PARALLEL 303: Phase 2 randomized study of pamiparib vs placebo as maintenance therapy in patients (pts) with inoperable locally advanced or metastatic gastric cancer that responded to platinum-based first-line (1L) chemotherapy.

3109 Background: A subset of gastric cancers exhibits platinum sensitivity and genomic instability that is characteristic of homologous recombination deficiency (HRD). Cells with HRD are sensitive to poly (ADP-ribose) polymerase (PARP) inhibition. PARP inhibitor maintenance therapy following platinum-based chemotherapy has been a successful treatment strategy in pts with ovarian cancer. Pamiparib is an orally administered selective PARP protein 1 and 2 (PARP1/2) inhibitor that has shown potent DNA-PARP trapping activity and crosses the blood brain barrier in preclinical studies. In early phase clinical studies (NCT02361723; NCT03333915), pamiparib showed an acceptable safety profile and pr…