Mepact

Mepact (mifamurtide) is approved by the European Medicines Agency (EMA) for the treatment of high-grade, resectable, non-metastatic osteosarcoma after macroscopically complete surgical resection in children, adolescents, and young adults (2–30 years), used in combination with post-operative multi-agent chemotherapy. Note: Not FDA-approved in the US; EMA-approved in the EU.

EMA-approved dose: 2 mg/m² IV infusion over 1 hour, twice weekly for 12 weeks, then weekly for an additional 24 weeks (36 weeks total). Administer via liposomal infusion. Must be diluted and administered per protocol specifications.

Powder for suspension for infusion: 4 mg (as liposomal mifamurtide) — for reconstitution

Known hypersensitivity to mifamurtide or any component. Use with NSAIDs is not recommended.

• Hypersensitivity/Anaphylaxis: Severe acute hypersensitivity reactions have been reported. Pre-medication not routinely required but equipment for managing anaphylaxis should be available.
• Pericarditis/Myocarditis/Pleuritis: Inflammatory reactions in these compartments have occurred. Monitor for signs of pericarditis.
• Immunosuppression: May be diminished by immunosuppressive agents including ciclosporin and corticosteroids. Avoid concomitant use.
• Hepatic/Splenic Infarction: Cases have been reported. Monitor.
• Transient Reduction in Renal Function: Monitor creatinine during treatment.
• Embryo-Fetal Toxicity: Contraindicated in pregnancy.

Fever (90%), Fatigue (61%), Chills (55%), Nausea (49%), Headache (46%), Vomiting (39%), Tachycardia (32%), Anorexia (27%)

Consult the complete prescribing information for a comprehensive list of adverse reactions and their frequencies.

NSAIDs: May diminish efficacy of mifamurtide; avoid concurrent use.
Corticosteroids/ciclosporin: May diminish immunostimulatory effects; avoid.
Nephrotoxic agents: Use with caution given potential for transient renal changes.

Can cause fetal harm. Advise females of reproductive potential to use effective contraception. Consult the full prescribing information for pregnancy risk details.

Advise women not to breastfeed during treatment and for a period after the last dose. Refer to prescribing information for duration guidance.

Safety and effectiveness in pediatric patients have not been established unless otherwise noted in the full prescribing information.

Dose modifications for organ impairment are specified in the complete prescribing information.

Mifamurtide (muramyl tripeptide phosphatidylethanolamine; MTP-PE) is a synthetic analog of muramyl dipeptide (MDP), a component of bacterial cell walls. Encapsulated in liposomes, it is taken up by monocytes and macrophages, activating them to cytotoxic states that can kill tumor cells. It also stimulates secretion of inflammatory cytokines (TNF-α, IL-1, IL-6) that enhance anti-tumor immune activity.

Route: IV liposomal. Peak serum levels within 1 hour of infusion. Biphasic elimination with initial half-life of ~15 minutes (distribution) and terminal half-life of ~18 hours. Primarily eliminated via bile/feces. Liposomal formulation ensures macrophage-targeted delivery.

Clinical efficacy and safety data supporting the approval are available in the full prescribing information and from the clinical trials listed below.

• INT-0133 — Mifamurtide added to chemotherapy (MAP regimen) for non-metastatic osteosarcoma. Phase III cooperative group study.
  📄 Primary Publication ↗

Mepact has FDA-approved indications across the following cancer types covered on CancerDrugEvidence: