The drugmaker hopes to show CagriSema leads to at least 25% weight loss, without increased side effects. Its lead in a red-hot market hinges on it.

Novo Nordisk A/S's appetite-blocking shot semaglutide, sold under the brand names Ozempic and Wegovy, will probably become the world's top-selling drug franchise next year. It broke open a market that could reach $130 billion by 2030 and has a cultural reach broader than any new drug since Viagra. Yet to keep its lead in the red-hot field of obesity, Novo must prove by December that it has something even better.

The Danish drugmaker's arch-rival Eli Lilly & Co. has introduced another shot -- Zepbound, also known as Mounjaro -- that so far has shown even more weight loss than Wegovy. A pack of other companies are hot on both their heels with next-generation drugs, including shots that could be more effective and simple pills that could be easier to take. And semaglutide is facing US price negotiations as soon as next year and European patent expiry by 2031. In China, where the compound will lose patent protection in 2026, potential generic challengers are already lining up to enter the market.