Alvotech v. Regeneron Pharmaceuticals, Inc.

This dispute represents a critical battle in the high-stakes biosimilar market, pitting Icelandic biopharmaceutical company Alvotech against U.S. biotechnology giant Regeneron Pharmaceuticals, Inc. Alvotech is a global biopharmaceutical company focused exclusively on developing and manufacturing biosimilar medicines to increase patient access to more affordable treatments. Regeneron is a prominent, research-driven operating company known for inventing and commercializing blockbuster drugs, most notably Eylea® (aflibercept), a leading treatment for serious retinal diseases. The conflict is a classic brand-versus-biosimilar fight, centered on Alvotech's efforts to bring a lower-cost alternative to one of Regeneron's most profitable products to the U.S. market.

The central issue is the patent validity of Regeneron's high-dose version of its drug, marketed as Eylea HD®. Alvotech has developed a proposed biosimilar, and this administrative litigation seeks to invalidate the intellectual property protecting Regeneron's new product iteration. The patent at issue is U.S. Patent No. 12,168,036, which covers methods of treating eye disorders with a high-dose (at least 8 mg), high-concentration formulation of a VEGF receptor fusion protein like aflibercept. Alvotech alleges the patent is invalid on grounds of obviousness and lack of written description, arguing that creating a more concentrated version of the original drug was not a patentable invention.

The case, PGR2025-00085, is a Post-Grant Review (PGR) proceeding before the Patent Trial and Appeal Board (PTAB), a specialized tribunal within the U.S. Patent and Trademark Office. This venue is strategically important for Alvotech because a PGR must be filed within nine months of a patent’s grant and permits a wider range of invalidity challenges than other PTAB proceedings. The PTAB has instituted the review, meaning Alvotech successfully demonstrated a reasonable likelihood that it would prevail in challenging at least one of the patent's claims. This case is highly notable due to Eylea's multi-billion dollar annual sales and is just one part of a complex web of global litigation between Regeneron and multiple biosimilar developers. The outcome of this PGR will significantly influence the competitive landscape for ophthalmic biologics and could accelerate the market entry of a biosimilar to Eylea HD®, potentially saving the healthcare system millions. The importance of this patent is underscored by the fact that another biosimilar maker, Biocon, has also filed a PGR and requested to join Alvotech's challenge.

Key Legal Developments

Below is a chronological list of the key developments in the Post-Grant Review (PGR) of U.S. Patent No. 12,168,036, including parallel proceedings influencing the case.

2024-12-17: Patent Grant
The United States Patent and Trademark Office (USPTO) issues U.S. Patent No. 12,168,036, titled “Methods for Treating Angiogenic Eye Disorders with High Doses of VEGF Receptor Fusion Proteins,” to Regeneron Pharmaceuticals, Inc. The patent covers methods of treatment using a high-dose (at least 8 mg), high-concentration formulation of aflibercept, the active ingredient in Eylea HD®.

2025-09-17: Alvotech Files Petition for Post-Grant Review
Alvotech files a petition for Post-Grant Review, initiating case PGR2025-00085 at the Patent Trial and Appeal Board (PTAB). Alvotech challenges all 38 claims of the '036 patent on grounds of obviousness and lack of written description. The petitioner argues that creating a high-concentration, high-dose version of aflibercept was an unpatentable and obvious step for a person of ordinary skill in the art, contending that Regeneron had previously disclosed the key elements and that there was no "viscosity problem" to be solved, contrary to arguments made during prosecution.

2025-11-26 (approx.): Regeneron Files Patent Owner's Preliminary Response
Regeneron files its preliminary response to Alvotech's petition. In this filing, Regeneron argues that the PTAB should exercise its discretion and deny institution of the PGR. According to a subsequent Alvotech filing, Regeneron contended that the claims were valid and that the USPTO should decline to review the patent.

2026-03-03: PTAB Institutes Post-Grant Review
The PTAB institutes the Post-Grant Review, determining that Alvotech has established a reasonable likelihood that it would prevail in challenging at least one of the patent's claims. This decision formally begins the trial phase of the proceeding. The institution decision was reportedly made without a detailed written opinion, a practice that can occur under the USPTO Director's revised procedures for institution decisions that took effect in late 2025.

2026-04-02: Parallel Challenge Filed by Biocon with Request for Joinder
Another biosimilar competitor, Biocon, files its own petition for Post-Grant Review of the '036 patent (PGR2026-00039). Biocon’s petition is substantively identical to Alvotech’s and includes a motion to be joined to the already-instituted PGR2025-00085. This move signals a consolidated effort by biosimilar makers to invalidate the patent protecting Eylea HD®.

