Cigna Corp (CI.N) shareholders on Friday voted in favor of the health insurer’s proposed $52 billion acquisition of pharmacy benefit manager Express Scripts Holding Co (ESRX.O), although the deal still needs clearance from antitrust authorities.

The U.S. Department of Justice is still conducting an antitrust review of the combination that is not expected to close until later this year.

According to the preliminary results, about 90 percent of the votes cast were in favor of the merger, the health insurer said.

Cigna expects the merger to close by end of 2018.