Forest Laboratories loses Federal Circuit fight against Teva

Forest Laboratories, a subsidiary of Allergan, has failed in its attempt to overturn a district court ruling in its patent battle with Teva.

On Monday, December 11, the US Court of Appeals for the Federal Circuit affirmed a decision by the US District Court for the District of Delaware to invalidate six patents licensed exclusively to Forest.

The six patents are US numbers 8,168,209; 8,173,708; 8,283,379; 8,329,752; 8,362,085; and 8,598,233.

They describe and claim pharmaceutical compositions, and methods of administering pharmaceutical compositions, that contain extended-release formulations of memantine.

Forest holds a New Drug Application for Namenda XR, a memantine hydrochloride formulation, used to treat moderate to severe Alzheimer’s.

In December 2013, Teva filed an Abbreviated New Drug Application seeking approval to sell a generic version of Namenda XR. Teva told Forest that the six patents covering Namenda XR were invalid or would not be infringed by the generic.

Forest retaliated by suing Teva in Delaware.

But, during claim construction, the district court determined that all of the asserted patent claims were invalid for indefiniteness.

The term at the centre of the controversy was “change in memantine concentration as a function of time (dC/dT) that is less than 50% that of an immediate release dosage form comprising the same dose of memantine as the composition”.

Forest argued that the language should be left unconstrued or the term should be construed as “change in plasma memantine concentration of the extended [sustained] release dosage form as a function of time (dC/dT) that is less than 50% that of an immediate release dosage form comprising the same dose of memantine as the extended [sustained] release dosage form”.

Teva contended that the term requires a comparison of a concentration profile of an immediate-release formulation and a concentration profile of an extended-release formulation.

Teva added that the claim language and specification didn’t describe how to conduct the studies to obtain the concentration profiles.

The Delaware court construed the claim to require this comparison to be measured in human pharmacokinetic studies, which determined the fate of substances administered to a living organism.

It went on to conclude that the evidence doesn’t disclose a specific human-study design or provide guidance on designing such a study.

The district court entered a final judgment of invalidity based on indefiniteness, so Forest appealed, arguing that the court had erred by requiring that both of the concentration profiles had to be derived from measurements in human pharmacokinetic studies.

Forest claimed that, although the profile for the extended-release formulation must be measured in a human study, the profile to which it is being compared—the profile for the immediate-release formulation—must be a computer-generated profile.

But the Federal Circuit sided with the lower court, finding that Forest’s claim construction was contrary to the intrinsic evidence, profiles of an immediate-release formulation and an extended-release formulation generated by a predictive pharmacokinetic software.

Circuit Judge Richard Taranto, on behalf of the court, said: “The descriptions of the figures are no more than what they purport to be: descriptions of the figures. They do not constitute a definition and are not even directed to the meaning of the claim terms.”

The prosecution history also provided no support for Forest’s proposed construction, according to the Federal Circuit.

Did you enjoy reading this story?  Sign up to our free daily newsletters and get stories like this sent straight to your inbox.