JSR Corp v. Cytiva BioProcess R&D Ab

1. Case Identification

• Case #: IPR2022-00044
• Patent #: 10,343,142
• Filed: October 12, 2021
• Petitioner(s): JSR Corporation and JSR Life Sciences, LLC
• Patent Owner(s): Cytiva Bioprocess R&D AB
• Challenged Claims: 1-7, 10-20, and 23-30

2. Patent Overview

• Title: Process for Isolating a Target Compound
• Brief Description: The ’142 patent is directed to a process for isolating target compounds, such as antibodies, using an affinity chromatography matrix. The process utilizes a ligand based on the C domain of Staphylococcal protein A (SPA) engineered with a specific G29A mutation (glycine at position 29 replaced by alanine) to improve stability in alkaline conditions.

3. Grounds for Unpatentability

Ground 1: Claims 1-7, 10-20, and 23-30 are obvious over Berg in view of Linhult

• Prior Art Relied Upon: Berg (Application # 2006/0134805) and Linhult (a 2004 peer-reviewed journal article).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Berg taught all fundamental elements of the claimed process, including using an SPA-based affinity chromatography matrix with ligands preferably based on SPA's C domain for purifying antibodies. Berg, however, did not explicitly disclose the G29A mutation. Petitioner asserted that Linhult supplied this element by identifying the asparagine-glycine sequence (at positions 28-29) as the "most sensitive amino acid sequence to alkaline conditions" and teaching that exchanging glycine 29 for alanine (a G29A mutation) was a known method to "avoid" this alkali-sensitive combination and improve stability.
  • Motivation to Combine: A POSITA would combine Berg and Linhult to improve the alkali-stability of the chromatography matrix described in Berg. This modification would address the well-known need for more robust and reusable matrices capable of withstanding repeated "cleaning-in-place" (CIP) procedures with alkaline solutions like NaOH.
  • Expectation of Success: A POSITA would have a reasonable expectation of success because Linhult presented the G29A mutation as a known solution to the known problem of alkali sensitivity in SPA domains. Applying this solution to Berg's C domain-based matrix was argued to be a predictable improvement.

Ground 2: Claims 1-2, 5-7, 10-15, 18-20, and 23-26 are obvious over Berg in view of Abrahmsén

• Prior Art Relied Upon: Berg (Application # 2006/0134805) and Abrahmsén (Patent 5,143,844).

• Core Argument for this Ground:

  • Prior Art Mapping: Similar to the first ground, Petitioner contended that Berg taught the foundational chromatography process. Abrahmsén, a patent with a 1985 priority date, was argued to provide an even more direct teaching of the claimed mutation. Abrahmsén explicitly disclosed creating a recombinant DNA fragment coding for "any of the E D A B C domains of [SPA]," wherein the glycine codon at the position corresponding to 29 is replaced by an alanine codon.
  • Motivation to Combine: The motivation was to improve the alkali-stability of the SPA-based matrix in Berg by incorporating the known stability-enhancing mutation from Abrahmsén. Petitioner noted that Berg itself acknowledged the applicability of Abrahmsén in the context of creating mutated SPA domains.
  • Expectation of Success: Abrahmsén allegedly confirmed a high expectation of success by stating that computer simulations concluded the G29A change "would not interfere with folding [of SPA] or binding to [antibodies]." This directly addressed potential concerns about the mutation's effect on the ligand's primary function.

• Additional Grounds: Petitioner asserted additional obviousness challenges based on combinations that also included Hober (WO 03/080655). Hober was used to teach specific dependent claim limitations, such as retaining at least 95% binding capacity after alkaline exposure (claims 3 and 16) and using linker segments to couple polypeptide monomers (claims 2 and 15).

4. Key Claim Construction Positions

• Petitioner asserted that no terms required formal construction but proceeded based on the Patent Owner's implicit construction in related litigation for the term "the ligand comprising at least two polypeptides."
• This term was interpreted to mean a multimeric ligand (e.g., a dimer or tetramer) comprised of multiple polypeptide monomers. Petitioner argued this construction was consistent with the prior art's disclosure of multimeric SPA ligands.

5. Key Technical Contentions (Beyond Claim Construction)

• Inherency of Alkali Stability: Petitioner contended that the limitation in claims 3 and 16 (retaining at least 95% of binding capacity after 5 hours in 0.5 M NaOH) was an inherent property of the proposed obvious combination. This argument relied on data in the ’142 patent itself, which allegedly showed that the unmodified, wild-type C domain already possessed the claimed stability, meaning the property would necessarily be present in the slightly modified version.
• Inherency of Fab Binding: Petitioner similarly argued the capability of the ligand to bind to the Fab part of an antibody (claims 4 and 17) was also inherent or, alternatively, rendered obvious. This was based on prior art (Linhult) allegedly teaching that all SPA domains, including the C domain, show affinity for Fab fragments.

6. Arguments Regarding Discretionary Denial

• §314(a) / Fintiv: Petitioner argued against discretionary denial under Fintiv, stating that the parallel district court case was in its early stages, with a trial date more than two years after the petition's filing. Petitioner noted its intent to seek a stay upon institution and that its invalidity contentions had not yet been served in the litigation, minimizing any potential overlap.
• §325(d): Petitioner argued denial under §325(d) was inappropriate because the core prior art references, Linhult and Abrahmsén, were never considered during the prosecution of the ’142 patent. While Hober was cited in an Information Disclosure Statement, it was never substantively analyzed or used as the basis for a rejection, and the specific obviousness combinations and arguments presented in the petition were new.

7. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-7, 10-20, and 23-30 of the ’142 patent as unpatentable.