Roche Holding named Pascal Soriot to head its drugs operations, by far its largest business, replacing veteran William Burns who retires at the end of the year. It marks the completion of a changing of the guard at the top of the Swiss drugmaker, which is reshuffling top management following its $47 billion buyout of U.S. biotech partner Genentech. Soriot will work with chief executive Severin Schwan, who took up the reins last year, and Roche also named Daniel O'Day, who currently heads its molecular diagnostics business, as new chief of its diagnostics division, replacing Juergen Schwiezer. Soriot has been co-leading the team integrating Genentech and designing the future set-up of the combined company.