A contract with Aetna to become the state’s Medicare Advantage administrator for the state health plan that will save $400 million over three years is another blow against Connecticut’s sizable debt, Gov. Ned Lamont said Wednesday.

The state faces daunting challenges to reduce long-term debt bonded for capital projects, unfunded pensions and other benefits. Lamont, seeking a second term this November, used a news conference outside the state office building to announce the welcome cost savings.

The contract that Aetna won in a competitive bid covers 57,000 Medicare-eligible retirees and their dependents and is estimated to reduce the state’s unfunded liability by $7.5 billion. Medicare Advantage is a popular health insurance plan that provides Medicare benefits through a private sector health insurer.

Lamont said he’s been “fixated” on fixed costs, such as debt hindering economic growth that he compared to “running the road race with cement overshoes.” The state is paying down pension obligations and is spending less as a percentage of the budget on bonded debt, he said.

“One place where we were having a little bit of trouble was health care costs,” the governor said. “We don’t have as much control over health care costs.”

He said his administration has reduced bonded indebtedness and pensions “and as of today we made big progress when it comes to health care costs.”

Connecticut faces $30 billion in bonded debt and $23 billion to $25 billion in unfunded pension obligations, the governor said. Other post-employment benefits face a liability of $23.5 billion, which will be reduced by the agreement with Aetna. He called that a “red flag” because it stood out among other debt totals that have been declining.

The state last November reported total debt of $95.4 billion, which has been declining.

“We have a long way to go. Don’t understate that, but we made progress,” Lamont said.

The agreement must still be negotiated with Aetna, the Hartford-based health insurance subsidiary of CVS Health Corp. It ensures that retirees covered by the state health plan “will continue to receive the care they need,” state Comptroller Natalie Braswell said.

Retirees will pay Aetna a premium of $175 a month, down from more than $320 a month, state officials said.

The state used a reverse auction process, with each bidding company scored and ranked across several categories, including pricing and service commitments. After each round of scoring, the companies had an opportunity to improve their bids to place higher, state officials said.

CVS Chief Executive Officer Karen Lynch cited Aetna’s presence in Hartford dating to 1853 as she celebrated the deal. CVS Health bought Aetna in 2018 for $69 billion, disappointing many in Hartford and the state as the insurer lost its independence and became a subsidiary of the Woonsocket, R.I.-based CVS.

“Serving Connecticut’s retirees builds on our nearly two-century relationship with the state, where thousands of CVS Health employees call home,” she said.

The contract will be effective Jan. 1, 2023.

Stephen Singer can be reached at ssinger@courant.com.