Legal Opinions - U.S. District Court, Maryland: October 20, 2008

Daily Record, The (Baltimore), Oct 20, 2008

Here, Wyeth argued that Lupin's proposed generic drug infringed its patents-in-suit. Lupin asserted that Wyeth's claim construction was incorrect and, under proper construction, its product did not infringe the patents-in-suit.

Infringement requires a showing that every element of a patent is infringed, either literally or under the doctrine of equivalents. See Leggett & Platt, Inc., 285 F.3d at 1358. Because there were issues of material fact as to infringement of some of the claims in issue, summary judgment was denied.

COMMENTARY: Wyeth alleged the claim "extended release formulation" should be construed to mean "a formulation, other than a hydrogel tablet, which releases the active ingredient at a slower rate than the immediate release formulation of the active ingredient such that the dosing frequency is once-a-day rather than the plural daily dosing for the immediate release formulation."

That was the construction given to the term in Wyeth v. Impax Lab. Inc., 526 F.Supp.2d 474, 480 (D. Del. 2007). In that case, Wyeth filed suit against Impax for infringement of the same patents at issue here. Unlike Lupin's arguments, Impax alleged that the term "extended release formulation" required specific inactive ingredients. Lupin instead argued that "extended release formulation" requires a spheroid formation, rather than specified ingredients. The Impax court agreed with Wyeth that "extended release formulation" should not be construed to require specific ingredients, but did not touch on the issue of whether "extended release formulation" required spheroid form. Id.

The specifications for the patents-in-suit are the first source of information as to the ordinary meaning of "extended release formulation." See Phillips, 415 F.3d at 1315. The specification in the 171 Patent was representative of all three specifications at issue. As it was first defined in both the Brief Description and Detailed Description, the term "extended release formulation" was not modified by the term "spheroids." Despite that, the specification used "spheroid" with the term "extended release formula" throughout the remainder of the specification. As a result, the specification provided conflicting evidence as to the scope of the term "extended release formulation."

The prosecution histories also presented conflicting evidence as to the scope of the term "extended release formulation." In one of the patent prosecutions, the patent examiner referred to the invention as "spheroids." At other points in the prosecution history, Wyeth asserted that its invention was not limited to spheroid forms, and a patent examiner made a similar statement in the prosecution history.

The conflicting evidence in the specification and prosecution histories was not resolved by the claims. None of the disputed claims contained the term "spheroid." Undisputed claims mentioned spheroids in connection with "extended release formulation," however. Under the theory of claim differentiation, claim construction, which makes claims redundant is to be avoided. See Honeywell Intern. Inc. v. Universal Avionics Systems Corp., 488 F.3d 982, 994 (Fed. Cir. 2007).