Amgen to buy Onyx Pharmaceuticals for US$10.4bn

Amgen is to acquire Onyx Pharmaceuticals, a US biopharmaceutical firm developing cancer drugs, for $125 a share, which takes the total purchase price to US$10.4bn.

The deal has been approved by both boards.

South San Francisco-based Onyx has a growing multiple myeloma franchise, with Kyprolis (carfilzomib) for Injection already approved in the US. In addition, the firm has three partnered oncology assets: Nexavar (sorafenib) tablets (an Onyx and Bayer HealthCare Pharmaceuticals compound) for kidney and liver cancer; Stivarga (regorafenib) tablets (a Bayer compound); and palbociclib (a Pfizer compound). Onyx also has multiple oncology compounds in various stages of clinical development.

Amgen expects to close the deal at the beginning of the fourth quarter, subject to customary closing conditions, including the receipt of regulatory clearance.

'We believe that Amgen is ideally suited to realise the full potential of Onyx's portfolio,' said Robert Bradway, Chairman and Chief Executive of Amgen.

'Amgen has a unique opportunity to add value to Kyprolis, a product which is at an early and promising stage of its launch.'

Onyx holds the global rights to Kyprolis, excluding Japan. Kyprolis has an orphan drug designation in the US with exclusivity until July 2019, and patents in the US which extend until at least 2025.

Amgen says it will benefit from the global rights to Onyx's innovative oncology portfolio and pipeline. It aims to maximise Kyprolis' potential in the US and the rest of the world.

The acquisition also adds to Amgen's late-stage pipeline, which includes nine products for which registration-enabling data are anticipated by 2016. Four of these are oncology products.