The Massachusetts Democrat said Monday the country has already seen great concentration in the pharmaceutical industry, drugstores and health insurers.
She says the deal could cut down on competition and drive up prices for consumers. Warren says she hopes the Department of Justice Antitrust Division gives the proposal careful scrutiny.
The deal would let CVS position itself as a one-stop shop for Americans' health care needs with prescription drugs, clinics and insurance plans to cover those goods and services.
The mammoth acquisition would pair a company that runs more than 9,700 drugstores and 1,100 walk-in clinics with an insurer covering around 22 million people.
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