In the United States, current treatment for osteosarcoma typically follows a treatment protocol referred to as the “MAP” protocol: M = Methotrexate, A = Adriamycin (doxorubicin) and P = CisPlatin.  However, oncologists may also decide on additional treatments.  These may include Ifosomide and Etoposide, which are additional chemotherapies, or other targeted agents used as therapies after tumor removal. 

In certain countries outside of the United States, a different type of therapy called Mepact® (mifamurtide) is commercially available.  In Europe, for example, Mepact is approved for use in children, adolescents and young adults for the treatment of high-grade resectable, non-metastatic osteosarcoma, after macroscopically complete surgical resection in combination with post-operative multi-agent chemotherapy.  According to the product labeling and information made available by the European Medicines Agency, Mepact activates two types of white blood cells, macrophages and monocytes, which in turn leads to increased production of several interleukins and other cytokines (small molecules which play a part in cell signaling in the immune system).  This is believed to help the patient’s body kill cancer cells, but the exact mechanism by which Mepact leads to antitumor activity is not currently known. 

In the United States, a multi-center clinical trial involving approximately 600 children and young adults with newly diagnosed, resectable, high grade osteosarcoma was conducted to assess, among other things, treatment with Mepact and the standard-of-care MAP protocol as compared to treatment with the MAP protocol alone.  Based on the results of this study, a pharmaceutical company sought approval to sell mifamurtide in the United States.  However, due to concerns regarding the study design and analysis, the product did not obtain approval from the U.S. Food and Drug Administration (FDA). 


Mifamurtide in Metastatic and Recurrent Osteosarcoma:

A Patient Access Study with Pharmacokinetic, Pharmacodynamic, and Safety Assessments

(written by Dr. Peter Anderson, MD, PhD)

This non-randomized, patient-access protocol, assessed both safety and efficacy outcomes following liposomal muramyl –tripeptide-phosphatidylethanolamine (L-MTP-PE; mifamurtide) in patients with high-risk, recurrent and/or metastatic osteosarcoma.