CVS Health Corp. is reportedly in talks to buy health insurer Aetna for more than $66 billion in a bid to gain a competitive advantage as Amazon.com Inc. looks to enter the pharmaceutical business. Sources cited by The Wall Street Journal on Thursday said the pharmacy chain has offered $200 per share. The companies’ chief executives, Larry Merlo at CVS and Mark Bertolini at Aetna, have reportedly met several times over six months to discuss the potential deal. The move is seen as a way for CVS to attract huge numbers of customers to its pharmacy benefit-management arm and drugstores, and also gain an edge in the health-care industry. Amazon’s potential entry into the market partly prompted the talks, one source cited by the Journal said.