Judge Richard Leon of the US District Court for the District of Columbia could block the merger agreement between CVS and Aetna, according to CNBC. If he finds it does not, the companies can either appeal or renegotiate. The article stated that Leon is considering concerns from groups, such as the American Medical Association, asking regulators to block the deal on the grounds it could reduce competition and harm consumers. In approving the deal, the Justice Department required CVS and Aetna to eliminate the overlap between their Medicare Part D, which prompted Aetna to sell its WellCare Health Plans. If the judge finds this move does not satisfy anti-competitive issues, the companies can either appeal or renegotiate the merger, according to the report.