US Federal Circuit overturns AIDS drug patent decision

The US Court of Appeals for the Federal Circuit has overturned a decision on patent claims for a drug used to treat anorexia and cachexia in AIDS patients.

In a decision issued yesterday (December 3), the court said the US District Court for the District of Maryland erred when it said Par Pharmaceutical’s patent claims for its own version of Megace (Megestrol acetate), produced by Bristol-Myers Squibb, were obvious.

Par had brought litigation against TWi Pharmaceuticals, which itself had filed an application to produce a nanosized formulation of Par’s drug.

The case, which centred on claims included in Par’s US patent number 7,101,576, has been sent back to the district court for further deliberation.

Earlier this year, the district court found the claims obvious based upon prior art references.

The district court said that the claims should not carry weight in the obviousness analysis because they were simply describing a result inherent to the formulation.

The Federal Circuit disagreed and vacated the judgment for further fact-finding.

According to the Federal Circuit, the district court “incorrectly applied our law on inherency in the context of obviousness”.

Bill Baton, partner at Saul Ewing, said the Federal Circuit had previously held that the inherency doctrine must be limited when applied to obviousness.

“In this case, the Federal Circuit found that the district court had not required TWi to present facts that would support application of the inherency doctrine to establish the existence of a claim limitation (a known food effect in megestrol) that was not specifically disclosed in the prior art,” he told LSIPR.

Neither Par nor TWi responded immediately to a request for comment.