This blog is part of an ongoing series on A Brave New World: Therapeutic Area Deep Dives.

When it comes to the commercial success of a brand, the degree of payer access can be a game changer, either driving its commercial success or substantially hindering its uptake. For expensive drugs such as glucagon-like peptide 1 receptor agonists (GLP-1s), payer coverage is crucial for patient affordability. However, this also means that payers will implement cost controls. Payers are known to vary their level of control between different indications for the same drug and between different payer channels, and the GLP-1 market is no exception.

The GLP-1 market, originally formulated for patients with Type 2 diabetes but now widely used for obesity, has undergone differing payer access across patient populations and payment channels. While Medicare does not broadly cover weight-loss therapeutics, some Commercial payers do, albeit with varying levels of control. As fear of spillover from one indication to another increases, and indication expansions broaden, payer control evolves and continues to shape the market in unique ways. Understanding the intricate relationship between payer control, channel distribution, and volume uptake can provide invaluable insights, not just within the diabetes and anti-obesity medicines (AOM) markets.

Restrictions to Control Spillover

The distribution of a brand’s prescriptions across different payer channels is typically a combination of the demographics of the patient base plus the payer control within each channel. When two products have the same patient base but a varying distribution of payer channel, payer control is most likely shaping these differences. Understanding this within the context of GLP-1s helps to shed light on crucial learnings from this class.

Since the early 2000s, two classes have become the most popular of the branded Type 2 Diabetes (T2D) products: GLP-1s and sodium-glucose co-transporter 2 inhibitors (SGLT2s). Both classes have cardiovascular and kidney disease benefits, but while GLP-1s have far superior weight-loss results, they are also over 1.5 times more expensive at list price than SGLT2s. Interestingly, though products like Ozempic and Mounjaro are indicated for T2D like SGLT2s, the distribution of claims by payer channel differs between the classes. Anti-obesity (AOM) GLP-1 prescriptions skew very heavily to the Commercial channel (81%), while anti-diabetic GLP-1s show a more balanced distribution: a smaller proportion of Commercial claims than AOM GLP-1s but a notably larger proportion than SGLT2s.

Note: Anti-obesity GLP-1 includes Wegovy and Zepbound; Anti-Diabetic GLP-1 includes Ozempic and Mounjaro; SGLT2 includes Jardiance, Farxiga, and Invokana
Source: IQVIA Market Share Library; IQVIA LAAD Pharmacy Claims Data

The difference in payer distribution across classes is tied very closely to payer control. For anti-obesity GLP-1s, Medicare’s policy of not covering AOMs means that utilization skews heavily Commercial. For anti-diabetic GLP-1s, Medicare’s policy and Commercial payers’ reluctance to offer widespread coverage of AOMs leads to a bolus of comorbid patients in both channels attempting to initiate anti-diabetic GLP-1 therapy for their weight-loss advantages. However, there are heavier controls in Medicare for anti-diabetic GLP-1s than SGLT2s, as new patients attempting to fill GLP-1s increasingly face prior authorization (PA) restrictions.

These PAs are meant to ensure appropriate on-label use of the anti-diabetic GLP-1s. Though PAs are utilized by both Commercial and Medicare payers, it is far less common to see PAs in Medicare and thus have a more meaningful impact. Putting these factors together leads to an uncharacteristic skewing of anti-diabetes GLP-1s towards Commercial patients.

The takeaway is clear: in both Commercial and Medicare channels, payers trying to protect their budgets from weight-loss patient spillover is shaping the market in a meaningful way.

