Maguire Properties Inc., downtown Los Angeles’ largest office landlord, said its board designated former Amgen Inc. general counsel George A. Vandeman as its new chairman following an election of directors at the annual shareholders meeting Thursday.

Vandeman succeeds Walter L. Weisman, who became chairman in May after then chairman and chief executive Robert Maguire was forced to leave the struggling real estate investment trust he founded. Weinstein has retired from the board.

Vandeman became a director last October as turnover on the board increased after Robert Maguire sought to retain control rather than sell the company. He has been the principal of Vandeman & Co., a private investment firm, since he retired from Amgen in 2000.

His rise to the chairman’s seat may renew speculation that the company may seek a buyer. Before joining Amgen in 1995, Vandeman was head of the mergers and acquisitions practice at the law firm Latham & Watkins.

At the annual meeting, shareholders voted to elect six additional director-nominees in addition to Vandeman to one-year terms: Chief Executive Nelson Rising, Jonathan M. Brooks, Christine N. Garvey, Cyrus S. Hadidi, Paul M. Watson, and David L. Weinstein.

Maguire shares were down 11 cents, or 2 percent, to $5.80 in morning trading on the New York Stock Exchange.