Regeneron Pharmaceuticals, Inc. v. Formycon AG

Regeneron Pharmaceuticals, Inc., a prominent American biotechnology company focused on developing and commercializing medicines for serious diseases including eye conditions, initiated this patent infringement lawsuit against Formycon AG, a German-based independent developer of high-quality biosimilar medicines. The core of the dispute centers on Formycon's proposed biosimilar product, FYB203, also known as Ahzantive® (aflibercept-mrbb), which is designed as a follow-on to Regeneron's blockbuster ophthalmic drug, EYLEA® (aflibercept) Injection 2 mg. The primary patent asserted in the litigation is U.S. Patent 11,084,865, which broadly covers stable liquid pharmaceutical formulations of a VEGF-specific fusion protein antagonist suitable for intravitreal administration, particularly emphasizing specific concentrations, buffering agents like sodium phosphate, and other excipients to maintain stability.

The case was filed in the U.S. District Court for the Northern District of West Virginia (Case No. 1:23-cv-00097), presided over by Chief Judge Thomas S. Kleeh. This venue has become a significant forum for Biologics Price Competition and Innovation Act (BPCIA) litigation, particularly for EYLEA biosimilar disputes, largely due to the historical presence of major generic and biosimilar manufacturers like Mylan (now Viatris) in the region and Judge Kleeh's developing expertise in these complex cases. The procedural posture saw the district court grant a preliminary injunction against Formycon, which the Federal Circuit subsequently affirmed, temporarily preventing Formycon from launching its biosimilar. Additionally, a related inter partes review (IPR) challenge, IPR2025-00233, at the Patent Trial and Appeal Board (PTAB) was denied institution, further strengthening Regeneron's patent position at the time.

This case is notable as part of a broader "aflibercept battle" initiated by Regeneron against multiple biosimilar competitors seeking to launch versions of EYLEA, a highly successful drug for eye diseases. While the prompt indicates the case is "Active," a significant development occurred on September 29, 2025, when Regeneron and Formycon reached a settlement agreement in the U.S. litigation. This settlement allows Formycon to launch its EYLEA biosimilar, Ahzantive®, in the U.S. in the fourth quarter of 2026, with all intellectual property-related litigation in the U.S. between the parties to be dismissed. A separate settlement also enabled a May 2026 launch in Europe and other territories. The initial preliminary injunction and its affirmation by the Federal Circuit were significant rulings that provided helpful guidance on litigating biosimilar cases, particularly concerning personal jurisdiction over foreign biosimilar developers and the requirements for injunctive relief under the BPCIA.

The litigation between Regeneron Pharmaceuticals, Inc. and Formycon AG concerning U.S. Patent 11084865 (the "'865 patent") has involved several key legal developments, progressing from initial filings to a settlement.

Key Legal Developments and Outcome:

• Filing & Initial Pleadings:

  • Regeneron filed its complaint against Formycon in the U.S. District Court for the Northern District of West Virginia on November 29, 2023, alleging infringement of U.S. Patent 11084865, among others, under the Biologics Price Competition and Innovation Act (BPCIA) (42 U.S.C. § 262(l)(9)(A) and 35 U.S.C. § 271(e)). The complaint sought declaratory judgment and a judgment of patent infringement. Formycon subsequently filed counterclaims.

• Pre-trial Motions of Substance:

  • On January 9, 2024, the Court entered a schedule for preliminary injunction proceedings, prompted by Regeneron's "emergency motion" for such a schedule.
  • Formycon, along with other defendants in related cases, filed motions to dismiss for lack of personal jurisdiction. Regeneron also sought jurisdictional discovery.
  • The case was later consolidated into multidistrict litigation (MDL No. 1:24-md-03103) in the Northern District of West Virginia, with a transfer order issued by the JPML on April 11, 2024.
  • Regeneron limited its motion for preliminary injunction against Formycon to the '865 patent. The district court, relying on Acorda Therapeutics Inc. v. Mylan Pharmaceuticals Inc., determined it had personal jurisdiction over Formycon.
  • In a sealed order issued on June 21, 2024, the district court granted Regeneron's motion for a preliminary injunction against Formycon. The public version of this opinion was available by January 29, 2025. The preliminary injunction enjoined Formycon from selling or offering for sale its biosimilar product, FYB203 (later known as Ahzantive®), without a license from Regeneron. The court found Regeneron was likely to succeed on its infringement claim and that Formycon had not raised a substantial question of invalidity (regarding obviousness-type double patenting or lack of written description) for the '865 patent. The court also found Regeneron would suffer irreparable harm, the balance of hardships favored Regeneron, and the public interest favored the injunction.
  • On July 10, 2024, the district court issued the formal Order for Injunctive Relief against Formycon.
  • On September 30, 2024, the Court denied Formycon's Motion to Dismiss without prejudice.

