The first recombinant thrombin on the market will be used to control bleeding during surgery. Credit: Derek Miller/iStockphoto

Four years ago, protein drug developer Zymogenetics in Seattle began developing a recombinant version of the blood-clotting protein thrombin. On 17 January, it received US marketing approval for Recothrom, and a broad label for its use to control bleeding during surgery. Recothrom is the first recombinant thrombin and will compete with a bovine thrombin product sold by Bristol, Tennessee–based King Pharmaceuticals, the market leader, and a human plasma-derived thrombin, Evithrom, from Omrix Pharmaceuticals in New York. (Evithrom was approved in 2007 and is being sold by Johnson & Johnson, of New Brunswick, New Jersey.) Zymogenetics decided to enter the thrombin market after watching King increase pricing and grow its Thrombin-JMI franchise to well above $200 million annually, even with a 'black box' warning for potential immunogenicity. It has reason to think its product could compete because “at the end of the day, there isn't a single example where a recombinant protein fails to take the market over something from plasma or tissue,” notes Zymogenetics CEO Bruce Carter. Nonetheless, Wall Street's reaction to the approval was swift and negative: Zymogenetics' stock fell $2 on approval. “We are mystified that there isn't more enthusiasm in the investor community,” says Carter. Analyst skepticism is twofold: King has apparently begun discounting the price of Thrombin-JMI to try to keep its market share, and Wall Street fears that Johnson & Johnson hasn't made its best moves yet in promoting Evithrom. All three products appear effective. “Thrombin stops bleeding, whether it's in a cow or a person,” notes Piper Jaffray analyst Edward Tenthoff, in New York, and “there isn't a meaningful difference in time to hemostasis” among the three products. With respect to the benefits of a recombinant product, he adds that “in a litigious environment, some will say safety for an increased price is worth it.” Tenthoff says Recothrom will eventually succeed and that the market for thrombin will grow: according to Zymogenetics, there are currently 1.3 million US thrombin procedures, 3.5 million topical hemostat procedures and over 11 million potential procedures annually where thrombin may be used. MR