Almurtide
Also known as: MDP-butyl ester, Murabutide, N-acetylmuramyl-L-alanyl-D-glutamine n-butyl ester
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Summary
Almurtide (also known as Murabutide or MDP‑butyl ester) is a synthetic analogue of the bacterial cell‑wall component muramyl dipeptide. It belongs to the immunomodulatory peptide family and has been investigated experimentally as an immune‑stimulating adjuvant. Research has examined its ability to modulate lymphocyte proliferation, enhance macrophage‑related colony‑stimulating activity, and act as a vaccine adjuvant, while animal studies have also reported joint inflammation with certain formulations.
Mechanism of Action
Almurtide mimics muramyl dipeptide, a ligand for intracellular pattern‑recognition receptors that detect bacterial peptidoglycan fragments. Binding to these receptors (e.g., NOD‑like receptors) triggers downstream signaling that promotes cytokine release, up‑regulates colony‑stimulating factors, and activates monocyte‑macrophage lineages. The resulting cascade can amplify both innate and adaptive immune responses, including enhanced proliferation of certain lymphocyte subsets and increased production of IgA and IgM antibodies. Formulation‑dependent delivery influences the intensity of the inflammatory response.
What the Research Shows
Three peer‑reviewed studies provide the experimental basis for Almurtide. In vitro work with human peripheral blood mononuclear cells showed that Almurtide, like native MDP, did not universally induce DNA synthesis but could modulate responses to mitogens and enhance pokeweed‑induced IgA and IgM production in a subset of donors. In vivo mouse experiments demonstrated that subcutaneous injection of Almurtide raised serum monocyte‑macrophage colony‑stimulating activity, expanded bone‑marrow stem‑cell proliferation, and increased granulocyte‑macrophage progenitors, suggesting a boost in myelopoiesis. Conversely, rat studies revealed that aqueous administration of Almurtide and related acyl‑MDP derivatives provoked acute polyarthritis, which could become chronic with repeated dosing, whereas oil‑in‑water emulsions did not produce the same effect. Together, the data indicate immunostimulatory potential but also a propensity for inflammatory joint pathology under certain conditions.
Reported Benefits
Experimental evidence supports Almurtide’s capacity to enhance innate immune cell activity, increase colony‑stimulating factor levels, and augment specific antibody responses (IgA, IgM) in vitro. These properties suggest utility as an immune adjuvant to strengthen vaccine efficacy or to bolster host defenses, particularly in settings where macrophage activation is desirable. However, benefits are documented only in cell cultures and murine models, not in human clinical trials.
Limitations of the Evidence
The literature consists of a limited number of pre‑clinical studies, with variable responses among human donors and no data from controlled human trials. The immunostimulatory effects have not been correlated with clinical outcomes, and the observed arthritis in rats raises concerns about safety. Translation of murine myelopoiesis findings to humans remains uncertain, and the dose‑response relationship is undefined.
Safety Considerations
Animal data indicate that aqueous formulations of Almurtide can trigger acute and, with repeated exposure, chronic polyarthritis, characterized by joint inflammation and new bone formation. No human safety data are reported in the cited literature. Potential inflammatory reactions, especially when delivered in soluble form, warrant caution. Formulation choice (e.g., oil‑in‑water emulsion) appears to influence toxicity, but definitive safety guidance is lacking.
How It Is Administered
Research protocols have employed intravenous and subcutaneous injections of Almurtide. The compound has been studied both as a simple aqueous solution and as part of emulsified preparations; the latter seem to mitigate joint inflammation in rats. No approved therapeutic formulation exists, and dosing regimens are experimental.
