The consequences of expressly recited claim limitations and how patentees can be held to these limitations was illustrated in the Federal Circuit's recent decision in Par Pharmaceutical, Inc. v. Eagle Pharmaceuticals, Inc.
The case arose in ANDA litigation over Eagle's application to market a generic version of Par's Vasostrict® product, an injectable form of vasopressin used to treat patients with critically low blood pressure. Par Orange Book-listed U.S. Patent Nos. 9,744,209 and 9,750,785, the '785 patent claiming vasopressin compositions and the '209 patent claiming methods for raising blood pressure using the claimed compositions. Relevant to the issues before the Court was a limitation in all asserted claims that the vasopressin compositions were to have a pH of between 3.65 and 3.94, rounded to 3.7 and 3.9. Eagle in its Paragraph IV assertions under 35 U.S.C. § 355(j)(2)(A)(vii)(IV) contended its product would not infringe because it had a pH of between 3.36-3.64 (round to 3.4-3.6) upon market release and throughout its shelf life, as well as allegations that the '209 and '785 patents were invalid. Par brought suit under 35 U.S.C. § 271(e)(2) and for a declaratory judgment of infringement under § 271(a) and (b).
At trial, Eagle stipulated that its product satisfied all limitations of the asserted claims except the pH of the claimed compositions, and Par argued that despite the difference in pH there were two "undisputed facts" that weighed in favor of a finding of infringement. The first was purportedly "real world" evidence that the pH of Eagle's product "drifts up" over time, and the second was that Eagle had sought approval to market compositions having a pH of 3.64, "just 0.01 beneath the infringing range." Par argued that these facts supported its argument that by a preponderance of the evidence ("more likely than not") Eagle's compositions would "inevitably drift into Par's claimed [pH] range" and thus infringe.
The District Court ruled against Par on this argument, finding the asserted facts "neither undisputed nor correct," particularly that the "drift" in pH values for Eagle's product did not have "any discernable trend" into the claimed range (calling them "minor fluctuations") nor that any such drift was "steady and inevitable." The District Court further found that while the release specification permitted Eagle's product to have a pH as high as 3.64, the stability specifications required the product to maintain a pH no higher than 3.6. The District Court held that Par had not established infringement under 35 U.S.C. §§ 271(a), 271(b), nor 271(e)(2), and this appeal followed.
The Federal Circuit affirmed, in an opinion by Chief Judge Moore joined by Judges Prost and Hughes. The basis for the Court's affirmance was the clear error standard for factual determinations by a district court that applies to appellate review under, for example, Allergan, Inc. v. Sandoz Inc., 796 F.3d 1293, 1303 (Fed. Cir. 2015), and Scanner Techs. Corp. v. ICOS Vision Sys. Corp. N.V., 528 F.3d 1365, 1374 (Fed. Cir. 2008). The same standard applies to questions of infringement, under Alzo Corp. v. Mylan Labs., Inc., 464 F.3d 1286, 1289 (Fed. Cir. 2006). Applying this standard, the Court made short work of Par's arguments. The opinion notes that an ANDA applicant is constrained upon approval to market its generic product "by strict statutory provisions to sell only those products that comport with the ANDA," and if the ANDA "defin[es] a proposed generic drug in a manner that directly addresses the issue of infringement, [it] control[s] the infringement inquiry," citing Abbott Labs. v. TorPharm, Inc., 300 F.3d 1367, 1373 (Fed. Cir. 2002). Thus, in ANDA litigation comparison between the claimed invention and the specifications of the proposed generic product "directly resolves the infringement question" according to the opinion, citing Ferring B.V. v. Watson Labs., Inc.-Fla., 764 F.3d 1401, 1409–10 (Fed. Cir. 2014). In this case, the infringement inquiry "begins and ends" with Eagle's ANDA specification, according to the Court. The opinion asserts that this specification mandates that the pH of the generic product remain outside the pH range claimed in the '785 and '209 patents upon release and throughout the shelf life of the product accused of infringement. To prevail, the opinion indicates that Par would have had to establish that Eagle would not remain bound by its product specification, an assertion the opinion characterizes as "unsupported conjecture" that is not sufficient to establish infringement under In re Brimonidine Patent Litig., 643 F.3d 1366, 1378 (Fed. Cir. 2011). Thus, Par failed to establish infringement under 35 U.S.C. § 271(e)(2) and the Federal Circuit affirmed the District Court's determination thereof.
Turning to Par's declaratory judgment cause of action under 35 U.S.C. §§ 271(a) and 271(b), the panel held that because the District Court did not commit clear error in deciding that Eagle's generic vasopressin product would not infringe, it was not an abuse of discretion to refuse to find in Par's favor on the declaratory judgment question because Par would only be entitled to a declaratory judgment of infringement if it had established that Eagle was "engaged in activity directed toward an infringing activity or is making meaningful preparation for such activity" and Par had not done so.
Accordingly the Federal Circuit affirmed the District Court's judgment and awarded costs to Eagle.
Par Pharmaceutical, Inc. v. Eagle Pharmaceuticals, Inc. (Fed. Cir. 2022)
Panel: Chief Judge Moore and Circuit Judges Prost and Hughes
Opinion by Chief Judge Moore