- within Transport and Cannabis & Hemp topic(s)
This past year contained a number of significant developments in litigation involving biologics and biosimilars. The following is a recap of the top three legal developments that we covered on the Big Molecule Watch last year.
- The Aflibercept BPCIA Litigations Start to Resolve
As in 2023 and 2024, Regeneron's multi-district litigation in the Northern District of West Virginia against aflibercept biosimilar competitors once again topped our list.
Notably, before 2025, the Federal Circuit had issued very little decisions on the merits of an injunction in a BPCIA case. That changed in 2025, with three new decisions, all stemming from the aflibercept disputes.
The year kicked off with a win for Regeneron. On January 29, 2025, the Federal Circuit affirmed the district court's entries of preliminary injunction preventing Samsung Bioepis Co., Ltd. ("Samsung") and Formycon AG ("Formycon") from marketing their aflibercept biosimilars. The Federal Circuit agreed with that the district court that there was personal jurisdiction over Samsung and Formycon, and that the defendants had not raised a "substantial question of invalidity" of the asserted claims of the '865 patent.
On March 5, 2025, the Federal Circuit affirmed the district court's entry of a preliminary injunction preventing Celltrion, Inc. ("Celltrion") from launching CT-P42, its aflibercept biosimilar of EYLEA®. The Federal Circuit concluded that Celltrion's conduct also satisfied the minimum-contacts requirement for personal jurisdiction, and that Celltrion had not raised a substantial question of invalidity of the '865 patent based on obviousness-type double patenting.
Just a few weeks later, on March 14, 2025, Regeneron was hit with a loss at the Federal Circuit. The Federal Circuit affirmed the district court's denial of a preliminary injunction against Amgen Inc., holding that Regeneron had not established a likelihood of success on the merits of its infringement allegations. The claims were directed to an ophthalmic formulation with, among other elements, "a vascular endothelial growth factor (VEGF) antagonist" and a "buffer." The Federal Circuit agreed with the district court that Amgen's formulation did not contain a "buffer," and therefore Regeneron had not shown a likelihood of success on the merits.
After the string of Federal Circuit decisions, several of the pending aflibercept cases reached a resolution.
- In April 2025, while their appeal to overturn a permanent injunction granted against them was pending, Mylan and Biocon entered into a settlement agreement with Regeneron that allows Biocon and Mylan to launch their aflibercept biosimilar, YESAFILI® (aflibercept-jbvf), in the United States in the second half of 2026 or earlier.
- In September 2025, Sandoz and Regeneron entered into a settlement agreement that allows Sandoz to launch its aflibercept biosimilar, ENZEEVU® (aflibercept-abzv) in the fourth quarter of 2026 or earlier.
- Later in September 2025, Formycon and Regeneron entered into a settlement agreement that allows Formycon to launch its aflibercept biosimilar, AHZANTIVE® (aflibercept-mrbb) in the fourth quarter of 2026 or earlier.
- In October 2025, just over a week before Celltrion was expected to file a motion to dissolve the preliminary injunction granted against them, Celltrion and Regeneron entered into a settlement agreement that allows Celltrion to launch its aflibercept biosimilar, EYDENZELT® (aflibercept-boav), on December 31, 2026.
- Finally, in December 2025, prior to litigation, Alvotech and Teva entered into a settlement agreement with Regeneron that allows Alvotech and Teva to launch their proposed aflibercept biosimilar candidate, AVT06, in the fourth quarter of 2026 or earlier.
Despite being the first to launch an aflibercept biosimilar, Amgen remains in active litigation against Regeneron. In June 2025, Regeneron filed another complaint against Amgen—alleging that Amgen's PAVBLU infringed a new patent, U.S. Patent No. 12,331,099, that issued after PAVBLU had launched. Amgen responded by filing counterclaims alleging patent misuse, antitrust violations, and unfair competition. Regeneron subsequently moved to strike or dismiss some of these counterclaims and bifurcate or stay Amgen's antitrust claims. The district court has yet to rule on those motions.
Regeneron's case against Amgen and its case against Samsung are the only remaining matters in the aflibercept multidistrict litigation. A Markman hearing for both cases is scheduled for November 23, 2026.
- Denosumab BPCIA Litigations Continue To Expand Despite Settlements
Denosumab BPCIA litigations continued to expand in 2025, with Amgen filing six new complaints against Alkem, Amneal, Hikma/Gedeon, Dr. Reddy's/Alvotech, Biocon, and Henlius, each concerning the companies' respective denosumab biosimilars.
These new cases were in addition to several ongoing litigations, which Amgen sought to consolidate in late 2024. In February 2025, the U.S. Judicial Panel on Multidistrict Litigation granted Amgen's motion to transfer and consolidate the active denosumab BPCIA litigations in the District of New Jersey. At the time of the motion, the four pending denosumab BPCIA litigations were at different stages: the Celltrion case was in fact discovery with a potential expedited trial only months away; the Samsung case was in early fact discovery; and the Fresenius Kabi and Accord Biopharma cases remained at the pleading stage. Nonetheless, the panel found consolidation appropriate because the actions shared common factual issues—including infringement, claim construction, and patent‑validity questions. The panel also concluded that the cases almost certainly would involve overlapping patents because each proposed biosimilar was necessarily similar to Amgen's reference product.
Although denosumab litigation remained highly active in 2025, several disputes were resolved. In January 2025, shortly before the multi-district panel issued its consolidation opinion, Celltrion became the second company—after Sandoz—to settle its denosumab BPCIA litigation with Amgen. Under the agreement, Celltrion was enjoined from launching its biosimilars, STOBOCLO® (denosumab‑bmwo) and OSENVELT® (denosumab‑bmwo), in the United States until June 2025. Over the remainder of the year, Amgen also resolved its denosumab BPCIA litigations with Fresenius, Accord, Samsung, Biocon, and Hikma/Gedeon—paving the way for these companies to bring their biosimilars to the U.S. market.
With these newly filed complaints and recent settlements, Amgen's cases against Alkem, Amneal, Dr. Reddy's/Alvotech, and Shanghai Henlius remain pending in the denosumab multi-district litigation.
- The First Pertuzumab BPCIA Litigation Is Filed
In August 2025, Genentech commenced the first BPCIA litigation against a proposed biosimilar of its PERJETA® (pertuzumab) product when it filed a complaint in the District of New Jersey against Henlius and Organon regarding their pertuzumab biosimilar POHERDY® (pertuzumab-dpzb). Henlius and Organon previously entered into a licensing agreement whereby Henlius licensed the commercialization rights to several of its biosimilar candidates, including POHERDY®.
Genentech's complaint alleges infringement of 24 patents and seeks several forms of relief, including judgments of infringement, a preliminary and/or permanent injunction enjoining Henlius and Organon from infringing via sale and/or importation of the proposed biosimilar, damages, and attorneys' fees. The initial scheduling conference is set for March 2026.
Henlius and Organon's POHERDY®, which subsequently received FDA approval as an interchangeable in November 2025, is currently the only FDA approved pertuzumab biosimilar.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
