SY617

SY617 is an investigational, orally bioavailable small molecule inhibitor of the influenza virus polymerase acidic (PA) protein endonuclease, developed by Jiaheng (Zhuhai Hengqin) Pharmaceutical Technology. It belongs to the class of cap-dependent endonuclease (CEN) inhibitors, a mechanism of action similar to that of baloxavir marboxil. By targeting the CEN activity within the viral RNA polymerase complex, SY617 blocks the "cap-snatching" process required for the initiation of viral mRNA synthesis, thereby effectively inhibiting the replication of both influenza A and B viruses. The drug is currently being evaluated in Phase 2 clinical trials in China for the treatment of uncomplicated influenza.