PARP inhibitors (PARPi) have become the paradigm of targeted drug‐mediated synthetic lethality in tumors with homologous recombination repair (HRR) deficiency, showing clinical efficacy in patients with BRCA1/2‐related breast and ovarian cancers, or as maintenance treatment in ovarian cancer patients with platinum‐sensitive relapse. The gene discussed is PARP1; the disease is ovarian cancer.