In Actelion Pharmaceuticals Ltd. v. Mylan Pharmaceuticals Inc. No. 2022-1889, __ F.4th ____ (Fed. Cir. Nov. 6, 2023), the case addresses whether a district court needs to consider the extrinsic evidence when the intrinsic record does not sufficiently render the term non-ambiguous.

Background

This is an appeal of the district court’s claim construction order. More specifically, this appeal relates to the parties’ dispute over the meaning of the limitation “a pH of 13 or higher.” In the district court, both “parties proposed the plain and ordinary meaning of the term but disagreed on what that means.” Actelion Pharmaceuticals Ltd. (“Appellee” or “Actelion”), took the position that a pH of 13 “would ordinarily encompass those values that round up or down to 13, 12.5 to 13.4” because an ordinary rounding is necessary in view of the three textbooks. Contrarily, Mylan Pharmaceuticals Inc. (“Appellant” or “Mylan”) took the position that an ordinary rounding is not necessary. Further, Mylan took the position, if rounding is necessary, “a pH of 13 would involve rounding to the hundredths place, encompassing 12.995-13.004” based on the three textbooks cited by Actelion. The district court did not address this extrinsic evidence to conclude whether: (i) an ordinary rounding is necessary or (ii) narrower range of rounding is necessary. Rather, the district court agreed with Actelion’s proposed construction and issued a claim construction order solely based on findings from the intrinsic record. In particular, the district court stated “under its conventional significant figure meaning, the term a pH of 13 would ordinarily encompass those values that round up or down to 13, 12.5 to 13.4[,]” “the claims consistently expressed a pH of 13 with two significant figures[,] and that the claim language [and prosecution history] provides no basis for inferring any higher level of precision.” Based on this claim construction order, the parties stipulated to the final judgment of infringement. Mylan appealed the order.

Issue

Whether the district court needs to consider the extrinsic evidence when the intrinsic record alone does not establish the clear meaning of a claim term.

Holding

The Federal Circuit reviews claim construction solely based on an intrinsic record de novo. The panel found that the disputed claim term remains ambiguous after the “analysis of intrinsic evidence.” As such, the district court should have “consider[ed] the extrinsic evidence and its impact on claim construction.” Accordingly, the final judgment of infringement is vacated and remanded for further consideration.

Reasonings

The Federal Circuit found the meaning of the disputed term “a pH of 13 higher” “remains unclear even after consulting the specification” and “the prosecution history. “ First, the claim language (i.e., “a pH of 13 or higher”) alone is not sufficient to conclude the claim is limited to the “specified lower limit.” Indeed, “there is no blanket rule that ranges, or specifically open-ended ranges, must foreclose rounding.”

Second, lack of an approximation claim language (e.g., about) may not foreclose rounding. Although “absence of approximation language might suggest no approximation,” practicality may suggest approximation because “it is not practically possible to measure exact pH values.”

Third, disclosure that “[t]he pH of the bulk solution is preferably adjusted to about 12.5-13.4, most preferably 13,” may not foreclose rounding. Although such disclosure may show that the patentee “knew how to use approximation language” and “chose not to” use the language, the disclosure also shows that rounding is necessary “or else a preferred embodiment . . . would be excluded from the claim scope.”

Fourth, one disclosure that “seems to equate a pH of 13.0 to that of 13” may not foreclose rounding because the specification uses both values with “various degrees of precision.”

Fifth, AstraZeneca AB v. Mylan Pharmaceuticals Inc. is not applicable. 19 F.4th 1325 (Fed. Cir. 2021). Unlike AstraZeneca where rounding resulted with a claim scope that included products the specification explicitly disclosed to exclude, here, no similar evidence exists.

Accordingly, the disputed claim term remains ambiguous after the “analysis of intrinsic evidence.” As such, remand for further consideration is necessary because the Federal Circuit may not make factual findings about the extrinsic evidence.