Last week, the U.S. Court of Appeals for the Federal Circuit issued an opinion in AstraZeneca AB v. Mylan Pharmaceuticals Inc., No. 2021-1729 (Dec. 8, 2021), reversing the Northern District of West Virginia’s claim construction and vacating entry of infringement based on the erroneous construction. The Federal Circuit also affirmed the district court’s determination after a bench trial that the claimed invention was not obvious.
The asserted patents cover certain pharmaceutical compositions delivered using a pressurized metered dose inhaler (pMDI). pMDIs aerosolize medications. This requires a stable liquid solution. The Federal Circuit’s analysis focused on the concentration in the claimed composition of a particular inactive ingredient called PVP K25 (PVP), which is a formulation stabilizer. Each of the asserted claims recited a concentration of “0.001% w/w” of PVP. The district court construed “0.001%” to mean 0.001% within one significant figure—i.e., 0.0005% to 0.0014%. Under this construction, Mylan stipulated to judgment of infringement. After a bench trial finding the asserted patents not invalid, Mylan appealed, among other things, the district court’s claim construction and entry of judgment of infringement.
On appeal, the Federal Circuit reversed the district court’s construction, finding that the specification of the asserted patents and prosecution history required a construction of 0.001% as “that precise number, with only minor variations, i.e., 0.00095% to 0.00104%.” Importantly, the written description identified a concentration of 0.001% PVP as uniquely suited to a highly stable solution. Testing reported in the written description demonstrated that even slight variations in PVP concentrations resulted in less stable solutions. Solutions with a PVP concentration of 0.0005%, which was included in the district court’s construction of 0.001%, were shown to be significantly less stable. Moreover, during prosecution, the asserted claims were amended multiple times to narrow the claimed range of PVP concentration with multiple statements from the applicant regarding the critical nature of the 0.001% concentration. The Court thus found that a narrow range of concentrations was required by the claims and construed 0.001% to include only 0.00095% to 0.00104%, vacated the district court’s judgment of infringement, and remanded.
The Federal Circuit also affirmed the district court’s finding that Mylan had not demonstrated that the asserted claims were obvious, finding no clear error in the district court’s factual determinations.
Judge Taranto dissented from the portion of the majority decision relating to claim construction and infringement, finding that the district court’s construction of 0.001% was correct.