A Study of ZYC300 Administered With Cyclophosphamide Pre-Dosing

This is an open-label study of ZYC300 in the treatment of advanced stage malignancy of the kidney in patients who have not had previous immune-based therapies or treatment of advanced stage malignancies (cancerous growths) of the ovary, breast, colon, or hormone-refractory prostate in patients who have failed at least one but no more than two prior regimens of chemotherapy. Patients who meet all entry criteria will be administered 600 mg/m\^2 cyclophosphamide intravenously 3 days before each dose of ZYC300. ZYC300 will be administered at 400 micrograms DNA/total dose every two weeks for a maximum of six doses (6 cycles). ZYC300 is a plasmid DNA formulated within biodegradable microencapsulated particles. This is the first time that ZYC300 and Cyclophosphamide will be given together. Cyclophosphamide is a chemotherapy drug approved by the FDA that has been used for many years in many different kinds of cancer. In this trial the study drug will be used to boost the immune system. Sometimes the immune system cannot fight infected or abnormal cells because of other cells called T reg cells. The T reg cells limit the immune systems attack on infected or abnormal cells. In this study, the hope is that Cyclophosphamide will inhibit the T regs cells so that the ZYC300 can work better to attack the cancer cells.