Astrazeneca share price tumbles as investors doubt merger with US rival

Astrazeneca’s share price declined sharply in early trading after investors cast doubt over the potential merger with its US rival. The UK drugmaker’s shares suffered a six per cent decline in early trading to 11,866p, after reports it was exploring a possible $400bn megadeal with Bristol Myers Squibb.  The FTSE 100 giant has been holding…