Topical Botulinum Toxin Will Turn Market 'Upside Down'
EXPERT ANALYSIS FROM THE SDEF HAWAII DERMATOLOGY SEMINAR
The proposed commercial product that will undergo phase III testing entails mixing the viscous topical gel in a one-step applicator, which is then used in treating the lateral canthal lines. The mixing and application takes only a couple of minutes. The gel is left on for perhaps 30 minutes – the optimal time is yet to be determined – and then removed with a proprietary cleanser.
Dr. Carruthers said that as many know, increasing competition has arrived among the manufacturers of the three Food and Drug Administration–approved injectable botulinum toxin type A products.
"I doubt that the battle, such as it is, will be fought on intellectual, scientific issues. I think it will be fought based upon cost, marketing, and other intangibles," he predicted.
Brand loyalty, company sponsorship of medical education, appeals to nationalism – one manufacturer is U.S.-based, the others German and French – these are the sorts of issues he expects to see brought forth.
That’s because the things that really matter to clinicians, such as onset of therapeutic effect, its spread, duration, and side effects, are all a function of dose – and there is no agreement as to what the comparable dose is between the various commercial preparations. Despite manufacturers’ claims, it’s not possible to detect small differences in effectiveness, immunogenicity, or other end points without doing studies that would require enormous numbers of patients, according to Dr. Carruthers.
He advised that given the uncertainty regarding dosing comparability, the best practice is to have only one botulinum toxin type A product in the office. This avoids the thorny issue of trying to use comparably effective dilutions.
In a separate presentation at the annual meeting of the American Society for Dermatologic Surgery, Dr. Gary D. Monheit, a dermatologist in private practice in Birmingham, Ala., agreed that the topical botulinum toxin could be practice changing.
He said that RT001 is best for superficial musculature such as crows’ feet, and possibly in the future for perioral and forehead wrinkles.
The investigational product affects pore size and helps smooth the skin, he said. And since the product is mostly absorbed in the superficial musculature, it could eventually be used on the eyelids and lips for superficial wrinkles and to brighten up dull skin.