Hong Kong, China, August 10, 2026
Ascletis Pharma Inc. has announced the initiation of two Phase I clinical studies in the United States evaluating its next-generation therapies for obesity, ASC36 and ASC36_35FDC. The studies follow recent clearance of Investigational New Drug (IND) applications by the U.S. Food and Drug Administration (FDA) and represent a significant step in the company’s development of potentially first-in-class, long-acting treatments for chronic weight management. ASC36 is an amylin receptor peptide agonist designed for once-monthly to once-quarterly subcutaneous administration, while ASC36_35FDC is a once-monthly fixed-dose combination targeting the amylin receptor, GLP-1R, and GIPR pathways.
Two Phase I Studies Advance Long-Acting Obesity Therapies
The ASC36_35FDC Phase I study is a randomized, double-blind, placebo-controlled trial designed to assess the safety, tolerability, pharmacokinetics, and pharmacodynamics of the candidate following single and multiple ascending doses. The study will enroll participants with obesity or overweight accompanied by weight-related comorbidities and will evaluate two different fixed-dose combination formulations. Injection A is planned for 88 participants and Injection B for another 88 participants. Both formulations combine the ultra-long-acting peptide agonists ASC36 and ASC35, with ASC35 targeting GLP-1R and GIPR.
The separate ASC36 Phase I study is also randomized, double-blind, and placebo-controlled and will evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of ASC36 following single and multiple ascending doses. The study will assess two formulations, with Injection A planned for 72 participants and Injection B for another 72 participants. The clinical program is designed to evaluate the potential of long-acting amylin receptor activation as an approach to chronic weight management.
Triple-Target Approach Designed for Monthly Dosing
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Ascletis describes ASC36_35FDC as a potentially first-in-class fixed-dose combination designed to simultaneously target three validated pathways: amylin receptor, GLP-1R, and GIPR. The company is developing the formulation as a once-monthly subcutaneous injection, potentially reducing the frequency of administration compared with certain existing or emerging multi-drug approaches.
ASC36 is being developed as a potentially first-in-class once-monthly to once-quarterly amylin receptor peptide agonist. According to Ascletis, both ASC36 and ASC36_35FDC use the company’s Self-Assembling Lipid Depot (SALD) formulation, developed through its proprietary Ultra-Long-Acting Platform technology. Following subcutaneous administration, the low-viscosity formulation forms a gel-like depot in tissue that gradually releases the active pharmaceutical ingredient over a month or longer. In non-human primate studies, the ASC36 SALD formulation demonstrated an approximately six-fold longer observed half-life than eloralintide, supporting the company’s proposed once-monthly to once-quarterly administration strategy. ASC36_35FDC also demonstrated long observed half-lives for both peptide components in non-human primate studies.
Preclinical Data Support Continued Clinical Development
Ascletis reported promising findings from head-to-head diet-induced obese (DIO) rat studies evaluating the efficacy of its candidates. In these studies, ASC36 monotherapy targeting the amylin receptor demonstrated approximately 91% greater relative body weight reduction than petrelintide and approximately 32% greater reduction than eloralintide. The company also reported that ASC36_35FDC demonstrated approximately 51% greater relative body weight reduction compared with co-administration of eloralintide and tirzepatide in a head-to-head DIO rat study. These findings are being used by Ascletis to support continued development of its long-acting obesity pipeline, although animal findings do not establish clinical efficacy in humans.
Both ASC36 and ASC36_35FDC were discovered in-house using Ascletis’ Artificial Intelligence-assisted Structure-Based Drug Discovery (AISBDD) platform. The company is also developing additional metabolic disease programs, including oral and injectable candidates targeting GLP-1, GIP, amylin, and related pathways. The initiation of the two U.S. Phase I studies marks an important clinical development milestone for Ascletis’ once-monthly peptide obesity pipeline. Future clinical data will determine the safety, tolerability, pharmacokinetic, pharmacodynamic, and potential efficacy profiles of ASC36 and ASC36_35FDC as the programs advance through development.
Source: Ascletis Pharma press release
