US drugs giant company Pfizer has agreed a deal to buy Allergan for $160bn making this the biggest deal in history on pharmaceutical industry.

The merger will create the world’s biggest drugmaker, to be called Pfizer.

The deal involves Pfizer paying 11.3 of its shares for each Allergan share and will make Pfizer the world’s biggest drugmaker.

Pfizer’s Chief Executive Ian Read, 62, will be CEO of the combined company, while Allergan’s CEO Brent Saunders, 45, will serve in a very senior role focused on operations and the integration.