The merger was allowed on condition Aetna sell its Medicare prescription drug plan business to WellCare Health Plans, Both deals have already closed.
U.S. District Judge Richard Leon had questioned whether the settlement did enough to protect competition and consumers in health-care markets.
Judge Leon on Wednesday the health-care markets at issue in the case "are not only very competitive today, but are likely to remain so post-merger." The settlement "is well within the reaches of the public interest," the judge concluded, according to Dow Jones.
The merger brings together the third-largest health insurer with CVS's network of pharmacies and its pharmacy-benefit-management business