- Acumen Powered by Robins Kaplan LLP®
- Affirmative Recovery
- American Indian Law and Policy
- Antitrust and Trade Regulation
- Appellate Advocacy and Guidance
- Business Litigation
- Civil Rights and Police Misconduct
- Class Action Litigation
- Commercial/Project Finance and Real Estate
- Corporate Governance and Special Situations
- Corporate Restructuring and Bankruptcy
- Domestic and International Arbitration
- Entertainment and Media Litigation
- Health Care Litigation
- Insurance and Catastrophic Loss
- Intellectual Property and Technology Litigation
- Mass Tort Attorneys
- Medical Malpractice Attorneys
- Personal Injury Attorneys
- Telecommunications Litigation and Arbitration
- Wealth Planning, Administration, and Fiduciary Disputes
Acumen Powered by Robins Kaplan LLP®
Ediscovery, Applied Science and Economics, and Litigation Support Solutions
-
September 10, 2024Robins Kaplan Ranks Among Top Firms In 2024 American Lawyer Mid-Level Associates Survey
-
September 9, 2024Federal Judge Orders Transformative Reforms at West LA VA Campus in Major Victory for Disabled Veterans
-
September 9, 2024Robins Kaplan Partners Named to 2025 Lawdragon 500 Leading Litigators in America Guide
-
September 27, 2024Minnesota’s Largest Patent Jury Verdict: The Inside Story
-
October 9, 2024Perception vs. Reality in Trust and Estate Matters:
-
October 20, 2024License Agreement Disputes:
-
September 2024Q&A with Alan Harter, Founder of Pactolus Private Wealth Management
-
August 2024Recruiting & Retaining Diverse Attorneys: Building an Inclusive Legal Profession
-
August 22, 2024Prior Art Takeaways From Fed. Circ. Public Disclosure Ruling
-
September 16, 2022Uber Company Systems Compromised by Widespread Cyber Hack
-
September 15, 2022US Averts Rail Workers Strike With Last-Minute Tentative Deal
-
September 14, 2022Hotter-Than-Expected August Inflation Prompts Massive Wall Street Selloff
Find additional firm contact information for press inquiries.
Find resources to help navigate legal and business complexities.
Silvergate Pharms. Inc. v. Bionpharma Inc.
Epaned® (enalapril maleate)
April 29, 2021
Case Name: Silvergate Pharms. Inc. v. Bionpharma Inc., No. 18-1962-LPS, 19-1067-LPS, 2021 WL 1751148 (D. Del. Apr. 29, 2021) (Stark, J.)
Drug Product and Patent(s)-in-Suit: Epaned® (enalapril maleate); U.S. Patents Nos. 10,039,745 (“the ’745 patent”) and 10,153,987 (“the ’987 patent”)
Nature of Case and Issue(s) Presented: The patents-in-suit claimed enalapril formulations for the FDA-approved medication Epaned, which was an angiotensin converting enzyme (“ACE”) inhibitor used to treat hypertension and other cardiovascular conditions. After Bionpharma filed its ANDA seeking to make and sell a generic version of Epaned, Silvergate sued, alleging infringement of the patents-in-suit by the ANDA product under the doctrine of equivalents. Following a five-day bench trial, the court found that Bionpharma’s generic product did not infringe, on the basis of prosecution-history estoppel and the disclosure-dedication doctrine.
Why Bionpharma Prevailed: Two claim limitations were central to the issue of infringement under the doctrine of equivalents: the buffer limitation and preservative limitation. The buffer limitation required the presence of “a buffer comprising about 0.8 to about 3.5 mg/ml of citric acid and about 0.1 to about 0.8 mg/ml sodium citrate.” The ANDA product contained no citric acid and no sodium citrate. Silvergate argued that certain compounds in the generic product were equivalent to the claimed buffer, but this argument was rejected by the court. It found that under amendment-based prosecution-history estoppel, Silvergate was precluded from arguing that Bionpharma’s generic product infringed under the doctrine of equivalents. Specifically, the court found that during patent prosecution, Silvergate amended its claims in response to an obviousness rejection to include the limitation of “0.1 to about 0.8 mg/ml sodium citrate” and made clear to the Examiner that it was the specific concentrations of citric acid and sodium citrate that distinguished its invention from the prior art. As a narrowing amendment was presumed to be a surrender of all equivalents within the territory between the original claim and the amended claim, the court sided with Bionpharma’s argument that Silvergate sought to exclude formulations that did not contain sodium citrate at the requisite concentration, which included Bionpharma’s generic product. Armed with that finding, the court held that Silvergate failed to prove, by a preponderance of the evidence, that Bionpharma’s product contained a buffer equivalent to the claimed buffer.
The preservative limitation required “about 0.7 to about 1.2 mg/mL sodium benzoate.” Agains, Bionpharma’s generic product did not contain sodium benzoate. But Silvergate argued that it infringed under the doctrine of equivalents. The court rejected Silvergate’s argument in view of the disclosure-dedication doctrine, which foreclosed infringement theories concerning equivalents that are described in the patent specification but not claimed. The court found that Silvergate dedicated the embodiment in Bionpharma’s generic product to the public, and moreover, that a POSA could identify from the patent disclosure the alleged equivalent’s existence and suitability as an alternative to the claim sodium benzoate.
Related Publications
Related News
If you are interested in having us represent you, you should call us so we can determine whether the matter is one for which we are willing or able to accept professional responsibility. We will not make this determination by e-mail communication. The telephone numbers and addresses for our offices are listed on this page. We reserve the right to decline any representation. We may be required to decline representation if it would create a conflict of interest with our other clients.
By accepting these terms, you are confirming that you have read and understood this important notice.