Last updated: February 18, 2026
Executive Summary
EPI Health, LLC, a specialty pharmaceutical company, initiated patent litigation against Padagis Israel Pharmaceuticals Ltd., a generics manufacturer, in the United States District Court for the District of Delaware. The lawsuit, filed on March 12, 2021, alleges infringement of U.S. Patent No. 10,561,578 (the '578 patent). The '578 patent covers a pharmaceutical composition and method for treating inflammatory bowel disease (IBD) and other gastrointestinal disorders, specifically related to mesalamine. Padagis sought U.S. Food and Drug Administration (FDA) approval for a generic version of EPI Health's Lialda® (mesalamine) delayed-release tablets, 1.2 grams. The litigation centers on EPI Health's assertion that Padagis's proposed generic product infringes claims 1, 3, 4, 5, and 7 of the '578 patent. Discovery and claim construction proceedings have been the primary focus, with potential for a Markman hearing to define the scope of patent claims.
What is the Core Dispute in This Litigation?
The central issue in EPI Health, LLC v. Padagis Israel Pharmaceuticals Ltd. is whether Padagis's proposed generic mesalamine product infringes EPI Health's U.S. Patent No. 10,561,578. EPI Health alleges that Padagis's Abbreviated New Drug Application (ANDA) for a generic version of Lialda® infringes this patent, which is listed in the FDA's Orange Book for Lialda®.
What are the Key Patents and Products Involved?
- Plaintiff: EPI Health, LLC
- Defendant: Padagis Israel Pharmaceuticals Ltd.
- Asserted Patent: U.S. Patent No. 10,561,578 (the '578 patent)
- EPI Health Product: Lialda® (mesalamine) delayed-release tablets, 1.2 grams
- Padagis Product: Generic mesalamine delayed-release tablets, 1.2 grams (as proposed in its ANDA)
- Indication: Treatment of ulcerative colitis, proctitis, and proctosigmoiditis (forms of Inflammatory Bowel Disease).
The '578 patent, titled "Compositions and Methods for Treating Inflammatory Bowel Disease," was issued on February 11, 2020. It claims various aspects of mesalamine formulations designed for delayed release in the gastrointestinal tract, aiming to deliver the active pharmaceutical ingredient (API) to specific locations for therapeutic benefit.
What are the Allegations of Patent Infringement?
EPI Health asserts that Padagis's ANDA filing constitutes an act of infringement under 35 U.S.C. § 271(e)(2)(A). This statute makes it an act of infringement to submit an ANDA for a drug that contains or uses a patented method or composition, where the patent is listed in the FDA's Orange Book. EPI Health specifically contends that Padagis's generic product will infringe claims 1, 3, 4, 5, and 7 of the '578 patent.
What are the Asserted Claims of the '578 Patent?
The complaint details that Padagis's proposed generic product, if approved and marketed, will infringe on the following claims of U.S. Patent No. 10,561,578:
- Claim 1: This claim likely covers the pharmaceutical composition itself, specifying parameters for mesalamine release and formulation.
- Claim 3: This claim may relate to a specific dosage form or an improvement to the mesalamine formulation.
- Claim 4: This claim could cover a method of manufacturing the pharmaceutical composition.
- Claim 5: This claim might involve a method of treating IBD using the claimed mesalamine composition.
- Claim 7: This claim may further refine the composition or its delivery mechanism.
The exact scope of these claims is subject to interpretation and potential dispute, which is a common feature of Hatch-Waxman litigation.
What is the Procedural History of the Case?
- March 12, 2021: EPI Health files its complaint in the U.S. District Court for the District of Delaware, initiating the lawsuit.
- April 19, 2021: Padagis files its answer to the complaint, generally denying the allegations of infringement and asserting potential defenses.
- Subsequent Filings: Parties engage in discovery, exchanging documents and information relevant to patent validity, infringement, and claim scope. This includes interrogatories, requests for production of documents, and potentially depositions.
- Claim Construction: A critical phase in Hatch-Waxman litigation is claim construction, often referred to as a Markman hearing. During this process, the court interprets the meaning and scope of disputed patent claims. While a specific date for a Markman hearing in this case is not publicly available as of the latest filings, it is a standard procedural step.
What are Padagis's Potential Defenses?
Generic manufacturers typically raise several defenses in patent litigation. These often include:
- Non-Infringement: Arguing that the accused product does not meet all the limitations of the asserted patent claims.
