RecruitingPhase 1ProcedureTesting How the Body Responds to the Drug CX-5461 (Pidnarulex) in Patients With Metastatic Solid CancersThis phase I trial tests the safety, side effects, and best dose of pidnarulex (CX-5461) in treating patients with solid tumors that have spread from where it first started (primary site) to other places in the body (metastatic). Pidnarulex is an oral inhibitor of ribonucleic acid polymerase I, with potential antineoplastic activity. It blocks a certain enzyme needed for cell division and deoxyribonucleic acid (DNA) repair and may kill cancer cells.