WASHINGTON (CN) - The Food and Drug Administration must revoke its approval of a generic version of a Bayer bovine respiratory drug until it address Bayer's concerns about off-label use, a federal judge ruled.
Bovine respiratory disease is one of the most common ailments in the U.S. cattle industry, according to Purdue University.
Bayer's drug Baytril 100 treats the disease in two ways: a lower-strength, multiple-day dosage, and a stronger, single-use dosage, U.S. District Judge Rosemary M. Collyer wrote in her opinion and order.
When the patent for Baytril's multi-day dosage was set to expire in 2006, Bayer wrote to the FDA to express concern about off-label use.
Though generic versions of the drug would be labeled for the three-day treatment, veterinarians and ranchers would "inevitably" administer it in a single dose, Bayer claimed, citing "affidavits and market research."
The FDA issued a tentative response in December 2006, saying it needed more time to evaluate the petition. But the agency never officially responded to the petition, Judge Collyer found.
In 2008, Norbrook Laboratories submitted an application for a generic version of Baytril called Enroflox 100.
Bayer sued for patent infringement, but gave Norbrook permission to sell Enroflox in a 2012 settlement.
In March this year the FDA approved Norbrook's application for Enroflox. Its label, which says it can be used as a single-dose treatment for swine and a multi-dose course for cattle, is virtually identical to Baytril's label, the judge wrote.
Bayer challenged the FDA decision in April, claiming that approving Enroflox despite evidence that people would not follow the label's multi-day dosage directions violated 21 U.S.C. § 360b(c)(2)(A)(ii).
Bayer also claimed that approving Enroflox without responding to its 6-year-old petition showed the FDA decision was arbitrary and capricious.
While the FDA acknowledged that it should have addressed Bayer's petition before approving Enroflox, it argued that the court must uphold its approval "in light of the agency's expertise in veterinary medicine."
But Collyer sided with Bayer, and issued a temporary restraining order against the FDA.
"Bayer's concern for off-label use of a generic to Baytril cannot be said to be unreasonable or illogical," Collyer wrote. "The labels for both drugs are very similar and the instructions on Enroflox's label are identical to Baytril's instructions for multiple-day therapy in cattle. ... Bayer makes the commonsensical argument that when administering the very same drug as Baytril, given the many advantages of Baytril's single, high-dose administration well known to veterinarians and ranchers, users are reasonably certain to use a single high dose off-label in lieu of the multiple-day therapy specified on the label."
Collyer found that FDA approval of Enroflox violated the agency's statutory duties under the Administrative Procedures Act.
The APA requires courts to defer to an agency's decision unless evidence demonstrates that the agency failed to consider the "relevant data" before issuing a decision, and did not adequately explain how the facts support its decision.
The FDA argued that since Enroflox's label explicitly prohibits off-label use, the court cannot prove that it "knew" off-label use would occur, and must find that the FDA's decision was reasonable.
Collyer was not persuaded.
"The court rejects FDA's formulation of the issue: resolution does not turn here on what FDA 'knew' in a vacuum, but whether, based on all the facts before it, FDA had found that the conditions of use specified in the proposed labeling were not reasonably certain to be followed in practice," Collyer wrote.
Since the FDA had access to Bayer's petition for more than 6 years, its refusal to challenge the facts offered undermines its claim that its decision to approve Enroflox is supported by the record.
"FDA offers no evidence that it considered any of the concerns, facts, or arguments raised in Bayer's citizen petition when it approved Enroflox 100 - concerns which strongly suggest that approval of a generic for Baytril only for multi-day use might well violate 21 U.S.C. § 360b(c)(2)(A)(ii)," Collyer wrote. "It says only that it trusts veterinarians and ranchers to follow the Enroflox 100 labeling for multi-day use and an applicable regulation, despite the ready ease (and benefits) with which Enroflox 100 could be administered in a single dose contrary to its label."
The ruling adds: "The court cannot find that the FDA engaged in reasoned decisionmaking as the APA requires. The court has thus concluded that, on this record, Bayer is likely to prevail on the merits of its claim that FDA acted arbitrarily and capriciously."
Collyer found that Bayer would suffer irreparable harm in the form of significant financial loss if Enroflox is allowed to hit shelves, and that the harm to Bayer is more significant than the harm the FDA and Norbrook might suffer if Enroflox's approval is delayed a little longer.
Collyer ordered the FDA to rescind its approval of Enroflox to treat cattle, but not to treat swine. She directed the agency to "notify all interested parties of the order."
(Treatment, or overtreatment, of cattle and pigs is believed to be a major cause of the rise of antibiotic-resistant diseases. Livestock producers dose their animals with low levels of the drugs in the belief that it will keep them healthy and help them add weight faster. The issue is not addressed in the ruling, nor has it been addressed seriously by the FDA, despite repeated expressions of concern from medical experts.)
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