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We are entering a new era in dermatology where numerous drugs are available with the sole purpose of improving appearance and not treating disease. New criteria are needed for measuring success of these drugs.
We are entering a new era in dermatology where numerous drugs are available with the sole purpose of improving appearance and not treating disease. Certainly, aging could be considered a disease that affects all humans, but it is possible to argue that since all humans age, it is normal and not a disease.
Whether the appearance degradation of aging is normal or a disease, the neurotoxins that are being used to treat the condition are considered drugs and are studied and examined for safety in the same manner as all drugs designed to treat disease. This is exemplified by most recent draft guidance issued in August 2014 by the FDA on Upper Facial Lines: Developing Botulinum Toxin Drug Products. This guidance states that for a neurotoxin to be approved as efficacious, it must remove all motion in the injection area receiving a rating in the category of “none” or zero. While this is quite desirable in the glabellar area, where frowning is almost always considered an unattractive facial expression, it might not be desirable to eliminate all movement around the eyes, a common area of neurotoxin injection. Many have observed that failure of skin movement around the eyes when smiling leads to the perception by others of insincerity. Indeed, some contraction of the skin around the eyes when smiling is normal since the lower eye contracts simultaneously with the corner of the mouth, which produces lifting of the mouth corner and smiling.
Need for new criteria
Dermatologic drugs are studied on an ordinal scale of 0 to 4 where 0=clear, 1=almost clear, 2=mild, 3=moderate, and 4=severe. This scale works quite well for the evaluation of acne or psoriasis medications where clear or almost clear is the standard by which excellent drugs should be judged. I am not sure this same scale works for the evaluation of new neurotoxins hoping for approval. It might be that the reduction of periorbital movement and wrinkling from moderate to mild would be superior to the reduction of periorbital wrinkling from moderate to none. No movement is not aesthetically pleasing and aesthetic assessment is a much different realm than drug treatment success.
There is a need for new evaluation criteria for drugs that function in the aesthetic realm. The same ordinal scale can be used, but the ordinal rating required for success and subsequent drug approval must be reconsidered. With neurotoxins, wrinkles in some locations are good while wrinkles in other locations are bad. Foreheads that are shiny and eyebrows that cannot elevate are dead giveaways that chemodenervation is at work. As a matter of fact, the difference in appearance from the totally paralyzed forehead one week after injection to the partially moving forehead 2 months after injection to the total moving forehead 3 months after injection eliminates any doubts that the appearance change is natural. It is obvious that neurotoxins are at work!
There is certainly something to be said for projecting natural good looks as opposed to the sometimes contorted appearance created by neurotoxins. Using some neurotoxins that eliminate movement and others that simply decrease movement could sculpt a more natural appearance. For example, it would be beneficial to paralyze the frown with an aggressive toxin application, but the fine lines on the lateral cheeks that appear with smiling could be softened with a milder toxin effect. I liken the facial use of neurotoxins to painting a portrait. Using oil pigments on canvas to capture the essence of a beautiful face takes more than one brush. Imagine if Leonardo da Vinci used one large brush to paint the Mona Lisa! The outcome would have been much different. Similarly, the dermatologist artist crafting a beautiful face also needs more than one toxin with different degrees of denervation to achieve success.
I think cosmetic dermatology must revisit the “none” or “almost none” phenomenon for treatment success. None or almost none has tremendous importance when addressing drugs where success is defined as cure. It is not really possible to cure wrinkles other than by early death, which clearly would not defined as treatment success. Perhaps for drugs that address appearance issues, a new ordinal static scale should be developed that is clinically meaningful from an aesthetic standpoint.