ASN51

ASN51 is an investigational small molecule drug developed by Asceneuron for the treatment of neurodegenerative tauopathies, most notably Alzheimer's disease. It acts as a potent and selective oral inhibitor of O-GlcNAcase (OGA), an enzyme involved in the removal of O-linked N-acetylglucosamine from proteins such as tau. By inhibiting OGA, ASN51 increases tau protein O-GlcNAcylation, which stabilizes tau in a state less prone to forming toxic aggregates—potentially slowing or modifying disease progression. The drug has demonstrated favorable safety and pharmacokinetic profiles in multiple Phase 1 trials, showing effective central nervous system penetration and high target engagement. Although it advanced to Phase 2 clinical trials for early Alzheimer's disease, development was halted in March 2025 for strategic reasons. Beyond Alzheimer’s disease, ASN51 has also been explored preclinically or clinically for other neurodegenerative disorders including Parkinson’s disease and amyotrophic lateral sclerosis (ALS)[2][5][6][7].