The first wave of obesity drugs, which dominate the market, has mainly focused on the gut hormone GLP-1, but drugmakers are now looking for medicines that target other hormones or help preserve muscle mass during fat-loss with their next generation of drugs.

The experimental once-weekly drug, eloralintide, belongs to the class of drugs that mimic the pancreatic hormone amylin which slows digestion and suppresses hunger.

In an early-stage trial the drug helped some patients lose more than 11% of their body weight at 12 weeks.

In the mid-stage trial, patients on 1 mg dose of Lilly's drug lost 9.5% or 10.2 kilograms and 20.1% or 21.3 kgs at the highest 9 mg dose. This compares to 0.2 kg weight loss seen in patients on placebo at 48 weeks. The study enrolled 263 adults who were overweight with at least one obesity-related comorbidity and without type 2 diabetes.

Lilly's drug also showed improvement across factors like waist circumference, blood pressure, lipid profiles, glycemic control, and markers of inflammation.

The most common side effects were mild to moderate gastrointestinal symptoms and fatigue, which were seen more frequently at higher doses. The incidence of these side effects were lower with slower dose escalation and were similar to placebo for the 1 mg and 3 mg doses.

The data shows eloralintide offers the potential for strong efficacy with improved tolerability and could serve as an alternative to incretin therapies, said Kenneth Custer, president of Lilly Cardiometabolic Health.

Based on these trial results, Lilly will begin enrolling patients for late-stage trial next month. The drug is also being studied as a standalone treatment and in combination with Lilly's blockbuster GLP-1 drug, tirzepatide, sold as Zepbound, in mid-stage trials.