Routes of Administration
Goals & Uses
- Vaccine adjuvantVaccinologyLow
- Immunostimulation / innate immune activationImmunologyModerate
- Cancer immunoadjuvantOncologyLow
- HIV infection adjunct therapyInfectious DiseaseModerate
Contraindications
- Known hypersensitivity to MDP analoguesAllergy/ImmunologyHigh
- Autoimmune disease (active)ImmunologicalModerate
Adverse Effects
- Injection site reactionsLocalCommon
- Transient fever / flu-like symptomsSystemicUncommon
- Transient leukocytosisHematologicalUncommon
- FatigueGeneralUncommonLow energy or tiredness
Drug Interactions
- Immunosuppressants (e.g., corticosteroids, cyclosporine)Moderate
- Antiretroviral therapy (ART)Low
Population Constraints
- PregnancyReproductive SafetyRelative
- Pediatric patientsAgeRelative
- Severely immunocompromised patientsImmunologicalRelative
Regulatory Status
- European UnionInvestigationalInvestigated in European clinical trials, particularly in France, for HIV and immune modulation; not approved.
- United StatesUnapprovedNot approved by the FDA for any indication; research use only.
- United KingdomUnknownNo known UK regulatory approval; research compound.
Almurtide (murabutide) has not received FDA, EMA, or other major regulatory approval for any indication. It has been studied in clinical trials in Europe, particularly in France, for HIV infection and as an immunoadjuvant. It remains a research/investigational compound.
Evidence & Sources
- Journal ArticleLowBahr GM, et al.1984-01-01T00:00:00.000000Z
- Journal ArticleLowGalelli A, Chedid L1983-01-01T00:00:00.000000Z
- Journal ArticleLowKohashi O, et al.1986-01-01T00:00:00.000000Z
Frequently Asked Questions
What type of immune response does Almurtide influence?
Almurtide primarily stimulates innate immunity by activating monocyte‑macrophage pathways and increasing colony‑stimulating factors. It can also modulate adaptive responses, enhancing IgA and IgM antibody production in certain in vitro settings.
Has Almurtide been tested in humans?
The cited studies include only in vitro experiments with human cells and animal models. No human clinical trials or approved therapeutic uses are reported for Almurtide.
Why did rats develop arthritis after receiving Almurtide?
In rats, aqueous administration of Almurtide and related acyl‑MDP derivatives provoked acute joint inflammation, likely due to excessive innate immune activation. Repeated dosing led to chronic polyarthritis, suggesting a formulation‑dependent inflammatory risk.
Could Almurtide be used as a vaccine adjuvant?
Pre‑clinical data show that Almurtide can enhance certain antibody responses and macrophage activity, properties desirable in adjuvants. However, without human safety and efficacy data, its use as a vaccine adjuvant remains speculative.
What routes of administration have been explored for Almurtide?
Experimental work has used intravenous and subcutaneous injections. The impact on immune activation and adverse effects appears to depend on the delivery vehicle, with emulsified formulations reducing joint inflammation in animal studies.
What is Almurtide?
Almurtide (also known as Murabutide or MDP‑butyl ester) is a synthetic analogue of the bacterial cell‑wall component muramyl dipeptide. It belongs to the immunomodulatory peptide family and has been investigated experimentally as an immune‑stimulating adjuvant. Research has examined its ability to modulate lymphocyte proliferation, enhance macrophage‑related colony‑stimulating activity, and act as a vaccine adjuvant, while animal studies have also reported joint inflammation with certain formulations.
What is Almurtide used for?
Almurtide is educationally associated with: Vaccine adjuvant, Immunostimulation / innate immune activation, Cancer immunoadjuvant, HIV infection adjunct therapy. Educational only — not medical advice.
How is Almurtide administered?
Recorded routes of administration: Intravenous, Subcutaneous.
What are the potential side effects of Almurtide?
Reported adverse effects include: Injection site reactions, Transient fever / flu-like symptoms, Transient leukocytosis, Fatigue. This list is not exhaustive — consult a qualified clinician.
Who should avoid Almurtide?
Recorded contraindications: Known hypersensitivity to MDP analogues, Autoimmune disease (active). Consult a qualified clinician before use.