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In clinical trials
Immune & defense
Murepavadin
Murepavadin is an investigational peptidomimetic antibiotic built to target Pseudomonas aeruginosa. Learn how it works and why its Phase 3 program halted.
- Reviewed by
- William Maish, MD MBA MPH, Clinical Product Lead
- Published
- October 5, 2026
- Last updated
- October 5, 2026
Key takeaway
Murepavadin is an investigational antimicrobial peptidomimetic that targets a protein unique to Pseudomonas aeruginosa, developed by Polyphor for serious lung infections. Its intravenous Phase 3 program was halted after an unexpected rate of kidney injury, and later inhaled development did not mature. As of 2026 it is not approved.
What is murepavadin?
Murepavadin is an experimental antibiotic built as a protegrin-derived peptidomimetic, a cyclized peptide-like molecule. It was developed by Polyphor (later Spexis) specifically against Pseudomonas aeruginosa, a bacterium that causes serious hospital and lung infections and is often resistant to other drugs. It was studied intravenously for hospital- and ventilator-associated pneumonia and later explored as an inhaled formulation. It is investigational and not approved.
How does it work?
Murepavadin acts through a species-specific, non-lytic mechanism. It targets LptD1, an outer-membrane protein that Pseudomonas aeruginosa needs to transport and assemble lipopolysaccharide, a building block of its outer membrane. Disrupting LptD impairs the bacterium's outer-membrane construction and kills it.
In the laboratory, it was active against multidrug-resistant and even colistin-resistant strains. This describes the mechanism, separate from the safety outcome below.
Is it FDA-approved?
No. Murepavadin is investigational and not approved. Its intravenous Phase 3 program was halted, and the company that developed it was later restructured, leaving no active development.
What does the research show?
The pivotal program was stopped for safety.
| Program | Population | Outcome |
| Phase 1 study2, indexed on PubMed | Healthy volunteers | Characterized the drug's intravenous pharmacokinetics and early safety |
| Phase 3 PRISM program, which followed | Patients with pneumonia | Closed in 2019 after a higher-than-expected incidence of acute kidney injury in the murepavadin group; enrollment had already been suspended |
A review1 summarizes the drug's novel class and antibacterial profile. There is no positive confirmatory efficacy trial, and the IV program ended on a safety signal.
Sources: a Phase 1 pharmacokinetic and safety study (Wach et al., Antimicrobial Agents and Chemotherapy, 2018, DOI: 10.1128/AAC.02355-172) and a review of murepavadin (Martin-Loeches et al., Expert Review of Anti-infective Therapy, 2018, DOI: 10.1080/14787210.2018.14410241), both indexed on PubMed; and reporting on the Phase 3 program closure. This document is educational, is not medical advice or a health claim, and is not an offer to sell any product.