Thermo Fisher and Patheon could not be reached for comment outside regular business hours.
An agreement between Thermo Fisher and the Dutch drug ingredients maker could be reached as early as this week, Bloomberg reported, citing people with knowledge of the matter.
The discussions could still falter, and there's no certainty a deal will be reached, Bloomberg added. bloom.bg/2qirdlR
Thermo Fisher has seen its stock rise over 21 percent in 2017, bringing its market value to about $67.1 billion, according to Thomson Reuters data.
Shares of Patheon have fallen about 9.4 percent this year, valuing the company at about $3.8 billion.
Reporting by Ismail Shakil in Bengaluru; Editing by Sunil Nair