On 8 July 2025, Celltrion announced the US launch of Stoboclo® and Osenvelt® (CT-P41), biosimilars to Amgen’s Prolia® and Xgeva® (denosumab), respectively. Celltrion is the third sponsor to launch denosumab biosimilars in the US, following Sandoz’s launch of Jubbonti® and Wyost® in June 2025 and the announcement of Fresenius Kabi’s launch of Conexxence® and Bomyntra® on 1 July 2025.
Celltrion secured FDA approval for its denosumab biosimilars in March 2025, following submission of its abbreviated Biologics Licence Application in December 2023. In May 2024, Celltrion was sued by Amgen in the District Court of New Jersey for alleged infringement of 29 patents regarding denosumab. That litigation was settled in January 2025, allowing Celltrion to launch its denosumab biosimilars in the US from 1 June 2025.
Samsung Bioepis is the only other sponsor with denosumab biosimilars approved in the US (Ospomyv™ and Xbryk™, approved February 2025), but it has not yet launched the products. BPCIA litigation commenced by Amgen against Samsung Bioepis regarding its denosumab biosimilars remains pending.
Amgen also has pending US BPCIA litigation against Accord/Intas, Hikma/Gedeon Richter and Shanghai Henlius/Organon, and Biocon, which have all had denosumab biosimilar applications accepted for review by the FDA.