CVS Caremark forces the largest molecule switch in the class to date

CVS Caremark, one of the largest pharmacy benefit managers in the US, dropped Eli Lilly's Zepbound (tirzepatide) from its main commercial template formulary effective July 1, 2025, and made Novo Nordisk's Wegovy (semaglutide) the preferred option for weight management ^[1][2]. The change applies to CVS Caremark's most common formulary template, which represents between 25 and 30 million people ^[2].

In a letter sent to affected members in May, CVS Caremark wrote: "This change is happening because there's another covered medication that's safe and effective for your condition and may cost less. Please keep in mind, if you refill your current medication on or after 7/1/2025, you'll need to pay the full cost" ^[2]. CVS Health said the move is meant to force manufacturers to compete on price, calling "the egregiously high list prices set by drug manufacturers of GLP-1s for weight loss" the biggest barrier to access ^[2]. The company said that when both drugs were available, members picked Wegovy and Zepbound at roughly equivalent levels ^[2].

How the switch was handled

Members with an active prior authorization for Zepbound did not have to start over. According to the Massachusetts Group Insurance Commission, which uses CVS Caremark for its non-Medicare plans, existing overrides were transitioned so members could get Wegovy without repeating the process ^[1]. Zepbound approvals expire on their original end date, after which a new prior authorization for Wegovy is required ^[1].

Other covered options in the category include orlistat, Qsymia and Saxenda ^[1]. People with type 2 diabetes taking Mounjaro, the other brand of tirzepatide, were not affected ^[1].

A formulary exception route opened June 16, 2025, for people who had already tried Wegovy and either had severe or intolerable side effects or did not lose enough weight ^[1]. Prescribers must submit documentation such as chart notes or lab results, and standard rules still apply: for weight management, six months in a comprehensive weight management program before therapy, BMI documentation, and, for continuation, proof of at least 5% loss of baseline body weight or maintenance of that loss ^[1]. If an exception for Zepbound is approved, the member pays the tier 3 copay; for Mounjaro, the tier 2 copay ^[1]. If it is denied, a member can still fill Zepbound but pays the full cost ^[1].

The removal also covers obstructive sleep apnea. All existing Zepbound prior authorizations, including those approved for moderate-to-severe OSA, transitioned to Wegovy, and all members must try and fail Wegovy before accessing tirzepatide ^[1].

Why it matters for patients

The two drugs are not identical. CVS Caremark's position, as relayed by the Massachusetts GIC, is that while controlled trials may show Zepbound to be more effective for weight loss, real-world evidence suggests the two are comparable in actual use ^[1]. CNN reports that studies have found people using tirzepatide lost more weight and were more likely to hit specific weight-loss targets than those on semaglutide ^[2]. That is a real disagreement in framing, and readers will see both versions.

There are also indication differences. Wegovy is currently the only drug in the class with FDA approval to reduce the risk of major cardiovascular events in adults with established heart disease; cardiovascular outcomes for tirzepatide are still under investigation ^[1]. Zepbound is approved for sleep apnea in people with obesity; Wegovy is not ^[1][2].

Dosing is not a one-to-one swap. Both drugs require titration, so the right starting Wegovy dose depends on where someone is in treatment, and the Massachusetts GIC notes that clinical data on direct transitions is limited ^[1].

Clinicians described the disruption. "It's very stressful for patients who have been doing really well, who are having good tolerance and feel like they have hit their stride," said Dr. Jody Dushay, an endocrinologist at Beth Israel Deaconess Medical Center ^[2]. One affected patient, Tara Eacobacci, said she gained 10 pounds and saw her A1C rise within a month off the medication ^[2].

A formulary change is not a qualifying event, so members could not switch plans or drop coverage mid-year because of it ^[1].

What happens next

More coverage changes are queued up. CNN reported that in January, Blue Cross Blue Shield of Massachusetts will exclude all GLP-1s for obesity treatment, covering them only for type 2 diabetes ^[2]. Whether other PBMs follow CVS Caremark's exclusive-preferred approach is not addressed in these sources.