An orally bioavailable inhibitor of PARP1 and PARP2 (IC50s = 3.8 and 2.1 nM, respectively); inhibits the proliferation of BRCA1 and BRCA2 mutant cancer cells in vitro (IC50s = 10-100 nM) and has efficacy alone against a xenograft of BRCA1-deficient cancer in mice