JSR Corp v. Cytiva Bioprocess: Federal Circuit Affirms-in-Part on Protein A Chromatography Patents
JSR Corporation and JSR Life Sciences appealed PTAB inter partes review decisions challenging three patents covering protein A chromatography ligands used in antibody isolation. The Federal Circuit affirmed unpatentability for the majority of claims but reversed on four specific claims across two patents — a split outcome spanning 483 days of appellate proceedings.
Federal Circuit splits outcome on JSR’s protein A ligand patent portfolio
JSR Corporation and its affiliate JSR Life Sciences, LLC brought this appeal before the Court of Appeals for the Federal Circuit (Case No. 23-2253), challenging PTAB inter partes review determinations that found the majority of claims across three patents — US10875007, US10343142, and US10213765 — to be unpatentable. The patents collectively protect domain C variants of Staphylococcus aureus protein A used as chromatography ligands for antibody purification, a critical step in biopharmaceutical manufacturing. The defendant and IPR petitioner, Cytiva Bioprocess R&D AB, is a major supplier of bioprocess chromatography technology.
The Federal Circuit issued an affirmed-in-part and reversed-in-part decision on 4 December 2024. For the vast majority of challenged claims — including claims 1–7, 10–20, 23–26 of the ‘765 patent, claims 1–3, 5–7, 10–16, 18–20, 23–30 of the ‘142 patent, and claims 1–10, 12–14, 16–28, 30–32, and 34–37 of the ‘007 patent — the court upheld PTAB’s unpatentability findings. However, it reversed PTAB’s determination on claims 4 and 17 of the ‘142 patent and claims 11 and 29 of the ‘007 patent, finding those claims not unpatentable.
The 483-day appellate timeline is broadly in line with Federal Circuit norms for IPR appeals. The partial reversal suggests JSR identified genuine legal error in PTAB’s analysis for a discrete subset of claims, though the commercial scope of the surviving claims relative to Cytiva’s products remains unclear from the public record. The basis of termination records the appeal as dismissed in part, consistent with the mixed affirmed/reversed disposition. What drove the board’s error on the four reversed claims — whether claim construction, obviousness analysis, or prior art scope — is not detailed in publicly available records.
Filing to Appeal Dismissed in Part in 483 days
483 days from filing to decision — consistent with Federal Circuit IPR appeal timelines of 12–18 months
Federal Circuit affirms-in-part, reverses-in-part: what the split ruling means
What affirmed-in-part and reversed-in-part means at the Federal Circuit
When the Federal Circuit issues an affirmed-in-part and reversed-in-part ruling on a PTAB IPR appeal, it means the court found no reversible error in the board’s unpatentability determinations for most claims, but identified legal error in the board’s analysis of a discrete set of claims. The four reversed claims — 4 and 17 of the ‘142 patent and 11 and 29 of the ‘007 patent — are restored as patentable unless further challenge succeeds.
Partial appellate reversalJSR preserves four claims — but loses the bulk of its challenged portfolio
JSR and JSR Life Sciences secured a meaningful but limited win. The Federal Circuit’s reversal on four claims means those claims survive and remain enforceable against Cytiva and potentially other competitors. However, the affirmance of unpatentability across the large majority of claims across all three patents substantially narrows JSR’s protein A chromatography IP position. Commercial enforceability now turns on how broadly the four surviving claims read on Cytiva’s and third-party products.
Four claims survive IPRCytiva achieves broad clearance but faces residual claim exposure
Cytiva Bioprocess R&D AB largely succeeded: PTAB’s unpatentability rulings across the overwhelming majority of JSR’s claims were affirmed, providing strong freedom to operate across the protein A chromatography ligand space. However, the reversal on four specific claims means Cytiva retains exposure on those claims and cannot treat the patents as fully cleared. Further IPR petitions or design-around strategies may be necessary to address the surviving claims.
Residual exposure on 4 claimsProtein A chromatography IP landscape: strengthened selectively, not broadly
The decision confirms that most of JSR’s broad protein A ligand claims will not block competitors in the antibody purification market. For biopharmaceutical manufacturers and chromatography resin suppliers, this outcome suggests wider freedom to operate around domain C protein A ligand designs. The four surviving claims, however, signal that JSR retains a residual IP position that competitors and licensees should monitor, and any future product development in this space warrants targeted claim mapping against those claims.
Narrowed but live IP positionFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | JSR Corporation | Company | Bioscience materials company — holder of US10875007, US10343142, and US10213765Search in Eureka ↗ |
| Co-Plaintiff | Jsr Life Sciences, LLC | Company | Search in Eureka ↗ |
| Defendant | Cytiva Bioprocess R & D, AB | Individual | Cytiva Bioprocess R&D AB — bioprocess chromatography supplier and IPR petitionerSearch in Eureka ↗ |
| Plaintiff counsel | Naveen Modi | Attorney | Counsel for JSR CorporationSearch in Eureka ↗ |
| Plaintiff law firm | Paul Hastings, LLP | Law Firm | Representing JSR CorporationSearch in Eureka ↗ |
| Defendant counsel | David M. Krinsky | Attorney | Counsel for Cytiva Bioprocess R & D, ABSearch in Eureka ↗ |
| Defendant law firm | Williams & Connolly LLP | Law Firm | Representing Cytiva Bioprocess R & D, ABSearch in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The Federal Circuit’s affirmed-in-part and reversed-in-part disposition reflects a nuanced application of the substantial evidence standard of review applicable to PTAB factual findings, combined with de novo review of legal conclusions such as claim construction. The court’s affirmance of unpatentability for the large majority of claims signals that the prior art record before the board was sufficient to sustain those cancellations. The reversal on claims 4 and 17 of the ‘142 patent and claims 11 and 29 of the ‘007 patent suggests PTAB committed legal or factual error in its analysis of those specific claims — potentially in the way it applied prior art or construed claim terms. The four surviving claims now carry enforceable weight.
