If you wonder what "prosecution history estoppel" in a patent infringement case means, you might check out MarcTec, LLC v. Johnson & Johnson, No. 10-2085 (Fed. Cir. Jan. 3, 2012), in which the court affirmed an award of $4,683,653.03 in fees and expenses to the defendants.

MarcTec alleged infringement by the "Cypher stent" — "a balloon expandable drug-eluting stent" that aims to help people with coronary artery disease. But, during the prosecution of the patents, MarcTec overcame objections to the applications by saying two key things — that coating of the device with medicine had to occur as a result of applying heat and that the patent didn't cover — you guessed it — stents. The record revealed that the drug on the Cypher stent didn't bond to it as a result of heat. Yet MarcTec insisted that the Cypher stent infringed.

The district court ruled that patent history estoppel barred MarcTec from claiming that the patents covered the Cypher stent. It also deemed the case "exceptional" due to MarcTec's "bad faith" in pressing the claims and awarded Johnson & Johnson and Cordis more than $4.6 million in fees, expert expenses, and other outlays. The court of appeals affirmed.

On the "heat" bonding issue, the panel wrote:

As Cordis correctly argues, MarcTec cannot claim to be ignorant of the references to heat in the claims, the language in the specification discussing the importance of heat to the bonding process, or Dr. Bonutti’s statements to the PTO. Indeed, as we noted in the prior appeal, the doctrine of prosecution history estoppel prevented MarcTec from asserting its construc-tion of the term "bonded." After careful consideration and review of the record, we agree with the district court that MarcTec’s proposed claim construction, which ignored the entirety of the specification and the prosecution history, and thus was unsupported by the intrinsic record, was frivolous and supports a finding of bad faith.

MarcTec, slip op. at 18. On the question of stent v. no stent, the court said:

While it is clear that "[d]efeat of a litigation position, even on summary judgment, does not warrant an auto-matic finding that the suit was objectively baseless," here the record supports the district court’s finding that Marc-Tec pursued objectively baseless infringement claims. . . . The district court found that the "written description and prosecution histories of the patents-in-suit, and other documentary evidence, demonstrate that MarcTec’s patent infringement case was baseless." . . . . The court further found that, because MarcTec disclaimed stents to overcome the prior art, it could not turn around and assert infringement against the Cypher stent. Because the specification and prosecution history clearly refute MarcTec’s proposed claim construction, the district court did not err in finding that MarcTec’s infringement claims were objectively baseless.

Id. at 19 (omitting citations).