Although Ozempic, Wegovy and Zepbound were three of the top 10 best-selling drugs in 2025, a new study published in JAMA shows they’re also among the brand-name drugs most rejected by payers. In fact, payers only approved the drug class 14.8% of the time on the first try for weight loss.
The research team, led by Joseph Levy, an assistant professor in the Johns Hopkins Bloomberg School’s Department of Health Policy and Management, initially set out to uncover the relationship between formulary restrictions and prescription rejections.
After analyzing data from 1.17 million individuals attempting to fill more than 2 million single-source branded drugs, researchers found formulary-based rejections rose by 67% between 2018 and 2024. Researchers attribute this to payers’ growing desire to curb costs but warn the rejections may hamper care. Nearly one-third of prescriptions studied were rejected on a patient’s first attempt to fill, and, among those, nearly 50% went unfilled at 90 days.
The study also identified details about trends in prescription denials by class, uncovering challenges to GLP-1 access.
“We looked at the top 10 most attempted classes, and then observed their rejection rates,” Levy told PharmaVoice by email.
Ozempic and other GLP-1 receptor agonists had the most rejections as an absolute number — in part because they accounted for the single biggest prescription class included in the study — and were only covered about 65% of the time on the first try, he said.
“Weight management incretin products, like Wegovy, were rejected at a much higher rate [than other drugs],” he said.
As the study signals possible payer pressures on newly launched drugs, here’s what pharma companies need to know.
Changes are coming that could bridge access gaps
Payers usually rejected weight loss and other drugs because of formulary restrictions or utilization management rules. For instance, Medicare typically only covers GLP-1s for Type 2 diabetes, not obesity.
But changes could be coming for obesity drugs as payer coverage broadens.
A short-term pilot program called the Medicare GLP-1 Bridge was launched on July 1, providing eligible Medicare Part D beneficiaries access to certain GLP-1 drugs for weight loss for a $50 month copay through the end of next year.
CMS also recently launched the Balance Model, which will be used to negotiate drug pricing and coverage terms with GLP-1 manufacturers on behalf of state Medicaid agencies and Medicare Part D plan sponsors.
Navigating payer coverage issues will remain critical for GLP-1 drug developers as they score more FDA approvals for new indications, which prompts spikes in new prescriptions.
For instance, in the six months after Medicare said it would cover Wegovy for heart problems, prescription requests increased 136% across all payers and 598% for Medicare beneficiaries, according to other newly published research from the USC Schaeffer Center for Health Policy & Economics.
Other drugs hitting coverage delays
The study revealed coverage delays for a range of treatments. Of the prescriptions that were rejected on the first try, about 39% of individuals ended up getting the drug they were initially prescribed within 90 days. Another 13% received a medication in the same therapeutic class and 48% received no medication in the same therapeutic class within 90 days.
Weight management incretin products were by far the most rejected drugs followed by diabetes-indicated dual GIP/GLP-1 products (47% initially paid) and diabetes-indicated GLP-1 receptor agonists (65% paid on the first try). Long-acting insulins and sodium-glucose cotransporter 2 inhibitors were the next largest category of rejected drugs, while other branded treatments were grouped into an “all other classes” bucket that was initially paid about 63% of the time.
The most-covered classes were direct-acting oral anticoagulants, bowel preparations for radiologic procedures and dipeptidyl peptidase 4 inhibitors.
The study also highlighted that access problems can occur in the doctor’s office where prescribers often don’t know which drugs are covered by patients’ insurance plans.
“[T]hese results highlight that formulary restrictions commonly manifest at the pharmacy as opposed to the point of prescribing,” the authors wrote. “In other words, prescribers are frequently writing prescriptions for drugs that are not covered by a patient’s insurance or for which prior authorization or step therapy is required. Efforts to improve the visibility of utilization management requirements at the point of prescribing may reduce avoidable pharmacy rejections and limit delays for patients.”
