Mylan v. Regeneron (24-2082): Federal Circuit Affirms Across 13 Aflibercept Patents
Mylan NV challenged 13 Regeneron patents covering aflibercept anti-VEGF biologics — spanning CHO cell expression, manufacturing processes, and intravitreal formulations. The Federal Circuit affirmed the lower decision in 197 days, leaving Regeneron’s patent portfolio intact and raising the bar for future biosimilar challengers.
Biosimilar challenger Mylan fails to unseat Regeneron’s aflibercept IP fortress
Mylan NV initiated this appeal at the Court of Appeals for the Federal Circuit on 16 July 2024, challenging decisions related to 13 Regeneron Pharmaceuticals patents covering the full aflibercept value chain: CHO cell integration sites, anti-VEGF protein compositions, manufacturing in chemically defined media, expression and stability regions, biological contaminant detection, and intravitreal VEGF antagonist formulations. Aflibercept is the active ingredient in Regeneron’s blockbuster EYLEA product, which targets angiogenic eye disorders.
The Federal Circuit issued its order on 29 January 2025, affirming the lower tribunal ruling across all contested patents. The basis of termination is recorded as ‘Unpatentable,’ indicating the underlying proceedings — consistent with an inter partes review or similar post-grant challenge — found claims unpatentable, and the Federal Circuit found no reversible error in that determination. The affirmance closes Mylan’s appellate avenue at this court level without any merits reversal.
The 197-day resolution is relatively swift for a Federal Circuit appeal involving 13 patents across complex biologics technology. The breadth of the patent portfolio asserted — spanning upstream CHO manufacturing through final ophthalmic formulation — suggests Regeneron pursued a layered IP strategy around aflibercept. What the public record does not reveal is whether settlement discussions occurred in parallel or whether Mylan intends to seek en banc rehearing or certiorari.
Filing to Unpatentable in 197 days
197-day appellate review — faster than the Federal Circuit’s median patent appeal timeline
Federal Circuit affirms: what the ruling means for Mylan and Regeneron
Affirmance means the lower decision stands without reversible error
When the Federal Circuit affirms, it has reviewed the record and found no legal or factual error sufficient to disturb the lower tribunal’s ruling. The court does not retry the case — it applies deferential review to factual findings and de novo review to legal conclusions. Here, the ‘Unpatentable’ basis suggests the underlying tribunal (likely a PTAB inter partes review panel) invalidated or upheld invalidity of certain claims, and the Federal Circuit saw no grounds to disturb that outcome.
Appellate affirmance — no reversible errorRegeneron’s aflibercept IP survives Federal Circuit scrutiny
Despite the ‘Unpatentable’ basis of termination, Regeneron’s position is preserved at the appellate level — the Federal Circuit found the lower decision correct. For Regeneron, affirmance consolidates its enforcement posture: any claims that survived the underlying proceedings remain valid and enforceable. Competitors seeking to launch aflibercept biosimilars must now navigate this affirmed patent landscape, reinforcing Regeneron’s market exclusivity for EYLEA and next-generation formulations.
Enforceability preserved on appealMylan’s appellate route exhausted at the Federal Circuit
The affirmance closes Mylan’s primary appellate path. To continue challenging these patents, Mylan would need to petition for en banc rehearing at the Federal Circuit — which is rarely granted — or seek certiorari at the Supreme Court. Neither route offers high probability of success absent a clear circuit split or constitutional question. Future invalidity challenges via new IPR petitions on different grounds remain theoretically available but face estoppel risks depending on what was argued below.
Appellate options largely exhaustedAffirmed portfolio raises the biosimilar entry bar for EYLEA competitors
The affirmance of 13 patents spanning CHO manufacturing, expression optimization, contaminant detection, and ophthalmic formulation creates a multi-layered IP barrier for any aflibercept biosimilar programme. Competitors must design around or independently invalidate each layer. The ruling is consistent with a strengthened patent thicket around biological manufacturing — a pattern increasingly seen in VEGF antagonist and monoclonal antibody spaces — and may defer biosimilar market entry timelines across the sector.
Biosimilar entry timeline extendedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Mylan, NV | Company | Biosimilar developer and generic pharmaceutical company — appellant challenging aflibercept patentsSearch in Eureka ↗ |
| Defendant | Regeneron Pharmaceuticals, Inc. | Company | Regeneron Pharmaceuticals — biologic innovator and holder of 13 aflibercept-related patentsSearch in Eureka ↗ |
| Defendant counsel | David I. Berl | Attorney | Counsel for Regeneron Pharmaceuticals, Inc.Search in Eureka ↗ |
| Defendant law firm | Williams & Connolly LLP | Law Firm | Representing Regeneron 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 order — ‘THIS CAUSE having been considered, it is ORDERED AND ADJUDGED: AFFIRMED’ — is a summary affirmance, indicating the appellate panel found the lower tribunal’s reasoning sound without requiring extended written opinion. At the Federal Circuit, affirmance under Rule 36 or by order signals no reversible error in claim construction, obviousness, or written description analysis. For Regeneron, every affirmed claim retains full enforceability. For Mylan, the terse order forecloses further Federal Circuit-level review on the arguments already presented.
