Regeneron Pharmaceuticals, Inc. v. Mylan Pharmaceuticals Inc. et al.

Regeneron Pharmaceuticals, Inc. initiated patent infringement litigation against Mylan Pharmaceuticals Inc. and Biocon Biologics Inc., both global generic and biosimilar pharmaceutical manufacturers. Regeneron, a leading U.S. biotechnology company, developed and markets Eylea® (aflibercept), a blockbuster anti-VEGF (vascular endothelial growth factor) therapy for various retinal diseases, administered via intravitreal injection. The defendants' accused product was their proposed aflibercept biosimilar, initially designated M710 and later approved as Yesafili™ (aflibercept-jbvf), which sought to enter the market as a biosimilar to Eylea®. Mylan, a subsidiary of Viatris, Inc., later transferred its biosimilar rights to Biocon Biologics.

The central patent at issue was U.S. Patent 11,084,865 (the '865 patent), though Regeneron initially asserted a portfolio of 24 patents, later reducing them to a subset including the '865 patent, U.S. Patent 10,888,601, and U.S. Patent 11,253,572. The '865 patent generally covers ophthalmic formulations of a VEGF-specific fusion protein antagonist, specifically aflibercept (referred to by amino acid sequence SEQ ID NO:4), suitable for intravitreal administration, encompassing both stable liquid and lyophilizable formulations. The litigation was filed in the U.S. District Court for the Northern District of West Virginia, with Chief District Judge Thomas S. Kleeh presiding. This venue became particularly significant as the case was part of an MDL consolidation (MDL No. 1:24-md-03103), centralizing multiple patent infringement actions brought by Regeneron against various aflibercept biosimilar developers. The District of West Virginia is relevant due to Mylan/Viatris's historical operational presence in Morgantown, West Virginia.

This case is notable for several reasons, primarily its position within the high-stakes Eylea® biosimilar litigation landscape, a multi-billion dollar market segment. Regeneron pursued an aggressive intellectual property enforcement strategy to delay biosimilar market entry, as evidenced by the multiple lawsuits consolidated in the MDL and numerous Inter Partes Reviews (IPRs) filed against its patents, including the '865 patent. Although Regeneron initially secured a district court victory finding infringement of the '865 patent and a subsequent permanent injunction in June 2024, the case ultimately resolved through a confidential settlement. This settlement led to the vacatur of the permanent injunction and the dismissal of the district court case, as well as the related Federal Circuit appeal (CAFC Appeal No. 24-2002), allowing Mylan/Biocon's biosimilar to launch in the U.S. in the second half of 2026. This outcome reflects an industry trend where originator biologic companies often opt for negotiated market access agreements, controlling biosimilar entry timelines, rather than pursuing litigation to a final appellate resolution.

The patent infringement litigation Regeneron Pharmaceuticals, Inc. v. Mylan Pharmaceuticals Inc. et al. (1:22-cv-00061, N.D.W. Va.) concerning Regeneron's Eylea® (aflibercept) product, involved several key legal developments before ultimately settling.

Key Legal Developments and Outcome:

• Filing & Initial Pleadings:

  • Regeneron Pharmaceuticals, Inc. filed its initial complaint against Mylan Pharmaceuticals Inc. on August 2, 2022, in the U.S. District Court for the Northern District of West Virginia. The complaint asserted infringement of 24 patents related to Eylea®, including US Patent 11084865, against Mylan's proposed biosimilar, M710 (later known as Yesafili™).
  • Mylan Pharmaceuticals Inc. filed its First Amended Answer, Defenses, and Counterclaims, broadly denying infringement and asserting that Regeneron's patents were invalid, unenforceable, or not infringed. Mylan also included counterclaims related to inequitable conduct during patent prosecution. Biocon Biologics Inc. was later added as a defendant by stipulation.

