FDA committee Oks food animal antimicrobial

WASHINGTON— As the Food and Drug Administration (FDA) works to curb antimicrobial resistance in humans by limiting antibiotics for food-producing animals, a new drug designed to fight bovine and swine respiratory disease appears to have gained a preliminary green light.

In what supporters describe as a "historic moment," the FDA's Veterinary Medicine Advisory Committee (VMAC) issued its first approval of a veterinary antibiotic in October, deeming the drug microbially safe. VMAC, formed last year as part of FDA's Guidance for Industry No. 152, is part of the science-based process manufacturers can employ when seeking approval of an antimicrobial for use in food animals.

Pfizer, the first drug maker to move through the system, presented tulathromycin, an injectable commercially known as Draxxin and designed to maintain therapeutic levels of active drug in the lungs for up to nine days. If approved by FDA's Center for Veterinary Medicine (CVM), tulathromycin will be the longest-acting, single-dose, full-course therapy available to U.S. veterinarians, company officials say.

While the drug is notable, VMAC's approval is "momentous," committee Chair Dr. John Waddell says.

"This was the first time a drug sponsor brought forth a new article completely under the guidance document 152," he says. "Pfizer presented a strong case for why tulathromycin should be approved. CVM was there for that, and we advised them. They wanted to know the opinions of the committee so they can formulate their next step."

What's ahead

The guidance document, formally titled "Evaluating the Safety of Antimicrobial New Animal Drugs with Regard to their Microbiological Effects on Bacteria in Human Health Concern," outlines a comprehensive evidence-based approach to preventing antimicrobial resistance that might result from the use of antimicrobial drugs in animals, FDA officials say.

While FDA officials refuse to comment on drugs before they are approved, CVM is preparing to review tulathromycin. The process could take years, says Dr. Tom Burkgren, executive director of the American Association of Swine Veterinarians.

"Even if it takes a long time to go through the process, this is very significant," he says. "We're always happy if we get a new approval. This only happens once every five to 10 years."

About tulathromycin

Pfizer researchers discovered tulathromycin in the mid-1990s and have been reviewing the antimicrobial ever since, says Dr. William Baker, who works for Pfizer's research and development team.

Much of the company's data was presented to the European Union in 2003, where Draxxin subsequently was approved for use. Pfizer spokesman Bob Fauteux says he hopes FDA will follow suit.

"We pride ourselves on developing and marketing only drugs in which these products pose no significant risk to the efficacy of trying to treat human diseases," Fauteux says. "At Pfizer, our top priority is human health. We're looking forward to a decision from CVM in 2005."