Biocon Biologics, Inc. et al. v. Regeneron Pharmaceuticals, Inc.

This case represents a strategic challenge by a biosimilar drug manufacturer against a key patent protecting a blockbuster biologic treatment for eye disease. The petitioner, Biocon Biologics, is a global, fully integrated biosimilar company based in India that develops and commercializes lower-cost versions of established biologic medicines. The patent owner, Regeneron Pharmaceuticals, is a major U.S.-based biotechnology company known for inventing, developing, and commercializing innovative medicines, including its highly successful drug Eylea®. The dispute centers on Regeneron's high-dose formulation of Eylea®, marketed as Eylea HD®, a treatment for serious retinal conditions like wet age-related macular degeneration (AMD) and diabetic macular edema (DME). Biocon has already developed Yesafili™, an approved biosimilar to the original 2 mg version of Eylea®, and this challenge targets a patent protecting the newer, high-dose 8 mg formulation.

The proceeding is a Post-Grant Review (PGR) filed at the U.S. Patent and Trademark Office's Patent Trial and Appeal Board (PTAB), an administrative venue for challenging the validity of newly issued patents. The patent at issue, U.S. Patent No. 12,168,036, covers methods of treating angiogenic eye disorders by administering a high-dose, high-concentration formulation of a VEGF receptor fusion protein, the class of drug to which Eylea® (aflibercept) belongs. Procedurally, Biocon's petition (PGR2026-00039), filed on April 2, 2026, is substantively identical to a prior PGR filed by another biosimilar competitor, Alvotech (PGR2025-00085), which the PTAB has already instituted. Biocon is seeking to join its case with Alvotech's, a common strategy to efficiently participate in an ongoing validity challenge.

This case is notable as part of a multi-front battle over the multi-billion dollar market for Eylea®. Eylea HD® represents a critical life-cycle extension strategy for Regeneron, offering less frequent dosing for patients, but it faces intense competition from biosimilar developers like Biocon and Alvotech. These companies use PTAB proceedings as a key tool to clear patent hurdles that could otherwise block the launch of their more affordable biosimilar versions. Such challenges often run in parallel with district court litigation under the Biologics Price Competition and Innovation Act (BPCIA). Biocon and Regeneron previously settled litigation over the original Eylea®, paving the way for a 2026 launch of Biocon's Yesafili™ biosimilar. This new PTAB challenge on the high-dose version underscores the ongoing strategic patent disputes that define the entry of biosimilar competition for major biologic drugs.

Key Legal Developments in PTAB Post-Grant Review

As of the current date, May 5, 2026, this matter is an active Post-Grant Review (PGR) at the Patent Trial and Appeal Board (PTAB) and has not involved district court litigation between Biocon and Regeneron over this specific patent. The key developments are centered on Biocon's petition to invalidate Regeneron's patent on a high-dose formulation of Eylea® and its strategic move to join a parallel proceeding.

Chronology of Developments

2025-09-17: Parallel PGR Filed by Alvotech
A related proceeding began when Alvotech, another biosimilar competitor, filed a PGR petition (PGR2025-00085) challenging the validity of U.S. Patent No. 12,168,036. Alvotech's petition argued that the patent's claims covering the high-dose Eylea HD® formulation were invalid due to, among other grounds, obviousness and lack of written description.

2026-03-03: Alvotech's PGR is Instituted
The PTAB determined that Alvotech established a sufficient likelihood of prevailing on its arguments and instituted a trial on the validity of the '036 patent.

2026-04-02: Biocon Files PGR Petition and Motion for Joinder
Biocon Biologics, Inc. and Biocon Biologics Limited filed their own PGR petition, assigned case number PGR2026-00039, against Regeneron's '036 patent. The petition challenges claims 1-38, asserting invalidity on grounds of obviousness and lack of written description, similar to the arguments made by Alvotech.

Concurrently, Biocon filed a motion to join its case with the already-instituted Alvotech PGR (PGR2025-00085). The petition filed by Biocon is described as "substantively identical" to Alvotech's, a common strategy for a second petitioner to efficiently enter an ongoing validity challenge without re-litigating the same initial issues.

Present Posture and Next Steps

The case is currently in its earliest stages. The most critical pending event is the PTAB's decision on Biocon's motion for joinder.