• Pre-trial Motions of Substance:

  • On December 16, 2022, Regeneron filed a motion for judgment on the pleadings regarding Mylan's inequitable conduct defenses and counterclaims. This motion was granted by Judge Kleeh a week before trial, clearing these counterclaims.
  • The parties filed cross-motions for summary judgment, which the Court denied.
  • An earlier motion by Mylan to compel further claim narrowing by Regeneron beyond the scheduling order's stipulations was opposed by Regeneron, arguing it had already complied and Mylan had violated discovery deadlines.
  • In April 2024, the Judicial Panel on Multidistrict Litigation granted Regeneron's motion to consolidate six actions against various aflibercept biosimilar applicants, including the Mylan case, in the Northern District of West Virginia for coordinated pretrial proceedings (MDL No. 1:24-md-3103).

• Claim Construction (Markman) Outcomes:

  • The court held a Markman hearing on January 24, 2023.
  • An Order on Claim Construction was issued on April 19, 2023. Following this order, Regeneron narrowed its asserted patents and claims to include claims 4, 7, 9, 11, and 14-18 of the '865 Patent, among others, and stipulated to the invalidity of certain other claims under the court's construction.

• Discovery Milestones with Strategic Significance:

  • The scheduling order set out various deadlines for claim narrowing and discovery. There were disputes over discovery, including Mylan serving late expert reports.
  • Non-party Amgen Inc. moved to intervene for the limited purpose of unsealing certain judicial records, highlighting the public interest in access to sealed filings, particularly claim construction briefs, summary judgment motions, and discovery materials. Judge Kleeh ordered the unsealing of 30 docket entries and some related exhibits in response.

• Trial Events, Verdict, and Post-trial Motions:

  • A 10-day bench trial commenced on June 12, 2023, and concluded on June 23, 2023.
  • On December 27, 2023, the District Court for the Northern District of West Virginia issued a detailed Memorandum Opinion and Order Following Bench Trial, finding that Mylan (and Biocon) infringed certain claims of the '865 patent and that the defendants had not proven the claims invalid.
  • Subsequently, the court granted Regeneron's motion for a permanent injunction against Biocon (Mylan's associate) on June 11, 2024, preventing the commercial launch of Yesafili™ until the expiration of the '865 patent in June 2027. A Final Judgment (ECF No. 163) and a Final Order for Injunctive Relief (ECF No. 189) were also issued on June 11, 2024, and June 21, 2024, respectively.

• Settlement, Dismissal, Judgment, or Appeal:

  • Mylan and Biocon appealed the district court's judgment and permanent injunction to the Federal Circuit (CAFC Appeal No. 24-2002).
  • On April 15, 2025, Regeneron and Biocon reached a settlement agreement, leading to the dismissal of the district court case (1:22-cv-00061) and the related Federal Circuit appeal (CAFC Appeal No. 24-2002).
  • The settlement allows Biocon to commercialize its Eylea® biosimilar, Yesafili™, in the U.S. in the second half of 2026, or potentially earlier under undisclosed circumstances.
  • A critical aspect of the settlement was the stipulated vacatur of the permanent injunction and final judgment orders, meaning these orders no longer establish binding precedent. The district court case was officially closed on April 22, 2025.

• Parallel PTAB IPR/PGR Proceedings:

  • US Patent 11084865 was the subject of inter partes review (IPR) petitions filed by other biosimilar developers, including Samsung Bioepis (IPR2025-00176) and Formycon (IPR2025-00233).
  • In June 2025, a PTAB panel denied institution of these IPR petitions, exercising its discretion under 35 U.S.C. § 314(a) based on the Fintiv factors, citing the advanced state of parallel district court proceedings, including the Mylan litigation. The panel noted the significant investment in the parallel proceedings as weighing heavily in favor of discretionary denial.## Regeneron Prevails in District Court Against Mylan Over Eylea Biosimilar Patent, Case Later Settles

The patent infringement litigation, Regeneron Pharmaceuticals, Inc. v. Mylan Pharmaceuticals Inc. et al. (1:22-cv-00061, N.D.W. Va.), concluded with a district court victory for Regeneron on U.S. Patent 11084865, followed by a settlement that dismissed the case and its appeal, permitting Mylan's biosimilar to launch in 2026.

