The news: Eli Lilly will no longer offer CVS Health’s prescription drug benefit plan for its employees, per Bloomberg. Starting January 1, Lilly workers will automatically be switched to pharmacy benefit coverage offered through Rightway, a smaller pharmacy benefit manager (PBM) than CVS Caremark. Lilly employs roughly 50,000 people, about half of whom work in the US.

Driving the news: Earlier this year, CVS Caremark dropped Lilly’s GLP-1 Zepbound from its commercial drug formularies in favor of rival Novo Nordisk’s GLP-1, Wegovy. Some Caremark plans still cover Zepbound, but offering those Rx plans to members costs more for insurers and employers, according to Bloomberg. For context, Zepbound is included on Rightway’s comprehensive formulary for the 2025 plan year.

Lilly did not confirm that it switched PBMs because CVS chose Wegovy over Zepbound as its preferred GLP-1 medicine. But it likely was a big factor, since CVS’ decision steered potentially tens of thousands of Caremark members toward a competing GLP-1.

The bigger picture: Lilly’s decision underscores the growing tension between employers/drugmakers and the Big 3 PBMs—CVS Health’s Caremark, Cigna’s Express Scripts, and UnitedHealth’s Optum Rx.

• For context, Caremark, Express Scripts, and Optum Rx control about 80% of the US PBM market, per Drug Channels.
• Each of the Big 3 is vertically integrated with a health insurance company, which lets these companies control more aspects of the pharma supply chain.

Drugmakers and the Big 3 PBMs routinely point the finger at each other for rising prescription drug costs, including most recently when President Trump demanded that pharma manufacturers lower their US drug prices and when the FTC sued the Big 3 over insulin pricing.

Employers are increasingly challenging opaque PBM contracts that obscure the true costs and savings of their drug plans. Nearly one-third (31%) of employers this year say they use a transparent PBM model (such as Rightway), up from 12% in 2024, per a September 2025 survey from the National Alliance of Healthcare Purchaser Coalitions.

Implications for pharma companies and PBMs: As an employer, there’s the possibility that Lilly was considering a pivot to a non-Big 3 PBM anyway. But it seems likely that CVS’ decision to promote Wegovy over Zepbound was Lilly’s breaking point—showing that even employee benefit plans can be used as leverage in the battle for weight loss drug dominance.

The Big 3 PBMs’ grip on drug pricing and access may be waning as regulators tighten oversight and drugmakers sell more of their medicines directly to consumers. This trend could help smaller PBMs gain market share while pressuring the Big 3 to finally meet industry demands for greater pricing transparency.