Atrogi announces first subjects dosed in human trial for lead candidate ATR-258

• First-in-class oral therapy ATR-258 mimics the effects of exercise – driving fat loss, increasing muscle, and improving metabolism – with broad potential as a novel treatment for muscle-sparing weight loss
• Study led by Associate Professor Morten Hostrup, a leading authority on β2-adrenergic receptor signaling in skeletal muscle at the University of Copenhagen, to evaluate muscle physiological aspects of ATR-258's highly selective β2-adrenergic signaling
• Atrogi's breakthrough technology, validated by publication of landmark research in Cell in June 2025, enables, for the first time, development of next-generation, highly selective β2-agonists for chronic use

STOCKHOLM, March 18, 2026 /PRNewswire/ -- Atrogi AB, a clinical stage biotech company pioneering novel GPCR pathway-signalling modulators to transform metabolic and muscle health, today announces that the first subjects have been dosed in a human trial for its lead candidate, ATR-258, evaluating the muscle physiological effects of its highly selective GRK-targeted β2-adrenergic signaling pathway.

The 8-week, investigator-initiated, interventional study will examine biased β2-adrenergic receptor (β2-AR) signaling in human skeletal muscle, in overweight male volunteers, who will receive daily oral dosing of ATR-258, Atrogi's GRK-selective long-acting β2-agonist. The study aims to measure the extent to which ATR-258 recapitulates the muscle physiological effects of classic β2 agonists, as well as its potential across a range of muscle atrophic conditions.

Morten Hostrup, Associate Professor at the University of Copenhagen and Principal Investigator of the study, said: "This trial will allow us to rigorously interrogate targeted downstream effector signaling associated with the β2-adrenergic receptor in human skeletal muscle using a highly selective next generation modulator. By combining detailed muscle physiological measurements with advanced molecular readouts, we aim to better understand how biased β2-adrenergic signaling regulates muscle growth and function, and how it can potentially be harnessed to preserve, or even augment, muscle function in various conditions of muscle wasting, such as immobilization, aging, and weight loss."

Professor Tore Bengtsson, Chief Scientific Officer and Founder of Atrogi, added: "Professor Hostrup is widely recognised as the leading expert in the field, and so we are excited about his commitment to investigate the muscle signaling effects of ATR-258, building on the work published in Cell in June 2025. His decision to sponsor this study speaks to the strength of our science and technology, and we look forward to sharing the results later this year."

This trial builds on the strong momentum at Atrogi, following the publication of a landmark study in Cell in June 2025 which validated Atrogi's novel GRK2-biased signaling pathway approach, unlocking the therapeutic potential of muscle-targeted β2-agonists while avoiding the cardiovascular side effects typically associated with this approach. The paper also detailed first-in-human trial data from a 69-subject Phase 1 trial, demonstrating the safety and tolerability of ATR-258 in both healthy volunteers and patients with type 2 diabetes.

Paul Little, Chief Executive Officer at Atrogi, commented: "The initiation of this study, and dosing of the first subjects, marks an important milestone for Atrogi. With safety established in Phase 1 and a validated mechanism of action, the generation of key muscle physiology data from this trial will underpin ATR-258's further development across metabolic and muscle-wasting conditions."

Additional information on the study for ATR-258 can be found on www.clinicaltrials.gov, NCT identifier NCT07421024.

About Atrogi

Atrogi AB is a Stockholm-based, clinical-stage biotech pioneering novel GPCR pathway-signalling modulators to transform metabolic and muscle health. Its lead candidate, ATR-258, is a first-in-class oral GRK2-biased β2-agonist designed to safely stimulate muscle metabolism and preserve lean mass, offering a novel approach to treating diabetes, obesity, and muscle loss.

Atrogi's proprietary compound library, developed under the scientific leadership of Professor Tore Bengtsson, serves as the foundation for a broader platform aimed at discovering selective GPCR modulators across multiple disease areas. Learn more at www.atrogi.com and on LinkedIn.