SAN FRANCISCO, March 3 -- A new study comparing the efficacy and tolerability of two different formulations of botulinum toxin type A has shown that, at recommended doses, effects of treatment with BOTOX^® Cosmetic (botulinum toxin type A), also known as VISTABEL^® / VISTABEX^® in Europe, for moderate to severe glabellar lines (the vertical "frown lines" between the brows) last longer and patients are more satisfied with their appearance than patients treated with Dysport^®, a brand of botulinum toxin type A that is available in Europe but not yet approved for use in the U.S. The study is being presented at the American Academy of Dermatology's Annual Winter Meeting in San Francisco.(i)

"There are important biological, pharmacological and clinical differences between botulinum toxin formulations and they are not interchangeable at a single dosing ratio," said Nicholas Lowe, M.D., FRCP, principal investigator for the study. "This study suggests that Dysport^® may need to be used at higher doses than the currently recommended dose of 50 units for the treatment of glabellar lines to achieve duration of effect and patient satisfaction comparable to BOTOX^® Cosmetic."

For this 16-week, randomized, double-blind study, 62 patients with moderate to severe glabellar lines were treated with either BOTOX^® Cosmetic at the dose approved by the U.S. Food and Drug Administration (FDA) for the treatment of glabellar lines (20 units), or with Dysport^® (50 units, reported in a recent study to be the optimal dose of this formulation(ii)). To evaluate treatment efficacy, investigators assessed standardized photographs of patients' glabellar lines taken at baseline and weeks 2, 8, 12, and 16 - one of the most objective means of assessing glabellar line severity. In addition, patients rated their feelings of attractiveness and feelings of satisfaction with their appearance on a 7-point scale.

In both treatment groups, the number of patients with at least a 1-grade improvement in the severity of their glabellar lines peaked at week 8. However, this improvement lasted longer in the BOTOX^® Cosmetic-treated group than in the Dysport^®-treated group, with 77% of BOTOX^® Cosmetic patients vs. 59% of Dysport^® patients maintaining improvement at week 12; and with 53% vs. 28% maintaining improvement at week 16. In addition, patients' mean scores for how attractive they felt and how satisfied they felt with their appearance were consistently higher in the BOTOX^® Cosmetic treatment group than in the Dysport^® group throughout the 16-week study period, with statistical significance achieved for both criteria at week 12. Both products were well-tolerated.

"Other studies have suggested that instead of the 2.5:1 Dysport^® to BOTOX^® Cosmetic ratio used in our study, a more appropriate dose comparison may be 4:1 or 5:1 Dysport^® to BOTOX^® Cosmetic," said Dr. Lowe. "Further dose escalation studies are needed to determine an optimum comparative dosage and whether higher doses can achieve comparable efficacy to BOTOX^® Cosmetic without raising the incidence of unacceptable side effects."

This study was funded by an unrestricted grant from Allergan, Inc. to Clinical Research Specialists, Santa Monica, CA.

(i) Lowe P, Patnaik R, Lowe N. Comparison of two formulations of botulinum toxin type A for the treatment of glabellar lines: a double-blind, randomized study. Presented at the 64th annual meeting of the American Academy of Dermatology, March 3-7, 2006, San Francisco, CA. Poster #232.

(ii) Ascher B, Zakine B, Kestemont P, et al. A multicenter, randomized, double-blind, placebo-controlled study in the efficacy and safety of 3 doses of botulinum toxin A in the treatment of glabellar lines. J Am Acad Dermatol 2004;51:223-233.