CAFC Vacates Infringement Ruling Against Mylan Pharmaceuticals Over Improper Claim Construction

On December 8, the United States Court of Appeals for the Federal Circuit (CAFC), in a precedential decision authored by Judge Stoll, vacated a  judgment of infringement against Mylan Pharmaceuticals Inc. and affirmed the nonobvious determination of the United States District Court for the Northern District of West Virginia. While the Federal Circuit disagreed with the district court’s claim construction on which the infringement judgment was based, it found no clear error in the district court’s conclusion that the prior art taught away from the claimed invention. Judge Taranto partially dissented from the majority’s judgment on claim construction/ infringement.

The decision relates to AstraZeneca AB’s and AstraZeneca Pharmaceuticals LP’s (collectively “AstraZeneca”) lawsuit against Mylan and Kindeva Drug Delivery LP (collectively “Mylan”) for infringing all claims of U.S. Patent Nos. 7,759,328; 8,143,239; and 8,575,137 (collectively “asserted patents”).

AstraZeneca markets both a dry powder inhaler version of Symbicort® called Symbicort® Turbuhaler and a pressurized metered-dose inhaler (pMDI) version called Symbicort® pMDI. A dry powder inhaler is a powdered medication, the administration of which requires patients to inhale deeply. This can be difficult for certain patient populations. However, a formulation that used pMDI, uses a propellant gas that is in liquid form when under pressure in the pMDI device. Therefore, this method of administration removes the need for deep inhalation and makes it easier for certain populations like the young or elderly to take this medication. The asserted patents cover the work done by inventors to develop a stable composition of the drug capable of administration via a pMDI.

3M Company submitted Abbreviated New Drug Application (ANDA) No. 211699 to the FDA seeking approval to manufacture and sell a generic version of Symbicort® pMDI. Certain interests in ANDA No. 211699 were later transferred to Mylan. Once those interests were transferred, Mylan notified AstraZeneca using a “Paragraph IV letter” that it had submitted ANDA No. 211699 for a generic version of Symbicort® pMDI. This letter argued that the asserted patents are invalid, unenforceable, and/or not infringed. In response, on October 12, 2018, AstraZeneca sued Mylan for patent infringement.

District Court Determinations

As the trial date neared, it became apparent that it was necessary for the district court to construe the term “0.001%.” The district court construed this term according to its “plain and ordinary meaning, that is, expressed with one significant digit.” Following this construction, Mylan stipulated to infringement of some claims of the asserted patents and the district court entered a final judgment of infringement. Following Mylan’s stipulation, the district court held a bench trial to decide the validity of the asserted claims. The district court held that Mylan failed to provide clear and convincing evidence that the asserted claims would have been obvious in view of the prior art.

CAFC Analysis

On appeal, Mylan argued that the district court’s construction of the claim term “0.001%” was incorrect. Additionally, Mylan argued that that the district court made several incorrect factual findings which led to their improper conclusion of nonobvious related to the asserted patents.

Claim Construction

The CAFC first addressed the issue of claim construction. Mylan argued that the term “0.001%” should be construed to mean that value alone. In contrast, AstraZeneca contended, and the district court agreed, that this term meant within one significant figure of 0.001%, that is between the range of 0.0005% and 0.0014%. The CAFC first recognized that both parties agreed that the term “0.001%,” being expressed using only a significant figure, would ordinarily encompass a range from 0.0005% to 0.0014%. However, citing Eon Corp. IP Holdings, the CAFC also noted that the “ordinary meaning of a claim term is not the ‘meaning of the term in the abstract’… Instead, ‘the ordinary meaning’ of a claim term is its meaning to the ordinary artisan after reading the entire patent.” Eon Corp. IP Holdings v. Silver Spring Networks, 815 F.3d 1314, 1320 (Fed. Cir. 2016). Therefore, the CAFC concluded that the proper lens through which to view a claim term is in view of the written description and prosecution history.

Turning first to the written description, the CAFC noted multiple instances where AstraZeneca touted the superiority of formulations with precise concentration of active ingredient at 0.001% , including multiple graphs showing the results of testing. Citing these instances, the CAFC concluded that “it [was] clear that the inventors understood that a formulation comprising 0.001% …[was] more stable than another formulation with even a slight difference in the concentration.”

