EX-039

EX-039 is a small molecule inhibitor of D-amino acid oxidase (DAAO) being developed by Excelsior for the treatment of mild Alzheimer's disease. The drug functions by inhibiting the DAAO enzyme, which is responsible for the degradation of D-amino acids such as D-serine. D-serine serves as an essential co-agonist at the glycine site of the N-methyl-D-aspartate (NMDA) receptor. By preventing the breakdown of D-serine, EX-039 increases its synaptic availability, thereby enhancing NMDA receptor activity and potentially improving cognitive and neurological function. It is currently being evaluated in Phase 2 clinical trials as an oral add-on therapy to standard-of-care acetylcholinesterase inhibitors in patients with early-phase Alzheimer's disease.