Pfizer yesterday unveiled a $68bn takeover of Wyeth, reasserting its flagging position as the world's largest pharmaceuticals group and paving the way for a fresh bout of consolidation across the sector.

The acquisition - to be paid for using equal amounts of cash, equity and debt - creates a group with $71bn in sales from a broad range of products and plans to save $4bn in annual operating costs by cutting 15 per cent of its combined workforce.