Despite warnings, FDA set to OK drug

The government is on track to approve a new antibiotic to treat a pneumonia-like disease in cattle, despite warnings from health groups and a majority of the agency’s own expert advisers that the decision will be dangerous – for people.

The drug, called cefquinome, belongs to a class of highly potent antibiotics that are among medicine’s last defense against several serious human infections. No drug from that class has ever been approved in the United States for use in animals.

The American Medical Association and about a dozen other health groups warned the Food and Drug Administration that giving cefquinome to animals would probably speed the emergence of microbes resistant to that important class of antibiotic, as has happened with other drugs. Those super-microbes could then spread to people.

Echoing those concerns, the FDA’s advisory board last fall voted to reject the request by InterVet Inc. of Millsboro, Del., to market the drug for cattle.

Yet by all indications, the FDA will approve cefquinome this spring. That outcome is all but required, officials said, by a recently implemented “guidance document” that codifies how to weigh threats to human health posed by proposed new animal drugs.

The wording of “Guidance for Industry 152” was crafted within the FDA after a long struggle. In the end, the agency adopted language that, for drugs such as cefquinome, is more deferential to pharmaceutical companies than is recommended by the World Health Organization.

Industry representatives say they trust Guidance 152’s calculation that cefquinome should be approved. “There is reasonable certainty of no harm to public health,” Carl Johnson, InterVet’s director of product development, told the FDA last fall.

But others say Guidance 152 makes it too difficult for the FDA to say no to some drugs.

“The industry says that ‘Until you show us a direct link to human mortality from the use of these drugs in animals, we don’t think you should preclude their use,’ ” said Edward Belongia, an epidemiologist at the Marshfield Clinic Research Foundation in Wisconsin. “But do we really want to drive more resistance genes into the human population? It’s easy to open the barn door, but it’s hard to close the door once it’s open.”

Cefquinome is a fourth-generation cephalosporin, the most recent of several steadily improving versions of the cephalosporin family of antibiotics. Only one medicine from that family has been approved in the United States – a powerful human drug called cefepime (brand name Maxipime), which is the only effective treatment for serious infections in cancer patients and a reliable lifesaver against several other nearly invincible infections.

InterVet invented cefquinome to treat bovine respiratory disease, the most common disease in cattle. Recognizing the potential public health implications of using a close cousin of cefepime in animals, the FDA’s Center for Veterinary Medicine, which oversees animal drug approvals, convened its expert advisers in September.

One of the first things the group learned was that more than a dozen medicines are on the market for the respiratory syndrome, and all are effective.

“If we have no susceptibility problem, why do we need one more new drug?” asked James Leggett, a professor of medicine at Oregon Health & Science University, whom the FDA brought in as a consultant on the cefquinome question.

The panel also learned that the disease would be a relatively minor issue but for the conditions under which U.S. cattle are raised, including high-density living conditions and routine shipment on crowded trains for hundreds or thousands of miles, which suppress the animals’ immune systems.

Concerned that the FDA is poised to approve cefquinome, Congress’s only microbiologist recently wrote to the agency.

“Given the recent outbreaks of E. coli and other food-borne illnesses across the nation, it is hardly the time to ignore the advice of scientists and potentially impair our ability to treat deadly infections,” wrote Rep. Louise Slaughter, D-N.Y., who chairs the House Rules Committee.