Botox is a now a household name and one of the most popular and commonly performed cosmetic procedures in the world. Botox represents one form of botulinum A toxin of which there are at least eight forms. Currently, there are three additional forms of botulinum under some level of clinical development. The ones we are likely to hear about in the next year or so is Reloxin and PurTox. Besides the name, these different botulinum toxins are differentiated by how quickly they start to work, how long they will work, and how far from the injection site the drug will diffuse.
Reloxin, which is the name used in current U.S. clinical trials, is known as Dysport in Europe and other countries. Like Botox, Reloxin is a type A botulinum which lasts twice as long after mixing and has a different unit dosage. My understanding from readings at present is that the dose comparison is 3:1. (300 unit vial compared to 100 unit vial for Botox) Because Reloxin has a slightly different molecular structure than Botox, it diffuses out further from the injection site than Botox which may mean it can treat a larger area. (potentially needing less units than Botox to treat the same area and keeping a smoother look as it wears off) As of this writing, the Reloxin application to the FDA has been denied to being judged as having incomplete documentation. This certainly means that Reloxin will not likely be available in the U.S until 2009.
PurTox is not as far along in clinical development as Reloxin and is in very early clinical trials. I do not expect to hear much about these botulinum analogues until 2010 or even later. Even when they do become available for clinical use, it is not year if they offer any significant advanatage over the Botox that we now use.
Dr Barry Eppley