chemotherapeutic agents doxorubicin and methotrexate, with or without cisplatin and ifosfamide.

[5][6] Common side effects include fever (about 90%), vomiting, fatigue and tachycardia (about 50%), infections, anaemia, anorexia, headache, diarrhoea and constipation (>10%).

[8] Mifamurtide is a fully synthetic derivative of muramyl dipeptide (MDP), the smallest naturally occurring immune stimulatory component of cell walls from Mycobacterium species.

[9] After application of the liposomal infusion, the drug is cleared from the plasma within minutes and is concentrated in lung, liver, spleen, nasopharynx, and thyroid.