Lilly's Zepbound and Mounjaro Dominate Q3, Surpassing Expectations Despite Formulary Challenges

Eli Lilly's obesity and diabetes medications, Zepbound and Mounjaro, have continued their meteoric rise in the pharmaceutical market, delivering a combined $10.1 billion in global sales for the third quarter of 2025. This impressive performance comes despite challenges in formulary listings and showcases the growing dominance of Lilly's incretin franchise in the metabolic disease space.

Zepbound Defies Formulary Exclusion with Strong Growth

Zepbound (tirzepatide), Lilly's dual-action obesity medication, achieved sales of nearly $3.6 billion in Q3, representing a staggering 185% year-over-year growth. This performance exceeded consensus expectations by over $500 million, according to analysts at Citi Research. The drug's success is particularly noteworthy given that CVS Caremark, the largest U.S. pharmacy benefit manager, removed Zepbound from its formulary in July in favor of Novo Nordisk's Wegovy.

Despite this setback, Zepbound's growth remained robust, with analysts attributing its continued success in part to Lilly's direct-to-consumer sales channel, LillyDirect. This platform allows patients to purchase certain medications at a discount when paying out of pocket, potentially mitigating the impact of formulary exclusions.

Mounjaro Leads the Charge in Diabetes Treatment

Mounjaro, Zepbound's sister medication for diabetes, also exceeded expectations with $6.5 billion in quarterly revenue. The drug's sales grew 109% compared to the same quarter in 2024, outpacing both Citi and consensus projections by approximately $1 billion. The combined performance of Zepbound and Mounjaro has now surpassed that of Merck's cancer blockbuster Keytruda, which previously held the industry's sales crown.

Lilly's Overall Performance and Future Outlook

Driven by the success of its incretin franchise, Lilly reported a 54% year-over-year increase in overall sales, reaching $17.6 billion for the quarter. In response to this strong performance, the company has raised its full-year guidance and now anticipates 2025 sales between $63 billion and $63.5 billion, up from the previous forecast of $60 billion to $62 billion.

The continued growth of Lilly's metabolic disease portfolio bodes well for the expected launch of its oral GLP-1 asset, orfoglipron, anticipated next year. However, not all areas of Lilly's business saw equal success. The breast cancer medication Verzenio grew more modestly, with sales increasing 7% to $1.47 billion, falling short of analyst expectations.

As Lilly's incretin franchise continues to reshape the pharmaceutical landscape, the industry watches closely to see how competitors will respond and whether this remarkable growth trajectory can be sustained in the face of ongoing market challenges and evolving healthcare policies.