Lilly's eloralintide shows up to 20.1% weight loss in Phase 2 trial

Eli Lilly said Nov. 6, 2025 that its experimental once-weekly drug eloralintide helped adults with obesity or overweight lose 9.5% to 20.1% of their body weight over 48 weeks in a Phase 2 trial, compared with 0.4% for placebo ^[1].

The trial enrolled 263 adults who had obesity or were overweight with at least one weight-related health condition and did not have type 2 diabetes ^[1]. Their average starting weight was 109.1 kilograms, or about 240.5 pounds ^[1]. Results were presented at ObesityWeek 2025 and published in The Lancet at the same time ^[1].

Weight loss rose with dose. The 1 mg arm lost an average of 9.5% (10.2 kg, or 22.5 pounds), the 3 mg arm 12.4% (13.3 kg, or 29.3 pounds), the 6 mg arm 17.6% (18.7 kg, or 41.2 pounds) and the 9 mg arm 20.1% (21.3 kg, or 47.0 pounds) ^[1]. A group that escalated from 6 mg to 9 mg lost 19.9%, and a group that escalated from 3 mg to 6 mg to 9 mg lost 16.4% ^[1]. The placebo group lost 0.4%, or about 0.2 kg ^[1]. Every eloralintide arm met the study's primary goal of beating placebo ^[1].

Lilly reported those figures using what it calls the efficacy estimand, which the company describes as efficacy had all randomized participants remained on the study drug for 48 weeks, with possible dose interruptions or changes ^[1]. The numbers therefore describe people who stayed on treatment. Lilly also said eloralintide improved secondary measures including waist circumference, blood pressure, lipid profiles, blood sugar control and markers of inflammation ^[1].

The most common side effects were mild to moderate gastrointestinal symptoms and fatigue, which appeared more often in the higher-dose arms, were less frequent with slower dose increases, and were similar to placebo in the 1 mg and 3 mg arms ^[1]. Lilly called the tolerability profile favorable ^[1]. The announcement did not report how many participants stopped treatment because of side effects, how many had serious side effects, or any long-term safety data ^[1].

Eloralintide is an amylin receptor agonist, meaning it mimics the pancreatic hormone amylin, which slows digestion and suppresses hunger. Reuters reported it activates amylin receptors in the brain and slows gastric emptying, with the potential for less severe side effects than GLP-1 drugs ^[2]. The obesity drugs that dominate the market, including Zepbound and Wegovy, are GLP-1s ^[2].

Lilly said eloralintide "could serve as an alternative to incretin therapies" and might also be a complementary option for patients who need higher levels of efficacy ^[1]. Jefferies analyst Lucy Codrington told Reuters the data offer the strongest evidence yet that the amylin class can deliver GLP-1-like or greater weight loss ^[2]. Analyst Kevin Gade of Lilly shareholder Bahl and Gaynor said the results put Lilly in the "driver's seat" for amylin treatments, and analysts said the results set a new bar for rival amylin drugs ^[2]. Shares of Zealand Pharma, which is developing the amylin drug petrelintide, fell 11% ^[2]. Zealand CEO Adam Steensberg told Reuters the data validate the company's belief in the potential of amylin drugs ^[2].

Why it matters for patients

Eloralintide is not approved, and these are mid-stage results, not proof that the drug works or is safe over the long term. The trial did not compare eloralintide head to head with semaglutide or tirzepatide products, so how it stacks up against medicines people take today has not been reported ^[1][2]. Because it works through a different hormone system than GLP-1 drugs, it is being studied as a possible alternative for people who cannot tolerate or do not respond well to GLP-1s, and as an add-on for those who need more weight loss ^[1]. Whether either use holds up in later trials is not yet known.

The company did not disclose the route of administration, price, or whether it would be a pill or an injection ^[1].

What happens next

Lilly said it plans to begin enrolling Phase 3 studies of eloralintide as a monotherapy for obesity by the end of 2025 ^[1]. Reuters reported the company will start late-stage trials in December ^[2]. Lilly is also running a Phase 2 trial (NCT06603571) testing the drug alone and in combination with tirzepatide in adults with obesity or overweight who have type 2 diabetes ^[1]. Zealand's mid-stage data for petrelintide are expected in the first half of 2026 ^[2]. No approval or regulatory filing timeline has been disclosed.