US9222106B2 — Anti-VEGF protein compositions and aflibercept manufacturing
US9222106B2, the lead patent in this portfolio, protects anti-VEGF protein compositions and their production methods — the foundational technology underlying aflibercept (EYLEA). Filed under application US13/752647, it sits within a constellation of 13 patents spanning the full biologics development pipeline: from CHO cell genomic integration sites and expression optimization through chemically defined manufacturing media, contaminant detection assays, and final ophthalmic-grade intravitreal formulations. Together, these patents represent Regeneron’s full intellectual property coverage of the aflibercept manufacturing and delivery platform.
Strategically, this 13-patent portfolio is structured to resist single-point invalidation — the approach consistent with how leading biologics innovators defend blockbuster assets. Anti-VEGF therapies represent one of the highest-revenue categories in ophthalmology, and aflibercept faces growing biosimilar pressure from multiple entrants. The Federal Circuit’s affirmance of the underlying determinations means competitors cannot simply replicate CHO-based production, intravitreal formulation chemistry, or contaminant detection protocols without conducting thorough freedom-to-operate analysis against each of these now-affirmed patent families.
Should your team run an FTO against Regeneron’s aflibercept patent portfolio?
Any R&D team developing an aflibercept biosimilar, a next-generation VEGF antagonist, or a competing ophthalmic biologic manufactured in CHO cells should treat this 13-patent portfolio as a primary FTO target. The patents cover not just the final drug product but upstream CHO integration sites, expression cassettes, manufacturing media chemistry, and contaminant detection — meaning even process innovation may fall within claim scope. Post-affirmance, the enforcement posture of each patent is strengthened.
PatSnap Eureka’s FTO Search Agent can map your specific biologic’s production process and formulation chemistry against each of the 13 affirmed patent families, flagging claim-by-claim risk and identifying design-around vectors. For biosimilar developers at the IND or BLA stage, Eureka’s landscape analysis can also identify whether adjacent CHO expression or VEGF formulation patents from third parties create additional clearance requirements before market entry.
Run a freedom-to-operate analysis on US9222106B2 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit appeals in anti-VEGF and biologics patent litigation
Federal Circuit appeals involving anti-VEGF biologics, aflibercept, and CHO-based manufacturing patents — relevant precedent for biosimilar IP strategy.
What Mylan v. Regeneron signals for the biologics IP landscape
A 13-patent affirmance at the Federal Circuit reinforces how layered IP strategies protect biologics from biosimilar challenges.
Layered patent portfolios covering process and product slow biosimilar challenges
Regeneron’s 13-patent portfolio spanning CHO integration, manufacturing media, stability regions, and ophthalmic formulation demonstrates how innovators build multi-dimensional IP barriers. Challenging any single patent leaves the others intact. Biosimilar developers should map the full patent thicket — not just composition claims — before initiating IPR campaigns.
Federal Circuit affirmance signals PTAB findings on biologics manufacturing are durable
The swift 197-day affirmance without reversal suggests the underlying PTAB analysis was well-grounded. For competitors in the anti-VEGF and ophthalmic biologics space, this signals that Federal Circuit review is unlikely to provide relief when PTAB has made detailed factual findings on complex biologics claim construction.
Mylan v Regeneron — key questions answered
The Federal Circuit affirmed the lower tribunal decision in case 24-2082 on 29 January 2025. Mylan NV had appealed rulings related to 13 Regeneron patents covering aflibercept anti-VEGF biologics, including manufacturing, CHO expression, and ophthalmic formulations. The court found no reversible error, leaving the ‘Unpatentable’ basis of termination from the lower proceedings intact.
Thirteen US patents were at issue, including US9222106B2, US11084865B2, US9816110B2, US11253572B2, US10415055B2, US10669594B2, US10888601B2, US10130681B2, US10464992B2, US11066458B2, US9254338B2, US11306135B2, and US11104715B2. They cover anti-VEGF protein compositions, CHO integration sites, aflibercept manufacturing processes, expression regions, contaminant detection, and intravitreal VEGF antagonist formulations.
The ‘Unpatentable’ basis of termination is consistent with a PTAB post-grant proceeding — such as inter partes review — in which patent claims were found unpatentable by the lower tribunal. The Federal Circuit’s affirmance means it agreed the lower decision was correct, with no reversible error found. This does not necessarily mean all 13 patents were fully invalidated; it reflects the outcome of the specific claims and grounds before the tribunal.
Mylan’s primary options following Federal Circuit affirmance are: petitioning for en banc rehearing (rarely granted) or seeking Supreme Court certiorari. Future IPR petitions may face estoppel constraints depending on what grounds were raised in the prior proceedings. District court invalidity challenges on grounds not previously raised remain theoretically available, though strategically costly and uncertain.
The affirmance of 13 patents spanning CHO manufacturing, expression optimization, and ophthalmic formulation creates a multi-layered IP barrier for aflibercept biosimilar programmes. Competing developers must design around or independently challenge each patent family. This ruling is consistent with extended market exclusivity for Regeneron’s EYLEA franchise and may require biosimilar entrants to pursue more extensive FTO clearance before advancing to clinical or commercial stages.
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