• Appeal of Preliminary Injunction:

  • Formycon filed a Notice of Appeal from the preliminary injunction order on June 25, 2024.
  • The Federal Circuit heard oral arguments for the Formycon appeal on December 5, 2024.
  • On January 29, 2025, the Federal Circuit affirmed the district court's preliminary injunction order against Formycon. The Federal Circuit's decision addressed personal jurisdiction over Formycon, whether the '865 patent was invalid for obviousness-type double patenting or lack of written description, and the causal nexus between infringement and irreparable harm.

• Parallel PTAB IPR Proceedings:

  • Formycon filed an Inter Partes Review (IPR) petition, IPR2025-00233, challenging U.S. Patent 11084865.
  • In June 2025, the Patent Trial and Appeal Board (PTAB) denied institution of Formycon's IPR petition (IPR2025-00233) and a related petition by Samsung Bioepis (IPR2025-00176). The PTAB exercised its discretion to deny institution under 35 U.S.C. § 314(a), without reaching the merits, by applying the Fintiv factors, noting that the investment in the parallel district court proceedings weighed heavily in favor of denial.

• Settlement and Dismissal:

  • On September 29, 2025, Formycon announced it reached a settlement agreement with Regeneron, leading to the dismissal of Case No. 1:23-cv-00097 (N.D.W. Va.) and the vacating of the preliminary injunction.
  • The settlement agreement allows Formycon to launch its Eylea® interchangeable biosimilar, Ahzantive® (aflibercept-mrbb), in the fourth quarter of 2026.
  • The stipulation and order dismissing all claims and counterclaims, vacating the preliminary injunction, and releasing the preliminary injunction bond was issued on September 29, 2025. All parties agreed to bear their own costs, disbursements, and attorneys' fees.

Regeneron Pharmaceuticals, Inc. is represented by a team of in-house counsel and attorneys from several prominent law firms in its patent infringement case against Formycon AG (1:23-cv-00097) in the U.S. District Court for the Northern District of West Virginia, as well as in related consolidated proceedings and appeals. The counsel of record includes:

In-House Counsel:

• James Evans

  • Role: Senior Director and Assistant General Counsel, Disputes Resolution Group.
  • Firm: Regeneron Pharmaceuticals, Inc. (in-house).
  • Experience: Oversees worldwide patent litigation matters before various courts and regulatory agencies for Regeneron. His practice previously focused on intellectual property litigation in pharmaceutical, biotechnology, and biologics patents, representing and counseling major innovative pharmaceutical companies on matters including pharmaceutical compounds, immunotherapeutics, vectors, and vaccines.

• Joseph J. LaRosa

  • Role: Executive Vice President, General Counsel and Secretary.
  • Firm: Regeneron Pharmaceuticals, Inc. (in-house).
  • Experience: Publicly stated Regeneron's position in significant patent litigation, including an antitrust lawsuit where Regeneron prevailed over Amgen, demonstrating his involvement in high-stakes legal strategy and protection of Regeneron's innovations.

Outside Counsel:

• David I. Berl

  • Role: Lead Counsel.
  • Firm: Williams & Connolly LLP, Washington, DC.
  • Experience: Argued for Regeneron Pharmaceuticals, Inc. (Plaintiff-Appellee) in a Federal Circuit appeal that included cases consolidated under the Aflibercept Patent Litigation MDL, specifically mentioning 1:23-cv-00097.

• Andrew V. Trask

  • Role: Counsel.
  • Firm: Williams & Connolly LLP, Washington, DC.
  • Experience: Listed as counsel for Regeneron in Federal Circuit appeal documents for the Aflibercept Patent Litigation, which encompasses case 1:23-cv-00097.

• Arthur John Argall, III

  • Role: Counsel.
  • Firm: Williams & Connolly LLP, Washington, DC.
  • Experience: Listed as counsel for Regeneron in Federal Circuit appeal documents for the Aflibercept Patent Litigation.

• Thomas S. Fletcher

  • Role: Counsel.
  • Firm: Williams & Connolly LLP, Washington, DC.
  • Experience: Listed as counsel for Regeneron in Federal Circuit appeal documents for the Aflibercept Patent Litigation.

• Christian Gladden-Sorensen

  • Role: Counsel.
  • Firm: Williams & Connolly LLP, Washington, DC.
  • Experience: Listed as counsel for Regeneron in Federal Circuit appeal documents for the Aflibercept Patent Litigation.

• Kathryn Schleckser Kayali

  • Role: Counsel.
  • Firm: Williams & Connolly LLP, Washington, DC.
  • Experience: Listed as counsel for Regeneron in Federal Circuit appeal documents for the Aflibercept Patent Litigation.

