Enzon Pharmaceuticals, Inc. (Nasdaq: ENZN) today announced that the first patient has been treated in the Phase 2 studies of PEG-SN38 for metastatic breast cancer. PEG-SN38 or EZN-2208 is Enzon's PEGylated form of SN38, the active metabolite of the cancer drug Camptosar® (irinotecan HCl...