(CN) – The Federal Circuit dashed drug maker Wyeth’s hopes for a nearly four-year patent extension on a drug that treats parasites in cattle, deeming the Food and Drug Administration’s interpretation of an ambiguous federal law plausible and reasonable.
The Washington, D.C.-based appellate panel ruled that Wyeth submitted its application for the drug Cydectin in January 1998, not August 1995, as the company claimed.
The date is important because federal law allows a company to extend a drug’s patent for a period “equal to half of the duration of the testing phase plus the entire duration of the approval phase, not to exceed five years.”
Wyeth and the FDA disagreed over when the approval phase for Cydectin began, with Wyeth arguing that the phase began when it submitted the first part of its application into the FDA’s streamlined review process, which allows companies to work closely with FDA staff throughout the often multi-year effort to bring a new drug to market. Cydectin spent nearly eight years in the FDA system, and Wyeth applied for a patent extension of 1,434 days.
But the FDA cut that number down to 16 days, arguing that the approval phase for purposes of patent extension begins “when the marketing application is complete.”
Wyeth sued the FDA in federal court, challenging the agency’s interpretation of the law. The judge ruled for the FDA, saying the law’s definition of “application” is ambiguous, and the agency’s interpretation was based on a “permissible construction of the statute.”
The Federal Circuit agreed.
“We reject Wyeth’s argument that [the statute] unambiguously indicates that an application is initially submitted when a sponsor submits its first technical section,” Judge Kimberly Moore wrote. “A technical section addresses only one substantive area. A technical section does not contain all of the information required, and therefore it can not constitute ‘an application.’ This interpretation conflicts with the statutory language.”
Moore concluded that the lower court correctly found the statute to be “ambiguous,” and that “both parties advanced plausible interpretations.”
But when interpretations collide, she said, a court must defer to the agency’s “reasonable interpretation.”