Before it asked the FDA to yank a drug made by its chief competitor, King Pharmaceuticals, off the U.S. market, ZymoGenetics learned that physicians had attributed the deaths of two patients to bad reactions to the drug, says ZymoGenetics CEO Doug Williams.
I spoke with Williams this morning shortly after the Seattle biotech issued a statement saying that it has filed a formal citizen petition with the FDA, asking the agency to force Bristol, TN-based King to withdraw a rival treatment for surgical bleeding from the U.S. market. ZymoGenetics (NASDAQ: ZGEN) contends that King’s Thrombin-JMI product poses a risk of immune-system reactions that can lead to severe bleeding episodes, and even death.
ZymoGenetics has been trying to grab away King’s market share, primarily by arguing its drug is safer. The King product, which has been around for years, is the dominant drug used to control bleeding in an estimated 1 million surgeries a year in the U.S. It generated $255 million in U.S. revenues last year. But ZymoGenetics has sensed an opportunity to supplant King’s drug, because it is derived from cow’s blood, and therefore recognized as foreign by the immune system, which it says can lead to complications with repeated use. ZymoGenetics won FDA approval for its recombinant version of human thrombin, called Recothrom, in January 2008. Just as with insulin for diabetes, animal-derived products eventually lose in the marketplace when safer, genetically engineered human products come along to replace them, the company contends.
Yet ZymoGenetics it has struggled to capture much of the market for surgical bleeding drugs. It generated just $8.8 million in first-year sales—partly because physicians were unaware of the risks associated with the animal-derived product they had been using for many years, Williams says. Now the company hopes to change that, by asking the FDA to take a closer look at how to handle that risk from the cow-derived clotting agent.
“There are physicians using Thrombin-JMI without a clear understanding of its risks,” Williams says. “There are at least three better alternatives in the marketplace now, that don’t have the same risk profile.”
When reached by phone this morning, King Pharma’s vice president of investor relations, Jack Howarth, said the company has no comment.
The 31-page citizen petition, which I reviewed this morning, highlights 25 cases published by researchers that drew a link between cow-derived blood control treatments and bad immune-system reactions that led to severe complications, or death. One report by a physician to the FDA last October attributed a death to usage of Thrombin-JMI, and just this month, ZymoGenetics said it learned of a second case.
The prescribing information for Thrombin-JMI has carried the FDA’s strictest warning, called a “Black Box,” since 1996. It warns physicians of potentially dangerous immune reactions. But ZymoGenetics said few physicians seem aware of the risk, and keep using King’s product anyway. Now that ZymoGenetics’ genetically engineered version is on the market, along with two other products that use clotting proteins derived from human blood—Johnson & Johnson’s Evithrom and Baxter Healthcare’s Gelfoam Plus—there’s no longer any reason to use a product derived from animal proteins, Williams says.
“An animal product is intrinsically immunogenic. In this day and age, there’s no reason for it,” Williams says.
ZymoGenetics spent months doing its homework preparing the citizen petition, Williams says, including getting advice from people familiar with the citizen petition process, and former FDA staff. The agency now has 180 days to take some kind of action, although the process can carry on longer than that before the agency makes a decision, he says.
The best case scenario for ZymoGenetics would be a decision by the FDA to pull Thrombin-JMI off the market—which would create a big void that somebody would have to fill. But short of that, ZymoGenetics has asked the FDA to consider a couple of other alternatives. It suggested in the petition that the FDA might want to change Thrombin-JMI’s prescribing information to restrict it for use as a second-choice option after the newer products; set up a strict risk-monitoring program for patients who get the treatment; or warn patients in advance of the risk they are taking with Thrombin-JMI,Williams says.
What are the odds that FDA will pull the King product off the market? As Williams pointed out, a lot of citizen petitions get submitted each year, and some result in a drug getting yanked, but “it’s not the usual outcome.”
When I asked what it says about ZymoGenetics as a company that it’s willing to use such hardball tactics to get more footing in the marketplace, he didn’t directly answer.
“We’re doing this in the interest of patient safety,” Williams says. “Patients are being exposed to a product without a scientific grounding for it. We want to see that there are no more deaths.”
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