Botulinums on the Horizon

By Joel Schlessinger, M.D., FAAD, FAACS
Published in Skin & Aging, 2008, 16;2:48–50

Introduction

Four forms of Botulinum toxin type A are currently being tested in the USA, while 8 forms are being tested around the world. Reloxin (Medicis, Scottsdale, AZ), one of the forms tested is expected to hit the US market first.

Methods and Materials

Reloxin is a 900-KD molecule much like Botox. With a large molecule structure at 150- KD Reloxin also contains a protein structure around it creating the known botulinum toxin. With the basic structure but subtle differences, it allows each botulinum toxin to vary resulting in diffusion of characteristics, onset time, and duration of action. Reloxin is also a type A botulinum like Botox, distinct from Myobloc® (Solstice Neurosciences, Inc., South San Francisco, CA). While other botulinums are being tested, only types A and B have been successfully developed.

Reloxin, also known as Dysoprt in Europe, is marketed by Ipsen and has been in use since 1991 for both medical and cosmetic use depending on the country. Per the instructions of use, once reconstituted Reloxin has an 8 hour length of use, can be stored in the refrigerator, and contains lactose. Scientists have found that even though Botox and Reloxin have similar protein structures there is a potential difference in the diffusion characteristic once injected. This difference refers to the attachment to the presynaptic membrane, which in some cases may allow more attachments or in other cases, a retention. Because of these differences scientists have found that Reloxin may be a potential in treating larger areas.

While there is still a concern about higher adverse effects with Reloxin there are no studies of adverse events compared to Botox. A true correlation is difficult to say as studies were done at different times and are not head to head in nature.

Results

While there are no set rules as far as reconstitution studies from Europe, diverse investigators found that a 3:1 ratio of Reloxin to Botox is a good estimate. A 2:5:1 was found to be ineffective for the frontal muscles in situations while a 4:1 was found to lead to adverse events. With this being said, it is proposed that a 300 unit vial of Reloxin will be more likely an equivalent to the dose of Botox and also reconstitute the same as Botox.

Reloxin shows a similar profile to that of Botox. Expected ocular events are 8% vs. 0% placebo and non statistical significant events such as headache and injection site pain.

Conclusions

With a history of competition in the cosmetic marketplace, this will be another opportunity for rivalry. While Allergan, the producer of Botox, has had the availability of both a filler and Botox, this will allow Medicis, who has only been a market to the family of fillers, an opportunity to complete the package with a neurotoxin. Once Reloxin is introduced it will bring the two companies, Allergen and Medicis, to an even ground. Several European companies already exposed to Dysport and Botox appear to be using a similar amount. The hope is that with the release of Reloxin the competition in the US will bring more options and benefits to dermatologists and consumers.

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