US10875007, US10343142, US10213765 — Protein A chromatography ligands
The three patents — US10875007B2, US10343142B2, and US10213765B2 — cover engineered variants of domain C from Staphylococcus aureus protein A, configured as affinity chromatography ligands for the isolation and purification of antibodies. Protein A affinity chromatography is the dominant platform technology for monoclonal antibody purification in biopharmaceutical manufacturing. The patents were filed via applications US16/443600, US16/189894, and US15/603285 respectively, suggesting a continuation family strategy building on a common technical foundation.
These patents sit at the commercial heart of the bioprocess chromatography market, where protein A resin suppliers including Cytiva (formerly GE Healthcare Life Sciences) command significant market share. Engineered domain C variants that offer improved alkaline stability, binding capacity, or ligand density are differentiating features in premium chromatography resin products. The Federal Circuit’s decision, which leaves most claims cancelled but preserves four, suggests the surviving claims may cover specific structural features of the domain C variant that the prior art did not anticipate — making them potentially significant for any competitor seeking to commercialise next-generation protein A resins.
Should you run an FTO against US10875007, US10343142, and US10213765?
Any company developing, manufacturing, or supplying protein A affinity chromatography resins — including domain C-based ligands for antibody purification — should treat this case as a trigger for a targeted freedom-to-operate analysis. While the Federal Circuit affirmed unpatentability for the large majority of claims, the four surviving claims across the ‘142 and ‘007 patents remain enforceable. CDMOs, resin manufacturers, and biopharma in-house teams sourcing or developing alternative protein A resins should map their specific ligand designs against claims 4 and 17 of US10343142 and claims 11 and 29 of US10875007.
PatSnap Eureka’s FTO Search Agent can rapidly identify the structural and functional scope of the surviving claims, map them against your product specifications, and surface any relevant prior art or design-around opportunities. Given that these patents form part of a continuation family, Eureka can also identify related pending applications that may present future claim risk — critical intelligence for any long-horizon product development programme in the antibody purification space.
Run a freedom-to-operate analysis on US10875007B2 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit IPR appeals in protein A and bioprocess chromatography
Federal Circuit IPR appeals involving protein A affinity chromatography and biopharmaceutical purification patents — cases with comparable claim scope and PTAB review posture.
What this case signals for the bioprocess chromatography IP landscape
A split Federal Circuit ruling on protein A ligand patents has concrete consequences for antibody purification IP strategy across the biopharma supply chain.
Most protein A ligand claims are now cleared — but four survive scrutiny
The Federal Circuit’s affirmance of PTAB’s unpatentability findings on the bulk of JSR’s claims reduces the enforcement risk across domain C protein A chromatography ligands. Companies active in this space — resin manufacturers, CDMOs, and antibody developers — should map their processes against the four surviving claims of the ‘142 and ‘007 patents before concluding freedom to operate.
IPR petitions remain an effective tool against broad bioprocess patents
Cytiva’s IPR strategy achieved invalidation of the large majority of claims across three patents at the Federal Circuit level. This outcome is consistent with the broader trend of high IPR success rates at PTAB for chemistry and biotech process patents, and suggests that inter partes review remains a viable first-line defense for competitors facing broad protein A or affinity chromatography ligand assertions.
JSR v Cytiva — key questions answered
The Federal Circuit issued an affirmed-in-part and reversed-in-part ruling on 4 December 2024. It affirmed PTAB’s unpatentability findings for the large majority of claims across US10875007, US10343142, and US10213765, but reversed PTAB on claims 4 and 17 of the ‘142 patent and claims 11 and 29 of the ‘007 patent, finding those four claims not unpatentable.
Four claims survived: claims 4 and 17 of US10343142B2 and claims 11 and 29 of US10875007B2. The Federal Circuit reversed PTAB’s determination that these claims were unpatentable, meaning they remain valid and enforceable. All other challenged claims across the three patents were affirmed as unpatentable.
The three patents cover engineered variants of domain C from Staphylococcus aureus protein A used as affinity chromatography ligands for isolating and purifying antibodies. Protein A chromatography is the industry-standard platform for monoclonal antibody purification in biopharmaceutical manufacturing. Cytiva Bioprocess R&D AB is a leading supplier of protein A chromatography resins.
An affirmed-in-part and reversed-in-part ruling means the appellate court found no reversible error for most PTAB determinations (those claims are cancelled), but identified legal or factual error in PTAB’s analysis of specific claims (those claims are restored as patentable). The reversed claims remain enforceable, and the patent holder may assert them in infringement proceedings.
Cytiva’s IPR strategy successfully invalidated the large majority of claims across JSR’s three protein A ligand patents at both PTAB and Federal Circuit levels, substantially clearing the field for Cytiva’s chromatography resin products. The four claims reversed by the Federal Circuit represent JSR’s residual IP position and may be the subject of ongoing commercial or licensing disputes. The outcome is consistent with high IPR success rates for chemistry and bioprocess technology patents.
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