Lilly's amylin drug eloralintide shows about 11% weight loss in early trial

Eli Lilly's experimental obesity drug eloralintide helped patients lose about 11% of their body weight over 12 weeks in a phase 1 trial, according to early data released ahead of the American Diabetes Association conference in Chicago ^[1][2]. The drug is an amylin analog, part of a class that has drawn heavy investment as companies look beyond GLP-1 medicines ^[1][2].

The trial enrolled 100 patients who received a range of doses ^[2]. In the best-performing dose cohort, weight loss reached 11.3% at 12 weeks, while one dose cohort lost as little as 2.6% ^[2]. A Cantor Fitzgerald investor note described the top result as 11.5% ^[1]. The doses used and the number of patients in each group have not been reported.

Amylin is a pancreatic hormone released alongside insulin; it slows digestion and suppresses hunger ^[1]. Part of the appeal of amylin analogs is the potential to drive weight loss without the same level of tolerability problems seen with GLP-1 receptor agonists ^[2]. In this trial, Lilly reported relatively low rates of gastrointestinal side effects: 10% of participants had diarrhea, and fewer had nausea or vomiting ^[2]. The specific rates for nausea and vomiting have not been disclosed.

Analysts responded positively. Cantor Fitzgerald's Prakhar Agrawal said the data looked strong on both weight loss and safety, and that expectations for the drug had been low ^[1]. Jefferies analyst Akash Tewari said, "We think the data today is a sign that the real successor to tirzepatide is the tirzepatide-eloralintide combo" ^[1]. Tirzepatide is Lilly's GLP-1/GIP drug, sold as Mounjaro and Zepbound ^[2].

Agrawal said eloralintide's weight loss is tracking better than Roche and Zealand Pharma's amylin candidate petrelintide and is meaningfully better than Novo Nordisk's monotherapy, and that 12-week data is also competitive with other drug classes such as GLP-1 ^[1]. Mid-stage trials of eloralintide are continuing, both on its own and combined with tirzepatide ^[1].

Not everyone is convinced the approach will hold up. Zealand Pharma CEO Adam Steensberg questioned the durability of Lilly's amylin-selective approach, saying his company sees benefits in engaging two amylin receptors and the calcitonin receptor. "I think in order to achieve a molecule that can provide a true alternative, with a significant weight loss as a monotherapy, you probably want to be on all three receptors," Steensberg said. "If you're only on two, maybe you get into some issues at the higher doses where you also see the higher weight losses. That is something we would speculate" ^[2].

Amylin has become a crowded field. In March, Roche acquired the rights to petrelintide in a collaboration valued at up to $5.3 billion ^[1]. Novo Nordisk is developing amycretin and CagriSema, which pairs an amylin analog with the GLP-1 drug semaglutide ^[1][2]. AstraZeneca has an amylin-based obesity drug in early trials ^[1]. AbbVie and Metsera are also in the race, and other companies are pursuing different mechanisms, routes of administration and dosing schedules ^[2].

Why it matters for patients

Eloralintide is not approved and is not available. These results come from a phase 1 trial, the earliest stage of human testing, and cover only 12 weeks of treatment ^[1][2]. Whether weight loss continues past 12 weeks with this drug has not been reported, and longer-term safety data are not yet available ^[2].

If the drug eventually reaches the market, analyst interest points to two possible uses: as a stand-alone obesity treatment, or paired with tirzepatide for people who need more weight loss than one drug provides ^[1][2]. Tolerability is central to that interest, because amylin analogs are being pursued partly for the potential to cause fewer digestive side effects than GLP-1 receptor agonists ^[2].

Nothing about currently available treatments changes based on these results. The first wave of obesity drugs focused mainly on GLP-1; amylin is one of several approaches companies are testing for the next generation, along with drugs that target other hormones or aim to preserve muscle during weight loss ^[1].

What happens next

Lilly is scheduled to present the eloralintide data on June 22 at the American Diabetes Association conference, which could give a clearer picture of the drug's risks and benefits ^[2]. A phase 1 study of eloralintide combined with tirzepatide started in April, and those results have not been shared ^[2]. Mid-stage trials of eloralintide alone and with tirzepatide are ongoing ^[1]. No dates for later-stage results have been disclosed. Lilly did not immediately respond to a Reuters request for comment on the phase 1 data ^[1].