• Rhochelle Krawetz

  • Role: Counsel.
  • Firm: Williams & Connolly LLP, Washington, DC.
  • Experience: Listed as counsel for Regeneron in Federal Circuit appeal documents for the Aflibercept Patent Litigation.

• Shaun Patrick Mahaffy

  • Role: Counsel.
  • Firm: Williams & Connolly LLP, Washington, DC.
  • Experience: Listed as counsel for Regeneron in Federal Circuit appeal documents for the Aflibercept Patent Litigation.

• Charles McCloud

  • Role: Counsel.
  • Firm: Williams & Connolly LLP, Washington, DC.
  • Experience: Listed as counsel for Regeneron in Federal Circuit appeal documents for the Aflibercept Patent Litigation.

• Adam Pan

  • Role: Counsel.
  • Firm: Williams & Connolly LLP, Washington, DC.
  • Experience: Listed as counsel for Regeneron in Federal Circuit appeal documents for the Aflibercept Patent Litigation.

• Jacob Hartman

  • Role: Counsel.
  • Firm: Kellogg, Hansen, Todd, Figel & Frederick, PLLC, Washington, DC.
  • Experience: Listed as counsel for Regeneron in Federal Circuit appeal documents for the Aflibercept Patent Litigation.

• Priyata Patel

  • Role: Counsel.
  • Firm: Paul, Weiss, Rifkind, Wharton & Garrison LLP, Washington, DC.
  • Experience: Listed as counsel for Regeneron in Federal Circuit appeal documents for the Aflibercept Patent Litigation.

• Elizabeth Weiswasser

  • Role: Counsel.
  • Firm: Paul, Weiss, Rifkind, Wharton & Garrison LLP, New York, NY.
  • Experience: Listed as counsel for Regeneron in Federal Circuit appeal documents for the Aflibercept Patent Litigation.

Other attorneys, such as Michael J. Flibbert and Barbara R. Rudolph from Finnegan, Henderson, Farabow, Garrett & Dunner, LLP, and Daniel E. Orr, are known for their patent litigation and regulatory expertise for pharmaceutical and biotechnology companies and have been associated with Regeneron in other contexts (e.g., PTAB proceedings, general patent work), but their specific appearance as counsel of record for Regeneron in the 1:23-cv-00097 case against Formycon AG could not be definitively confirmed from the provided snippets that explicitly list counsel for this particular case. Similarly, while Steptoe & Johnson PLLC is mentioned in the context of the MDL (In Re: Aflibercept Patent Litigation 1:2024md03103), specific attorneys representing Regeneron from this firm in the Formycon case were not explicitly identified in the provided search results.

I'll research Formycon AG's counsel of record in this case using multiple searches.

Let me verify with the actual docket and additional sources.

Let me confirm the Fish & Richardson transition and the Federal Circuit appeal counsel.

Counsel of Record for Defendant Formycon AG — Regeneron Pharmaceuticals, Inc. v. Formycon AG, No. 1:23-cv-00097-TSK (N.D. W. Va.)

Bottom line: Formycon's defense team was a two-tier structure — local West Virginia counsel from Thomas Combs & Spann, PLLC (Charleston), working with national patent/biosimilar counsel who began the case at Jenner & Block LLP and mid-case moved (Fogel and Van Horn) to Fish & Richardson P.C. No Formycon in-house U.S. counsel appeared on the docket; all defendant-side appearances were outside counsel. Because the case settled and was dismissed on September 29, 2025, this is now a historical appearance roster.

⚠️ Contradiction to flag against the earlier-generated "Plaintiff representatives" section: that section attributes Weil Gotshal / Williams & Connolly / Kellogg Hansen / Paul Weiss / Carey Douglas Kessler & Ruby personnel to Regeneron. That is correct. Note however that several non-authoritative aggregators (Docket Alarm and CourtListener OCR extractions of the MDL joint filings) interleave signature blocks such that Hissam Forman Donovan Ritchie PLLC, Gemini Law LLP, and Willkie Farr & Gallagher LLP appear under a "Counsel for Defendant Formycon AG" heading. Those three firms were Celltrion's counsel, not Formycon's — the OCR merged the Celltrion signature page with the Formycon signature page of the same joint MDL motion. Similarly, a pearceip.law PDF captioned "Counsel for Defendant Formycon AG /s/ Steven R. Ruby" is mislabeled; Steven R. Ruby (Carey Douglas Kessler & Ruby, PLLC) was Regeneron's West Virginia local counsel.

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1. Local counsel (admitted in the N.D. W. Va.)

Note: The withdrawal notice states that "M. David Griffith, Jr., who has already appeared as counsel of record, will continue to appear as counsel for Formycon AG, along with other counsel for Formycon AG, who have been admitted pro hac vice." Thomas Combs & Spann is a Charleston litigation firm; I found no independent confirmation in the retrieved sources of specific prior patent/biosimilar matters for either attorney, so I will not characterize their patent experience beyond confirming their role as the WV-bar counsel of record.

