Y-6 (Nanjing NeuroDawn Pharmaceutical)

Y-6 is a small molecule neuroprotective agent being developed by Nanjing Ningdan New Drug Technology (Ningdan Therapeutics) for the treatment of acute ischemic stroke (AIS). It functions as an inhibitor of postsynaptic density protein 95 (PSD-95), specifically disrupting the protein-protein interaction between the N-methyl-D-aspartate (NMDA) receptor and neuronal nitric oxide synthase (nNOS). By binding to the PDZ2 domain of PSD-95, Y-6 prevents the recruitment of nNOS to the NMDA receptor complex, thereby inhibiting the downstream production of neurotoxic nitric oxide and superoxide during ischemic events. This mechanism provides neuroprotection by mitigating excitotoxicity without interfering with the essential ionotropic functions of the NMDA receptor. Y-6 is formulated as a sublingual tablet to facilitate rapid systemic absorption and ease of administration in emergency settings. It is currently in Phase III clinical development in China, particularly for AIS patients undergoing endovascular therapy.