Here's a chronological breakdown of the key legal developments:

• 2022-08-02: Complaint Filed. Regeneron Pharmaceuticals, Inc. initiated the lawsuit against Mylan Pharmaceuticals Inc. in the U.S. District Court for the Northern District of West Virginia. The complaint asserted infringement of 24 patents, including U.S. Patent 11084865, against Mylan's proposed Eylea® (aflibercept) biosimilar, M710 (later known as Yesafili™).
• Initial Pleadings. Mylan Pharmaceuticals Inc. filed its First Amended Answer, Defenses, and Counterclaims, denying infringement and alleging that Regeneron's patents were invalid, unenforceable, or not infringed. Mylan also raised counterclaims of inequitable conduct during patent prosecution. Later, Biocon Biologics Inc. was added as a defendant.
• 2022-12-16: Motion for Judgment on Pleadings. Regeneron filed a motion for judgment on the pleadings concerning Mylan's inequitable conduct defenses and counterclaims. This motion was granted prior to trial, dismissing those counterclaims.
• 2023-01-24: Markman Hearing. The court held a Markman (claim construction) hearing.
• 2023-04-19: Claim Construction Order. The court issued its Order on Claim Construction. Following this order, Regeneron narrowed its asserted claims, including claims 4, 7, 9, 11, and 14-18 of the '865 patent, and stipulated to the invalidity of certain other claims.
• 2023-05-23: Amgen Motion to Intervene. Non-party Amgen Inc. moved to intervene for the limited purpose of unsealing judicial records, arguing for public access to various sealed filings, including claim construction briefs and summary judgment motions. In response, Judge Kleeh ordered the unsealing of 30 docket entries and associated exhibits.
• Summary Judgment Motions Denied. The parties filed cross-motions for summary judgment, both of which were denied by the court.
• 2023-06-12 to 2023-06-23: Bench Trial. A 10-day bench trial took place.
• 2023-12-27: District Court Verdict. The District Court for the Northern District of West Virginia issued a detailed opinion finding that Mylan and Biocon infringed certain claims of the '865 patent and had not proven the claims invalid.
• 2024-04-11: MDL Consolidation. The Judicial Panel on Multidistrict Litigation granted Regeneron's motion to consolidate several aflibercept biosimilar cases, including this one, into MDL No. 1:24-md-3103 in the Northern District of West Virginia.
• 2024-06-11: Permanent Injunction Issued. The court granted Regeneron's motion for a permanent injunction against Biocon, prohibiting the commercial launch of Yesafili™ until the '865 patent's expiration in June 2027. A Final Judgment and a Final Order for Injunctive Relief were also entered on June 11, 2024, and June 21, 2024, respectively.
• Federal Circuit Appeal Initiated. Mylan and Biocon appealed the district court's judgment and permanent injunction to the Federal Circuit (CAFC Appeal No. 24-2002).
• 2025-04-15: Settlement and Dismissal. Regeneron and Biocon reached a confidential settlement agreement, leading to the dismissal of the district court case (1:22-cv-00061) and the related Federal Circuit appeal (24-2002). The settlement includes a stipulated vacatur of the permanent injunction and final judgment orders.
• 2025-04-22: Case Terminated. The district court case was officially terminated. The settlement allows Biocon to launch its Eylea® biosimilar in the U.S. in the second half of 2026.
• Parallel PTAB Proceedings (2025-06): IPR Petitions Denied. The Patent Trial and Appeal Board (PTAB) denied institution of inter partes review (IPR) petitions filed by Samsung Bioepis (IPR2025-00176) and Formycon (IPR2025-00233) against U.S. Patent 11084865. The PTAB exercised its discretion under the Fintiv factors, citing the advanced stage and significant investment in the parallel district court litigation, including the Mylan case, as a reason for denial.

Regeneron Pharmaceuticals, Inc. was represented by a robust legal team, including attorneys from Williams & Connolly LLP, Paul, Weiss, Rifkind, Wharton & Garrison LLP, Kellogg, Hansen, Todd, Figel & Frederick, PLLC, and in-house counsel from Regeneron Pharmaceuticals, Inc.. While Carey, Douglas, Kessler & Ruby, PLLC was also mentioned as part of the plaintiff's team, specific attorneys and their roles from this firm were not explicitly detailed in the available records.

