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.
At a glance
| FDA status | Investigational antimicrobial peptidomimetic, not approved by the FDA |
| Target | Pseudomonas aeruginosa, including drug-resistant strains |
| Intravenous program | Phase 3 halted for kidney toxicity |
| Inhaled program | Later development did not advance |
| Evidence strength | Low research |
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.
More for immune & defense
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.