On Aug. 03, 2020, Delaware district court denied Gilead’s Motion for Summary Judgment of non-infringement.
ViiV Healthcare / Shionogi & Co., Ltd. (Plaintiffs) filed lawsuit accusing Gilead Sciences, Inc. (Defendant) of infringement of US 8,129,385 patent. The US’385 patent covers pharmaceutical compounds for treating the human immunodeficiency virus (HIV). ViiV alleged that Gilead’s HIV drug product, Bictegravir infringes claim 6 of the US’385 patent under the doctrine of equivalents. Bictegravir has a benzyl ring with three fluorines.
Claim 6 of the US’385 patent claims four compounds, and pharmaceutically acceptable salts thereof, each with a benzyl ring that has two fluorines. Gilead moved for summary judgment of noninfringement based on the argument that two-fluorines limitation in claim 6 specifically excludes compounds with three fluorines.
Court said that the implicit disclaimer-known as the “specific exclusion principle” precludes a finding of equivalency infringement when a feature of the accused product is “the opposite of, or inconsistent with, [a] recited limitation” of the asserted claim. Here it is undisputed that a difluoro benzyl ring is not the same thing as a trifluoro benzyl ring. But it is not clear from the claims or written description of the US’385 patent that a difluoro benzyl ring necessarily excludes a trifluoro benzyl ring. Gilead has neither alleged nor submitted record evidence such as an expert affidavit to establish that a difluoro benzyl ring is the opposite of or incompatible with a trifluoro benzyl ring. ViiV, on the other hand, has alleged, and has submitted an expert affidavit to establish, that a trifluoro benzyl ring is not the opposite of and not incompatible with a difluoro benzyl ring. Accordingly, the specific exclusion principle does not bar ViiV from alleging that Bictegravir infringes claim 6 under the doctrine of equivalents.