PTAB

IPR2025-01107

MSN Pharmaceuticals Inc v. Breckenridge Pharmaceutical Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Oral Pharmaceutical Compositions of Dabigatran Etexilate
  • Brief Description: The ’729 patent describes an oral pharmaceutical composition containing the thrombin inhibitor dabigatran etexilate. The composition uses a mixture of two distinct particle types: one containing the active drug, and a second containing a pharmaceutically acceptable organic acid with a protective coating to separate it from the drug until administration.

3. Grounds for Unpatentability

Ground 1: Obviousness over Brauns in view of Leane - Claims 1-18 are obvious over Brauns in view of Leane.

  • Prior Art Relied Upon: Brauns (Application # 2006/0183779) and Leane (Application # 2006/0115525).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Brauns disclosed all key components of the claimed invention, including dabigatran etexilate mesylate and tartaric acid, for improving bioavailability. Brauns taught spatially separating these components for stability within a single, multi-layered pellet (acid core, insulating layer, active layer). Petitioner asserted that Leane, which was not considered during prosecution, taught an alternative, well-known method for separating incompatible components: a two-particle system. Leane specifically disclosed compositions comprising drug particles mixed with separate, coated organic acid particles (agglomerates) to improve the dissolution of an acid-sensitive compound (chitosan). A POSITA would have found it obvious to apply Leane’s two-particle separation technique to Brauns’ components, resulting in a first particle type containing dabigatran etexilate (per Brauns) free from acid, and a second particle type containing tartaric acid (per Brauns) with a protective coating (per Leane).
    • Motivation to Combine: A POSITA would combine Brauns and Leane for two primary reasons. First, to design around the pending claims of Brauns, which focused on a single multi-layered pellet structure. Second, the multi-layered pellet in Brauns was known to be difficult to manufacture reliably, motivating a search for simpler, known alternatives. Leane provided such an alternative, teaching that using separate particles was a “convenient way” to deliver chemically incompatible substances, like the acid-sensitive dabigatran etexilate and tartaric acid.
    • Expectation of Success: Success was predictable because Leane demonstrated that a two-particle system with coated acid pellets successfully solved the same technical problem faced in Brauns: improving the dissolution of a pH-dependent substance while maintaining stability by separating it from an organic acid until administration. Applying this known formulation strategy to the components of Brauns would have been a straightforward implementation with a predictable outcome.
    • Key Aspects: Petitioner emphasized that Leane was not before the examiner during the original prosecution of the ’729 patent. The examiner’s previous rejection relied on a different reference (Habib), which the PTAB found unpersuasive because it taught inhibiting drug dissolution—the opposite goal of the ’729 patent. Leane, in contrast, directly addresses the same goal of enhancing dissolution.

Ground 2: Obviousness over Brauns in view of Sugimoto - Claims 1-18 are obvious over Brauns in view of Sugimoto.

  • Prior Art Relied Upon: Brauns (Application # 2006/0183779) and Sugimoto (Application # 2004/0109890).
  • Core Argument for this Ground:
    • Prior Art Mapping: The argument paralleled Ground 1, with Sugimoto providing the rationale for a two-particle system. Brauns again supplied the drug (dabigatran etexilate) and organic acid components and established the need for their separation. Sugimoto, also not cited during prosecution, taught orally disintegrating tablets for drugs with pH-dependent solubility. Sugimoto explicitly disclosed using a mixture of drug-containing granules and separate, coated organic acid-containing granules. The coating prevents premature contact, improving stability and taste, while enabling rapid dissolution in the digestive tract. Petitioner contended it would have been obvious to modify Brauns’ formulation by adopting Sugimoto’s two-particle approach, leading directly to the claimed composition.
    • Motivation to Combine: The motivations were identical to Ground 1: designing around Brauns’ specific layered-pellet claims and seeking a more robust and manufacturable formulation. Sugimoto taught a proven solution for the exact problem of formulating an acid-sensitive drug with an organic acid to enhance dissolution. A POSITA would combine Brauns and Sugimoto to achieve the known benefits of dabigatran stability and bioavailability using a well-established formulation platform.
    • Expectation of Success: A POSITA would have a high expectation of success because Sugimoto demonstrated that its two-granule system provided high bioavailability for a drug with pH-dependent solubility. The reference confirmed that this approach predictably achieved the desired outcome of enhancing dissolution while preventing premature interaction between the drug and acid. Applying this established method to the dabigatran composition of Brauns was a predictable path to a successful formulation.

4. Key Claim Construction Positions

  • “particles”: Petitioner argued this term should be construed as “any solid or semi-solid portions of a substance or a composition having defined physical boundaries, such as powder, granules, pellets, beads, and minitablets,” based on the patent’s explicit definition. This broad construction allows prior art disclosing granules or agglomerates (like Leane and Sugimoto) to meet the claim limitation.
  • “a protective coating layer”: Petitioner proposed construing this term as “a coating layer that prevents the organic acid from contacting dabigatran etexilate until after the composition is administered.” This construction was based on the specification’s definition and arguments made during prosecution, emphasizing the coating's function of preventing premature contact.

5. Arguments Regarding Discretionary Denial

  • Petitioner asserted that discretionary denial is unwarranted and stated its intent to use the PTAB’s bifurcated briefing process to rebut any such arguments if raised by the Patent Owner.

6. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-18 of the ’729 patent as unpatentable.