Regeneron v. Mylan Pharmaceuticals: Federal Circuit Affirms EYLEA® Patent Decision
Regeneron Pharmaceuticals, joined by Amgen, Biocon Biologics, Formycon, Celltrion, and Samsung Bioepis, faced Mylan Pharmaceuticals at the Federal Circuit over EYLEA® (aflibercept) patent US11084865B2. The court affirmed the lower court’s ruling in a case resolved in 181 days — a notably swift appellate disposition for a high-stakes biologics patent dispute.
Federal Circuit backs EYLEA® patent holder in swift biosimilar appeal
Case 24-2156 pitted Regeneron Pharmaceuticals — lead plaintiff and holder of US11084865B2 covering the blockbuster anti-VEGF biologic EYLEA® (aflibercept) — against Mylan Pharmaceuticals, a biosimilar entrant seeking market access. The appeal, filed 1 August 2024 before the Court of Appeals for the Federal Circuit in the District of Columbia circuit, also drew in a coalition of co-plaintiffs including Amgen, Biocon Biologics, Formycon AG, Celltrion, and Samsung Bioepis, reflecting the broad commercial interest in the EYLEA® biosimilar pathway.
The Federal Circuit issued its affirmance on 29 January 2025, closing the appeal after just 181 days. An affirmance at this level means the appellate panel found no reversible error in the lower court’s decision — the judgment below stands and Mylan’s challenge did not succeed in overturning it. For the plaintiff coalition, the ruling preserves the legal enforceability of US11084865B2 as previously adjudicated, maintaining the competitive barrier against Mylan’s biosimilar product at the appellate stage.
The 181-day resolution is notably compact for Federal Circuit pharmaceutical patent litigation, suggesting the panel may have found the issues sufficiently settled — whether on procedural or substantive grounds — to resolve without extended briefing cycles. The public record does not disclose the specific grounds for affirmance or the reasoning applied, and the basis of termination is recorded as ‘Appeal Dismissed,’ which may indicate the affirmance was entered on procedural rather than full-merits grounds. What drove the swift resolution — and whether Mylan retains any further avenue of challenge — is not determinable from the available public record.
Filing to Appeal Dismissed in 181 days
181-day appellate resolution — faster than the Federal Circuit median for pharma patent appeals
Federal Circuit affirms: what the ruling means for both parties
What ‘AFFIRMED’ means at the Federal Circuit
When the Federal Circuit affirms, it confirms that the lower tribunal committed no reversible error — legally or factually. The appellate court does not re-try the case; it reviews whether the decision below was legally sound. Affirmance leaves the prior judgment intact and operative. Here, the lower court’s ruling on US11084865B2 survives appellate scrutiny, and Mylan’s challenge at this level ends without success.
No reversible error foundRegeneron’s patent position strengthened by appellate validation
For Regeneron and its co-plaintiffs, affirmance means US11084865B2 retains whatever enforceability the lower court established. The patent has now survived appellate review, raising its legal durability in any future enforcement action. Competitors seeking to design around or challenge the same patent face a higher credibility bar — the claims have withstood scrutiny at two judicial levels, consistent with a stronger presumption of validity.
Patent enforceability preservedMylan’s appellate options exhausted at the Federal Circuit
For Mylan Pharmaceuticals, affirmance closes the Federal Circuit avenue. The remaining formal route is a petition for certiorari to the U.S. Supreme Court, which is granted sparingly in patent cases. Absent that, Mylan’s biosimilar EYLEA® pathway remains constrained by the patent as adjudicated. Alternative strategies — such as inter partes review or design-around development — may warrant assessment, though the public record does not indicate any parallel proceedings.
Federal Circuit avenue closedBiosimilar EYLEA® market entry faces sustained legal barrier
The affirmance reinforces Regeneron’s commercial position in the multi-billion-dollar anti-VEGF retinal disease market. For the broader biosimilar industry, a validated patent following appellate review typically signals that market entry timelines must account for the full remaining patent term unless a design-around or successful IPR challenge is secured. Other biosimilar developers — including co-plaintiffs who have their own commercial interests — will be closely watching the downstream implications for their respective EYLEA® programmes.
