New Orleans — Botulinum toxin type A (Botox, Botox Cosmetic; Allergan) can be used safely and effectively in a range of doses to simultaneously treat a spectrum of upper facial rhytids in adult women, although use of a higher dose affords benefits for improved magnitude and durability of response without compromising safety, according to the results of a dose-comparison study presented by Alastair Carruthers, M.D., and Jean Carruthers, M.D., at the 63rd Annual Meeting of the American Academy of Dermatology (AAD).
In the primary efficacy analysis of Subject's Global Assessment of Improvement, 95 percent to 100 percent of patients in all groups at week two were judged to be responders based on achieving a score > 0 on the 9-point rating scale (+4 = 100 percent improvement; 0 = no change; 4 = 100 percent worsening at week two). However, by week 12, there were significant dose-related differences in the responder rates, and responses were sustained past 24 weeks only among women treated with the 6 U dose.
Analyses of adverse event data collected at each visit showed there were no dose-related differences in either the incidence or type of adverse events reported. Brow ptosis, skin tightening, eyelid swelling and headache occurred at rates ranging from 5.0 percent to 8.3 percent and were the most commonly reported adverse events.
Analysis "The safety and efficacy of botulinum toxin type A injection for the treatment of hyperfunctional facial lines has been demonstrated in numerous clinical trials, but many studies involve the treatment of a single facial area. The current investigation indicates that simultaneous treatment of glabellar rhytids, crow's feet and horizontal forehead lines can be undertaken safely. However, the response is increasingly positive as the dose increases in the range of 2 to 6 U per injection site," says Dr. Alastair Carruthers, clinical professor of dermatology, University of British Columbia, Vancouver.
Study participants The study participants in each of the three groups were similar with respect to mean age (42 years) and race (95 percent white). Women were screened for study participation based on presence and severity of upper facial rhytids. Using the 4-point Facial Wrinkle Scale (0 = none, 1 = mild, 2 = moderate; 3 = severe), eligible women were required to have scores of 2 for glabellar lines at maximum frown and 1 for forehead lines at maximum eyebrow elevation. In addition, they needed to have bilaterally symmetrical crow's feet rated as 2 at maximum smile.
Study results Results of analyses of magnitude of response showed that while all women had a significant treatment benefit at week two, 90 percent of women in the highest-dose group achieved a 75 percent or greater improvement at that visit compared with only 70 percent of those treated with the 2 U dose and 55 percent of those in the intermediate dose group. By week 20, nearly one-fourth of the women in the 6 U dose group still maintained 75 percent or greater improvement compared with none of the women in the other study groups.