Azelaic acid has been the focus of recent studies for treating rosacea – and the results have been encouraging, according to Dr. Julie C. Harper.
In a study published this year, 15% azelaic acid was shown to modulate the inflammatory response in normal human keratinocytes through peroxisome proliferator–activated receptor (PPAR)–gamma activation (Exp. Dermatol. 2010;19:813-20), said Dr. Harper of the department of dermatology at the University of Alabama at Birmingham.
Dr. Julie C. Harper
"Azelaic acid was shown to suppress UVB light–induced interleukin-1 beta, IL-6, and [tumor necrosis factor]–alpha mRNA expression and protein secretion, and it induces PPAR-gamma in RNA; PPAR-gamma suppresses inflammation," she explained, adding that the study suggested this might be a pathway in which azelaic acid exerts its anti-inflammatory effects.
Azelaic acid has also been the focus of several clinical studies, she reported at the Las Vegas Dermatology Seminar sponsored by Skin Disease Education Foundation (SDEF).
In a 12-week, double-blind parallel group study of 72 patients, a 15% gel formulation used once daily was shown to be as effective as the same formulation used twice daily. No significant difference was found between the once- and twice-daily groups in regard to mean investigator global assessment scores, treatment success, treatment response, mean number of inflammatory lesions, or erythema intensity (J. Drugs Dermatol. 2008;7:541-6).
In a randomized, phase IV parallel group study of 207 patients with mild to moderate rosacea, topical azelaic acid 15% gel plus 40 mg oral doxycycline was shown at treatment week 6 to be associated with significantly greater improvement in mean inflammatory lesion count, compared with metronidazole 1% gel plus oral doxycycline (J. Drugs Dermatol. 2010;9:607-13). A greater proportion of patients in the azelaic acid group achieved 25%, 50%, and 75% improvement in mean inflammatory lesion count. However, differences between the groups were not significant at other time points, Dr. Harper noted.
Finally, azelaic acid 15% gel plus oral doxycycline, and azelaic acid maintenance monotherapy, were shown in a two-phase study to provide rapid initial improvement in moderate to severe rosacea, and to maintain remission in 75% of patients, respectively. The first phase was an open-label, multicenter study of topical azelaic acid 15% gel plus oral doxycycline as initial therapy given for up to 12 weeks; the second phase was a multicenter, double-blind, randomized vehicle-controlled phase comparing maintenance azelaic acid gel twice a day versus a vehicle gel for 24 weeks in those who achieved at least a 75% reduction in inflammatory lesions in the first phase (J. Drugs Dermatol. 2009;8:639-48).
"Azelaic acid is a commonly prescribed topical medication for the treatment of rosacea. These new developments give us insight into why this product works so well," Dr. Harper noted. "We are also learning a great deal about the pathogenesis of rosacea and other skin diseases. The more we learn, the more efficiently and effectively we can treat these diseases."
Dr. Harper disclosed that she is a speaker and consultant for Allergan, and a speaker for Coria, Galderma, Intendis, and Stiefel/GlaxoSmithKline. She serves on advisory boards for Coria, Intendis, and Ranbaxy, and is a researcher for Intendis and Medicis. She has also received an honorarium from Ranbaxy.
SDEF and this new organization are owned by Elsevier.