Background: In April, the U.S. Food and Drug Administration approved a new U.S. formulation of botulinum neurotoxin type A (Dysport; Medicis Aesthetics, Inc., Scottsdale, Ariz.). This formulation has demonstrated inhibition of glabellar lines at a 50-unit dose. Standard clinical practice is to adjust the dose based on muscle mass. Methods: Patients stratified by race/ethnicity were randomized to receive a single treatment of Dysport administered in various doses or placebo. Dysport was administered in a total volume of 0.4 to 0.6 ml for women (50, 60, or 70 units) and 0.5 to 0.7 ml for men (60, 70, or 80 units), based on procerus/corrugator muscle mass. Efficacy was assessed by a blinded evaluator and patient self-evaluation on days 14, 30, 60, 90, 120, and 150 after treatment. Results: At day 30, 85 percent and 87 percent of Dysport-treated patients were responders as assessed by blinded evaluator and patient self-evaluation, respectively, compared with 3 percent and 5 percent of placebo-treated patients, respectively (p < 0.001). Median duration of effect was 109 days for Dysport versus 0 days for placebo (blinded evaluator) and 107 days for Dysport versus 0 days for placebo (patient self-evaluation). Response and duration of action were slightly higher in African American patients. The majority of treatment-emergent adverse events were mild or moderate in severity. Conclusion: A single treatment with Dysport, with the dose based on gender and muscle mass, is well tolerated and provides a greater and longer-lasting improvement in glabellar lines compared with placebo.
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