Note: Durable approval is the status of a claim 30 days after an initial attempt at the pharmacy counter; Anti-obesity GLP-1 includes Wegovy and Zepbound; Anti-Diabetic GLP-1 includes Ozempic and Mounjaro; SGLT2 includes Jardiance, Farxiga, and Invokana
Source: IQVIA Market Share Library; IQVIA LAAD Pharmacy Claims Data

Indication Expansion and Unique Payer Responses

Despite restrictions on anti-obesity medications in Medicare, Wegovy and Zepbound have found ways to improve their coverage. By adding additional indications, such as cardiovascular (CV) risk for Wegovy, and obstructive sleep apnea for Zepbound, they have increased their value proposition and bargaining power with payers. Obstructive sleep apnea is a particularly salient indication in that there are no other FDA-approved products specifically indicated for the condition. Following Wegovy’s addition of the CV risk indication, payer approval rates in Medicare Part D increased from 12% to 20% over the course of one year. Zepbound saw an even more dramatic transformation after the addition of the sleep apnea indication, increasing its approval rates in Part D from 10% to 28% in half a year. As anti-obesity GLP-1s gain additional indications, patients and providers will be afforded even more pathways to access, especially in the Medicare channel.

Note: Durable approval is the status of a claim 30 days after an initial attempt at the pharmacy counter
Source: IQVIA Market Share Library; IQVIA LAAD Pharmacy Claims Data

However, despite the overall increased approval rates in Medicare Part D following these indication additions, individual payers still behave independently. Payer contracting plays a key role in this market as brands compete for preferred formulary placement. In 2024, gross-to-net margin across GLP-1s ranged from 23% to 45%, indicating that brands were spending over half of their gross sales in rebates, discounts, and affordability programs to achieve maximum access. As expanded indications allow for a larger patient base to be eligible for these drugs, payers may increase their utilization management to protect their overall spend.

Two top Medicare payers illustrate this dynamic. While one payer’s access to the weight-loss products improved from rejecting 100% of claims to approving 86% of Wegovy and 72% of Zepbound claims in Q2-2025, another payer took a different tactic. Before Wegovy’s indication addition, a second payer had been approving around 50% of weight-loss claims yet required an average patient out-of-pocket cost of over $800. Cost sharing as a tactic in itself is an effective utilization management technique, as more than half of all patients abandoned their prescriptions. While Wegovy and Zepbound added non-weight-loss indications, this second payer, instead, moved to outright rejecting claims between 70% and 80% of the time. Though both payers had similar approval rates for anti-obesity GLP-1s in Medicare by Q2-2025, the paths to that point were unique to each payer.

Source: IQVIA LAAD 3.0; US Market Access Strategy Consulting

Payer Control Shapes the Market

The evolution of payer control in the GLP-1 space across different indications and products highlights the impact of specific indications and product strategy on patient access. The disparity in coverage between the anti-diabetic and anti-obesity GLP-1s shows how payer behavior is driven by the perceived medical necessity of products by their intended use, not by the molecule itself. Fear of patient spillover from one indication to another has increased payer control with prior authorization requirements being used as a primary obstacle to access. Recent efforts by Wegovy and Zepbound to pick up new indications to improve payer access have generally been a successful strategy but come with caveats at the payer level.

The Bottom Line

Accessibility can make or break the success of a product or a class of products. GLP-1s have seen unparalleled launch success despite the controls in place in the market. For manufacturers looking for optimal uptake of their brands, knowing the potential areas for increased utilization management and anticipating them ahead of time can ensure broad and sustainable adoption.

• Invest in clinical development that supports new, high-need indications that can improve the brand’s value proposition, especially in restrictive channels like Medicare.
• Tailor payer engagement strategies to the specific behaviors and cost controls of individual payers, recognizing that access and restrictions vary widely.
• Prepare for more intensive utilization management as indications expand. Develop robust real-world evidence and value-based contracts to support inclusion on formularies.
• Monitor gross-to-net dynamics closely and optimize rebate strategies to strike a balance between access, affordability, and profitability.
• Anticipate spillover fears and partner with payers to demonstrate appropriate use of products across indications, possibly through provider education, step therapy design, or PA alignment.

For manufacturers that recognize these key factors and have a plan from launch to successfully address them, a path to commercial success can be in reach. Please reach out to IQVIA to learn more on how to build successful payer control strategies like those seen in the GLP-1s.