Population control: New combination treatments reduce p. acnes colonies

March 1, 2009

Combination treatment for acne continues to evolve, helping doctors address the sometimes tough-to-tackle condition.

Key Points

Brooklyn, N.Y. - Clinical trials have shown that a combination approach to the treatment of acne often outperforms monotherapy, and the plethora of combination prescription and over-the-counter (OTC) products testify to the acceptance of the approach.

Though the combinations vary, most include a benzoyl peroxide component, which may not offer much to address inflammation, but can be powerful in attacking Propionibacterium acnes (P. acnes), and has long been regarded as an important tool for also boosting the effectiveness of some antibiotic therapies.

Clinical study

The results showed the clindamycin-benzoyl peroxide gel to be statistically superior to the vehicle, as well as to the individual active ingredients, with visibly greater improvement observed in the clindamycin-benzoyl peroxide group as early as week two.

No substantive differences in tolerability among treatment groups were seen (J Am Acad Dermatol. 2008 Nov;59(5):792-800).

Additional study

A more recent study looks at benzoyl peroxide in a cleanser formulation to find out if that, too, can be effective in reducing antibiotic-resistant strains of P. acnes.

The three-week, open-label, single-center study looked at 30 adults who were free of acne but had high facial P. acnes populations (10,000 colonies/cm2 or more) that were resistant to erythromycin and tetracycline at 8 micrograms/mL or more and 2 micrograms/mL or more, respectively.

After three weeks of using a 6 percent benzoyl peroxide cleanser, the total P. acnes counts and counts of each resistant strain decreased by approximately one log after one week of treatment, by at least 1.5 log after two weeks of treatment, and by at least two log after three weeks of treatment, with no differences between resistant and susceptible strains or between highly resistant and low-level resistant strains, according to the study (Cutis. 2008;82:417-421).

"Benzoyl peroxide cleanser 6 percent effectively reduced resistant P. acnes populations and offers a useful therapy for controlling antibiotic resistance in patients receiving antibiotics," the authors conclude.

The study indicates that doctors may have success in turning to a benzoyl peroxide cleanser if they are unable to use stronger products, says Alan R. Shalita, M.D., professor and chairman, State University of New York Downstate Medical Center, Brooklyn, N.Y.

Results

"The findings show that you don't necessarily have to use a leave-on benzoyl peroxide product to see results," Dr. Shalita tells Dermatology Times.

"It penetrates the follicle very quickly and gets right to where the P. acnes is, very rapidly," he says.

Systemic antibiotics

When it comes to systemic antibiotics combined with topicals such as benzoyl peroxide combinations, Dr. Shalita says he has had good results with a new minocycline product.

"My particular favorite antibiotic right now is the Solodyne brand of minocycline," he says. "The product has an extended release that I find works very well."

Epiduo

Another new product offering a treatment combination for acne is Galderma's Epiduo, a mix of the retinoid adapalene 0.1 percent and benzoyl peroxide 2.5 percent that just received Food and Drug Administration (FDA) approval in January.

"Epiduo will be the only product to combine a retinoid with benzoyl peroxide, so that adds an interesting new blend to the market," Dr. Shalita says.

"Adapalene is what we call a hard molecule, so it's not affected by the benzoyl peroxide, and that is the principle behind the combination," he says. "I think it will likely work in many patients and will probably sell very well."

Dr. Shalita speculates that one possible newcomer to the OTC market could be a mix from Johnson & Johnson (J&J).

"I think that because of the success of Proactive (Guthy-Renker), J&J will probably come out with a combination of its Clean & Clear Advantage Acne Cleanser salicylic acid acne gel cleanser and its Persa-Gel 10 benzoyl peroxide product," he says.

And as the OTC market continues to grow with other impressive acne treatments, dermatologists may hear less about the ones that do work than the ones that don't.

Disclosure: Dr. Shalita has been an investigator for Johnson & Johnson and Galderma, and he is a consultant to Galderma, Johnson & Johnson, Medicis and Stiefel.

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