Shares in Zymogenetics soared yesterday after US regulators opened the door to its bleeding agent Recothrom, making it the first and only recombinant, plasma-free thrombin approved for use as a topical agent during surgery, and triggering a $40 million milestone payment from Bayer HealthCare.

Recothrom is a recombinant form of human thrombin that is not made from animal or human blood, but from genetically-modified Chinese hamster ovary cells. Furthermore, these cells are free from known infectious agents and the product undergoes an additional process of viral inactivation, the US Food and Drug Administration notes.

Specifically, the product has been cleared for the control of minor bleeding from venules or capillaries during surgery, after Phase III trials showed the agent to be as effective as bovine-based thrombin but with a significantly lower incidence of antibody formation, thereby providing it with an important competitive advantage and surgeons with a new, plasma-free alternative to currently marketed options.

The company says it expects to begin shipping the product in the near future and that it is “well prepared” for the launch, which will be supported by its global partner Bayer for the next three years, and field representatives from both companies have been “thoroughly trained” for the roll-out.

Bayer to get 20% of sales
In return for Bayer’s assistance, Zymogenetics will pay the firm a tiered commission of up to 20% on US sales, and up to $20 million in sales bonus payments if certain goals are met during the co-promotion period, under a deal signed last year.

Commenting on the approval, Zymogenetics’ chief Bruce Carter said it was “good news for patients, surgeons and hospitals”, and reaffirmed his belief that Recothrom offers “important features and benefits” over existing products on the market.

The group’s stock closed up nearly 8% at $13.05 after rocketing as much as 27% during a day of frenzied trading, as investors revelled in the news.