ZIOPHARM Oncology, Inc. is a biopharmaceutical company, which is seeking to develop, acquire and commercialize, on its own or with partners, a portfolio of cancer therapies that address unmet medical needs. The Company is focused on developing products in immuno-oncology that employ gene expression, control and cell technologies to deliver cell- and viral-based therapies for the treatment of cancer and graft-versus-host-disease. It has developed an adenoviral vector, Ad-RTS-IL-12, which is administered intra-tumorally under the control of the RheoSwitch Therapeutic System (RTS) expression platform. Its initial clinical stage product candidate, which is being developed using the immuno-oncology platform is Ad-RTS-IL-12 + veledimex. Ad-RTS-IL-12 + veledimex uses its gene delivery system to produce interleukin-12. As of December 31, 2016, it had completed two Phase II studies evaluating Ad-RTS-IL-12 + veledimex, for the treatment of metastatic melanoma and metastatic breast cancer.