FDA approves Botox Cosmetic to treat crow’s feet lines

The FDA announced today that it has approved onabotulinumtoxinA for temporary improvement in the appearance of moderate to severe lateral canthal lines in adults.

Perspective from

OnabotulinumtoxinA (Botox Cosmetic, Allergan) is the only FDA-approved drug treatment for lateral canthal lines, according to a press release. Botox Cosmetic, which keeps muscles from tightening so wrinkles are less prominent, had been approved by the FDA in 2002 for temporary improvement of glabellar lines.

“This additional indication will provide people with a new FDA-approved treatment option for those seeking a smoother appearance by temporarily minimizing the appearance of crow’s feet at the sides of the eyes,” Susan Walker, MD, director of the division of dermatology and dental products in the FDA’s Center for Drug Evaluation and Research, said in the release.

The FDA’s approval was based on results of two clinical studies of onabotulinumtoxinA for treating lateral canthal lines. Eight hundred thirty-three adults with moderate to severe lateral canthal lines randomly were assigned onabotulinumtoxinA or placebo. Patients treated with onabotulinumtoxinA had greater improvement in appearance of lateral canthal lines compared with the placebo-treated patients, according to the release.

OnabotulinumtoxinA is given through intramuscular injections, and treatments for glabellar lines and lateral canthal lines can be given simultaneously.

Eyelid edema is the most common adverse reaction associated with Botox Cosmetic when used for lateral canthal lines.

OnabotulinumtoxinA also is marketed as Botox (Allergan) and is FDA-approved for treating chronic migraine, severe underarm sweating, blepharospasm and strabismus.

Botox and Botox Cosmetic contain box warnings that the effects of botulinum toxin may spread from the injection area to other parts of the body, causing symptoms similar to botulism. They include swallowing or breathing difficulties that could be life-threatening. When Botox and Botox Cosmetics have been used at the recommended dose for approved indications, there have been no confirmed cases of toxin spread, the release said.

Perspective

When we began to study the efficacy of botulinum toxin A (BoNT-A) in cosmetic indications, we focused on the glabellar area¹. But soon the lateral canthal area, or crow’s feet, became an area for study^2,3. The effectiveness of BoNT-A in this area has been documented in a number of studies^4,5 and the treatment of this area in combination with other areas has been documented⁶. This has led to the approval by the FDA of onabotulinumtoxinA for crow’s feet.

So, since BoNT-A has been used for this indication for over 20 years, what does this official approval mean? Firstly the approval of this product for this area has established that the treatment of crow’s feet is safe and effective. The material gathered in the registration studies is important and gives patients good data on what effect to expect, how long it may last and what adverse effects they might anticipate.

Alastair Carruthers

Secondly, FDA approval allows Allergan to educate injectors as to how these products can be used most safely and effectively.

Treatment of the lateral canthal area is different from treatment of the glabella. The treatment must be judged to enhance the facial appearance, not to produce a “frozen” look. Most of our patients would be delighted if they never frowned again whereas treatment in the crow’s feet area is more difficult. The facial expressions treated in the glabellar area are all negative whereas the crow’s feet area is an important component of the smile and must be treated with respect. The crow’s feet, especially in women, are regarded as evidence of age and are therefore negative. In men, they are more associated with experience and an outdoor life style and are therefore more positive. Treatment must be adjusted accordingly.

For years, FDA approval of areas beyond the glabella has been necessary, particularly for patient safety. Now that we have approval in the crow’s feet area, it is to be hoped that frontalis and other widely used areas will follow soon. We use BoNT-A to treat many areas of the face and elsewhere, and the wider this broad use is recognized, the better will be our treatment of our patients.

Alastair Carruthers, FRCPC
Clinical professor
Department of dermatology and skin science
University of British Columbia, Vancouver

Jean Carruthers, MD
Clinical professor
Department of ophthalmology
University of British Columbia, Vancouver

References:

1. Carruthers JDA, Carruthers A. Treatment of glabellar frown lines with C. botulinum A Exotoxin. J. Dermatol Surg Oncol. 1992;8:17-21.

2. Carruthers A, Carruthers J. The use of botulinum toxin to treat glabellar frown lines and other facial wrinkles. Cosmetic Dermatology. 1994;7:12-15.

3. Blitzer A, Brin M, Keen MS, et al. Botulinum toxin for the treatment of hyperfunctional lines of the face. Arch Otolaryngol-Head and Neck Surg. 1993;119:1018-1022.

4. Lowe NJ, Ascher B, Heckmann M. Double-blind, placebo-controlled, dose-response study of the safety and efficacy of botulinum toxin A in subjects with crow’s feet. Dermatol Surg. 2005;31:257-262.

5. Ascher B, Rzany BJ, Grover R. Efficacy and safety of botulinum toxin A in the treatment of lateral crow’s feet; a double-blind, placebo-controlled, dose-ranging study. Dermatol Surg. 2009;35:1478-1486.

6. Carruthers A, Carruthers J. A Single Center, Dose Comparison, Pilot Study of Botulinum Neurotoxin Type A in Female Patients with Upper Facial Rhytids: Safety and Efficacy. J Am Acad Dermatol. 2009;60:972–979.

Disclosures: Drs. Alastair Carruthers and Jean Carruthers are investigators and consultants to Allergan and Merz Pharmaceuticals GmbH. Dr. Alastair Carruthers is lead author for part of the crow’s feet approval data.