by Dennis Crouch
In a significant ruling that underscores the importance of strategic litigation planning in patent cases, the Federal Circuit has affirmed a district court's judgment barring Wisconsin Alumni Research Foundation (WARF) from pursuing doctrine of equivalents infringement claims against Apple after the patentee's failed bid to show literal infringement. Wisconsin Alumni Research Foundation v. Apple Inc., No. 22-1884 (Fed. Cir. Aug. 28, 2024). The case addresses two separate but related disputes: WARF I, concerning Apple's A7 and A8 processors, and WARF II, involving Apple's A9 and A10 processors. The Federal Circuit's decision hinges on three key legal principles: waiver, issue preclusion, and the Kessler doctrine. In particular, the court expanded the scope of both issue preclusion and the Kessler doctrine in favor of accused infringers.
