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Mifamurtide (Mepact)

Peptide

Mifamurtide is a synthetic muramyl tripeptide immunomodulator for osteosarcoma. EMA-approved March 2009 (FDA denied 2007). Phase 3 INT-0133 (n=662): 6-year overall survival 78% vs 70% with chemotherapy alone. 28% relative reduction in death risk (HR 0.72, P=0.031). Indicated for high-grade, non-metastatic, resectable osteosarcoma ages 2-30 combined with post-operative chemotherapy. First immunotherapy approved for osteosarcoma. LIMITATIONS: Not FDA-approved; EMA approval based on single trial with statistical controversies.

Quick Answer

What it is

Mifamurtide is a synthetic muramyl tripeptide immunomodulator for osteosarcoma. EMA-approved March 2009 (FDA denied 2007).

Key findings

  • Grade A: Flu-like Symptoms (Bone Cancer)
  • Grade B: Anti-Cancer Activity
  • Grade B: Immune Function

Safety

  • 28% relative reduction in death risk (HR 0.72, P=0.031).
  • Relative risk reduction 28% (HR 0.72; 95% CI 0.53-0.97; P=0.031).
  • Represents one-third reduction in death risk.
⚠️ Research Notice

This peptide information is for educational and research purposes only. Peptides may not be FDA-approved for human use and may only be legally available for research purposes. Consult qualified healthcare professionals before considering any peptide compounds.

ℹ️ Quick Facts: Mifamurtide (Mepact)

Quick Facts: Mifamurtide (Mepact)

  • Best Evidence:Grade A
  • Conditions Studied:1
  • Research Outcomes:10
  • Grade A Findings:1
  • Grade B Findings:4
  • Key Effect:Bone Cancer
A1
B4
C2
D3
1 conditions · 10 outcomes

Detailed Outcomes

A
Flu-like Symptoms
Expected immunostimulatory effects: Chills (89%), fever (85%), fatigue (53%), nausea, headache, myalgias. Generally mild-moderate, transient, respond to palliative treatment. Most occur within 2 hours of infusion. Tolerance develops over time.
large↑Worsens
B
Overall Survival Improvement
INT-0133 Phase 3 (n=662 non-metastatic): 6-year OS 78% with mifamurtide vs 70% chemotherapy alone. Relative risk reduction 28% (HR 0.72; 95% CI 0.53-0.97; P=0.031). Represents one-third reduction in death risk. Led to EMA approval.
moderate↑Improves
B
Event-Free Survival
INT-0133: Event-free survival improvement not statistically significant as primary endpoint. Significant interaction between mifamurtide and ifosfamide identified. Controversy over endpoint analysis contributed to FDA denial. EFS benefit less clear than OS benefit.
small↑Improves
C
Metastatic/Recurrent Disease
EuroSarc-Memos trial: No significant benefit in metastatic or recurrent osteosarcoma. Compassionate use data limited. Currently indicated only for non-metastatic, resectable disease after complete surgical removal.
none
B
Anti-Cancer Activity
23 human trials and systematic reviews support this finding. Evidence includes systematic reviews/meta-analyses. Human clinical trial data available.
moderate↑Improves
B
Immune Function
10 human trials support this finding. Human clinical trial data available.
moderate↑Improves
C
Liver Protection
4 preclinical studies support this finding. Primarily preclinical evidence.
small↑Improves
D
Safety/Tolerability
2 preclinical studies support this finding. Primarily preclinical evidence.
small↑Improves
D
Mortality
2 preclinical studies support this finding. Primarily preclinical evidence.
small↓Improves
D
GI Protection
2 preclinical studies support this finding. Primarily preclinical evidence.
small↑Improves

Research Citations (43)

Tumor Immune Microenvironment-Associated Prognostic and Mifamurtide-Response Gene Signatures for Localized Osteosarcoma: A Correlative Study of the ISG/OS-2 Trial.
(2025)
PMID: 40711479
The benefits of combining an immunomodulator with a chemotherapy agent in chondrosarcoma-a proof of concept with mifamurtide.
(2025)
PMID: 40960554
Long-Circulating and Targeted Liposomes Co-loading Cisplatin and Mifamurtide: Formulation and Delivery in Osteosarcoma Cells.
(2024)
PMID: 39592553
Microbe-mediated intestinal NOD2 stimulation improves linear growth of undernourished infant mice.
(2023)
PMID: 36821686
Outcomes from a mechanistic biomarker multi-arm and randomised study of liposomal MTP-PE (Mifamurtide) in metastatic and/or recurrent osteosarcoma (EuroSarc-Memos trial)
(2022)
PMID: 35778685
The addition of the immunomodulator mifamurtide to adjuvant chemotherapy for early osteosarcoma: a retrospective analysis.
(2022)
PMID: 35312944
Mucosal Adjuvants Delivered by a Mucoadhesive Patch for Sublingual Administration of Subunit Vaccines.
(2022)
PMID: 36362224
Gut microbial DL-endopeptidase alleviates Crohn's disease via the NOD2 pathway.
(2022)
PMID: 36049483
Phase 2 study for nonmetastatic extremity high-grade osteosarcoma in pediatric and adolescent and young adult patients with a risk-adapted strategy based on ABCB1/P-glycoprotein expression: An Italian Sarcoma Group trial (ISG/OS-2).
(2022)
PMID: 35201621
Strategies for Using Muramyl Peptides - Modulators of Innate Immunity of Bacterial Origin - in Medicine.
(2021)
PMID: 33959120

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