Abstract 2398: Activity of the PARP inhibitor olaparib in ATM-deficient gastric cancer: from preclinical models to the clinic

Olaparib is an oral inhibitor of the Poly-(ADP-ribose)-polymerases (PARP-1, -2 and -3), and has demonstrated clinical activity in trials of patients with BRCA-deficient tumors. The BRCA1 and BRCA2 proteins are both important for the repair of DNA double strand breaks (DSBs) by homologous recombination repair (HRR) and sensitivity to olaparib has further been shown preclinically to extend to other DNA DSB repair factor deficiencies, including those in the ataxia telangiectasia mutated (ATM) protein. We have demonstrated that a high proportion of gastric cancer (GC) cell lines (∼50%) are responsive (IC50