WAIKOLOA, HAWAII — In a regulatory turnaround, it looks like physicians will gain ready access to dapsone gel 5% for the treatment of acne vulgaris after all, Dr. David M. Pariser said at the annual Hawaii dermatology seminar sponsored by Skin Disease Education Foundation.
The favorable results of a phase IV safety study of the topical agent conducted in acne patients with known glucose 6-phosphate dehydrogenase deficiency recently persuaded the Food and Drug Administration to rescind its requirement that all acne patients be tested for G6PD deficiency before prescribing Aczone (dapsone gel).
That requirement, which came as a condition of FDA approval of Aczone in 2005, had convinced the drug's manufacturer, QLT Inc., that topical dapsone was not a marketable drug. Aczone has languished ever since.
Dr. Pariser of Eastern Virginia Medical School, Norfolk, was an investigator in the phase IV safety study, which involved 56 evaluable acne patients with G6PD deficiency and showed no safety problems. Hemolysis is a concern with systemically administered dapsone in G6PD-deficient patients, but there is virtually no systemic absorption of topical dapsone gel, he said.
In a pooled analysis of more than 3,000 patients, 40.5% of acne patients were clear or almost clear after 12 weeks of twice-daily dapsone dosing. Both inflammatory and noninflammatory lesion counts were significantly reduced, with inflammatory lesions responding within the first 2 weeks.
FDA marketing approval is anticipated for another novel topical acne therapy: the combination of the retinoid adapalene 0.1% and benzoyl peroxide 2.5% in a fixed-dose gel formulation applied once daily, according to Dr. Pariser.
The combination, known as Epiduo, showed rapid efficacy in a 517-patient, double-blind, 12-week Galderma-sponsored randomized trial in which it outperformed each of its separate constituents as well as vehicle alone.
At 12 weeks, 42.5% of patients in the fixed-dose combination therapy group were clear or almost clear, the primary study end point required by the FDA. That was significantly better than the 34.5% rate with adapalene only, 34.9% with benzoyl peroxide only, and 14.5% with vehicle. Fifty-three percent of patients on Epiduo experienced at least a 50% reduction in total lesion count, compared with about 35% with either agent alone and 25% with vehicle (J. Am. Acad. Dermatol. 2007;57:791-9).
Dr. Pariser led a 12-month safety and efficacy study of the fixed-dose combination in 452 acne patients. The study showed clinically significant reductions in both inflammatory and noninflammatory lesions as early as week 1, with sustained reductions of 75%–80% at 1 year. Only 2% of subjects discontinued the therapy because of adverse events (J. Drugs Dermatol. 2007;6:899-905).
He disclosed that he is a consultant to QLT and has been paid to conduct research by Galderma. SDEF and this news organization are wholly owned subsidiaries of Elsevier.