The study is being done to learn how safe and effective the study drug, RP- 3500, is when given with either niraparib or olaparib to treat advanced cancer. Niraparib and olaparib belong to a group of drugs called PARP inhibitors. These drugs are designed to block an enzyme called PARP which may stop cancer cells from growing. RP 3500 belongs to a class of drugs called ATR inhibitors that are design to stop cancer cells from growing. Are you Eligible? (Inclusion Criteria) Aged 18 years or older. Diagnosed with locally advanced or metastatic cancer. Have not received prior therapy with another...