For the first time, the Food and Drug Administration has succeeded in forcing off the market an antibiotic used to treat animals because of concerns that it will make similar antibiotics less effective in treating people. After a five-year battle, Bayer Corp. said yesterday that it would immediately stop selling its poultry antibiotic, Baytril, a close relative to its widely used human antibiotic, Cipro. The company could have appealed the FDA ban on the drug to a federal court but instead decided to comply.
"We disagree with the FDA's conclusion about our drug," said Bayer spokesman Robert Walker. "But we understand they made a scientific decision, and courts tend to defer back to the agency. . . . It seemed like the chances that we would be successful in court were small."
The resolution of the Baytril case opens the door to FDA action against other animal antibiotics. The agency has already told the makers of at least three types of penicillin used on farm animals that their products might raise similar concerns, and regulatory action might be needed.
Yesterday, public health advocates hailed Bayer's decision and the FDA actions that precipitated it.
"We applaud Commissioner [Lester M.] Crawford for defending the public's health and Bayer for finally recognizing the need to comply with the FDA's ruling," said Karen Florini, senior lawyer at Environmental Defense and chairwoman of the Keep Antibiotics Working coalition. "Cipro is a critical antibiotic for treating human illness. It simply makes no sense to allow its effectiveness to be squandered by continued use of near-identical drugs in poultry flocks."
All antibiotics grow less effective over time as bacteria evolve to become resistant to the drugs' effects. Experts say wider use of an antibiotic -- by either animals or people -- leads to a speedier development of resistance.
In its battle to continue marketing Baytril for use in poultry flocks, Bayer was joined by the Animal Health Institute, which represents drug makers, and four poultry trade associations. The company and the groups argued that no proof existed that Baytril was making drugs such as Cipro less effective, and that the drug's benefits were not properly considered.
"It's disappointing to us that the case played out this way," said Ron Phillips, spokesman for the Institute. "While we disagreed with the FDA's methodologies and conclusions, consumers should be comforted by the fact that the agency does have sufficient authority to act when it thinks there's a threat to public health."
Antibiotics are used on American farms to treat sick animals and promote faster growth. Makers of animal drugs do not have to report how much animal antibiotic they sell, and no firm statistics exist. The Union of Concerned Scientists has estimated that 24.6 million pounds of antibiotics are used on American farms yearly, about 75 percent of the nation's antibiotic consumption. The animal drug industry says most of the antibiotics on farms are used to treat disease, but UCS scientists, who oppose the widespread use of antibiotics for livestock, say most is to promote growth.
The FDA and critics of widespread antibiotic use on farms have argued that the use of Baytril to treat chickens and turkeys was especially worrisome because the drug is a fluoroquinolone, in the same family of antibiotics as Cipro (ciprofloxacin hydrochloride). The agency also said during a long administrative hearing that poultry farmers have alternatives that are as effective as Baytril but pose less of a threat to the human antibiotic supply.
In 2003, the World Health Organization urged that the use of antibiotics as animal growth promoters be stopped worldwide to preserve the effectiveness of important human drugs.
When the FDA first ordered Bayer to stop producing Baytril in 2000, it also told Abbott Labs to take its similar fluoroquinolone for poultry off the market. Abbott voluntarily withdrew the product, but Bayer appealed. An administrative law judge upheld the FDA position in March 2004, and Crawford affirmed the decision in July.
Last week, Bayer, the AHI and poultry associations made an eleventh-hour request to delay the ban, but Crawford rejected that petition on Friday.
Baytril, which was approved for sale in 1996, quickly became a popular treatment for respiratory diseases in chickens and turkeys. Because farm birds cannot be treated individually, entire flocks are regularly given the drug in their feed to treat those that are sick and to protect others. The FDA concluded that this kind of broad use led to increased antibiotic resistance.
The ban affects only the use of Baytril in poultry; the drug can still be given to pets and other farm animals that can be treated individually.
The withdrawal of Baytril is encouraging, Florini said, but she called on the FDA to go further.
"We certainly hope that Crawford's rock-solid analysis of this issue is an indication he will take the bull by the horns in dealing with the much bigger quantities of medical antibiotics that are used as feed additives," she said. "These are too valuable to be used to just make animals on big industrial farms grow faster."