TEANECK, NJ – Phibro Animal Health intends to challenge a US Food and Drug Administration (FDA) decision to withdraw approval of carbadox, a drug used to treat bacterial infections in swine.

On April 8, the FDA said the agency is taking steps to rescind approval of carbadox because the drug may leave trace amounts of cancer-causing residue. Phibro produces carbadox under the brand name Mecadox.

“Phibro has complete confidence in the safety of Mecadox,” the company said in a statement. “We are disappointed that the FDA would take this action when definitive studies are so close to being completed.”

The Center for Veterinary Medicine (CVM) said a preliminary risk characterization revealed a “potential risk to human health from ingesting pork, especially pork liver,” harvested from pigs treated with carbadox. FDA Deputy Commissioner Michael R. Taylor said Phibro “failed to provide sufficient scientific data to demonstrate the safety of this drug…”

Carbadox is an antimicrobial used to control bacterial diseases such as Salmonella and swine dysentery. A 42-day withdrawal period is required before harvest. Phibro explained that advanced detection methods revealed the persistence of carbadox residues in swine tissues longer than previously determined, and this finding prompted FDA to raise questions about the safety of the drug.

“Since that time, Phibro Animal Health has cooperated fully with the FDA’s inquiries, including undertaking comprehensive, rigorous new studies using the latest and most sensitive technology available,” the company said. “Phibro has been providing the data to the FDA as it is generated, and in accordance with the schedule submitted to the agency, and to date that evidence has been positive regarding the safety of Mecadox when used in accordance with the label.”

Phibro added that its studies will be completed in the next 90 days, and the company expects the remaining evidence to support the safety of Mecadox. Meanwhile, Phibro can continue to sell Mecadox in the US.

“Phibro will continue to market the product and to vigorously defend Mecadox based on more than 40 years of science and safe use,” the company said.