CS08399 is a brain-penetrant PRMT5-MTA inhibitor with global patent protection, independently developed by the Company using its AI + chemical genomics technology platform.

CS08399 is an MTA-cooperative protein arginine methyltransferase 5 (PRMT5) inhibitor that exhibits highly selective antitumor activity against methylthioadenosine phosphorylase (MTAP)-deficient tumor cells. CS08399 exerts epigenetic regulation on diverse cell types within the tumor microenvironment through PRMT5 inhibition, demonstrating therapeutic potential in overcoming tumor drug resistance and immune evasion.

The clinical trial application for CS08399 tablets was approved in March 2026, and the first patient was enrolled in June 2026.