16 August 2019Americas

Fed Circuit majority ‘problematically’ adds new rule in Actavis suit: chief judge

The US Court of Appeals for the Federal Circuit yesterday, August 15, blocked Actavis’s attempt to market a generic version of Nalpropion Pharmaceuticals’ weight-loss drug Contrave (naltrexone hydrochloride and bupropion hydrochloride).

In a  precedential decision, the Federal Circuit concluded that two of the three asserted patents were invalid, reversing a lower court’s finding that the patent claims wouldn’t have been obvious in view of prior art.

However, in a move which effectively prohibits Teva-subsidiary Actavis from marketing a generic, the Federal Circuit affirmed the validity of the final patent covering Contrave.

This patent, US number 8,916,195, is directed to methods of treating obesity, and its claims are drawn to “specific dosages of sustained-release naltrexone and bupropion that achieve a specific dissolution profile”. It expires in 2030.

Nalpropion accused Actavis of patent infringement after the Teva unit applied for an Abbreviated New Drug Application.

In response to the lawsuit, Actavis brought invalidity counterclaims, challenging claim 11 of the ‘195 patent as invalid for lack of adequate written description and challenging claims in the other two patents as invalid as obvious.

After a bench trial, the US District Court for the District of Delaware held that each claim was valid and infringed. Actavis appealed against the decision to the Federal Circuit and was handed a partial victory.

Circuit Judge Alan Lourie, on behalf of the court, said: “While as a general matter written description may not be satisfied by so-called equivalent disclosure, in this case, buttressed by the district court’s fact-finding, and where the so-called equivalence relates only to resultant dissolution parameters rather than operative claim steps, we affirm the district court’s conclusion.”

In affirming the district court’s finding that the ‘195 patent was valid, Lourie added that “rigidity should yield to flexible, sensible interpretation”.

However, in a dissenting opinion,  Chief Judge Sharon Prost claimed that the majority had added what appears to be a new rule to the Federal Circuit’s long-standing written description jurisprudence.

“It holds that a ‘substantially equivalent’ disclosure may satisfy the written description requirement when the relevant claim limitation recites only ‘resultant dissolution parameters rather than operative claim steps’. Respectfully, that is not the law,” said Prost, adding that on her understanding of the court’s precedent, claim 11 of the ‘195 patent is invalid.

According to Prost, the majority’s conclusion “problematically articulates” a new rule for written description.

Prost added: “According to the majority, written description for nonlimiting clauses may be satisfied by disclosure that is ‘substantially equivalent’ even though the same disclosure would not be sufficient for limiting clauses. This rule, however narrow, is at odds with this court’s precedent.”

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