FDA Answers Ramipril Letters, Explains Why Cobalt Has 180-Day Exclusivity

As we reported last November, the Federal Circuit's decision invalidating U.S. Patent No. 5,061,722 on Altace (ramipril) was followed by a flood of letters to FDA concerning 180-day exclusivity for ramipril.  FDA responded last week, shedding some light on how pre-MMA 180-day exclusivity issues are decided.

In FDA's response, posted January 29, FDA explained that Cobalt's 180-day exclusivity period began on December 10, 2007, when the Federal Circuit's mandate issued, and that no other ramipril ANDAs will be eligible for final approval until June 7, 2008, when Cobalt's exclusivity expires.  Although the Federal Circuit's decision came in the litigation involving Lupin, Cobalt was the first to file a ramipril ANDA.

Lupin argued first that Cobalt forfeited its 180-day exclusivity by entering into a settlement of its patent litigation with King Pharmaceuticals.  But FDA rejected this argument, concluding that there is no legal basis for it to find that Cobalt forfeited its exclusivity.  FDA stated, "Because the Act addresses directly the question of forfeiture as a result of a settlement [in 21 USC 355(j)(5)(D)(i)(V)], the agency does not have the discretion to determine that settlements not otherwise meeting the statutory requirements also will result in forfeiture."

In addition, Lupin argued that Cobalt's settlement rendered its paragraph IV certification inaccurate because, by settling its patent litigation, Cobalt had effectively stopped asserting that the '722 patent was invalid.  FDA rejected this argument as well, because "there is no evidence that at any point Cobalt conceded the '733 patent as valid, enforceable, and infringed by the product described in its ANDA."  Here, it appears important that Cobalt's settlement was made "without prejudice to Cobalt's allegations that the claims of the '722 patent are invalid and unenforceable."  FDA stated in its response that its regulations provide only three circumstances under which a patent certification should be amended, and none apply in this case.

Finally, Lupin argued that it "should be permitted to amend its certification so that its approval is not affected by Cobalt's exclusivity" because FDA's regulations provide for changes in certification when circumstances change.  FDA, however, was not persuaded, because its regulations also preclude the withdrawal of a paragraph IV certification until expiration of 180-day exclusivity.  FDA stated: "a subsequent applicant such as Lupin may not make an end run around the continued listing of an invalid patent--and the related 180-day exclusivity--merely by changing its certification.  The fact that Lupin, not Cobalt, was successful in obtaining a judgment that the '722 patent is invalid does not alter this conclusion."