Cytiva v. JSR: Federal Circuit delivers split ruling on Protein A chromatography patents
Cytiva Bioprocess R&D AB and JSR Corporation clashed at the Federal Circuit over three patents covering Protein A-based chromatography ligands used in antibody purification. The court issued a mixed judgment — affirming some claims and reversing others — across a 497-day appellate proceeding resolved in December 2024.
A split Federal Circuit verdict reshapes Protein A chromatography IP
Cytiva Bioprocess R&D AB, the Swedish bioprocess technology arm of the Cytiva group, brought this appeal before the U.S. Court of Appeals for the Federal Circuit against JSR Corporation and its U.S. affiliate JSR Life Sciences, LLC. The dispute centres on three patents — US10875007B2, US10343142B2, and US10213765B2 — all covering chromatography ligands derived from domain C of Staphylococcus aureus Protein A, a core technology used in the industrial-scale purification of monoclonal antibodies.
The Federal Circuit issued an affirmed-in-part and reversed-in-part ruling on 4 December 2024, recorded as a Mixed Judgment on patentability grounds. This outcome means some patent claims or inter partes review decisions survived appellate scrutiny while others did not — a result that leaves both parties with partial wins and continuing exposure. The specific claims affirmed versus reversed are critical to understanding each party’s post-appeal IP position.
The 497-day duration from filing (26 July 2023) to resolution suggests a substantive appellate record, consistent with the complexity of three separate patent families under review. The mixed result may reflect differing claim constructions or prior-art analyses applied across the patents. Because the public record reflects only the high-level Mixed Judgment designation, the precise scope of reversals — and whether any remand was ordered — requires review of the underlying Federal Circuit opinion.
Filing to Mixed Judgment in 497 days
497 days — above average for a Federal Circuit patent appeal
Federal Circuit’s split decision: what affirmed-in-part, reversed-in-part means for both parties
What ‘affirmed-in-part, reversed-in-part’ means at the Federal Circuit
A partial affirmance and partial reversal signals that the Federal Circuit found no reversible error in some aspects of the lower tribunal’s patentability determinations, while identifying legal or factual error in others. In the IPR context, this typically means some patent claims were correctly cancelled or upheld below, while the disposition of other claims is now overturned — potentially reinstating previously cancelled claims or invalidating previously surviving ones.
Split appellate dispositionCytiva wins on some claims, loses on others — enforceability is now fragmented
For Cytiva, the partial reversal is commercially significant: claims reversed in its favour may be reinstated as valid and enforceable, strengthening its ability to pursue or defend against competitors in the Protein A ligand space. However, claims affirmed against it remain cancelled or invalid, narrowing the protective scope of its patent portfolio in antibody purification technology. The net enforceability of the three patent families depends entirely on which specific claims fell on which side of the split.
Partial patent reinstatement possibleJSR retains freedom on some claim scope but faces renewed risk on reversed portions
JSR Corporation and JSR Life Sciences secured affirmance on at least a portion of the challenged claims — meaning those claims remain cancelled and cannot be asserted against JSR’s chromatography products. Where the Federal Circuit reversed, however, JSR may face reinstated patent claims with full enforceability. This split outcome likely requires JSR to reassess its product freedom-to-operate position against the surviving or reinstated Cytiva claims and may trigger further proceedings on remand.
FTO reassessment requiredMixed ruling sustains uncertainty across the Protein A antibody purification market
Protein A affinity chromatography is the dominant platform step in monoclonal antibody manufacturing. A split Federal Circuit ruling on three foundational ligand patents leaves commercial uncertainty for any manufacturer, CDMO, or resin supplier operating in this space. Competitors who modelled their FTO analysis on full invalidation of the Cytiva patents must now revisit that position. The ruling also signals that at least some of Cytiva’s claim drafting withstood Federal Circuit scrutiny, raising the bar for future IPR challenges.
mAb purification sector impactFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Cytiva Bioprocess R & D, AB | Individual | Bioprocess technology company — holder of US10875007B2, US10343142B2, and US10213765B2Search in Eureka ↗ |
| Defendant | JSR Corporation | Company | Japanese materials science conglomerate and its U.S. life sciences subsidiarySearch in Eureka ↗ |
| Co-Defendant | Jsr Life Sciences, LLC | Company | Search in Eureka ↗ |
| Plaintiff counsel | David M. Krinsky | Attorney | Counsel for Cytiva Bioprocess R & D, ABSearch in Eureka ↗ |
| Plaintiff law firm | Williams & Connolly LLP | Law Firm | Representing Cytiva Bioprocess R & D, ABSearch in Eureka ↗ |
| Defendant counsel | Eric William Dittmann Esq. | Attorney | Counsel for JSR CorporationSearch in Eureka ↗ |
| Defendant counsel | Hiroyuki Hagiwara | Attorney | Counsel for JSR CorporationSearch in Eureka ↗ |
| Defendant counsel | Isaac S. Ashkenazi Esq. | Attorney | Counsel for JSR CorporationSearch in Eureka ↗ |
| Defendant counsel | Michael Wolfe | Attorney | Counsel for JSR CorporationSearch in Eureka ↗ |
| Defendant counsel | Naveen Modi | Attorney | Counsel for JSR CorporationSearch in Eureka ↗ |
| Defendant counsel | Phillip W. Citroen | Attorney | Counsel for JSR CorporationSearch in Eureka ↗ |
| Defendant counsel | Stephen Blake Kinnaird | Attorney | Counsel for JSR CorporationSearch in Eureka ↗ |
| Defendant law firm | Paul Hastings Foreign Law Joint Enterprise | Law Firm | Representing JSR CorporationSearch in Eureka ↗ |
| Defendant law firm | Paul Hastings LLP | Law Firm | Representing JSR CorporationSearch in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The ‘affirmed-in-part and reversed-in-part’ disposition reflects a nuanced appellate review applying the APA’s substantial-evidence standard to PTAB factual findings and de novo review to legal conclusions such as claim construction. The split outcome — recorded as a Mixed Judgment on patentability grounds — indicates the Federal Circuit found the record sufficient to sustain some invalidity determinations below, while identifying reversible error in others. Practitioners should obtain the full opinion to determine which claims were reinstated and whether a remand to the PTAB was ordered, as both outcomes carry distinct downstream enforcement and licensing consequences for Cytiva and JSR.
