The Naked Neurotoxin
Move over Botox and Dysport. There's a new
botulinum on the market. Incobotulinumtoxin A, or Xeomin, is the latest
serotype A botulinum toxin available. Manufactured by Merz Aesthetics, it
has been used in Europe since 2008 with over 84,000 patients treated to date
worldwide. Xeomin was originally FDA approved in the US for the treatment
of cervical dystonia and blepharospasm in 2010. It was not until July 2011
that Xeomin was approved for the cosmetic treatment of moderate to severe
glabellar (frown) lines.
What sets Xeomin apart from its competition is that it
contains no binding proteins, giving it the nickname "naked" neurotoxin. In
this "naked" neurotoxin complex, the therapeutic or active component is
isolated and the surrounding ancillary proteins are removed. This
formulation yields high biologic activity and low protein load which could mean
less risk of the body developing antibodies against the product.
Such proteins may also have the potential to limit the
neurotoxin's effectiveness and potentially make patients resistant to
neurotoxins. Also in question is if removing the ancillary proteins
affects the diffusion factor of the product. Some physicians have concerns
about the spreading of Xeomin within tissue as it contains no proteins to
protect the stability around the active molecule.
Although the units between Botox and Xeomin appear
identical, they are not bioequivalent and therefore units of each are not
interchangeable. This will likely further be determined as it is used by
more providers and a certain comfort level with the product and efficacious
dosing is established. Xeomin does not require refrigeration prior to
reconstitution unlike all other botulinum toxins currently on the market. This
could lend to easier distribution as well as ensuring proper maintenance of
temperature and thus efficacy of the product.
What does this new addition mean for the world of
aesthetics? By having more options to choose from, competition among
manufacturers will increase and likely bring costs down. I don't hear
patients or providers complaining!
Among Xeomin are other botulinum toxin products which
are either under clinical investigation or currently seeking FDA approval. Such
agents to look out for include: Reloxin (a purified version of
Dysport, manufactured by Medicis) and Purtox (manufactured by Mentor). With
limited cosmetic data and provider experience with Xeomin, much remains to be
seen how it will fare in the aesthetics market. One thing is certain, as
the most popular cosmetic procedure in the world, we are sure to hear a lot
more about Xeomin and these other botolinums in the near future.