– KSQ-4279 is a USP1 and PARP inhibitor. KSQ-4279 showed anti-proliferative effects in a subset of cell lines, often characterized by the presence of homologous recombination deficiencies (HRD), including mutations in BRCA1/2. The combination of KSQ-4279 with olaparib was able to induce strong and durable regressions across a number of ovarian and TNBC PDX models.