On November 14, 2025, Amgen, Inc. (“Amgen”) launched another BPCIA denosumab litigation when it filed a complaint in the U.S. District Court for the District of New Jersey against Alkem Laboratories Ltd., Ascend Laboratories, LLC, and Enzene Biosciences Ltd. (“Alkem”) related to Alkem’s submission to the FDA of a Biologic License Application (“BLA”) seeking approval to manufacture and sell biosimilar versions of Amgen’s PROLIA and XGEVA products.
The lengthy Complaint is noteworthy for some of the disputes that it alleges arose during pre-litigation BPCIA exchanges as part of the patent dance. According to the complaint, at some undisclosed point before the complaint was filed, Alkem submitted a Biologics License Application to the FDA and that “[r]ather than produce the required copy [of the BLA] to Amgen, Defendants… offered to give individually identified attorneys representing Amgen view-only access to a vendor-hosted database set up by Defendants without input from Amgen, which purportedly contained ‘the information described in 42 U.S.C. 262(l)(2)(A)’.” Amgen alleges that the “view-only” disclosure of the BLA did not comply with the statute’s requirement to “produce a copy” of the BLA and was more akin to allowing inspection of the BLA. Compl. at 4, 22. Also, because the ability to view the BLA was controlled by a third party chosen by Alkem, Amgen asserted that there would be a risk that that Alkem “could monitor Amgen counsel’s access to and use of the database (e.g., which documents were reviewed and when; what notes may have been made; and the like), gaining access to counsel’s mental impressions and work product.” Compl. at 23.
Amgen also alleged that Alkem failed to produce “’such other information that describes the process or processes used to manufacture the biological product that is the subject of such application.’ 42 U.S.C. § 262(l)(2)(A).” Compl. at 4, 24. Specifically, Amgen alleged that because the Purple Book listed over 50 patents for PROLIA and XGEVA, and because Amgen had already litigated against five prior denosumab biosimilar developers, Alken either knew or should have known to include certain information in its initial patent dance disclosure such as information related to components and concentrations to be added to or included in the cell culture media, but failed to do so. Compl. at 24-25. Amgen alleges that it wrote to Alkem to obtain the “missing documents and information” but that Alkem never responded. Compl. at 26.
Notwithstanding the above issues, Amgen asserts that it “conducted an analysis to the best of its ability based on the limited information available.” Amgen also states that it provided its list of patents that could reasonably be asserted if Alkem’s proposed biosimilar pursuant to 42 U.S.C. § 262(l)(3)(A) (its “3A List”), while maintaining that Alkem had failed to comply with its disclosure requirements under the BPCIA. Amgen asserts that Alkem’s failure to provide adequate information in its section 262(l)(2)(A) disclosures provides Amgen with authorization to file an action for declaratory judgment. Compl. at 26-27.
The Complaint also contains allegations related to Alkem’s alleged importation of infringing material, namely that the FDA Dashboard indicates that “Enzene has imported at least two shipments containing denosumab from India into the United States on January 2, 2021,” and imported an “end-of-production denosumab cell bank and a plasmid DNA encoding denosumab” in 2023. Compl. at 28-29. Amgen also alleges that Alkem was not conducting clinical trials in the United States. Id. Based on these allegations together, it appears that Amgen is arguing that because these imported materials were not used for clinical trials, they were not covered by the safe harbor under 35 U.S.C. § 271(e)(1), and are therefore infringing.
Amgen asserts a total of 35 patents, which Amgen asserts “cover the denosumab antibody and pharmaceutical compositions comprising denosumab (the active ingredient in PROLIA and XGEVA), innovative methods of manufacturing therapeutic proteins, like denosumab, and denosumab products.” Amgen seeks, among other relief a judgment that Alkem has infringed the asserted patents; “a permanent injunction against the commercial manufacture, use, offer to sell, and sale within the United States, and importation into the United States, of Defendants’ denosumab biosimilar products before the expiration of each of the Patents-in-Suit that are found infringed”; damages; and a declaration that the case is exceptional and awarding Amgen its attorneys’ fees and costs.
This new case brought by Amgen brings the total number of BPCIA denosumab litigations to eleven, following Amgen’s litigations against Sandoz, Celltrion, Samsung Bioepis/Samsung Biologics, Fresenius, Accord Biopharma, Hikma Pharmaceuticals, Shanghai Henlius Biotech, Biocon Biologics, Dr. Reddy’s/Alvotech, and Amneal. Amgen has settled its denosumab litigation with Celltrion, Sandoz, Fresenius, Accord, and Samsung Bioepis, while the other litigations remain pending.
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