New Monthly Obesity Drug ASC35 Outperforms Rivals in Early Trials

Ascletis Pharma has developed ASC35, a new once-monthly injectable drug for obesity and metabolic diseases. The treatment is designed as a dual peptide agonist, targeting both GLP-1 and GIP receptors. Early studies suggest it could outperform existing therapies like tirzepatide in both potency and duration.

ASC35 is engineered to last longer in the body than current treatments. In non-human primate tests, its slow-release formulation had an average half-life of around 14 days—six times longer than tirzepatide. This extended effect supports once-monthly dosing, unlike the weekly injections required by some competitors.

The drug has also shown stronger results in weight loss trials. In a head-to-head study with diet-induced obese mice, ASC35 reduced body weight by 33.6%, compared to 19.6% for tirzepatide. This marks a 71% relative improvement in efficacy. Additionally, in vitro tests found ASC35 to be roughly four times more potent than tirzepatide for both GLP-1 and GIP receptors.

Ascletis plans to use ASC35 both on its own and alongside other drugs, such as ASC36 and ASC47, for broader metabolic disease treatments. The company's AISBDD and ULAP technologies enable the creation of these ultra-long-acting peptides. By February 2026, the U.S. FDA had already received applications for at least five clinical trials involving ASC35 or similar dual agonists, with ASC35 itself in Phase 2 testing.

Ascletis expects to submit an Investigational New Drug Application for ASC35 to the FDA in the second quarter of 2026. The drug's longer half-life and higher potency per dose could make it a leading option for obesity and related conditions. If approved, it may offer patients a more convenient and effective treatment compared to existing alternatives.