Mifamurtide
Also known as: CGP-19835A, L-MTP-PE, Mepact, Mifamurtide, MTP-PE, MTP‑PE, Muramyl tripeptide phosphatidylethanolamine
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Summary
Mifamurtide (liposomal muramyl tripeptide phosphatidyl‑ethanolamine, brand name Mepact) is an immunomodulatory agent approved in Europe for use after surgical resection of high‑grade, resectable osteosarcoma. It is administered intravenously alongside standard multi‑agent chemotherapy to stimulate the innate immune system and improve survival outcomes in children, adolescents and young adults with this bone sarcoma.
Mechanism of Action
Mifamurtide is a synthetic muramyl dipeptide analog packaged in a multilamellar liposome containing phosphatidylserine‑rich phospholipids. The liposome delivers the muramyl tripeptide to monocytes and macrophages, where it engages intracellular pattern‑recognition receptors (e.g., NOD2) and activates downstream NF‑κB signaling. This triggers cytokine release and enhances the phagocytic and cytotoxic activity of macrophages against residual osteosarcoma cells, particularly in the lung microenvironment.
What the Research Shows
A systematic review of two studies (802 patients) found no significant improvement in event‑free survival when mifamurtide was added to chemotherapy, but reported better progression‑free survival in pulmonary metastatic or relapsed disease and a significant overall‑survival benefit in non‑metastatic patients. A large phase‑III open‑label trial in Europe showed a statistically significant overall‑survival increase for newly diagnosed, non‑metastatic osteosarcoma when mifamurtide was added to standard postoperative chemotherapy. Practical reviews cite 5‑year overall‑survival gains of 8‑13% with the drug. Evidence remains limited by heterogeneity and the small number of trials.
Reported Benefits
Clinical data suggest mifamurtide can improve overall survival in patients with localized, high‑grade osteosarcoma when combined with standard chemotherapy. In metastatic or relapsed settings, it may extend progression‑free survival, particularly for lung metastases. The drug’s mechanism targets the innate immune system without direct cytotoxicity to normal or tumor cells, and no long‑term adverse effects have been reported to date.
Limitations of the Evidence
Evidence is confined to a few trials, most of which are open‑label and involve heterogeneous patient groups, limiting definitive conclusions. No clear benefit has been demonstrated for event‑free survival, and the overall‑survival advantage in metastatic disease remains uncertain. The agent is not approved in the United States, and broader applicability across age groups or sarcoma subtypes has not been established.
Safety Considerations
Mifamurtide is generally well tolerated. Common acute reactions include chills, fever, headache, flu‑like symptoms, nausea, myalgias and delayed fatigue. Some studies reported haematological, hepatic, renal, gastrointestinal, cardiac and neurological disturbances, but these were not statistically different from chemotherapy alone. Premedication with ibuprofen can reduce fever and rigors. No long‑term toxicities have been documented in the available literature.
How It Is Administered
The drug is given as an intravenous infusion of a liposomal formulation, typically administered in cycles alongside postoperative multi‑agent chemotherapy. Dosing schedules vary by protocol, and pre‑medication with ibuprofen is often used to mitigate infusion‑related fever and rigors.
Routes of Administration
Goals & Uses
- Adjuvant treatment of high‑grade osteosarcomaOncologyModerate
- Immunostimulation / macrophage activationImmunologyModerate
- Prevention of metastatic relapseOncologyModerate
- Osteosarcoma adjuvant treatmentOncologyHigh
- Investigational use in other sarcomasOncologyLow
Contraindications
- Severe active infectionsInfectionModerate
- Hypersensitivity to mifamurtide or liposomal componentsAllergyHigh
- Known hypersensitivity to mifamurtide or its excipientsAllergyHigh
- Concurrent high-dose NSAIDs or corticosteroidsDrug InteractionHigh
- Concurrent use of cyclosporine or other calcineurin inhibitorsDrug InteractionHigh
- Active autoimmune or inflammatory disease requiring immunosuppressionDisease StateModerate
Adverse Effects
- Anemia / thrombocytopeniaHematologicUncommon
- HeadacheNeurologicCommonPain in the head or upper neck
- HypotensionCardiovascularUncommonLow blood pressure
- Fever and chillsConstitutionalCommon
- Nausea and vomitingGastrointestinalCommon
- Tachycardia and hypertensionCardiovascularUncommon
- NauseaGastrointestinalCommonFeeling of sickness or urge to vomit
- FatigueGeneralCommonLow energy or tiredness
- Injection‑site reactionsLocalCommon
- Chills / rigorsSystemicCommon
- FeverSystemicCommonElevated body temperature
Drug Interactions
- Immunosuppressants (e.g., corticosteroids, azathioprine)Moderate
- Corticosteroids (high-dose)High
- Live vaccinesModerate
- CyclosporineHigh
- NSAIDsModerateMay increase renal risk in susceptible patients
- Doxorubicin / Cisplatin / MethotrexateLow
Population Constraints
- PregnancyReproductive SafetyRelative
- Adults over 30 yearsAgeRelative
- Patients with severe hepatic or renal impairmentOrgan ImpairmentRelative
- Patients with active infectionsInfectious DiseaseRelative
- Pregnant or breastfeeding womenReproductiveRelative
- Children under 2 yearsPediatricRelative
- Patients ≥2 years old with resectable high‑grade osteosarcomaIndicationAbsolute
Regulatory Status
- European UnionApprovedApproved: adjuvant treatment of high‑grade osteosarcoma post‑surgeryMarketed as Mepact.
