Scott Smith, president and chief operating officer of Celgene (NASDAQ: CELG), has left the company. The Summit, NJ, drug maker gave no reason for Smith’s departure. In a press release issued after the markets closed Monday, Celgene said that Smith’s employment ended “effective immediately” and his duties will now be handled by chairman and CEO Mark Alles. Smith joined Celgene in 2008 as vice president, global marketing for inflammation and immunology. He later held several senior management positions in inflammation and immunology until a year ago, when Celgene promoted him to president and COO.