ISM0900

ISM0900 is a potent, selective, and orally bioavailable small molecule inhibitor of ubiquitin-specific protease 1 (USP1), discovered and developed by Insilico Medicine using its proprietary AI platform, Chemistry42. USP1 is a deubiquitinating enzyme that plays a critical role in the DNA damage response (DDR) by regulating the translesion synthesis and Fanconi anemia pathways. By inhibiting USP1, ISM0900 promotes the accumulation of ubiquitinated substrates, leading to genomic instability and cell death, particularly in tumors with homologous recombination deficiency (HRD), such as those with BRCA mutations. The drug is being investigated for the treatment of advanced solid tumors, both as a monotherapy and in combination with PARP inhibitors, where it may overcome or prevent resistance mechanisms.