South Korea Approved a GLP-1 Drug Sanofi Had Given Up On

South Korea's drug regulator approved the country's first domestically developed GLP-1 obesity treatment this week, clearing a compound that Sanofi, the French pharmaceutical giant that originally licensed it, had walked away from only six years earlier.

The Ministry of Food and Drug Safety (MFDS) approved efpeglenatide, developed by Hanmi Pharmaceutical, for chronic weight management in adults with obesity or in overweight adults without diabetes, according to The Korea Times. It is Korea's 45th domestically developed novel drug and the first GLP-1 obesity drug built, tested and approved entirely by a Korean company.

The backstory is what makes the approval notable. Hanmi licensed efpeglenatide to Sanofi in 2015 to develop as a diabetes treatment. Sanofi returned the rights in 2020 as part of a broader retreat from diabetes research. The following year, a large outcomes trial Sanofi had already run on the drug reported results showing it reduced cardiovascular events and slowed kidney decline in people with type 2 diabetes — evidence that a drug the company had just given up on worked.

What the drug does

Efpeglenatide is a GLP-1 receptor agonist, the same drug class as semaglutide and tirzepatide, built on an exendin-4 backbone rather than the human-GLP-1-derived backbone most newer entrants use. GLP-1 receptor agonists mimic a gut hormone released after eating; activating the receptor slows stomach emptying, increases insulin release in response to food and acts on appetite centers in the brain to reduce intake. Hanmi extended the molecule's effective half-life using its in-house Lapscovery conjugation platform, which is designed to let the drug be dosed weekly instead of daily.

The strongest clinical evidence behind efpeglenatide so far doesn't come from an obesity trial at all. AMPLITUDE-O, published in the New England Journal of Medicine in 2021, randomized 4,076 adults with type 2 diabetes who already had cardiovascular disease or chronic kidney disease to weekly efpeglenatide or placebo. Over a median follow-up of 1.81 years, major cardiovascular events occurred in 7.0% of the efpeglenatide group versus 9.2% on placebo (hazard ratio 0.73), and a composite kidney-decline outcome occurred in 13.0% versus 18.4% (hazard ratio 0.68) — reductions in the range later GLP-1 outcome trials would also report for semaglutide and tirzepatide. That trial was funded and run by Sanofi, which published it a year after giving the drug back.

The obesity trial that led to this week's approval

The approval itself rests on a separate, more recent study: a Korean Phase 3 trial of 448 adults with obesity who did not have diabetes, run by Hanmi after it regained the rights. At an interim 40-week readout reported in Dailypharm in October 2025, participants on efpeglenatide lost an average of 9.75% of body weight, against 0.95% on placebo — a placebo-adjusted difference of roughly 8 percentage points. Measured by threshold instead of average, 79.4% of the drug group lost at least 5% of their starting weight, versus 14.5% on placebo, and about half lost more than 10%. Gastrointestinal side effects — nausea, vomiting, diarrhea — were two to four times more common on the drug than on placebo, consistent with every other drug in this class.

Hanmi's trial also did something Western pivotal trials for this drug class generally haven't: it enrolled on a Korean obesity threshold of BMI 25 or higher, rather than the 30-or-higher cutoff common in American and European obesity trials. The company and MFDS designated the drug for a fast-track "global innovative product" review in November 2025, a program the ministry says shortens review by roughly 25%, and Hanmi filed for approval the following month, according to Herald Corporation.

What's established versus what isn't

The cardiovascular and kidney protection shown in AMPLITUDE-O is strong, randomized, peer-reviewed evidence — but it was measured in people with diabetes and existing heart or kidney disease, not in the overweight, non-diabetic population this week's approval covers. Whether efpeglenatide's organ-protective effects, seen in a sicker population taking it for diabetes, extend to people taking it purely for weight loss is untested and shouldn't be assumed.

The obesity evidence itself is thinner than it may look. The reported results are a 40-week interim analysis from a single trial run at Korean university hospitals, with the full 64-week data not yet published; no peer-reviewed paper on the obesity trial has appeared yet, only company-reported topline figures relayed through trade press. There has been no head-to-head trial against semaglutide or tirzepatide, so comparative claims about efficacy are company framing, not measured fact. And a single-country trial in a population selected at a lower BMI threshold may not generalize to how the drug performs, or is regulated, elsewhere.

What this means for researchers

Efpeglenatide's path — licensed out, returned, outcome data published anyway, then repositioned entirely by the originating company for a different indication in a different country — is an unusual one even by pharma standards, and it's a reminder that a drug's commercial fate and its scientific evidence can diverge by years. The AMPLITUDE-O data didn't disappear when Sanofi walked away; it simply sat waiting for a company willing to act on it.

It's also an early test case for what obesity drug development looks like outside the US and EU duopoly that has otherwise defined this drug class. If the Korean trial's lower BMI enrollment threshold reflects a genuine population difference rather than just a regulatory choice, other national or regional regulators may eventually diverge from the American and European obesity cutoffs that most published trials, including an earlier triple-agonist trial covered here, were built around. Readers who want the general mechanism refresher on this drug class can find it on Torrey Labs' /learn page.

The cautious read: this is a genuinely new regulatory and commercial data point, not yet a genuinely new finding about the drug's biology. The biology — for better or worse, since Sanofi already paid to learn most of it — was mostly settled four years ago.