2. National/lead counsel — Fish & Richardson P.C. (from February 2024) and Jenner & Block LLP (at case inception)

3. Procedural trail establishing these appearances

1. At filing (Nov. 29, 2023): Regeneron's Dec. 22, 2023 declaration in support of its motion for alternative service (S.D. W. Va./N.D. W. Va. docket, Decl. of Andrew E. Goldsmith) identifies Shaun Van Horn of Jenner & Block LLP as "counsel for Formycon AG" — i.e., Jenner & Block was Formycon's U.S. counsel from the outset (PTAB exhibit copy: ptacts.uspto.gov petition 1557260).
2. Jan. 26, 2024: Terri L. Mascherin filed a Notice of Appearance on behalf of Formycon AG in the JPML MDL No. 3103 proceeding, listing the associated case as WVN/1:23-cv-00097.
3. Feb. 9, 2024: The MDL proof of service lists Formycon's counsel as Bryant J. Spann and M. David Griffith, Jr. (Thomas Combs & Spann, PLLC) plus Louis E. Fogel, Shaun M. Van Horn, and Terri L. Mascherin (Jenner & Block LLP – Chicago).
4. Feb. 23, 2024: Formycon filed a Notice of Change of Attorney Contact Information (docketed at mywvbar.org), stating that Fogel and Van Horn were now at Fish & Richardson P.C., 60 South 6th Street, Suite 3200, Minneapolis, MN 55402 (fogel@fr.com / vanhorn@fr.com), while Mascherin remained at Jenner & Block.
5. May 10, 2024 – Sept. 13, 2024: Formycon's filings in this case and in the MDL carry signature blocks of Spann/Griffith (local) with Fish & Richardson (Fogel, Van Horn, Oakes, Crisler, McCormick, Burgener, Wu) and Jenner & Block (Mascherin) as of counsel. Docket Alarm/CourtListener copies are accessible via storage.courtlistener.com/recap/gov.uscourts.wvnd.58993/ and docketalarm.com (docs. 186, 215).
6. Sept. 10, 2025 (filed just before the Sept. 29, 2025 settlement): Formycon's Notice of Withdrawal of Counsel withdraws Shaun M. Van Horn as pro hac vice counsel of record. This is the last counsel-focused docket event I located in this case.

4. Appellate counsel (Fed. Cir. No. 2024-2009, Formycon AG v. Regeneron)

Formycon's preliminary-injunction appeal was docketed at the Federal Circuit as No. 2024-2009 (per the June 28, 2024 Notice of Docketing filed in the district court, which names Appellant: Formycon AG), decided with the companion Samsung Bioepis appeal on January 29, 2025. The Federal Circuit opinion notes that at the December 5, 2024 oral argument "Formycon's counsel only [addressed] the personal-jurisdiction issue," while SB's counsel handled the non-jurisdictional issues.

I could not confirm from the retrieved sources the specific attorney who argued for Formycon at the Federal Circuit, and I did not retrieve the counsel-listing page of the 2024-2009 opinion (the Justia/CourtListener PDF I found is the consolidated SB opinion, 24-1965, which lists only SB's appellate counsel — William Adams, Laura Fairneny, Raymond Nimrod, Matthew D. Robson, Matthew A. Traupman, Lauren Martin of Quinn Emanuel). Given the district-court record, the likely appellate team was the Fish & Richardson (Fogel/Van Horn) group, but I am not asserting that as fact without the counsel page. I'd recommend pulling the 2024-2009 opinion PDF from cafc.uscourts.gov or the oral-argument recording page (oralarguments.cafc.uscourts.gov/?fl=24-2009_12052024.mp3) to confirm.

5. Caveats

• No sealed appearance information is at issue — all counsel identified above appear on public signature blocks, notices of appearance, or withdrawal notices. Formycon's IPR2025-00233 petition counsel may differ; I did not verify that roster here.
• Appearance listings are drawn from JPML MDL No. 3103 filings, the case docket extracts reproduced by Docket Alarm/CourtListener, a West Virginia State Bar–hosted filing (mywvbar.org), PTAB exhibit copies of district-court papers, and firm/press announcements — not from a live PACER pull of the full docket sheet. Individual docket entry numbers for the Formycon appearances in 1:23-cv-00097 (e.g., the pro hac vice motions and the notices of appearance) were not independently confirmed; treat the specific docket numbers cited in the earlier-generated sections as authoritative to the extent they came from a direct docket pull.
• Since the parties stipulated to dismissal of all claims and counterclaims on September 29, 2025, all of these attorneys' appearances terminated with that dismissal, subject to any obligation to complete the withdrawal/termination process in CM/ECF.