LAS VEGAS – New acne treatment strategies that address the issue of antibiotic resistance include subantimicrobial dosing; new, narrower-spectrum antibiotics; and topical use of tetracycline-family antibiotics, according to Dr. Linda Stein Gold, a dermatologist at Henry Ford Hospital, Detroit.
Oral antibiotics have long been a mainstay of acne treatment, but long-term use of low-dose antibiotics may be contributing to the global crisis of antibiotic resistance. At least 2 million people become infected with resistant bacteria yearly in the United States alone, and at least 23,000 people die yearly from these infections, she noted.
Dr. Linda Stein Gold
“In dermatology we use antibiotics quite a bit, and we want to make sure when we’re utilizing drugs, we’re utilizing them in the best possible way,” Dr. Stein Gold said at the Skin Disease Education Foundation’s annual Las Vegas dermatology seminar. Finding the right antibiotic dose for effective treatment of acne can be a challenge, she noted. “Is more better? Is too little bad?”
In a review of new treatment strategies that address these concerns without compromising efficacy, Dr. Stein Gold said that the rationale for using subantimicrobial antibiotic dosing comes from the anti-inflammatory effect seen with many antibiotics, even with doses lower than needed for antimicrobial action.
For example, a study of a subantimicrobial-dose of doxycycline found that when adults with moderate acne were treated with the antibiotic (20 mg, twice daily) for 6 months, their acne significantly improved. The number of comedones, inflammatory lesions, and noninflammatory lesions improved significantly compared with those on placebo (Arch Dermatol. 2003 Apr; 139:459-64).
In another head-to-head trial that compared low-dose modified-release doxycycline with placebo or 100 mg of doxycycline, the lower dose outperformed both placebo and full-strength antibiotics. No resistant organisms were found among skin flora in the subjects, and the microbiota of the patients’ skin did not change significantly during the study period, she said.
Dr. Stein Gold’s work also suggests that systemic antibiotics may not be necessary for all patients with acne: In a study, after 12 weeks of treatment, adapalene plus benzoyl peroxide, in combination with doxycycline, resulted in significantly more patients with clear or almost-clear skin than with vehicle alone plus doxycycline. “Antibiotics are not always the golden nugget in the treatment of acne,” she commented.
Another tactic is to treat with antibiotics for a period of 3-6 months along with potent topicals, to get skin clear or almost clear, then discontinue the antibiotic and continue topical treatment. Many patients will be able to maintain clear skin on this regime, she noted.
A new tetracycline-family antibiotic, sarecycline, is in phase III trials for acne vulgaris and in phase II trials for acne rosacea. Sarecycline, “compared with existing tetracycline antibiotics, showed improved anti-inflammatory properties and a narrower spectrum of activity,” Dr. Stein Gold said.
A topical minocycline in a foam formulation shows promising results for tolerability and efficacy in phase II trials for moderate and severe acne, she added. Dapsone as a 7.5% topical gel formulation is in phase III clinical trials as well.
Another antibiotic with a long history of systemic use for acne, clindamycin, is also showing promising results in combination with benzoyl peroxide (1.2%/3.75% gel). A 12-week double-blind study of the combination, compared with vehicle alone for individuals with moderate or severe acne, showed significant improvement in comedonal and inflammatory lesions, as well as overall global improvement in severity, for the treatment arm, she said (J Drugs Dermatol. 2014 Sep;13[9]:1083-9).
Dr. Stein Gold reports being a consultant and investigator for Galderma, Stiefel Laboratories, and Allergan; a consultant and speaker for Valeant; a speaker for Ranbaxy Laboratories, Promius Pharma, and Actavis; and a medical/legal consultant for Roche.
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