France's Ipsen is buying Syntaxin, a specialist in the field of botulinum toxins, in a deal that could be worth over 158 million euros to the UK privately-held life sciences group.

The firms started collaborating in 2010 and a year later signed a pact to develop new compounds in the area of recombinant botulinum toxins. Ipsen already had roughly a 10% stake in Syntaxin and has decided to buy the firm out.

Under the terms of the agreement, Ipsen will pay 28 million euros upfront, as well as further contingent payments that could reach 130 million or more depending on the achievement of development and commercial milestones. Furthermore, Syntaxin’s shareholders will receive the greater part of additional downstream payments related to the company’s most advanced asset, currently in Phase II.

That treatment, serenbotase, is being developed by Syntaxin in partnership with the other major botulinum toxin company Allergan, best-known for Botox (onabotulinumtoxin A). The drug is being evaluated as a treatment for both post-herpetic neuralgia and overactive bladder and the acquisition does not change the Syntaxin/Allergan agreement; Ipsen does not have rights to serenbotase.

Marc de Garidel, Ipsen chief executive, said the acquisition is "an important step in our ambition to become a global leader in targeted debilitating diseases". He added that Syntaxin is "a considerable addition to our neurology franchise and is fully aligned with our strategy of focus".

Meantime, Ipsen has also signed an agreement to fund research for at least three years at Harvard Medical School to discover and develop novel engineered recombinant botulinum toxins for the treatment of serious neurologic diseases. No financial details were disclosed.