• Pending Motion for Joinder: The PTAB must decide whether to grant Biocon's request to join the Alvotech PGR. If granted, Biocon will become a party to the PGR2025-00085 proceeding, and its own case (PGR2026-00039) will likely be terminated as redundant. Joinder would allow Biocon to participate fully in the trial, including discovery, motions, and the oral hearing.
• No District Court Litigation on the '036 Patent: As of this date, no parallel district court litigation between Biocon and Regeneron concerning the '036 patent has been identified. This is distinct from previous litigation between the parties over Biocon's biosimilar to the original 2mg version of Eylea®, which was settled in April 2025. That settlement paved the way for a 2026 launch of Biocon's Yesafili™ product and dismissed all then-pending intellectual property litigation in the U.S. between the two companies.
• Outcome of Alvotech PGR is Key: The ultimate outcome of this dispute for Biocon is currently tied to the fate of the underlying Alvotech PGR. A final written decision in that proceeding, which will determine whether Regeneron's patent claims are valid, will directly impact both Alvotech and Biocon if joinder is granted.

No substantive pre-trial motions, claim construction, or discovery milestones have occurred yet in Biocon's specific PGR, as the proceeding awaits the decision on joinder.

Counsel for Petitioner Biocon Biologics

Based on the Post-Grant Review (PGR) petition filed with the Patent Trial and Appeal Board (PTAB), counsel for petitioners Biocon Biologics, Inc. and Biocon Biologics Limited are from the law firm Sterne, Kessler, Goldstein & Fox P.L.L.C.

• J.C. Rozendaal (Lead Counsel)

  • Firm: Sterne, Kessler, Goldstein & Fox P.L.L.C., Washington, D.C.
  • Note: Rozendaal is a director at Sterne Kessler and chairs the firm's litigation group, with extensive experience in high-stakes pharmaceutical and biosimilar patent litigation, including cases before district courts, the Federal Circuit, and the PTAB.

• William H. Milliken (Lead Counsel)

  • Firm: Sterne, Kessler, Goldstein & Fox P.L.L.C., Washington, D.C.
  • Note: Milliken is a director in the Biotechnology & Chemical Practice Group and a founding member of the firm, known for his expertise in patent prosecution, interferences, and PTAB trials involving biologics and pharmaceuticals.

• Michael J. Speare (Counsel)

  • Firm: Sterne, Kessler, Goldstein & Fox P.L.L.C., Washington, D.C.
  • Note: Speare is a director at Sterne Kessler focusing on patent litigation and PTAB proceedings, particularly within the biotechnology and pharmaceutical industries.

• Anna G. Phillips (Counsel)

  • Firm: Sterne, Kessler, Goldstein & Fox P.L.L.C., Washington, D.C.
  • Note: Phillips is an associate at the firm whose practice includes PTAB trials and district court litigation related to biotechnology and pharmaceutical patents.

• Paul A. Calvo, Ph.D. (Counsel)

  • Firm: Sterne, Kessler, Goldstein & Fox P.L.L.C., Washington, D.C.
  • Note: Calvo is a director at Sterne Kessler with a practice concentrated on post-grant proceedings and strategic counseling for biosimilar and biotechnology clients.

As of May 6, 2026, Regeneron Pharmaceuticals, Inc. has not yet filed a formal notice of appearance in Biocon Biologics, Inc. et al. v. Regeneron Pharmaceuticals, Inc., PGR2026-00039. This is expected, as the case is in its earliest stage, awaiting a decision on Biocon's motion to join the parallel, instituted Post-Grant Review, Alvotech v. Regeneron Pharmaceuticals, Inc., PGR2025-00085.

The counsel representing Regeneron in the Alvotech PGR are certain to represent the company in the Biocon matter. The legal team that filed the Patent Owner's Preliminary Response in the Alvotech proceeding is listed below.

Defendant's Counsel of Record

The following attorneys from Jenner & Block LLP represent Regeneron Pharmaceuticals, Inc. in the related PTAB proceeding and are expected to serve as counsel in this matter.

• Name: Adam G. Unikowsky

  • Role: Lead Counsel
  • Firm: Jenner & Block LLP, Washington, D.C. office.
  • Note: A seasoned appellate and patent litigator, Unikowsky has argued numerous cases before the U.S. Supreme Court and the Federal Circuit, often representing major pharmaceutical and technology companies in high-stakes IP disputes.

• Name: Michael J. Krol

  • Role: Counsel
  • Firm: Jenner & Block LLP, Washington, D.C. office.
  • Note: Krol's practice focuses on patent litigation before the PTAB and federal district courts, with an emphasis on the life sciences and biotechnology sectors.

• Name: Fernando A. Ocampo

  • Role: Counsel
  • Firm: Jenner & Block LLP, Washington, D.C. office.
  • Note: Ocampo specializes in patent and appellate litigation, frequently representing clients in the pharmaceutical industry in matters involving the Hatch-Waxman Act and the BPCIA.

• Name: Michael T. Werner

  • Role: Counsel
  • Firm: Jenner & Block LLP, Washington, D.C. office.
  • Note: Werner has significant experience in PTAB trial proceedings, including inter partes reviews and post-grant reviews, often involving complex pharmaceutical patents.