DR Falk Pharma GmbH v. Ellodi Pharmaceuticals LP

1. Case Identification

• Case #: PGR2025-00086
• Patent #: 12,290,598
• Filed: September 19, 2025
• Petitioner(s): Dr. Falk Pharma GmbH
• Patent Owner(s): Ellodi Pharmaceuticals, L.P.
• Challenged Claims: 1-34

2. Patent Overview

• Title: Orally administered corticosteroid compositions
• Brief Description: The ’598 patent relates to orally disintegrating tablets (ODTs) containing a corticosteroid, such as budesonide or fluticasone propionate, for treating eosinophilic esophagitis. The claims require the tablet to disintegrate within 60 seconds, deposit the drug topically in the esophagus, and possess a specific hardness of 4-48 N or a friability of not more than 1%.

3. Grounds for Unpatentability

Ground 1: Lack of Written Description - Claims 1-34 are unpatentable under 35 U.S.C. §112(a).

• Prior Art Relied Upon: Not applicable.
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the claimed hardness range of "4-48 N" lacks written description support in the specification from which the ’598 patent issued. The limitation was added during prosecution, but the application’s only disclosure of hardness is a range of 8-48 N. The specification provides no teaching or example of a tablet with a hardness in the lower portion of the claimed range (i.e., 4-7 N).
  • Key Aspects: Because the inventors did not possess the full scope of the claimed invention at the time of filing, Petitioner contended the ’598 patent is not entitled to its claimed priority date. This renders the patent’s effective filing date January 5, 2022, making several intervening publications, including the Patent Owner’s own earlier patents, available as prior art.

Ground 2: Anticipation by Perrett - Claims 1-34 are anticipated by Perrett under 35 U.S.C. §102.

• Prior Art Relied Upon: Perrett (Patent 8,771,729).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Perrett, an earlier patent in the ’598 patent's purported priority chain, qualifies as prior art due to the ’598 patent’s defective priority claim. Perrett allegedly discloses every limitation of claim 1, including an ODT containing 4 mg of fluticasone propionate (satisfying the "about 0.5 mg to 6 mg" limitation), crospovidone as a disintegrant, and its use for topical administration to the esophagus. Critically, Perrett’s Example 1 discloses an ODT with a hardness of 8-48 N and friability of not more than 1%, which falls squarely within the ranges recited in claim 1. Petitioner mapped Perrett's disclosures to all dependent claims as well.

Ground 3: Obviousness over Dohil Combination - Claims 1-4, 9, 13-14, 18-20, 22-25, and 31-32 are obvious over Dohil in view of Kararli, the FDA Guidance, and the USP.

• Prior Art Relied Upon: Dohil (Application # 2007/0111978), Kararli (WO 2002/015884), the FDA Guidance (2008), and the United States Pharmacopeia (USP).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that Dohil taught a rapidly dissolving budesonide tablet or lozenge for topical coating of the esophagus, disclosing dosages within the claimed range. However, Dohil did not explicitly teach the specific hardness, friability, or USP disintegration test limitations. Kararli taught rapidly disintegrating tablets for treating the esophagus that preferably have a hardness of 9.8-49.1 N to ensure sufficient mechanical strength for handling and packaging. The FDA Guidance and the USP provided the industry-standard framework, recommending ODTs disintegrate in 30 seconds or less under USP <701> and have a friability of not more than 1.0%.
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine the teachings to improve Dohil's therapeutic tablet with the well-known and desirable structural and performance characteristics of a modern ODT. A POSITA would look to authoritative sources like the USP and FDA Guidance for standard disintegration parameters and to references like Kararli for achieving the necessary hardness to make a commercially viable product that could withstand packaging and transport.
  • Expectation of Success: The art of formulating ODTs was well-developed and predictable. Combining these known elements—a therapeutic agent (Dohil), standard ODT performance metrics (FDA Guidance, USP), and necessary mechanical properties (Kararli)—was a routine design choice with a high expectation of success.

• Additional Grounds: Petitioner asserted §112 grounds for lack of enablement and indefiniteness related to the hardness range. Petitioner also asserted additional obviousness challenges, including combinations based on Grother (WO 2000/044351) and further combinations adding Venkatesh988 (Application # 2005/0232988) or Venkatesh516 (WO 2009/006516) to teach specific particle sizes and friability targets, but relied on similar design modification theories.

4. Key Technical Contentions (Beyond Claim Construction)

• Indefiniteness of "Hardness": Petitioner contended that the term "hardness" renders the claims indefinite under §112(b). The prior art described numerous different methods and types of equipment for measuring tablet hardness (e.g., Monsanto, Strong-Cobb, Pfizer, Schleuniger), which produce significantly different and non-interchangeable results. Because the ’598 patent specification fails to specify which method to use, a POSITA could not determine the boundaries of the claimed "4-48 N" range with reasonable certainty. This ambiguity also formed the basis of an enablement challenge, arguing a POSITA could not be enabled to make and use the full scope of the invention without knowing how to measure its defining characteristic.

5. Relief Requested

• Petitioner requests institution of Post Grant Review and cancellation of claims 1-34 of Patent 12,290,598 as unpatentable.