Below is a breakdown of the counsel of record for the plaintiff:

Williams & Connolly LLP

• David I. Berl

  • Role: Lead Counsel
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: David Berl is a highly experienced trial lawyer specializing in intellectual property litigation, particularly in pharmaceutical and biotechnology cases, including Hatch-Waxman and BPCIA disputes.

• Thomas S. Fletcher

  • Role: Counsel
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: Thomas Fletcher focuses on complex civil litigation, with significant experience in patent and intellectual property matters.

• Andrew V. Trask

  • Role: Counsel
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: Andrew Trask's practice includes patent litigation, particularly in the life sciences and technology sectors.

• Ellen E. Oberwetter

  • Role: Counsel
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: Ellen Oberwetter is involved in patent litigation, with experience in the pharmaceutical industry.

• Teagan J. Gregory

  • Role: Counsel (Admitted Pro Hac Vice)
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: Teagan Gregory's practice includes intellectual property disputes and complex commercial litigation.

• Shaun P. Mahaffy

  • Role: Counsel
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: Shaun Mahaffy practices complex civil litigation, including patent and antitrust matters.

• Kathryn S. Kayali (listed as Kathryn Schleckser Kayali)

  • Role: Counsel
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: Kathryn Kayali is involved in intellectual property and complex commercial litigation.

• Arthur J. Argall, III

  • Role: Counsel
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: Arthur Argall's practice includes patent and intellectual property litigation.

• Adam Pan

  • Role: Counsel
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: Adam Pan focuses on intellectual property and complex civil litigation.

• Rebecca A. Carter

  • Role: Counsel
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: Rebecca Carter's practice includes patent litigation and other complex commercial disputes.

• Haylee Bernal Anderson

  • Role: Counsel
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: Haylee Bernal Anderson is involved in patent litigation and other complex civil matters.

• Renee M. Griffin

  • Role: Counsel
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: Renee Griffin's practice includes intellectual property litigation.

• Jennalee Beazley

  • Role: Counsel
  • Firm & Office: Williams & Connolly LLP, Washington, DC
  • Experience Note: Jennalee Beazley is involved in patent and complex commercial litigation.

Paul, Weiss, Rifkind, Wharton & Garrison LLP

• Priyata Patel

  • Role: Counsel
  • Firm & Office: Paul, Weiss, Rifkind, Wharton & Garrison LLP, Washington, DC
  • Experience Note: Priyata Patel has experience in patent litigation, particularly in the pharmaceutical and life sciences sectors.

• Elizabeth Weiswasser

  • Role: Counsel
  • Firm & Office: Paul, Weiss, Rifkind, Wharton & Garrison LLP, New York, NY
  • Experience Note: Elizabeth Weiswasser is a leading patent litigator with extensive experience in pharmaceutical patent disputes, including Hatch-Waxman and BPCIA cases.

Kellogg, Hansen, Todd, Figel & Frederick, PLLC (listed as Kellogg Huber Hansen Todd Evans & Figel PLLC in some sources)

• Jacob Hartman
  • Role: Counsel
  • Firm & Office: Kellogg, Hansen, Todd, Figel & Frederick, PLLC, Washington, DC
  • Experience Note: Jacob Hartman's practice includes intellectual property litigation, particularly in high-stakes patent disputes.

Regeneron Pharmaceuticals, Inc. (In-House Counsel)

• Adam J. Bernstein

  • Role: In-House Counsel
  • Firm & Office: Regeneron Pharmaceuticals, Inc., Tarrytown, NY
  • Experience Note: As in-house counsel, Adam Bernstein manages intellectual property strategy and litigation for Regeneron.

• Arunabha Bhoumik

  • Role: In-House Counsel
  • Firm & Office: Regeneron Pharmaceuticals, Inc., Tarrytown, NY
  • Experience Note: Arunabha Bhoumik contributes to Regeneron's intellectual property and patent litigation efforts.

• James Evans

  • Role: In-House Counsel
  • Firm & Office: Regeneron Pharmaceuticals, Inc., Tarrytown, NY
  • Experience Note: James Evans is involved in intellectual property and patent enforcement strategies for Regeneron.

