CAFC Says Generic Hypertension Drug Does Not Infringe Actelion’s Patents

The U.S. Court of Appeals for the Federal Circuit (CAFC) issued a precedential decision today affirming a district court ruling that Mylan Pharmaceuticals’ generic hypertension drug did not literally infringe Actelion Pharmaceuticals’ U.S. patents for its own hypertension drug, Veletri®. The CAFC also affirmed the district court’s holding that Actelion had not proven and was barred from asserting infringement by an equivalent.

Actelion owns U.S. Patent Nos. 8,318,802 and 8,598,227 for “certain pharmaceutical compositions involving epoprostenol.” Each independent claim of the patents recites a bulk solution pH of “13 or higher” or “greater than 13.” After Mylan submitted its Abbreviated New Drug Application (ANDA) to the FDA, Actelion sued Mylan for infringement of the patents. Mylan argued that its generic drug was “manufactured from a bulk solution with a pH outside the patents’ claims.”

Initially, the district court construed the claims to mean a pH of 12.5 or higher due to rounding rules, but the CAFC in 2023 remanded that ruling, explaining that “the proper claim construction cannot be reached without the aid of extrinsic evidence.” On remand, the district court determined that the pH of 13 or higher should be construed to mean a pH of 12.98 or higher. It was undisputed that Mylan’s bulk solution has a pH of well below 12.98, but Actelion argued that, when refrigerated, as the ANDA indicates the solution is when manufactured, “if measured at that cold temperature, has a pH of above 13.”

Actelion further argued that the generic drug is an equivalent to its patented product because “Mylan’s manufacturing process performs the same function (improved manufacturing stability) to achieve the same result (composition stability) in the same way (reducing hydrogen ion concentration) as the claimed invention.”

The district court rejected these arguments and, on appeal again to the CAFC, the opinion, authored by Judge Taranto, found that the district court properly construed the claim phrase “formed from a bulk solution having a pH of 13 or higher” and agreed with Mylan that there was no reversible error in its construction. As to the intrinsic evidence, the claim language on its own does not resolve the question of the proper interpretation of “a pH of 13 or higher”; the specification favors the district court’s construction in its definition of “an alkaline environment” as one with “pH>7,” which “undisputedly is accurate only at standard temperature”; and neither the examiner’s statement of reasons for allowance nor the supposed purpose of the invention supports Actelion’s construction, said the CAFC.

And turning to the extrinsic evidence—the USP, several general chemistry textbooks, and expert statements—the CAFC held that the district court properly found it showed “that those skilled in making pharmaceutical compositions, when referring to pH, mean a measurement at standard temperature unless they indicate otherwise, and we discern no clear error in how the district court evaluated the record.”

Actelion also argued that the district court improperly found that Mylan infringed by an equivalent and that Actelion was barred from asserting such a theory, but the CAFC found that, because Actelion narrowed its claims during prosecution, it was estopped “from later arguing that the subject matter covered by the original, broader claim was nothing more than an equivalent.” Actelion attempted to show that “the claim amendment is only tangential to the differences between the alleged equivalent and the literal claim scope,” but the district court and CAFC both rejected this argument.

Furthermore, the “disclosure-dedication rule” independently bars Actelion from asserting an equivalents theory, and Actelion’s contention that that rule should not apply because the disclosed alternative pH ranges “are not mutually exclusive with each other” is contrary to the rule, said the CAFC.

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