Thousand-Oaks based Amgen is losing Chief Financial Officer Jonathan M. Peacock, who is leaving to pursue broader career opportunities, the biopharmaceutical company announced Thursday.

Peacock will be stepping down from his role as CFO effective Friday, Jan. 10, but is expected to stay on with the company until May to aid with the transition.

Michael A. Kelly, who has been with Amgen since 2003, has been named acting CFO, reporting to Chairman and CEO Robert Bradway.

“Since joining Amgen over three years ago, Jon has played an important role in developing and implementing the company’s strategy for growth and in delivering value for shareholders,” Bradway said in a statement. “We thank Jon for his many contributions and fully support his desire to pursue broader opportunities.”

In his role as acting CFO, Kelly will be responsible for the company’s finance and investor relations operations. Since joining Amgen, he has served in a number of executive finance roles, including five years as chief accounting officer and more recently as CFO for international commercial operations. Prior to joining Amgen, Kelly had finance assignments at Tanox, Biogen and Monsanto Life Sciences.

“Michael Kelly is an experienced financial executive,” Bradway said. “I am delighted to have him reporting to me as acting CFO while we search for Jon’s successor.”

Amgen is the largest biotechnology company in the Tri-Counties, with 6,000 employees. Since 2010, Amgen has expanded globally and returned substantial capital to shareholders through buybacks and dividends.