Biosimilar entry timeline impactedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | REGENERON PHARMACEUTICALS, INC | Company | Biopharmaceutical company — holder of US11084865B2 covering EYLEA® (aflibercept)Search in Eureka ↗ |
| Co-Plaintiff | Amgen, Inc. | Company | Search in Eureka ↗ |
| Co-Plaintiff | Biocon Biologics, Inc. | Company | Search in Eureka ↗ |
| Co-Plaintiff | FORMYCON AG | Company | Search in Eureka ↗ |
| Co-Plaintiff | Celltrion, Inc. | Company | Search in Eureka ↗ |
| Co-Plaintiff | Amgen USA, Inc. | Company | Search in Eureka ↗ |
| Co-Plaintiff | Samsung Bioepis Co., Ltd. | Company | Search in Eureka ↗ |
| Defendant | Mylan Pharmaceuticals, Inc. | Company | Generic and biosimilar pharmaceutical manufacturer seeking EYLEA® market entrySearch in Eureka ↗ |
| Plaintiff counsel | ADAM PAN | Attorney | Counsel for REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Plaintiff counsel | ANDREW V. TRASK | Attorney | Counsel for REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Plaintiff counsel | ARTHUR JOHN ARGALL, III | Attorney | Counsel for REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Plaintiff counsel | CHRISTIAN GLADDEN-SORENSEN | Attorney | Counsel for REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Plaintiff counsel | David I. Berl | Attorney | Counsel for REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Plaintiff counsel | JACOB HARTMAN | Attorney | Counsel for REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Plaintiff counsel | KATHRYN SCHLECKSER KAYALI | Attorney | Counsel for REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Plaintiff counsel | Priyata Patel | Attorney | Counsel for REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Plaintiff counsel | RHOCHELLE KRAWETZ | Attorney | Counsel for REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Plaintiff counsel | SHAUN PATRICK MAHAFFY | Attorney | Counsel for REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Plaintiff counsel | THOMAS S. FLETCHER | Attorney | Counsel for REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Plaintiff law firm | Kellogg, Hansen, Todd, Figel & Frederick, PLLC | Law Firm | Representing REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Plaintiff law firm | Paul, Weiss, Rifkind, Wharton & Garrison LLP | Law Firm | Representing REGENERON PHARMACEUTICALS, INCSearch in Eureka ↗ |
| Defendant counsel | LOUIS FOGEL | Attorney | Counsel for Mylan Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | NITIKA GUPTA FIORELLA | Attorney | Counsel for Mylan Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | ROBERT M. OAKES | Attorney | Counsel for Mylan Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | SARAH JACK | Attorney | Counsel for Mylan Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant counsel | SHAUN VAN HORN | Attorney | Counsel for Mylan Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant law firm | Fish & Richardson PC | Law Firm | Representing Mylan Pharmaceuticals, Inc.Search 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 one-word disposition — AFFIRMED — confirms that the panel found no reversible error in the lower court’s resolution of the EYLEA® patent dispute. The appellate standard of review at the Federal Circuit typically applies de novo review to claim construction and legal conclusions, while factual findings are reviewed for clear error. The co-existence of ‘AFFIRMED’ alongside a ‘Basis of Termination: Appeal Dismissed’ entry in the docket suggests the affirmance may have rested on procedural rather than full-merits grounds, though the public record does not permit a definitive characterisation. Mylan’s challenge does not succeed at this level regardless of procedural framing.
US11084865B2 — aflibercept (EYLEA®) biologic composition patent
US11084865B2 (application number US16/739559) covers proprietary aspects of aflibercept, the active ingredient in Regeneron’s EYLEA® — a recombinant fusion protein that functions as a VEGF trap, blocking vascular endothelial growth factor to treat conditions including wet age-related macular degeneration, diabetic macular oedema, and retinal vein occlusion. The patent’s claims are directed at the composition or formulation level, protecting a commercially significant biologic asset in a therapeutic area with few substitutes.
EYLEA® has historically generated multi-billion-dollar annual revenues for Regeneron, making US11084865B2 a high-value enforcement asset. The entrance of multiple biosimilar developers — reflected in the coalition of co-plaintiffs in this appeal — underscores the commercial stakes. A patent that has now survived appellate review represents a meaningful barrier for any party seeking EYLEA® biosimilar approval via an abbreviated biologics licence application (aBLA) pathway, and should be prioritised in any freedom-to-operate or competitive landscape analysis in the anti-VEGF ophthalmology space.
