The U.S. Food and Drug Administration (FDA) approved to market Aczone (dapsone) Gel, 5 per cent for acne vulgaris topical treatment. But patients who have the enzyme deficiency, G6PD (Glucose 6-phosphate dehydrogenase), will need to be monitored with regular blood counts to detect if they are predisposed to one type of anemia (hemolytic anemia). Aczone, a trademark of QLT USA Inc., is an aqueous topical gel which contains 5 per cent dapsone. According to scientific research, combining dapsone in a Solvent Microparticulate (SMP) gel enables dapsone to be applied topically and safely. This product achieved significant per cent reduction in the number of acne lesions and better success rate on the Global Acne Assessment Score in two randomized double-blind, vehicle controlled clinical studies in 3000 acne patients. Oiliness/peeling, dryness, and erythema were the most common adverse events reported from controlled clinical trials. However, there were no significant differences in the adverse event rates between Aczone Gel and vehicle control treated patients. 1.4 per cent of about 3500 patients had the enzyme deficiency -in the Aczone clinical trial program- which is consistent with the incidence in the general North American population. The company QLT will undertake a post-approval Phase IV study in 50 acne patients who have G6PD deficiency and follow them for 6 months, after which QLT expects to submit an application to the FDA to re-evaluate the Aczone label. The President and Chief Executive Officer of QLT Inc., Paul Hastings, stated that “Aczone represents an important clinical advance in dermatology, has demonstrated safety and efficacy in over 4,000 patients. We are very pleased with the FDA's decision and confident in Aczone's potential as a new class of treatment for acne patients”.