Nearly all Medicare Part D plans require prior auth for GLP-1s

Nearly all Medicare Part D plans required prior authorization for glucagon-like peptide-1 receptor agonists, or GLP-1RAs, following changes to out-of-pocket maximums, according to a new study published in JAMA.

Prior authorizations are another obstacle consumers now face when trying to access GLP-1RAs, like semaglutide (oral and injectable), tirzepatide and dulaglutide. The demand for these drugs has skyrocketed recently as they prove effective for treating obesity, cardiovascular disease and other common conditions in addition to diabetes.

However, drug costs and off-label use have created significant hurdles to access.

The JAMA study found that prior authorization became virtually universal for GLP-1RAs covered by Medicare Part D plans by 2025, rising sharply from just 2.8% to 5.0% in 2023.

Out-of-pocket costs also increased in 2025, from $75 to $138 in 2024 to $122 to $167 in 2025 across the established GLP-1RAs. Those were oral semaglutide, dulaglutide, tirzepatide and injectable semaglutide.

Researchers from the University of Pennsylvania Perelman School of Medicine said the out-of-pocket cost increases reflected greater use of coinsurance by 2025, from 27% to 36% in 2024 versus 49% to 77% in 2025.

These increases were also more common in stand-alone Part D plans, with costs ranging from $99 to $109 in 2024 to $175 to $196 in 2025. In Medicare Advantage Part D plans, costs ranged from $52 to $64 in 2024 to $93 to $101 in 2025.

Despite increasing prior authorization requirements and out-of-pocket costs, coverage of most GLP-1RAs was still widespread over the last five years, particularly for diabetes. Observed declines in coverage were also attributed to the introduction of authorized generics.

Researchers said the rise in prior authorizations for GLP-1RAs may be an attempt to curtail off-label use; however, increases in out-of-pocket costs are likely from "broader shifts to coinsurance," particularly after the Inflation Reduction Act (IRA).

Effective in 2025, the IRA redesigned Part D plans to lower annual out-of-pocket cost maximums for prescription drugs to $2,000. The change this year was also partly financed by increasing Part D plans' liability from 15% to 60% of spending in the catastrophic coverage phase. This may have incentivized plans to restrict coverage and increase cost sharing of expensive frugs, like GLP-1RAs, researchers explained.

Still, prior authorizations and rising out-of-pocket costs hinder access to the drugs. Beneficiaries in Medicare Advantage plans may be able to avert the cost increases by shopping for plans, researchers pointed out. But many did not compare coverage, according to KFF.

Adding to access barriers, CMS also announced in April that Medicare and Medicaid will not cover GLP-1s for the treatment of obesity next year. Currently, Medicare Part D plans cover GLP-1 drugs for type 2 diabetes, sleep apnea and to prevent heart complications. However, President Joe Biden proposed expanding coverage for obesity treatment in 2026.

Jacqueline LaPointe is a graduate of Brandeis University and King's College London. She has been writing about healthcare finance and revenue cycle management since 2016.