Fresenius Kabi SwissBioSim GmbH v. Regeneron Pharmaceuticals Inc

1. Case Identification

• Case #: IPR2025-01268
• Patent #: 11,084,865
• Filed: July 14, 2025
• Petitioner(s): Fresenius Kabi Swissbiosim GmbH
• Patent Owner(s): Regeneron Pharmaceuticals, Inc.
• Challenged Claims: 1-5, 7-30, 32-50

2. Patent Overview

• Title: VEGF Antagonist Formulations Suitable for Intravitreal Administration
• Brief Description: The ’865 patent discloses stable ophthalmic formulations of a vascular endothelial growth factor (VEGF) antagonist protein, specifically aflibercept, for treating ocular diseases. The claimed formulations comprise the protein, an organic co-solvent, a buffer, and a stabilizing agent, and are defined by specific stability properties (e.g., percent native conformation) after storage.

3. Grounds for Unpatentability

Ground 1: Anticipation of All Challenged Claims - Claims 1-5, 7-30, and 32-50 are anticipated by Dix under 35 U.S.C. §102.

• Prior Art Relied Upon: Dix (Patent 10,406,226).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Dix, which shares inventors with the ’865 patent but qualifies as prior art, expressly taught every element of the challenged claims. Independent claims 1 and 26 recite a vial or pre-filled syringe (PFS) containing a formulation with a specific VEGF antagonist (aflibercept), an organic co-solvent, a buffer, and a stabilizing agent, which maintains at least 98% native conformation after two months of storage at 5°C.
  • Petitioner asserted that Dix explicitly disclosed formulations containing aflibercept with the same classes of excipients claimed in the ’865 patent, including polysorbate 20 (co-solvent), phosphate buffer, and sucrose (stabilizer). Dix also expressly disclosed using both vials and PFS for administration.
  • Regarding the stability limitation (≥98% native conformation), Petitioner contended it was both expressly disclosed and an inherent property of the Dix formulation. Data in Dix (e.g., Table 9) allegedly showed over 99% native conformation after 24 months of storage under similar conditions, directly anticipating the claimed stability. Petitioner argued that merely reciting a previously unappreciated but inherent property of a prior art composition does not render it patentable.
  • For dependent claims reciting specific concentrations, such as 40 mg/mL aflibercept, Petitioner argued that Dix’s disclosure of a 10-50 mg/mL range anticipated the specific value. The core of this argument was that because 40 mg/mL falls within the prior art range, the claim is anticipated unless the patentee can demonstrate that this specific concentration is "critical" and yields unexpected results not found at other points in the range. Petitioner asserted that the Patent Owner failed to show any such criticality for 40 mg/mL and that this legal standard was emphasized by the Federal Circuit in a related litigation.
  • Petitioner systematically mapped limitations from all other dependent claims—including specific pH ranges, buffer concentrations, sucrose concentrations, and polysorbate concentrations—to express disclosures or overlapping ranges within Dix.

4. Key Claim Construction Positions

• Petitioner contended that the preamble phrase “suitable for intravitreal administration” is a non-limiting statement of intended use that adds no patentable weight to the composition claims.
• In the alternative, Petitioner argued that even if the phrase were limiting, Dix’s formulations met the limitation. Dix disclosed formulations with excipients that were well-known in marketed products for ocular delivery, and a person of ordinary skill in the art (POSA) would have recognized them as suitable for injection into the eye without needing further testing.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §314(a) or §325(d) would be inappropriate. Petitioner acknowledged that prior inter partes review (IPR) petitions challenging the ’865 patent had been denied institution on discretionary grounds.
• However, Petitioner distinguished this petition by asserting that it is the first to rely on the Dix ’226 reference as the basis for an anticipation challenge. Because the Board has not previously considered this specific reference and ground in an IPR, Petitioner argued that the prior denials are not controlling and that institution is warranted.

6. Relief Requested

• Petitioner requests institution of IPR and cancellation of claims 1-5, 7-30, and 32-50 of the ’865 patent as unpatentable.