As a legal battle brews between Eli Lilly and Novo Nordisk, Wall Street is tuning into an even bigger story.

The drugmakers' bitter feud reached a tipping point on Friday when Novo Nordisk filed a motion for a preliminary injunction against its market rival, seeking to stop Lilly from advertising its GLP-1 drugs while a federal lawsuit proceeds.

Novo on Tuesday accused Lilly of using outdated trial data to promote tirzepatide, which is branded as Mounjaro for type 2 diabetes and Zepbound for weight management. The Danish drugmaker claims Lilly's advertisements pit the maximum doses of its injectables against lower doses of Novo's own diabetes and weight-loss medications.

Lilly has pushed back on the allegations, telling Barron's that the company stands firmly behind its advertising. "It is truthful, it is transparent, and it is grounded in the most direct scientific evidence available," Lilly said.

Lilly ticked slightly lower following the latest legal development, while Novo's American depositary receipts rose 1.1%.

Although the lawsuit has grabbed headlines, it seems Wall Street analysts are focused on the next major stock catalyst: two late-stage trials for retatrutide, Lilly's next-generation weight-loss drug.

Unlike older medications that target fewer metabolic pathways, retatrutide activates three different hormone receptors. Chief among them is glucagon-like peptide 1, the key mechanism behind Lilly's existing obesity and diabetes treatments.

According to Citi Research analyst Geoff Meacham, recent TRIUMPH-2 and TRIUMPH-3 data confirm the drug's efficacy in a harder-to-treat patient population while extending its profile into established cardiovascular disease.

"The weight-loss results are no longer headline-grabbing given prior retatrutide data, but further strengthen its position within Lilly's expanding cardiometabolic portfolio," Meacham said, adding that the results finalize the Phase 3 package for a regulatory submission early next year.

Jefferies analyst Akash Tewari cautioned that the data shouldn't be used to judge whether retatrutide helps or harms heart health since the study wasn't designed to answer that question. Even so, while clear cardiovascular outcomes were hard to extract, the drug's biomarkers point toward long-term benefits.

Looking at the bigger picture, Tewari believes high-dose retatrutide will mostly serve severely obese patients who need results comparable to weight-loss surgery. At the same time, he anticipates solid demand for lower doses among the general population, given that past clinical trials showed patients could lose nearly 20% of their body weight at a low-level dose.

Write to Mackenzie Tatananni at mackenzie.tatananni@barrons.com

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(END) Dow Jones Newswires

July 24, 2026 09:09 ET (13:09 GMT)

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