Epaned® (enalapril maleate)
Case Name: Silvergate Pharms., Inc. v. Bionpharma Inc., Civ. Nos. 18-cv-1962, 19-cv-1067, 2024 WL 4417104 (D. Del. Oct. 4, 2024) (Goldberg, J.)
Drug Product and Patent(s)-in-Suit: Epaned® (enalapril maleate); U.S. Patents Nos. 9,669,008 (“the ’008 patent”), 9,808,442 (“the ’442 patent”), 10,039,745 (“the ’745 patent”), and 10,154,987 (“the ’987 patent”)
Nature of the Case and Issue(s) Presented: Epaned is approved by the FDA for treating high blood pressure and other conditions. The active ingredient in Epaned was initially approved by the FDA in a tablet form in 1985, and Azurity, formerly known as Silvergate, created the liquid form Epaned® because children and elderly patients had difficulty swallowing tablets. Bionpharma submitted an ANDA seeking FDA approval to make and sell generic enalapril. In its Paragraph IV certification and throughout litigation, Bionpharma maintained that it would not infringe Azurity’s patents because its product did not contain: (i) the “buffer” limitation; and (2) the “preservative” limitation. In response, Azurity relied on the doctrine of equivalents (“DOE”). “Specifically, Azurity asserted that the enalapril maleate (active ingredient) in Bionpharma’s ANDA product would split apart to yield a buffer made from maleic acid, which would be equivalent to the buffer in the claim. Azurity also argued that a mixture of methylparaben and propylparaben in Bionpharma’s ANDA satisfied the preservative limitation.”
During the litigation, Bionpharma sought leave to file a dispositive motion. The district court judge denied Bionpharma leave to file its motion, stating that there remained fact disputes that would greatly benefit from expert assistance at trial. The court then presided over a five-day bench trial and ultimately entered judgment in favor of Bionpharma, finding that Azurity had not proved by a preponderance of the evidence that Bionpharma’s ANDA infringed any of Azurity’s asserted claims. Azurity appealed and the Federal Circuit affirmed.
Bionpharma moved for attorneys’ fees arguing that Azurity pursued its litigation “for an improper purpose, made arguments that were objectively baseless, and litigated this case in an unreasonable manner.” The court denied Bionpharma’s motion.
Why Azurity Prevailed: Bionpharma now argues it was exceptionally meritless for Azurity to rely on a clearly narrowing amendment to try to avoid amendment-based estoppel. The court was not convinced. Azurity did concede its amendment was narrowing for purposes of Bionpharma’s motion for leave to file a dispositive motion. Additionally, “even with the amendment being narrowing, Azurity could still potentially have succeeded in avoiding the effect of amendment-based estoppel had it prevailed on its theory that adding sodium citrate was tangential to the choice of acid—citric or maleic.”
Alternatively, Bionpharma argued that Azurity’s infringement position was exceptional because Azurity could not overcome argument-based estoppel. Put another way, the statements Azurity made in patent prosecution estopped it from claiming ownership of formulations that included ingredients not listed in Azurity’s—and Bionpharma’s accused product’s—claims. The court concluded that Azurity’s response to the argument-based estoppel argument did not warrant the imposition of fees. The standard for argument-based estoppel is high and while Azurity’s arguments were ultimately unpersuasive, they were not so exceptional as to make a fee award appropriate.
Next, Bionpharma argued that Azurity failed to conduct a pre-suit investigation and brought the case without a basis for believing the product was infringing because Azurity declined to review Bionpharma’s ANDA. But the court found that the confidentiality terms Azurity rejected pre-litigation and those it later accepted were different such that an award of attorneys’ fees was not justified. Also, before filing suit, Azurity had a limited time to review the potential merits.
Bionpharma also argued that Azurity filed its lawsuit without a good-faith belief in the merits of its case. Rather, the court found that while Azurity did change its position on the equivalent buffer, it was not convinced that Azurity’s conduct demonstrated unreasonable conduct that warrants attorneys’ fees. “While Azurity proposed several different ingredients as the possible buffer, those theories had a common theme: some ingredient in Bionpharma’s ANDA product such as maleate, enalapril, or the parabens had natural buffering capacity that obviated the need for a separately added buffer.”
Bionpharma also asserted that Azurity brought the lawsuit not on the merits but only to obtain the automatic 30-month stay. Specifically, Bionpharma argued that Azurity’s infringement position was so tenuous that the only benefit Azurity could have derived from the case was triggering the 30-month stay. The court was not persuaded. “While Azurity likely did benefit from the automatic stay, the mere assertion of that ‘statutory patent right’ based on a ‘reasonable belief in infringement would not, without more, render this case exceptional.”
Finally, the court also discounted Bionpharma’s argument that Azurity engaged in discovery misconduct.
