LONDON—Ketchum Pleon has appointed Avril Lee, most recently partner and deputy chief executive, as CEO of its London office. Lee will have responsibility for the day-to-day operations of the office, one of the agency’s largest. Senior partner and former London CEO David Gallagher becomes chairman of Ketchum Pleon London and continues in his role as president of Ketchum Pleon Europe.   Lee has served as London’s deputy CEO for more than three years, working with senior leadership to develop the office's healthcare, consumer and corporate affairs practices. She joined Ketchum London’s healthcare practice in 2003 as deputy managing director, and was quickly promoted to MD. In 2006, she was appointed to managing director of European healthcare where she led the London healthcare team and serviced multinational clients.   Prior to Ketchum she worked for more than 15 years in a variety of healthcare communications roles at Chandler Chicco, Hill & Knowlton and CPR Worldwide, where she worked with international and U.K.-based pharmaceutical clients.