Atrogi reports positive muscle data
Stockholm-based Atrogi has reported positive human data for ATR-258, its first-in-class oral therapy designed to improve muscle function and body composition. Over eight weeks, treatment was associated with an approximately 13% improvement in lower-extremity muscle power, together with more lean mass and less fat mass.
October 2, 2026
The open-label, single-arm study was investigator-initiated and led by Professor Morten Hostrup. It included thirteen overweight or obese subjects. ATR-258 was well tolerated across three ascending dose levels. Treatment was also associated with statistically significant mean reductions of 1.1 kg in fat mass and increases of 0.8 kg in lean mass.
The rise of incretin-based weight-loss drugs has sharpened the focus on preserving muscle, with studies suggesting that 25–45% of weight lost may be lean mass. ATR-258 is designed to selectively engage a pathway in skeletal muscle, initially targeting muscle-sparing weight loss.
“To see fat loss alongside an increase in lean muscle mass and improvement in muscle function represents a truly differentiated profile, and is highly encouraging,” says Professor Tore Bengtsson, Chief Scientific Officer and founder of Atrogi.
“Having worked extensively with classical β2-agonists, I know they can enhance power, but not to the extent we observed here,” says Hostrup.
The results provide first human proof-of-mechanism and support Atrogi’s plans to start a Phase 2 trial in 2027 in muscle-sparing weight loss and sarcopenia. Hostrup will present initial findings at the International Conference on Cachexia, Sarcopenia and Muscle Wasting in Washington, DC, on December 10–12, 2026.
Published: October 2, 2026
