A multicenter, randomized, double-blind, placebo-controlled study of efficacy and safety of 3 doses of botulinum toxin A in the treatment of glabellar lines.

Background: Botulinum toxin A (BTX-A) is used to treat glabellar lines but the rigorous demonstration of its efficacy in a well-designed study had never been reported.
Objective: This study was designed to evaluate the efficacy and the safety of 3 doses of BTX-A in the treatment of glabellar lines.
Methods: A total of 119 patients with moderate to severe glabellar lines at rest were treated with 25, 50, or 75 U of BTX-A (Dysport, Ipsen) or placebo divided into 5 intramuscular glabellar sites. Outcome measures included evaluations of glabellar lines by independent experts from blinded standardized photographs at rest 1 month after treatment, physician evaluations, and patient assessments during a 6-month period.
Results: A significant efficacy was reported for the 3 BTX-A groups for at least 3 months after injection (at least P <.015). Investigator and patient evaluations suggested that 50 U was the optimal dose. BTX-A was well tolerated. No blepharoptosis was reported. An evaluation in blinded conditions by independent experts was necessary because the results were overestimated by the investigators.
Conclusion: BTX-A is an effective and safe treatment for glabellar lines.