MIAMI BEACH — The latest trend in acne treatment is not new medications but innovative reformulations of existing agents, Dr. Dirk M. Elston said at a symposium sponsored by the Florida Society of Dermatology and Dermatologic Surgery.
Subantimicrobial-dose doxycycline (Oracea, CollaGenex Pharmaceuticals Inc.) and extended-release minocycline (Solodyn, Medicis Pharmaceutical Corp.) are good examples, he said.
The use of 40 mg of doxycycline for acne would be off label. The Food and Drug Administration approved the agent in May 2006 for the treatment of inflammatory rosacea lesions in adults. The efficacy studies that led to the rosacea indication, however, are a “proof of concept that you can separate its anti-inflammatory effect from its antimicrobial effect,” said Dr. Elston, director of the department of dermatology at Geisinger Health System, Danville, Pa.
Oral antibiotics used to treat acne vulgaris feature both antimicrobial and anti-inflammatory properties (JAMA 2004;292:726–35). A reduction in the emergence of doxycycline resistance is a potential benefit of staying below an effective antimicrobial dose, said Dr. Elston, who is on the advisory boards for both Medicis and CollaGenex.
Clinical concerns with doxycycline include esophageal injury and patient compliance. When physicians at Geisinger prescribe the drug, the electronic record system automatically prints out patient instructions to take the antibiotic with ample water or a meal. There is also a reminder never to take doxycycline at bedtime.
The FDA approved minocycline extended-release tablets, also in May 2006, for the treatment of inflammatory lesions of nonnodular moderate to severe acne vulgaris in patients aged 12 years and older. Extended-release minocycline features a reduced total dosage (1 mg/kg per day) with efficacy equal to higher doses, Dr. Elston said. It is available as a 45-mg, 90-mg, or 135-mg tablet. The once-a-day formulation increases compliance.
Minocycline is much less resistant to isolates of Propionibacterium acnes than is tetracycline or erythromycin, Dr. Elston said.
Adverse events in a phase III trial were similar between 674 patients taking extended-release minocycline and 364 taking a placebo. Headache, nausea, and fatigue were the leading events reported.
Interim results for 345 participants in an ongoing, open-label, long-term safety study show no increase in the number of antinuclear antibody-positive patients, a concern related to lupus. In addition, “there is no evidence of any interaction with birth control drugs,” Dr. Elston said.
In an open-label study with 30 patients, extended-release minocycline did not alter plasma estradiol, FSH, LH, or progestinic hormone levels.