Pexiganan (MSI-78)
Overview
Pexiganan is a 22-amino acid synthetic analog of magainin 2 designed to enhance antimicrobial potency and proteolytic stability. It disrupts bacterial membranes through electrostatic interaction and pore formation, demonstrating broad-spectrum activity against gram-positive and gram-negative organisms, including methicillin-resistant Staphylococcus aureus. Pexiganan was developed as a topical agent for infected diabetic foot ulcers, leveraging its rapid bactericidal action and low resistance potential. Structural modifications from the parent magainin sequence improve its pharmacological profile for clinical use.
Key Research Findings
Phase III clinical trials in diabetic foot infections showed non-inferiority to oral oxytetracycline in some analyses but failed to meet FDA approval criteria in 1999 due to insufficient efficacy margins. Subsequent reanalysis and additional studies were conducted, and pexiganan received a Complete Response Letter from the FDA in 2017 requesting further data. Development efforts have continued with regulatory submissions in other jurisdictions.
Topical
In Clinical Trials
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