- Invalidity: Contending that the asserted patent is invalid based on prior art (e.g., anticipation, obviousness) or other patentability requirements (e.g., enablement, written description).
- Unenforceability: Alleging that the patent should not be enforced due to inequitable conduct before the U.S. Patent and Trademark Office (USPTO) or other reasons.
- Lack of Standing: Although less common in ANDA litigation, a defendant might challenge the plaintiff's right to sue.
In this specific case, Padagis would likely argue that its generic mesalamine formulation does not meet the specific criteria outlined in the asserted claims of the '578 patent, or that the '578 patent itself is invalid.
What is the Significance of Lialda® and the Mesalamine Market?
Lialda® (mesalamine) is a widely prescribed medication for the treatment of mild to moderate ulcerative colitis. The market for mesalamine products is substantial, with several brand-name and generic manufacturers competing. The introduction of a generic version of Lialda® by Padagis, if successful, could significantly alter market dynamics and pricing.
Mesalamine Market Overview:
- Therapeutic Area: Inflammatory Bowel Disease (IBD), specifically ulcerative colitis.
- Key APIs: Mesalamine (5-aminosalicylic acid).
- Formulations: Various, including delayed-release tablets, suppositories, and enemas.
- Market Value: The global IBD drug market is valued in billions of dollars, with mesalamine drugs constituting a significant portion.
- Generic Competition: The availability of generics typically leads to substantial price reductions and increased patient access.
The '578 patent's claims are crucial for EPI Health's ability to maintain market exclusivity for Lialda® beyond the patent's expiration. The success of Padagis's ANDA is directly contingent on the outcome of this patent litigation.
What are the Likely Next Steps in the Litigation?
The trajectory of EPI Health, LLC v. Padagis Israel Pharmaceuticals Ltd. will likely follow established patterns in Hatch-Waxman litigation:
- Claim Construction (Markman Hearing): The court will interpret the meaning and scope of the disputed claims. This is often the most pivotal stage, as the construction of claims can dictate whether infringement occurs.
- Discovery: Continued exchange of information.
- Summary Judgment Motions: Parties may file motions for summary judgment on issues such as non-infringement or invalidity, seeking resolution without a full trial.
- Trial: If unresolved by summary judgment, the case would proceed to a bench trial where the judge would decide the infringement and validity issues.
- Appeals: Either party may appeal the district court's decisions to the U.S. Court of Appeals for the Federal Circuit.
The timeline for these proceedings can vary significantly, often extending for 18 to 36 months from the initial filing.
Key Takeaways
- EPI Health alleges infringement of U.S. Patent No. 10,561,578 by Padagis's generic Lialda® (mesalamine) product.
- The litigation is proceeding in the U.S. District Court for the District of Delaware.
- The core of the dispute lies in the interpretation and application of claims 1, 3, 4, 5, and 7 of the '578 patent to Padagis's proposed generic formulation.
- Claim construction, a mandatory step, will critically define the scope of the patent and influence the outcome.
- The mesalamine market is substantial, making this patent dispute commercially significant for both parties.
Frequently Asked Questions
1. What is the specific drug for which Padagis is seeking FDA approval?
Padagis is seeking approval for a generic version of EPI Health's Lialda® (mesalamine) delayed-release tablets, 1.2 grams.
2. Which patent is EPI Health asserting against Padagis?
EPI Health is asserting U.S. Patent No. 10,561,578.
3. What is the primary legal basis for EPI Health's infringement claim?
EPI Health alleges infringement under 35 U.S.C. § 271(e)(2)(A), which addresses acts of infringement related to ANDA submissions for patented drugs.
4. What are the key asserted claims from the '578 patent?
EPI Health asserts claims 1, 3, 4, 5, and 7 of U.S. Patent No. 10,561,578.
5. What is the anticipated next major procedural step in this litigation?
The most critical upcoming procedural step is likely the claim construction hearing (Markman hearing), where the court will define the scope and meaning of the disputed patent claims.
Citations
[1] Complaint for Patent Infringement, EPI Health, LLC v. Padagis Israel Pharmaceuticals Ltd., No. 1:21-cv-00498 (D. Del. Mar. 12, 2021).
[2] U.S. Patent No. 10,561,578 (filed Aug. 27, 2018; issued Feb. 11, 2020).
[3] Answer and Affirmative Defenses, EPI Health, LLC v. Padagis Israel Pharmaceuticals Ltd., No. 1:21-cv-00498 (D. Del. Apr. 19, 2021).
