The Centers for Medicare & Medicaid Services has rejected a state proposal to limit Medicaid drugs for beneficiaries in an effort to lower costs. CMS said Wednesday that the state’s request did not meet the agency’s requirements for such changes.

Gov. Charlie Baker (R)’s administration had proposed limited coverage for some prescription drugs to reduce costs in the Massachusetts Medicaid program, but planned to continue to collect manufacturer rebates.

Patient advocates said the agency’s rejection of Baker’s plan means beneficiaries can retain access to treatment. Massachusetts would have been the first state to choose which drugs are covered under Medicaid.

“By rejecting Massachusetts’ 1115 waiver request to establish a closed Medicaid formulary and still receive 23.1% mandatory manufacturer rebates, the administration is protecting patients’ access to critical treatments and upholding the bargain that Congress struck with states and manufacturers in the 1990s,” said Lindsay Bealor Greenleaf, health policy expert and director at ADVI Health.  “It’s a relief to see the administration do the right thing and reject this waiver request, because if Massachusetts had gotten its way, Medicaid patients would have limited treatment choices and industry would doubt whether future deals struck with the government will hold up over time.”

CMS stated there’s a chance the organization would reconsider giving Massachusetts the ability to exclude certain drugs from coverage, if the state would “forgo all manufacturer rebates available under the federal Medicaid Drug Rebate program,” according to CMS’ denial letter.