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May 2002
Vol. 5, No. 5, p 11.
news in brief


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In most adolescents and even some adults, acne rears its red, angry head sooner or later. Although individuals with mild acne often fare well with over-the-counter remedies, those with severe or recurrent acne require prescription drugs that are host to a range of unpleasant and even dangerous side effects.

Now, a team of scientists at Micrologix Biotech (Vancouver, BC) has devised a highly potent new acne therapy that overcomes the problems associated with conventional prescription therapies. They presented their findings at the 41st Interscience Conference on Antimicrobial Agents and Chemotherapy in Chicago last December.

Their compound, designated MBI 594AN, is under development and belongs to a class of antibiotics known as antimicrobial peptides. These highly lethal snippets of protein work by rapidly punching holes in bacterial cells. Produced by everything from amphibians to insects to humans, the antimicrobial peptides are the reason that frogs with open wounds can lounge about in swamp water without developing infection. MBI 594AN is a chemically modified analogue of a naturally occurring mammalian peptide.

Conventional antibiotics are currently the mainstay of acne therapy, and they have been used for more than 30 years to combat Propionibacterium acnes, the bacterium associated with severe, inflammatory acne. However, 62% of all P. acnes that are isolated are resistant to antibiotics, up from 20% in 1978. Vitamin A derivatives, known as retinoids, are another highly effective therapy but are not without serious side effects, most notably severe birth defects and potential psychological disturbances.

The new peptide antibiotic would be used externally as a topical lotion. Because the compound is attracted to lipids, it targets the sebum-containing follicles where P. acnes resides, using sebum to grow, says David Friedland, vice president of clinical development at Micrologix.

Moreover, it seems to work so fast that bacteria are killed before they can develop resistance.In preclinical studies, repeated attempts to generate P. acnes resistant to MBI 594AN were unsuccessful. In a Phase I clinical trial, P. acnes isolates obtained from volunteers treated with the peptide solution for six weeks were as susceptible to the antibiotic as they were before treatment. MBI 594AN also displayed anti-inflammatory properties, reducing inflammation in laboratory models by 60% relative to dexamethasone, the gold standard anti-inflammatory steroid.

Micrologix recently completed a Phase II clinical trial to assess the drug’s effectiveness at reducing acne lesions in 75 patients. The results of the six-week study demonstrated proof of concept, says Friedland. He also says that the treatment does not seem to cause unwanted side effects. A three-month acne study aimed at optimizing the dose is the next step.


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