By Blake Brittain
(Reuters) - Amgen Inc (NASDAQ:AMGN) sued Novartis AG's Sandoz in New Jersey federal court Monday, accusing Sandoz's proposed versions of its multibillion-dollar bone-strengthening drugs Prolia and Xgeva of infringing several patents.
Amgen asked the court to block Sandoz's biosimilars of the drugs until its patents expire. One of the patents named in the complaint does not expire until 2037.
Sandoz declined to comment on the lawsuit Tuesday. Novartis, which is also named in the complaint, is preparing to spin Sandoz off into a standalone company later this year.
Amgen's Prolia is used to treat osteoporosis. Xgeva, with the same active ingredient denosumab, treats bone cancer and prevents fractures in bone-cancer patients.
The U.S. Food and Drug Administration approved both drugs in 2010. Thousand Oaks, California-based Amgen sold $3.6 billion worth of Prolia and $2 billion worth of Xgeva last year, according to a company report.
The FDA accepted Sandoz's application for biosimilar versions of the Amgen biologic drugs — which are derived from living cells, unlike traditional small-molecule drugs — in February.
Amgen said the proposed biosimilars infringe 21 patents covering Prolia and Xgeva.