- United StatesUnapprovedInvestigational; not FDA‑approved.
- United KingdomApprovedApproved: adjuvant treatment of high‑grade osteosarcomaRegulated under EU framework post‑Brexit.
Approved in the European Union (Mepact) for post‑surgical osteosarcoma; not approved in the United States, where it remains investigational.
Evidence & Sources
- Journal ArticleHighJimmy R, et al.2017-01-01T00:00:00.000000Z
- Journal ArticleModerateAnderson PM, Tomaras M, McConnell K2010-01-01T00:00:00.000000Z
- Journal ArticleModerateAnderson PM2017-01-01T00:00:00.000000Z
- Journal ArticleModerateFerrari S, Serra M2015-01-01T00:00:00.000000Z
- Journal ArticleModerateKansara M, et al.2014-01-01T00:00:00.000000Z
- Journal ArticleModerateFrampton JE2010-01-01T00:00:00.000000Z
Frequently Asked Questions
Is mifamurtide a chemotherapy drug?
No. Mifamurtide is an immune‑stimulating agent that activates macrophages rather than directly killing cancer cells. It is used in combination with standard chemotherapy, not as a stand‑alone cytotoxic drug.
What type of osteosarcoma patients may benefit most?
Clinical trials have shown the most consistent overall‑survival benefit in patients with high‑grade, resectable, non‑metastatic osteosarcoma after complete surgical removal. Some data suggest progression‑free benefits for pulmonary metastatic or relapsed disease.
Are there any long‑term side effects?
To date, published studies have not reported chronic or late‑onset toxicities associated with mifamurtide. Reported adverse events are acute and usually resolve after the infusion, especially when pre‑medicated with ibuprofen.
Is mifamurtide available in the United States?
Mifamurtide holds orphan‑drug status in the U.S. and is considered investigational; it has not received FDA approval for routine clinical use, although compassionate‑use programs have provided access in some centers.
How is the drug formulated?
Mifamurtide is encapsulated in a multilamellar liposome containing synthetic phospholipids (e.g., POPC and OOPS) that target phosphatidylserine‑recognizing macrophages, allowing intravenous delivery of the muramyl tripeptide.
What is Mifamurtide?
Mifamurtide (liposomal muramyl tripeptide phosphatidyl‑ethanolamine, brand name Mepact) is an immunomodulatory agent approved in Europe for use after surgical resection of high‑grade, resectable osteosarcoma. It is administered intravenously alongside standard multi‑agent chemotherapy to stimulate the innate immune system and improve survival outcomes in children, adolescents and young adults with this bone sarcoma.
What is Mifamurtide used for?
Mifamurtide is educationally associated with: Adjuvant treatment of high‑grade osteosarcoma, Immunostimulation / macrophage activation, Prevention of metastatic relapse, Osteosarcoma adjuvant treatment, Investigational use in other sarcomas. Educational only — not medical advice.
How is Mifamurtide administered?
Recorded routes of administration: Intravenous, Subcutaneous.
What are the potential side effects of Mifamurtide?
Reported adverse effects include: Anemia / thrombocytopenia, Headache, Hypotension, Fever and chills, Nausea and vomiting, Tachycardia and hypertension, Nausea, Fatigue, Injection‑site reactions, Chills / rigors, Fever. This list is not exhaustive — consult a qualified clinician.
Who should avoid Mifamurtide?
Recorded contraindications: Severe active infections, Hypersensitivity to mifamurtide or liposomal components, Known hypersensitivity to mifamurtide or its excipients, Concurrent high-dose NSAIDs or corticosteroids, Concurrent use of cyclosporine or other calcineurin inhibitors, Active autoimmune or inflammatory disease requiring immunosuppression. Consult a qualified clinician before use.