Safety check: FDA reviews Botox, Myobloc

April 1, 2008

Washington-The Food and Drug Administration's decision to review the safety of botulinum-toxin drugs Botox, Botox Cosmetic and Myobloc has generated reactions ranging from surprise to cynicism in the dermatologic community

Key Points

The agency announced the review in February, after consumer advocacy group Public Citizen had filed a petition stating it had found 180 cases of adverse events and 16 reported deaths linked to the therapeutic use of such drugs. The FDA says the review is not directly related, however.

"Dermatologists are clearly surprised by the whole issue," says David J. Goldberg, M.D., director of Skin Laser & Surgery Specialists of New York/New Jersey and clinical professor of dermatology at New York's Mount Sinai School of Medicine. "All derms feel that Botox is one of the safest drugs we have used in our practices for decades."

"Public Citizen's concerns about Botox are, in many ways, irresponsible and unfounded," he tells Dermatology Times. "Dermatologists are very aware of the safety of Botox when used appropriately, and are unlikely to change their use or recommendation of the product.

"There is nothing new here to be alarmed about, and I have no concerns other than the fact that the use of Botox is a medical procedure, and the product should be injected by physicians who are experienced in its use."

Early communication

On Feb. 8, the FDA issued an "early communication" saying the agency had received "reports of systemic adverse reactions including respiratory compromise and death following the use of botulinum toxins types A and B for both FDA-approved and unapproved uses."

The agency said it was reviewing safety data from clinical studies submitted by the manufacturers of Botox, Botox Cosmetic and Myobloc, as well as post-marketing adverse event reports and the medical literature.

Allergan, based in Irvine, Calif., manufactures Botox and Botox Cosmetic (botulinum toxin type A). Neuroscience of Malvern, Pa., manufactures Myobloc (botulinum toxin type B).

Susan Walker, M.D., a dermatologist and director of the FDA's Division of Dermatology and Dental Products, tells Dermatology Times that the objective of the review is to ascertain "that the risk when using this product does not outweigh the benefits and it is safe to use in accordance with the approved labeling - as with all drug products."

She says the agency is reviewing safety of these products for cosmetic use, as well as for clinical use.

"Botox safety will be reviewed for the approved indications, that is, for treatment of conditions such as blepharospasm, cervical dystonia and severe primary axillary hyperhydrosis," Dr. Walker says. "Botox Cosmetic, also botulinum toxin Type A, is approved for temporary improvement in the appearance of moderate to severe facial frown lines."

Myobloc is FDA-approved for treating cervical dystonia in adults; it is not approved in the United States for cosmetic indications.

Dr. Walker adds that the agency has no specific timeframe within which the safety review will be completed.

Canada also reviews

Shortly after the FDA issued its early communication, Canadian regulatory agency Health Canada issued a statement saying it is conducting "a safety review of distant toxin spread potentially associated with Botox and Botox Cosmetic."

The Health Canada statement notes that Botox is authorized in Canada for noncosmetic purposes to decrease muscular responsiveness and that Botox Cosmetic is authorized for cosmetic purposes to decrease facial wrinkling.

Myobloc is not marketed in Canada.

In its announcement, the FDA notes that the most serious incidents it had been made aware of "included hospitalization and death, and occurred mostly in children treated for cerebral palsy-associated limb spasticity" - treatment for which neither Botox nor Myobloc are approved in the United States.