Novo Nordisk shares fall as weight loss drug fails to beat Eli Lilly

The headquarters of Novo Nordisk A/S in Bagsvaerd, Denmark, on Wednesday, November 5, 2025.

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Novo Nordisk The stock fell more than 15% on Monday after announcing that its next-generation weight loss drug failed to meet its main goal of showing it is not inferior Eli Lilly’s rival drug, the latest blow for the Danish drugmaker, whose shares are trading at multi-year lows after a series of disappointing announcements.

The experimental drug CagriSema failed to meet its primary endpoint of demonstrating non-inferiority in weight loss compared to Eli Lilly’s rival drug tirzepatide after 84 weeks, Novo said in a statement Monday morning.

Tirzepatide is the active ingredient in Lilly’s mega-blockbuster drugs Mounjaro and Zepbound, which have overtaken Novo Nordisk’s semaglutide, sold as Ozempic and Wegovy, in the US.

Novo’s Copenhagen-listed shares were last down 16% at 251 Danish crowns, reaching their lowest level since June 2021.

Eli LillyThe stock lost 4.7%. Lilly also launched a new form of Zepbound on Monday that offers a month’s worth of doses in a single pen.

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Novo Nordisk’s ADRs perform significantly worse than Eli Lilly shares.

Patients who took a 2.4 mg dose of CagriSema achieved a 23% weight loss at 84 weeks, compared with 25.5% for a 15 mg dose of tirzepatide, Novo said.

The study was a so-called open study, meaning the participants knew what treatment they were receiving. Such a design could introduce a risk of bias in favor of a known product when compared to an investigational therapy, Martin Holst Lange, Novo’s chief scientific officer, told CNBC’s Charlotte Reed.

There were some “slightly surprising results” for the market drug, in this case tirzepatide, he added.

Lilly’s own studies have shown that tirzepatide results in 20.2% weight loss over 72 weeks in people who are obese or overweight.

Eli Lilly did not immediately respond to a CNBC request for comment.

Next generation weight loss medications

Novo applied for approval of CagriSema from the US Food and Drug Administration late last year and a decision is expected in late 2026. The company has high hopes for the drug, which combines semaglutide and cagrilintide, another hormone released in the pancreas that affects appetite.

Despite Monday’s disappointing results, Novo CEO Mike Doustdar remained optimistic about CagriSema’s potential.

“We strongly believe that CagriSema currently has the best weight effectiveness than any other product currently on the market,” he said.

Novo is reviewing additional studies to test CagriSema, including higher-dose combinations, the company said.

“CagriSema has the potential to be the first GLP-1/amylin combination product to come to market for people with obesity. This demonstrates that cagrilintide complements the existing benefits of semaglutide and provides clinically meaningful additional weight loss effects above and beyond those observed with GLP-1 biology alone,” said Novo’s Lange, adding that further studies would “evaluate the full weight loss potential of CagriSema.”

However, CagiSema’s failure to demonstrate non-inferiority to Zepbound creates additional uncertainty, and the drug’s commercial positioning is becoming increasingly unclear, said Jefferies analyst Michael Leuchten.

CagriSema could account for between 15% and 25% of Novo’s revenue by 2030, “underscoring the urgent need for mergers and acquisitions,” Leuchten said, predicting that Novo could spend up to $35 billion on mergers and acquisitions this year.

Another blow

Monday’s test result is another blow for the Danish drugmaker as it lags a drug already on the market and comes after shares fell nearly 50% in 2025.

Earlier this month, Novo forecast its revenue and profit growth would fall 5% to 13% in 2026 as it copes with competition, lower prices in the U.S. and the loss of exclusivity for Wegovy and Ozempic in certain markets.

“People should expect it to go down before it goes back up,” Novo’s Doustdar told CNBC at the time.

Meanwhile, Lilly expects revenue to grow about 25% in 2026.

Novo started the year with a strong launch of the first GLP-1 weight loss pill in the US, the Wegovy pill. However, Doustdar said this was not enough to offset challenges in other areas of the business. Eli Lilly is expected to launch a rival pill in the second quarter of 2026.

In addition to competition from Lilly, Novo sales took a hit due to competition from compounding pharmacies that sell copycat versions of semaglutide at a lower price, which Novo describes as “illegal mass compounding that poses a significant risk to patient safety.”

The FDA announced earlier this month that it was taking legal action against the telehealth company Him and himincluding restricting access to ingredients and referring it to the Department of Justice after Hims offered a Wegovy pill copy for significantly less than Novo sells the brand-name pill. After the backlash, Hims quickly withdrew the pill.