Present Posture & Next Steps

As of May 6, 2026, the PGR is in the trial phase. Key upcoming events governed by a scheduling order (which has not been made public) will include:

• Decision on Biocon's Motion for Joinder: The PTAB must rule on whether to join Biocon's challenge with Alvotech's ongoing PGR.
• Patent Owner's Response: Regeneron is due to file its comprehensive response to the invalidity contentions raised in Alvotech's petition.
• Discovery, Petitioner's Reply, and Oral Hearing: Following Regeneron's response, the parties will proceed through a discovery period, the filing of a reply by Alvotech, and ultimately an oral hearing before a panel of PTAB judges. A final written decision on the patentability of the challenged claims is statutorily due within one year of institution, by approximately March 3, 2027.

There is no public record of a parallel district court litigation between Alvotech and Regeneron specifically concerning the '036 patent at this time. Such litigation is common under the Biologics Price Competition and Innovation Act (BPCIA), and if filed, a motion to stay the district court case pending the outcome of this PGR would be expected. The broader context includes numerous settlements between Regeneron and other biosimilar developers (including Alvotech and Biocon) related to the original 2mg version of Eylea, but those agreements do not resolve the dispute over the high-dose formulation covered by the '036 patent.

Counsel for Petitioner Alvotech

Based on a review of documents filed in the Post-Grant Review proceeding, the petitioner Alvotech is represented by attorneys from the law firm Goodwin Procter LLP.

Outside Counsel

Name	Role	Firm	Location	Notable Experience
Darlene C. Staines	Lead Counsel	Goodwin Procter LLP	Washington, D.C.	Her involvement was noted in an article covering the PGR filing. Specific details on her past cases were not available in the search results.
Natasha E. Daughtrey	Of Counsel	Goodwin Procter LLP	Boston, MA	Co-author of an article on a BPCIA complaint, indicating experience in biosimilar litigation. Further specific case experience was not identified.
Christopher R. Cassella	Of Counsel	Goodwin Procter LLP	Boston, MA	Also credited on an article regarding a BPCIA complaint, suggesting a focus on biosimilar-related patent law. Additional details on his litigation history were not found.

In-House Counsel

While specific in-house attorneys at Alvotech who are directly managing this PGR are not named in the filings, the following individuals hold key legal leadership roles within the company:

Name	Role	Firm	Location	Notable Experience
Tanya Zharov	General Counsel	Alvotech	Reykjavik, Iceland	Holds a Cand. Juris law degree and is a European Patent Attorney with over 25 years of experience in biotechnology and healthcare.
Philip A. Caramanica, Jr.	Chief IP Counsel & Deputy General Counsel	Alvotech	(Assumed U.S. based)	A U.S. patent attorney with over 20 years of experience, including roles as head of IP for biologics at Synthon and senior patent counsel at Sandoz.

Note: The specific attorneys from Goodwin Procter LLP were identified through their reporting on the case via the firm's "Big Molecule Watch" publication, which announced the filing of this PGR on September 19, 2025. Direct docket entries explicitly naming lead and back-up counsel were not available in the immediate search results, which is not uncommon for PTAB proceedings where some documents are not publicly accessible without direct access to the PTAB's filing system. The identification of Goodwin Procter is based on strong circumstantial evidence from their consistent and detailed reporting on this specific case.

Counsel for Defendant: Regeneron Pharmaceuticals, Inc.

Based on a review of documents filed in Post-Grant Review (PGR) proceeding PGR2025-00085, the counsel of record for patent owner Regeneron Pharmaceuticals, Inc. has not been publicly identified in available dockets or legal news reporting as of May 6, 2026.

Under 37 C.F.R. § 42.8, a patent owner has 21 days from the service of a petition to file Mandatory Notices, which must identify the lead and back-up counsel for the proceeding. Alvotech's petition was filed on September 17, 2025. Regeneron's responsive filings, including its Power of Attorney and Mandatory Notices that would name its legal representatives, have not yet been made publicly available through general legal research channels.

While Foley Hoag LLP frequently represents Regeneron in patent prosecution and litigation, including PTAB proceedings, their appearance in this specific matter has not been confirmed. Similarly, other firms with established relationships with Regeneron in the intellectual property space have not been named in connection with this case.

This section will be updated upon the public filing or reporting of Regeneron's Power of Attorney or Mandatory Notices in PGR2025-00085.