Magainin Moves Nearer To Marketing Peptide Antibiotic

Magainin Pharmaceuticals now looks on track to have its first product,the peptide antibiotic Cytolex (pexiganan acetate), filed with the regulatory authorities by the end of this year. The company has completed its second study of Cytolex in the treatment of diabetic foot ulcers, and has entered into an alliance with SmithKline Beecham for the marketing of the compound.

Cytolex is a magainin antibiotic, a class of compounds discovered in amphibians and thought to be behind why these animals are remarkably resistant to infection, despite living in contaminated environments. These agents, sometimes referred to as defensins, act locally at the site of infections. Their importance to these animals is indicated by the fact that they can form the bulk of proteinaceous compounds in one of the primary immune system cells which combat infections, neutrophils. The magainins, like most peptide antibiotics, are extremely broad-spectrum in their action, targeting Gram-negative and Gram-positive bacteria, as well as fungal infections.

Both the studies compared 1% Cytolex cream with the quinolone antibiotic ofloxacin, at a standard dose of 400mg bd. Study 303, reported last year, demonstrated that Cytolex was as effective as ofloxacin in healing ulcers, and offered equivalent antimicrobial efficacy, and the second study, 404 confirmed this finding. Furthermore, Cytolex was better tolerated than ofloxacin, and has the advantage of topical administration.