Caliway Biopharmaceuticals (TWSE: 6919) announced it has completed submission of an Investigational New Drug (IND) application to the U.S. Food and Drug Administration for a Phase 2 clinical study evaluating its novel fat-reduction drug candidate, CBL-514, for weight management. The study will assess CBL-514 in combination with Zepbound® (tirzepatide), Eli Lilly’s dual GLP-1/GIP receptor agonist, in adults with obesity or overweight.
The randomized, placebo-controlled Phase 2 trial, designated CBL-0201WR, will be conducted at multiple sites across the United States and is expected to enroll approximately 120 participants with a body mass index (BMI) greater than 30, or greater than 27 with associated comorbidities. The study aims to evaluate the efficacy, safety, and tolerability of CBL-514 when added to tirzepatide therapy, as well as its potential role in supporting long-term weight management after treatment discontinuation.
Key efficacy endpoints include changes in abdominal subcutaneous fat volume, measured by magnetic resonance imaging (MRI), and changes in body weight. The trial will also assess body composition parameters using dual-energy X-ray absorptiometry (DEXA), including body fat percentage, visceral fat, and muscle mass. To minimize bias, MRI and DEXA data will be independently analyzed in a blinded manner by a third-party contract research organization prior to statistical evaluation.
Notably, the study design incorporates an extended follow-up period after discontinuation of both tirzepatide and CBL-514. This phase will focus on long-term outcomes such as fat redistribution, body composition changes, and weight maintenance—areas increasingly recognized as critical challenges in contemporary obesity treatment.
GLP-1 receptor agonist–based therapies have driven rapid expansion of the global weight-loss market in recent years. However, clinical evidence suggests that while these drugs can produce significant weight reduction through appetite suppression, they primarily reduce adipocyte size rather than adipocyte number. As a result, patients often experience weight regain and unfavorable shifts in body composition after treatment cessation, including increased visceral fat and worsening metabolic markers.
Caliway said CBL-514 is designed to address these limitations through a distinct mechanism of action. The injectable small-molecule drug selectively induces adipocyte apoptosis, directly reducing fat cells in targeted areas. Preclinical and completed studies have also shown that CBL-514 may inhibit adipogenesis and promote fat metabolism, offering potential complementarity to appetite-regulating GLP-1 therapies.
In the Phase 2 study, CBL-514 will be introduced after an initial eight-week period of tirzepatide monotherapy, followed by six combination administrations. Participants will then undergo multiple post-treatment assessments to evaluate changes in abdominal subcutaneous fat, total fat mass, visceral fat, body weight, and other body composition–related parameters.
Supportive data from animal studies suggest that CBL-514, alone or in combination with GLP-1 therapies, may enhance fat composition improvements and help maintain weight loss after GLP-1 withdrawal. These findings were recently presented at the 25th Annual Congress of the Taiwan Medical Association for the Study of Obesity (TMASO 2025), where the combination of CBL-514 and tirzepatide was highlighted as a featured presentation.
According to market estimates, cumulative sales of tirzepatide reached approximately $24.8 billion in the first three quarters of 2025. Morgan Stanley Research projects the global weight-loss drug market could expand to roughly $150 billion by 2035, underscoring the commercial potential for differentiated therapies that address long-term weight maintenance and body composition.
CBL-514 is a first-in-class, 505(b)(1) small-molecule drug developed by Caliway. To date, the compound has been evaluated in 10 clinical trials involving 544 subjects, meeting all primary efficacy and safety endpoints. The drug is being developed for multiple indications, including non-surgical localized fat reduction, moderate-to-severe cellulite, and weight management, with additional formulations under investigation for rare adipose-related disorders.
Caliway Biopharmaceuticals is a clinical-stage company focused on the discovery and development of novel small-molecule therapies. Listed on the Taiwan Stock Exchange, the company aims to establish a leading position in aesthetic medicine and other therapeutic areas through innovative drug development.
