PARP1 and ovarian cancer: While PARP inhibitors are in late stage development for the treatment of ovarian cancers (olaparib approved, rucaparib Phase 3), based on this preclinical data, several clinical studies of PARP inhibitors are being conducted in SCLC to investigate the effect of these drugs as single agents or in combination with chemotherapy (Phase I–talazoparib, Phase II olaparib and veliparib) [6].