CVS Health is gearing up to defend its $69 billion takeover of the nation’s third-largest health insurer, Aetna, The Wall Street Journal reported. The pharmacy retailer has already integrated with Aetna after the deal was approved by regulators and closed last year, but a U.S. District judge has concerns about the antitrust issues imposed by the merger and has set a three-day proceeding this week to hear testimony from industry stakeholders.

CVS had previously asked Judge Richard Leon to block the witness testimony of opponents of the deal, who are scheduled to speak in court. The American Medical Association is one of those voices and has been vocal about anti-competition concerns about the merger. Six witnesses will be allowed to testify during the proceeding, which begins Tuesday.

The transaction was approved by the Department of Justice, but Judge Leon has been critical of that decision, citing worries that the DOJ rubber stamped the deal without doing enough to protect competition. Aetna agreed to sell its Medicare Part D business as part of the DOJ’s approval of the merger. However, it “isn’t clear” what would happen if the judge rejects the deal between the companies and the DOJ.

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