Based on claim construction informed by the intrinsic record, the U.S. Court of Appeals for the Federal Circuit affirmed a district court’s grant of summary judgment of non-infringement by Amgen’s Enbrel® product. Amgen, Inc. v. Ariad Pharmaceuticals, Inc., Case Nos. 09-1023 (Fed. Cir., June 1, 2009) (Moore, J.).

Ariad’s patent claims methods comprising “reducing NF-κB activity.” The reduction of NF-κB activity is desirable because NF-κB increases the harmful expression of certain genes. All of the asserted claims include the limitation “reducing NF-κB activity in cells.” The district court construed this phrase to mean “taking action inside cells to directly inhibit (interfere or block) an NF-κB activity.” Amgen’s Enbrel® works outside the cells by binding to free TNF-α, which in turn binds to cell surface receptors that respond by inducing NF-κB activity. The district court concluded that Amgen’s Enbrel®, which works outside the cell, could not infringe the asserted claims. Accordingly, district court granted Amgen’s summary judgment motion of non-infringement.

On appeal, the Federal Circuit noted that the district court agreed with Amgen that agents that act outside the cell do not infringe, while agents that act inside the cell may infringe. The Court pointed out that Ariad did not argue that the reducing act could occur anywhere. Rather, the Court observed, Ariad would place the boundary “at some indefinite place” outside of the cell, such that accused drugs including Enbrel® are captured, while certain prior-art drugs, such as antibiotics, are left out of the claim scope. While the Court agreed with Ariad that the asserted claims have a limited scope, it concluded that Ariad’s particular choice of boundary lacked foundation in the intrinsic evidence. After noting that the ordinary meaning of the term “reducing NF-κB activity in cells” admits alternative views, the Court relied on “unequivocal” statements by the patentee in the specification and prosecution history to conclude that the term limits the asserted claims to methods in which the action that reduces NF-κB activity takes place inside the cell.