US FDA opens safety review on Botox

The US Food and Drug Administration has issued a public statement warning that Botox and Botox Cosmetic (botulinum toxin type A) and Myobloc (botulinum toxin type B) have been linked in some cases to adverse reactions, including respiratory failure and death, following treatment of a variety of conditions using a wide range of doses.

The FDA said the reactions may be related to overdosing and noted there is no evidence that they are linked to a defect in the products. The adverse events were found in US-approved and non-approved usages and the most severe of these were seen in children treated for spasticity in their limbs associated with cerebral palsy which is not an FDA-approved use of botulism toxins, the agency noted.

On the day of the news, February 8, shares in Allergan, the manufacturer of Botox and Botox Cosmetic, fell 6% to $63.30. The wrinkle treatment injection is a key product for the USA-based company, with earnings of $1.36 billion expected this year. Myobloc is made by privately-held Solstice Neuroscience. The safety concerns cast further doubt on French drugmaker Ipsen's botulinum toxin type A in cosmetic indications. The FDA recently rejected an application for approval due to administrative issues, stating that the filing was "incomplete" (Marketletter February 11).