Should you run an FTO analysis against US11084865B2?
Any company developing, manufacturing, or commercialising an aflibercept biosimilar — or any anti-VEGF biologic formulation with structural or functional overlap with EYLEA® — should treat US11084865B2 as a primary FTO target. The Federal Circuit affirmance in Case 24-2156 means the patent has cleared a second layer of judicial review, raising the risk profile for non-assessed product candidates. R&D teams working on VEGF-trap biologics or related ophthalmology therapeutics should confirm their formulation and manufacturing process claims are mapped against the patent’s current claim set.
PatSnap Eureka’s FTO Search Agent enables rapid claim-by-claim mapping of your product against US11084865B2, surfacing prior art, design-around opportunities, and any post-grant proceedings that may affect claim validity. Eureka’s litigation monitoring tools can also alert your team to new Federal Circuit filings or USPTO actions involving Regeneron’s EYLEA® patent family — critical for biosimilar programme teams managing regulatory and IP timelines in parallel.
Run a freedom-to-operate analysis on US11084865B2 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit biosimilar and biologic patent appeals
Federal Circuit appeals involving biologics patents and biosimilar market-entry disputes — cases structurally comparable to Regeneron v. Mylan on EYLEA®.
What this case signals for the biologics and biosimilar IP landscape
The Federal Circuit’s affirmance in a 181-day window sends a clear signal about how EYLEA® patent rights may be defended at every judicial level.
Appellate affirmance raises the cost of biosimilar patent challenges
A patent that survives both district court and Federal Circuit review carries a stronger presumption of validity. Any biosimilar challenger targeting EYLEA® now faces a harder evidentiary hill — prior judicial analysis will be on record, and courts will expect materially new arguments or evidence to reopen the question.
Coalition plaintiffs signal coordinated IP defence strategy in biologics
The presence of Amgen, Biocon Biologics, Formycon, Celltrion, and Samsung Bioepis alongside Regeneron suggests a coordinated approach to defending biosimilar pathway access and patent positions. For in-house teams at biologics companies, this multi-party plaintiff structure is worth noting as a model for joint enforcement or defensive alignment.
REGENERON v Mylan — key questions answered
The Federal Circuit affirmed the lower court’s decision on 29 January 2025 in Case 24-2156. The affirmance means the appellate panel found no reversible error in the prior ruling concerning EYLEA® (aflibercept) patent US11084865B2. Mylan’s challenge at the Federal Circuit level was unsuccessful. The basis of termination is recorded as ‘Appeal Dismissed,’ which may indicate the affirmance was entered on procedural grounds, though the public record does not specify the panel’s reasoning.
The single patent asserted in Case 24-2156 is US11084865B2 (application number US16/739559), covering aflibercept — the active ingredient in Regeneron’s EYLEA®, an anti-VEGF biologic used to treat wet age-related macular degeneration, diabetic macular oedema, and related retinal conditions.
In addition to lead plaintiff Regeneron Pharmaceuticals, Inc., the co-plaintiffs in Case 24-2156 were Amgen Inc., Amgen USA Inc., Biocon Biologics Inc., Formycon AG, Celltrion Inc., and Samsung Bioepis Co. Ltd. The multi-party plaintiff structure reflects the breadth of commercial interest among biosimilar developers and partners in the outcome of EYLEA® patent litigation.
Affirmance means the Federal Circuit found no reversible error in the lower court decision, leaving the prior judgment intact. For Mylan Pharmaceuticals, this closes the Federal Circuit route for challenging EYLEA® patent US11084865B2 via this appeal. Mylan’s remaining options include a petition for certiorari to the U.S. Supreme Court (rarely granted in patent cases) or pursuing parallel routes such as inter partes review at the USPTO, subject to applicable time bars and estoppel considerations.
Case 24-2156 was filed on 1 August 2024 and closed on 29 January 2025 — a duration of 181 days. This is a relatively swift resolution for a Federal Circuit pharmaceutical patent appeal, which may suggest the panel resolved the matter on procedural grounds or found the legal questions sufficiently clear to decide without extended merits briefing. The public record does not disclose the specific basis for the speed of disposition.
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