Statements Made When Prosecuting Narrower Parent Application Do Not Necessarily Limit A Child Patent

• Published date: 27 June 2023
• Subject Matter: Intellectual Property, Real Estate and Construction, Patent, Construction & Planning
• Law Firm: Finnegan, Henderson, Farabow, Garrett & Dunner, LLP
• Author: Matthew M. Karas, Adriana Burgy and Stacy Lewis

Holding

In Supernus Pharm., Inc. v. Lupin Ltd., C.A. No. 21-1293 (D. Del. April 5, 2023), the United States District Court for the District of Delaware construed two claim terms disputed by the parties. The court did not apply the prosecution history of the parent application to narrow the claims at issue and also held that certain parts of the decided constructions were appropriate in this case based on the description in the specification.

Background

U.S. Patent Nos. 8,992,989 ("the '989 Patent"), 9,549,940 ("the '940 Patent"), 9,622,983 ("the '983 Patent"), and 10,314,790 ("the '790 Patent") relate to pharmaceutical compositions for topiramate. Independent claim 1 of the '989 Patent is representative of the first three of these patents and recites:

A sustained release formulation of topiramate comprising topiramate as an active ingredient, which is released immediately and continuously upon administration from the formulation, the formulation comprising:

(a) an extended release (XR) topiramate-containing component...

....

'989 patent at claim 1 (emphasis added).

Independent claim 1 of the '790 Patent recites:

A sustained release formulation of topiramate comprising topiramate as an active ingredient, the formulation comprising:

(a) at least two extended release (XR) topiramate-containing components...

....

'790 patent at claim 1 (emphasis added).

Regarding the phrase "an extended release (XR) topiramate-containing component" in the '989, '940, and '983 Patents, Supernus argued that no construction was necessary, but alternatively proposed a construction of "a component that releases topiramate over a prolonged period of time."

Lupin argued that the phrase should be construed narrowly based on statements made by Supernus during prosecution of the parent application of the patent at issue. Specifically, Lupin argued that the claim language included two additional limitations: (1) the XR component must be comprised of beads and (2) the XR component must have at least two populations of these beads. In connection with its arguments, Lupin pointed to statements made by Supernus during prosecution of a parent application. Lupin also argued that there was no "floor" to Supernus's phrase of "prolonged period of time" in its proposed alternative construction.

Regarding the term "at least two extended release (XR) topiramate-containing components" in the '790 Patent, Supernus again maintained that no construction was necessary, but alternatively proposed a...