The CAFC reasoned that their claim interpretation was also supported by the prosecution history. The court noted that the original version of claim 2 of the ‘328 patent recited a PVP concentration “from about 0.0005 to 0.05%w/w.” This claim was rejected by the Examiner as obvious over two prior art references. The inventors then amended the claims by deleting the PVP range limitation of claim 2 and amending claim 1 to recite a PVP concentration of “0.001% w/w.” The Examiner again rejected these claims, noting that the inventors failed to show the “criticality of the concentration of 0.001% w/w PVP. In response, the inventors argued that certain figures provided in the patent application showed the advantages of formulations specifically at 0.001%. Eventually, AstraZeneca was able to obtain a patent for concentration of exactly 0.001%. The CAFC concluded that the fact that AstraZeneca narrowed the claim construction during the prosecution history, along with the interpretation of the claim term in view of the written description, favored Mylan’s proposed claim construction. Accordingly, the CAFC vacated the stipulated judgment of infringement and remanded the case for the district court to find in the first instance if Mylan’s ANDA product infringes the asserted claims under the proper claim construction.

Obviousness

Turning to Mylan’s challenge of the district court’s nonobviousness determination, the CAFC, citing OSI Pharms., recognized that “obviousness is a question of law based on underlying findings of fact.” OSI Pharms., LLC v. Apotex Inc., 939 F.3d 1375, 1382 (Fed. Cir. 2019). On appeal, Mylan argued that several factual findings underlying the district court’s nonobviousness determination are “clearly erroneous,” including its finding that the prior art reference Rogueda taught away from the claimed invention.

Rogueda is a PCT application directed to “stable pharmaceutical aerosol formulations intended for inhalation.” Mylan argued that although Rogueda merely expressed a general preference for an alternative but did not teach away from the claimed invention. The CAFC rejected this argument, noting that although Rogueda does not explicitly disparage the claimed invention, the district court properly relied on expert testimony to reach their conclusion that a skilled artisan would interpret Rogueda as an implicit disparagement.

The CAFC found that Mylan’s remaining arguments amounted to requests to reweigh the evidence on appeal. Not finding a showing a of clear error, the CAFC declined to engage these requests. Therefore, the CAFC affirmed the district court’s judgment of no invalidity.

Judge Taranto’s Dissent

 Judge Taranto joined the majority opinion’s rejection of Mylan’s obviousness challenge but disagreed with the majority’s finding regarding the dispute over claim construction pertinent to the infringement judgment. In Taranto’s view, the term “0.001%” should be construed to have its significant figure meaning, that is, the interval 0.0005% to 0.0014%.

Taranto took issue with the argument’s that Mylan gave in support of its interpretation that the term “0.001%” meant that number with only “minor variations” as opposed to the more conventional significant figure range. As Judge Taranto noted, Mylan’s “minor variations” range argument was supported by two pieces of evidence. First, Mylan cited to the fact that the specification identified a concentration level of 0.0005% that the inventors tested separately from the level of 0.0001%. Additionally, Mylan noted that the significant figure interval of 0.001% overlaps with portions of the significant figure interval of 0.0005%.

The first issue that Judge Taranto identified with Mylan’s proposed “minor variations” construction is that, without more precision, this interpretation adds uncertainty compared to the claims ordinary meaning. Related to the imprecision issue, Judge Taranto noted that this interpretation effectively reinstated AstraZeneca’s ambiguous claim term “about,” which was originally found in claim one of the ‘328 patent but had been abandoned in favor of the more precise “0.001%.” Additionally, Judge Taranto noted the lack of support in the specification to support the notion that the term “minor variations” or a term of comparable meaning could be meant to supplant the ordinary meaning of significant figures. Judge Taranto recognized that Mylan attempted to supply more precision to the term “minor variations” by asserting that a “minor variation” means the significant figure interval that would exist if 0.001% were changed to 0.0010%, but the latter has two significant figures instead of one. Judge Taranto concluded that this should be rejected for violating the simplest of claim-construction principles because it would require an unsupported rewriting of the claim term.

Judge Taranto did not find merit in Mylan’s argument that overlap between the significant figures of 0.0005% and 0.001% implied no distinction between the two numbers. Judge Taranto agreed with the fact that AstraZeneca tested concentrations of 0.0005% and 0.001% and that these significant figures overlap, however, he disagreed that this supported the conclusion that there is no distinction between the two values. Additionally, Taranto noted that even if this overlap supported some limitation in the scope of the claim, it would only support limiting the claim to the extent 0.0005% and 0.001% overlap.