US10875007B2, US10343142B2 & US10213765B2 — Protein A domain C chromatography ligands
The three patents in suit — US10875007B2 (application 16/443600), US10343142B2 (application 16/189894), and US10213765B2 (application 15/603285) — each protect chromatography ligands derived from domain C of Staphylococcus aureus Protein A. Protein A affinity chromatography is the industry-standard capture step for monoclonal antibodies, and domain C-based ligands represent a class of engineered variants designed for improved alkaline stability and higher binding capacity. The patents reflect a continuation strategy across related application filings, suggesting a deliberate effort to build layered claim coverage over ligand architecture.
From a competitive standpoint, these patents sit at the heart of the global Protein A resin market, which underpins biologics manufacturing at every major pharmaceutical and CDMO facility. Cytiva (formerly GE Healthcare Life Sciences) holds a dominant commercial position in this segment, and patent protection over ligand domain engineering is central to maintaining that position against Japanese and other Asian competitors including JSR. A successful challenge to even a portion of this portfolio directly enables competitors to offer next-generation Protein A resins to biomanufacturers currently locked into Cytiva supply relationships.
Should your team run an FTO analysis against US10875007B2, US10343142B2, and US10213765B2?
Any organisation developing, manufacturing, or procuring Protein A affinity chromatography resins — including resin suppliers, CDMOs, and in-house bioprocess teams at biologics manufacturers — should treat the post-appeal claim scope of these three patents as a live FTO concern. The Federal Circuit’s partial reversal means the effective claim boundaries have shifted from what the original PTAB decisions established. Product teams planning to launch, scale, or switch to alternative Protein A ligand resins cannot rely on pre-appeal invalidity assumptions.
PatSnap Eureka’s FTO Search Agent can map the surviving and potentially reinstated claims of US10875007B2, US10343142B2, and US10213765B2 against your product specifications or target ligand sequences in minutes — identifying freedom corridors, claim overlap risk, and design-around opportunities. Given the mixed appellate outcome, an Eureka-powered claim landscape analysis across the full Cytiva Protein A portfolio is the most efficient first step before any product or partnership decision in this space.
Run a freedom-to-operate analysis on US10875007B2 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit appeals involving Protein A and bioprocess chromatography patents
Explore related Federal Circuit patentability appeals in the bioprocess chromatography and Protein A affinity ligand space, including comparable IPR-origin mixed-judgment cases.
What this case signals for the bioprocess chromatography IP landscape
A mixed Federal Circuit outcome on core Protein A ligand patents reshapes risk calculations for every mAb manufacturer and resin supplier.
Partial reversal means FTO analyses built on full invalidation are now stale
Any competitor or CDMO that assumed all three Cytiva patents were effectively neutralised by the IPR outcomes must urgently update their freedom-to-operate analysis. Reinstated claims at the Federal Circuit carry the same enforceability as originally granted claims — and can support injunctions or damages actions immediately.
JSR’s litigation strategy provides a template for multi-patent IPR campaigns
Challenging three related patents across separate IPR proceedings and then appealing to the Federal Circuit is a high-resource but strategically coherent approach in platform technology disputes. The mixed result suggests that differentiated claim construction arguments across patent families can produce asymmetric outcomes — a playbook worth studying for bioseparation IP disputes.
AB v JSR — key questions answered
The Federal Circuit issued an affirmed-in-part and reversed-in-part ruling on 4 December 2024, recorded as a Mixed Judgment. The court upheld some patentability determinations from the proceedings below while reversing others across the three Protein A chromatography ligand patents at issue: US10875007B2, US10343142B2, and US10213765B2.
Three patents were asserted: US10875007B2 (application 16/443600), US10343142B2 (application 16/189894), and US10213765B2 (application 15/603285). All three cover chromatography ligands derived from domain C of Staphylococcus aureus Protein A, used in the affinity purification of monoclonal antibodies.
This disposition means the Federal Circuit sustained some aspects of the lower tribunal’s patentability rulings while overturning others. In practice, at least some previously cancelled claims may be reinstated as valid and enforceable, while other claims remain invalidated. The precise commercial impact depends on the specific claims falling on each side — which requires review of the full Federal Circuit opinion.
Any FTO analysis premised on full invalidation of the three Cytiva Protein A patents is potentially stale following this mixed ruling. Reinstated claims regain full enforceability and could be asserted against competing resin products. Manufacturers, CDMOs, and biomanufacturers relying on or developing alternative Protein A chromatography ligands should conduct updated FTO assessments against the surviving and potentially reinstated claim scope.
The public case record designates the outcome as a Mixed Judgment (affirmed-in-part, reversed-in-part) but does not specify whether a remand to the PTAB was ordered. When the Federal Circuit reverses an IPR final written decision, remand for further proceedings is common but not automatic. Review of the full Federal Circuit opinion is necessary to determine whether the PTAB must conduct further proceedings on the reversed claims.
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