Biotechnology company Threshold Pharmaceuticals Inc. said Tuesday chief medical officer Dr. Alan Colowick will resign effective Oct. 13.

Colowick joined the company in January 2005. He will continue as a consultant for the company and as a member of Threshold's scientific advisory board.

Dr. Michael Brawer, who joined the company's management team earlier this year, will be interim chief medical officer.

"Alan has had a tremendous impact on the company, where he has overseen the recruitment of a world-class clinical team and the implementation of clinical trial practices capable of supporting multiple, simultaneous clinical trials worldwide," said Barry Selick, chief executive. "He has been a great colleague to all of us at Threshold and we wish him much success as he pursues new business interests."

Shares of Threshold fell 8 cents, or 3 percent, to close at $2.59 on the Nasdaq.