Lilly’s Zepbound faces a potential weight-loss rival. It’s made by a Chinese biotech

A Chinese-developed weight loss shot looked almost as good as Eli Lilly’s megablockbuster Zepbound in late-stage trial results rolled out Tuesday morning, in one more sign of the impending disruption that the booming Chinese biotech industry could bring to U.S. biopharma.

The Jiangsu, China-based company Hengrui Pharma and its privately held U.S. partner Kailera Therapeutics said early Tuesday that patients lost an average of 18% of their weight over 48 weeks on Hengrui’s drug, HRS9531.

Using a statistical measure that only takes into account patients who completed the trial, their average weight loss was 19%.

That’s still not quite as good as Zepbound, which led to 21% weight loss in a late-stage trial. But the Zepbound trial was longer, and Hengrui and Kailera say that patients were still losing weight when the Hengrui trial ended. What’s more, the latest Hengrui trial didn’t study HRS9531 at its highest dose level.

Hengrui plans to seek regulatory approval for the shot in China only “as soon as possible” based on the new results.

The drug won’t pose a threat to Lilly anytime soon, if ever. But Kailera, the U.S. company that licensed the rights to HRS9531 outside of China, thinks they may be able to show it works better than Zepbound in their own trials, which have yet to start, and which are aimed at getting global approvals for the drug.

“Today’s treatments are pretty much capped at about 20%” weight loss, said Kailera’s chief commercial officer, Jamie Coleman, in an interview Tuesday with Barron’s. “Our goal is to maximize that efficacy, go beyond that.”

Even if Kailera eventually does show that HRS9531 can help patients lose more weight than Zepbound, the drug is years from U.S. approval, and would likely launch later than retatrutide, a follow-up medicine from Lilly that already works better than Zepbound. Lilly’s hold on the weight loss market seems secure at least until the end of the decade, if not longer.

Still, the promising data on HRS9531 is a hint at the challenges that Chinese biotech is increasingly posing for U.S. biopharma. As Barron’s reported in June, U.S. drugmakers have spent tens of billions of dollars in recent months acquiring rights to experimental medicines invented by Chinese companies, in a sign of the growing quality and efficiency of the Chinese biotech sector.

HRS9531 is one of a big group of Chinese-developed weight loss assets licensed by U.S. companies. Merck licensed an oral GLP-1 for $112 million up front in December of last year from Hansoh Pharma, and Regeneron licensed a GLP-1/GIP from the same company in June for $80 million up front. AstraZeneca, Lilly, and Novo Nordisk also have similar deals with other companies.

It all adds complexity for investors trying to forecast the shape of the obesity market over the long term. And it’s a potential threat to the U.S. biotech ecosystem, which relies on big pharma cash going to U.S. biotechs to fund development of new drugs.

HRS9531, which Kailera calls KAI-9531, is very similar to Lilly’s Zepbound: Both are dual GLP-1/GIP receptor agonists, and both are injectable peptides. In an earlier trial, also conducted by Hengrui, patients on a higher dose of HRS9531 lost 22.8% of their weight after 36 weeks.

“Generally speaking, what we’ve seen out of China so far, this data looks very similar to tirzepatide,” said Coleman, using Zepbound’s chemical name. “We can go to higher doses without trading off tolerability, and we’ll study it longer.”

Though the latest study was a Phase 3 trial, it only enrolled 567 patients, far fewer than would be needed in a U.S. Phase 3.

Kailera launched in October with $400 million in private funding. It owns the rights outside of China to four Hengrui drugs including HRS9531.

The question for Kailera is what the market would be for a drug that may be similar or a bit better than Zepbound, and how the biotech could ramp up manufacturing. Making significant quantities of the drug has been a challenge for Lilly, which has invested many billions of dollars in expanding its manufacturing capacity.

Coleman, who was vice president, U.S. brand leader for Zepbound at Lilly before coming to Kailera, said that Kailera is already talking to contract manufacturers, and that more contract manufacturing capacity is available because Lilly and its competitor Novo Nordisk have brought much of their manufacturing in-house.

“We intend to focus and compete where weight loss matters the most, and where there are unmet needs in the market,” Coleman said. “There’s a high level of unmet need in people that need to lose more than what tirzepatide today is providing. And there are very few molecules that are really set up to deliver higher efficacy, especially with a mechanism that is well-known, well-understood, and a tolerability profile that’s pretty well accepted.”

Write to Josh Nathan-Kazis at josh.nathan-kazis@barrons.com