Astrazeneca’s share price declined sharply in early trading after investors cast doubt over the potential merger with its US rival.

U.K. pharmaceutical giant AstraZeneca is considering a deal to merge with its U.S. rival Bristol Myers Squibb.

AstraZeneca in talks to merge with Bristol Myers Squibb, creating $400B pharma giant, while talks ongoing for months, antitrust scrutiny is expected.