The agency that offers health insurance for state workers voted Thursday to stop covering GLP-1 drugs for weight loss, as Massachusetts tries to get a handle on the soaring health care costs that are squeezing the state budget.

“It’s certainly not an easy decision before us,” Dana Sullivan, who serves on the Group Insurance Commission’s board, said ahead of the vote. “No one likes talking about limiting access to effective drugs, but I believe it’s a strategic one.”

The explosion in popularity of expensive GLP-1 drugs, like Zepbound and Mounjaro, has been a driver behind the dramatic growth in state spending on health care. About 22,000 members take GLP-1s for weight loss, according to GIC staff.

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Climbing costs and a loss of federal aid are prompting tough choices in the state budget process this year.

After two years where Group Insurance Commission premiums grew by 10%, Healey directed the GIC to find about $100 million in savings for the coming fiscal year.

Healey said that, out of the nearly 12% premium increase last year, about a third of it was driven by GLP-1 costs. She’s also proposing to end MassHealth coverage for weight-loss GLP-1s.

The GIC approved the removal in a split 10-7 vote, which will go into effect for the new insurance year starting in July.

Sullivan, representing Healey’s budget office on the commission, said the decision is part of a longer-term strategy to give insurers more leverage with drugmakers.

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Many insurance carriers in Massachusetts, including the state’s Health Connector marketplace and an association that provides insurance for municipal government, as well as private insurers, have moved away from covering GLP-1s for weight loss. Those shifts, Sullivan said, could influence prices over time.

“As the largest purchaser of health insurance in Massachusetts, we’re a crucial part of the effort, and so if we continue to cover, there’s no incentive for them to come work with us,” Sullivan said. “If we cut coverage collectively we have market power to push those prices down to get access for our membership.”

Commissioner Melissa Murphy-Rodrigues, one of the “no” votes, said the move made her uneasy. She said she doubted coverage would be reinstated down the line, because once a budgetary cut is made, “other things fill that gap.”

“For me, it’s like, what’s next?” Murphy-Rodrigues said. “Is it EpiPens? Is it epidurals? What are we going to decide is not worthy of being insured?”

About 460,000 people — state and municipal workers and retirees, plus their families — get their health coverage through the Group Insurance Commission. GIC officials said that Thursday’s vote affects only members who use GLP-1 drugs strictly for weight management, not those treating other conditions like diabetes.

Health insurance premiums are still set to rise for GIC members, but the increase will not be as steep as if GLP-1 coverage was maintained.

The GIC had been considering other changes that would cut spending but raise members’ out-of-pocket costs, like higher copays and deductibles. Unions pushed back against the proposal, arguing that the state could take other actions to balance the budget instead of driving up costs for public workers.

Healey wrote to the commission this week, asking it to skip most of the changes in the name of affordability, and instead move forward only with dropping coverage for weight-loss GLP-1s.

The Massachusetts Teachers Association, which argued against the benefit changes overall, said Wednesday that union leaders and members oppose ending GLP-1 coverage for weight management. Julianna Keyes, the president of the Arlington Education Association, called the change “shortsighted.”

“For the first time, medical science has found an effective non-surgical treatment to treat obesity, and the insurance market complains about the price,” Keyes said in a statement. “The cost of not covering these medications will be far greater in the long run.”