A new guidance document released today by the US Food and Drug Administration (FDA) wants to help some biopharmaceutical manufacturers smooth the wrinkles out of the drug development process for products containing botulinum toxin, better known by many as Botox.

The guidance, Upper Facial Lines: Developing Botulinum Toxin Drug Products, is specifically intended only for those botulinum products intended to temporarily improve the appearance of wrinkles in the "upper facial" region, such as glabellar lines or lateral canthal lines.

So why the guidance? FDA notes that there is "an increase in demand for aesthetic procedures to treat the progressive development of facial lines that are associated with the aging process." And because the injection of botulinum toxin happens to be one of the "most common" procedures used to temporarily reduce the appearance of wrinkles, FDA said it's interested in helping potential sponsors of product applications reach the market more easily.

But even as the use of botulinum toxin is one of the most common procedures, it still holds the potential to cause serious adverse events if administered in incorrect doses. That's because the botulinum toxin—which causes botulism—is a potent neurotoxin which can cause paralysis. As FDA explains in its guidance, one of the single most important parts of any drug development process involving botulinum toxin will be the process of identifying a safe and effective dose.

"Botulinum toxin drug products present a unique set of safety concerns related to the potential for local and distant spread of toxin effect," the regulator explained.

"[S]ponsors should address unique concerns such as inadvertent injection, unintended mucosal exposure, and unintended transfer of the drug product," FDA wrote. "A delivery system designed to reduce the risk of inadvertent injection should be considered early in the development process."

FDA recommends sponsors conduct two "adequate and well-controlled trials" (i.e. Phase III trials) to establish the safety and efficacy of a botulinum product, utilizing both quantitative assessments and patient-reported outcomes (PROs) to determine the product's efficacy. Endpoints should be discussed with FDA prior to the initiation of a trial. Those trials should include patients representative of the population expected to use the drug, FDA added.

Sponsors can, however, request a waiver from pediatric testing since babies with wrinkles are, in FDA's words, "uncommon."

Upper Facial Lines: Developing Botulinum Toxin Drug Products (FR)