New Obesity Drug LET003 Shows Fat Loss and Muscle Protection in Preclinical Trials
Harbour BioMed has released new preclinical findings on LET003, an experimental antibody for obesity treatment. The drug targets ACVR2A/2B pathways and shows promise in improving body composition. Early tests suggest it outperforms competitors in key areas like fat reduction and muscle preservation. In studies using human FcRn transgenic mice and cynomolgus monkeys, LET003 cleared from the body more slowly than rival molecules. This improved stability could mean longer-lasting effects in patients. The drug also demonstrated stronger pharmacokinetic properties, setting it apart from other treatments in development.
When combined with semaglutide, LET003 delivered striking results. Fat mass dropped by 76.0% compared with a control group and by 34.7% when measured against semaglutide alone. The fat-to-body weight ratio fell by 17.5% versus controls and by 6.0% compared with semaglutide monotherapy. Lean mass benefits were equally notable. The combination therapy reduced lean mass loss to just 6.5% against controls while increasing it by 5.7% over semaglutide alone. The lean mass-to-body weight ratio rose by 15.2% compared with controls and by 5.3% over semaglutide monotherapy. LET003 also matched the muscle-promoting effects of 15 mg/kg bimagrumab at a lower 5 mg/kg dose. On its own, LET003 boosted lean mass by 18.3% over controls and 13.5% over a competitor molecule. These findings highlight its potential as a dual-action therapy for obesity.
The preclinical data positions LET003 as a strong candidate for obesity treatment. Its ability to reduce fat while protecting muscle—especially when paired with semaglutide—could offer advantages over existing options. Harbour BioMed plans further development based on these results.
