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– The Phase I trial is divided into two parts. Part A is a single ascending dose (SAD) study of the ASC35 Self-Assembling Lipid Depot (SALD) monthly formulation; Part B is a multiple ascending dose (MAD) head-to-head study comparing the ASC35 SALD monthly formulation with the U.S. Food and Drug Administration (FDA)-approved tirzepatide weekly formulation.
– In a head-to-head non-human primate study, the average observed half-life of ASC35 was approximately 6 times longer than that of tirzepatide, supporting once-monthly subcutaneous administration in humans.
– In a head-to-head diet-induced obesity (DIO) mouse study, the weight loss effect of ASC35 was relatively improved by approximately 71% compared to tirzepatide.
Hong Kong, June 23, 2026 /PRNewswire/ — Ascletis Pharma Inc. (HKEx: 1672, “Ascletis”) today announced that it has recently received U.S. Food and Drug Administration (FDA) Investigational New Drug (IND) approval for its Phase I study of ASC35. ASC35 is a potential best-in-class, once-monthly subcutaneous injectable GLP-1 receptor (GLP-1R)/GIP receptor (GIPR) dual agonist peptide for the treatment of obesity.
The Phase I trial is a randomized, double-blind, placebo-controlled clinical study designed to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of single and multiple ascending doses of ASC35 in 84 obese (body mass index (BMI) ≥30.0 kg/m²) or overweight (BMI≥27.0 kg/m²) subjects with weight-related comorbidities. The Phase I trial is divided into two parts. Part A is a single ascending dose (SAD) study of the ASC35 Self-Assembling Lipid Depot (SALD) monthly formulation; Part B is a multiple ascending dose (MAD) head-to-head study comparing the ASC35 SALD monthly formulation with the FDA-approved tirzepatide weekly formulation.
ASC35 was independently developed by Ascletis using its structure-based AI-assisted drug discovery (AISBDD) technology. The ASC35 SALD monthly formulation was developed using Ascletis’ Ultra-Long-Acting Platform (ULAP) technology.
The SALD formulation is a low-viscosity solution composed of lipids, a biocompatible organic solvent, and the active pharmaceutical ingredient (API). This low-viscosity solution can be easily injected into subcutaneous tissue using a pen injector or auto-injector equipped with a needle as fine as 29G (gauge). After subcutaneous injection, the solution transforms into a gel-like depot in the tissue. Under the action of biological enzymes in the subcutaneous tissue, the depot slowly degrades, controlling the sustained release of the API over a month or longer.
In a head-to-head non-human primate study, the average observed half-life of the subcutaneously injected ASC35 SALD formulation was approximately 6 times longer than that of the FDA-approved subcutaneous tirzepatide formulation. Compared to other incretin peptides, ASC35 exhibits a longer observed half-life and a smoother pharmacokinetic profile in non-human primates, which may also confer better gastrointestinal tolerability in humans.
In a head-to-head non-human primate study, drug exposure of ASC35 after intravenous and subcutaneous injection was approximately 80% and 70% higher, respectively, than that of tirzepatide after intravenous and subcutaneous injection.
In a head-to-head diet-induced obesity (DIO) mouse study (the DIO model has been shown to be highly predictive of efficacy in humans), when administered at the same molar concentration of ASC35 and tirzepatide, the weight loss effect of ASC35 was relatively improved by up to 71% compared to tirzepatide.
In vitro experiments showed that the agonistic activity of ASC35 on GLP-1R and GIPR was approximately 4 times stronger than that of tirzepatide. Combined with all preclinical studies, ASC35 is more efficient on a per-milligram peptide basis than tirzepatide.
“The FDA’s IND approval for the ASC35 monthly formulation, developed using our proprietary SALD formulation technology, is an exciting and important milestone for Ascletis’ peptide pipeline in treating obesity. We are currently advancing multiple once-monthly to once-quarterly subcutaneous injectable peptides into the clinical stage,” said Dr. Jinzi Wu, Founder, Chairman, and CEO of Ascletis. “ASC35’s outstanding weight loss potential, combined with a more flexible and patient-friendly once-monthly subcutaneous injection regimen, is expected to address the significant unmet needs in the rapidly growing obesity market.”
About Ascletis Pharma Inc.
Ascletis Pharma Inc. is a fully integrated biotechnology company focused on the development and commercialization of potential best-in-class and first-in-class drugs for the treatment of metabolic diseases. Leveraging its proprietary Artificial Intelligence-assisted Structure-Based Drug Discovery (AISBDD), Ultra-Long-Acting Platform (ULAP) technology, and Peptide Oral Transport ENhancement Technology (POTENT), Ascletis has independently developed multiple small molecule and peptide drug candidates, including its core program ASC30, an investigational small molecule GLP-1R agonist that can be administered either once-daily orally or once-monthly to once-quarterly subcutaneously as a weight loss therapy and weight maintenance therapy for long-term weight management; ASC36, an amylin receptor agonist peptide; ASC35, a once-monthly subcutaneous injectable GLP-1R/GIPR dual agonist peptide; ASC37, a GLP-1R/GIPR/GCGR triple agonist peptide; ASC39, a potent oral small molecule amylin receptor agonist similar to eloralintide with selectivity for amylin; and ASC30_39 FDC, a fixed-dose combination (FDC) of ASC30 (GLP-1RA) and ASC39 (amylin receptor agonist) for long-term weight management. Ascletis is listed on the Hong Kong Stock Exchange (1672.HK).
For more information, please visit: www.ascletis.com.
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