SPR04

SPR04 is a small molecule inhibitor of Ubiquitin-specific-processing protease 1 (USP1) currently in preclinical development by Shanghai Sipurui Pharmaceutical Technology (also known as SciBrunch). USP1 is a deubiquitinating enzyme that plays a pivotal role in the DNA damage response, specifically within the Fanconi Anemia (FA) pathway and translesion synthesis (TLS) by regulating the ubiquitination status of FANCD2 and PCNA. By inhibiting USP1, SPR04 prevents the deubiquitination of these proteins, thereby disrupting DNA repair mechanisms and inducing synthetic lethality in cancer cells with existing DNA repair deficiencies, such as those with BRCA mutations. The drug is primarily being developed for the treatment of various solid tumors.