• Larry Coury (listed as Larry A. Coury)

  • Role: In-House Counsel
  • Firm & Office: Regeneron Pharmaceuticals, Inc., Tarrytown, NY
  • Experience Note: Larry Coury works on patent matters and litigation for Regeneron.

• Petra Scamborova

  • Role: In-House Counsel
  • Firm & Office: Regeneron Pharmaceuticals, Inc., Tarrytown, NY
  • Experience Note: Petra Scamborova contributes to Regeneron's in-house intellectual property legal team.

The following counsel represented the defendant(s), Mylan Pharmaceuticals Inc. and Biocon Biologics Inc., in Regeneron Pharmaceuticals, Inc. v. Mylan Pharmaceuticals Inc. et al., Case No. 1:22-cv-00061:

Rakoczy, Molino, Mazzochi, Siwik LLP (Chicago, IL) - Lead Counsel (admitted pro hac vice)

• Deanne M. Mazzochi (Partner)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Founding partner specializing in life sciences law, with a focus on pharmaceutical patent litigation, including Hatch-Waxman cases. She has extensive trial and appellate experience, including appearances before the U.S. Court of Appeals for the Federal Circuit, and has been recognized as a "Top Lawyer" in Intellectual Property, Copyright & Trademark, and Patent Law.
• William A. Rakoczy (Partner)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Co-founder of Rakoczy, Molino, Mazzochi, Siwik LLP.
• Heinz J. Salmen (Attorney)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Regularly appears on dockets for patent infringement cases.
• Eric R. Hunt (Attorney)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Regularly appears on dockets for patent infringement cases.
• Neil B. McLaughlin (Attorney)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Involved in patent litigation and Patent Trial and Appeal Board (PTAB) proceedings.
• Lauren M. Lesko (Attorney)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Involved in patent litigation.
• Lawrence Scott Beall (Attorney)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Involved in patent litigation.
• Steven J. Birkos (Attorney)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Involved in patent litigation.
• Thomas H. Ehrich (Attorney)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Involved in patent litigation.
• Jeffery A. Marx (Attorney)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Regularly appears on dockets for patent infringement cases.
• Katie A. Boda (Attorney)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Regularly appears on dockets for patent infringement cases.
• Abraham J. Varon (Attorney)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Regularly appears on dockets for patent infringement cases.
• Jake R. Ritthamel (Attorney)
  • Firm & Office: Rakoczy, Molino, Mazzochi, Siwik LLP, Chicago, IL.
  • Experience: Regularly appears on dockets for patent infringement cases.

Steptoe & Johnson PLLC (Bridgeport, WV) - Local Counsel

• Gordon H. Copland (Attorney)
  • Firm & Office: Steptoe & Johnson PLLC, Bridgeport, WV.
  • Experience: Admitted to the West Virginia State Bar (WVSB #828). Represented Mylan Pharmaceuticals Inc.
• William J. O'Brien (Attorney)
  • Firm & Office: Steptoe & Johnson PLLC, Bridgeport, WV.
  • Experience: Admitted to the West Virginia State Bar (WVSB #10549). Represented Mylan Pharmaceuticals Inc.
• John D. Pizzo (Attorney)
  • Firm & Office: Steptoe & Johnson PLLC, Bridgeport, WV.
  • Experience: Listed as counsel for defendants.
• Garrett Matthew Spiker (Attorney)
  • Firm & Office: Steptoe & Johnson PLLC, Bridgeport, WV.
  • Experience: Listed as counsel for defendants.
• Stephenee Raychel Gandee (Attorney)
  • Firm & Office: Steptoe & Johnson PLLC, Bridgeport, WV.
  • Experience: Listed as counsel for defendants.

Bernstein-Burkley, P.C.

• While Bernstein-Burkley, P.C. was identified as being retained by Mylan, specific attorneys from this firm were not consistently listed in the provided docket excerpts as counsel of record for the defendants. Therefore, no individual attorneys from this firm can be definitively identified with roles and specific experience based on the provided search results.