Sanofi-Aventis, the French pharmaceutical group, is set to complete its acquisition of Acambis of the UK on Thursday, with plans to keep the vaccine developer partly autonomous, to maintain its entrepreneurial spirit.

Wayne Pisano, head of Sanofi-Aventis’ vaccines arm, said the cash deal would reinforce the group’s presence in biological medicines, and accelerate Acambis’ pipeline of experimental products by providing greater resources and capacity for manufacturing and late-stage development.