In the fifth-largest biotech deal in history, Amgen has agreed to buy cancer drug maker Onyx Pharmaceuticals. As part of the deal, Amgen will gain revenue from two of Bayer’s drugs, developed in partnership.

The California based biotech giant, Amgen, is paying $10 billion (7.47 billion euros) for Onyx Pharmaceuticals, which develops and markets cancer drugs. It is Amgen’s biggest deal since its $16 billion acquisition of Immunex in 2001.

As a result of the deal announced on Sunday, Amgen will benefit from Onyx’s partnership with German pharmaceutical giant Bayer AG. Amgen will gain a revenue stream from the liver and kidney cancer drug Nexavar that Onyx shares with Bayer and royalty payments on Bayer’s much newer colon cancer drug, Stivarga. Sales of Nexavar totaled $861 million in 2012. San Francisco based Onyx received $288 million in revenue from those sales.

Several other major pharmaceutical acquisitions have been announced in the last few months. In July, generic drug maker Perrigo bought Ireland’s Elan Corp for $8.6 billion. In May, generic drug company Actavis Inc. agreed to buy Warner Chilcott for $8.5 billion and Valeant Pharmaceuticals agreed to pay $8.7 billion to buy Bausch + Lomb in an expansion of its ophthalmology business. In April, scientific instrument maker Thermo Fisher Scientific agreed to buy life science and medical research instrument maker Life Technologies for $13.6 billion.

Bayer AG, the German chemical and pharmaceutical company was founded in Barmen, Germany in 1863. Headquartered in Leverkusen, North Rhine-Westphalia, it is best known for its original brand of aspirin.