Onyx Pharmaceuticals rejects takeover bid from biotech giant Amgen

Onyx Pharmaceuticals Inc. on Sunday rejected an unsolicited takeover bid from Amgen Inc., the Thousand Oaks biotech giant.

Onyx, headquartered in South San Francisco, confirmed in a statement that it had received a bid of $120 a share from Amgen, but said the offer “significantly undervalued” the company and was “not in the best interest of Onyx or its shareholders.’’

But Onyx added that it would consider other possible bids.

“We are actively exploring the potential to combine Onyx with another company,” Onyx Chief Executive N. Anthony Coles said in the statement.

Shares of Onyx jumped nearly 30% in extended trading Sunday after the Financial Post reported that Amgen may buy the company.

On Friday, Onyx shares closed up $1.62, or 1.9%, at $86.82 and had a market capitalization of $6.3 billion.

Onyx and its German partner Bayer sell the drug Nexavar, which is given to liver and kidney cancer patients, and Stivarga, which is for stomach cancer. Onyx markets Kyprolis, a blood cancer drug approved in 2012, on its own.

The company reported a net loss of $187.8 million on revenue of $362.2 million in 2012. That compared with a profit of $76.1 million on revenue of $447.2 million in 2011.