On May 28, 2024, Amgen filed a BPCIA litigation, Case No. 1:24-cv-06497 (D.N.J.), against Celltrion’s proposed Prolia® / Xgeva® (denosumab) biosimilar CT-P41 alleging infringement of 29 of Amgen’s patents, including one patent with formulation/composition claims, three patents with composition of matter claims, and 27 patents with manufacturing claims.  Celltrion submitted an aBLA for CT-P41 with a request for interchangeability in November 2023 (previously reported Celltrion Completes Application for FDA Approval of CT-P41, Biosimilar of Prolia® / Xgeva®).

This new litigation comes only weeks after Amgen settled Case No. 1:23-cv-02406 (D.N.J.) against Sandoz’s recently FDA-approved interchangeable biosimilars Jubbonti® / Wyost® (denosumab-bddz), with a market entry date set for May 31, 2025, or earlier under certain undisclosed circumstances (previously reported Amgen and Sandoz Settle Prolia® / Xgeva® Biosimilar Litigation).

On May 27, 2024, Fresenius Kabi announced the FDA acceptance of an aBLA for its biosimilar candidate, FKS518 (previously reported Fresenius Kabi Announces FDA Acceptance of aBLA for Prolia® / Xgeva® (denosumab) Biosimilar Candidate FKS518).

U.S. sales for Prolia® were $2.7 billion and $1.5 billion for Xgeva® in 2023.

For more information about these and other biosimilar aBLAs and patent disputes, please visit BiologicsHQ.



The author would like to thank April Breyer Menon for her contributions to this article.



    Information contained in the Venable BiologicsHQ database relates to FDA-approved drug products listed in the CDER Purple Book or on the FDA website ( Information relating to FDA licensed products, FDA-approved indications, and aBLA and 505(b)(2) applications is obtained from public sources including the U.S. FDA website ( Information relating to litigations is given only for cases active from January 31, 2010 onward. Information relating to foreign biosimilar / biologics follow-on products approved in Australia, Canada, the E.U., Japan and South Korea is from public sources. Statistics graphics are compiled from information contained in the Venable BiologicsHQ database.


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