Purpose: Ad5.SSTR/TK.RGD is an infectivity-enhanced adenovirus expressing a therapeutic thymidine kinase suicide gene and a somatostatin receptor (SSTR) that allows for noninvasive gene transfer imaging. The purpose of this study was to identify the maximum tolerated dose (MTD), toxicities, clinical efficacy, and biologic effects of Ad5.SSTR/TK.RGD in patients with recurrent gynecologic cancer. Experimental Design: Eligible patients were treated intraperitoneally for 3 days with 1 × 109 to 1 × 1012 vp/dose of Ad5.SSTR/TK.RGD followed by intravenous ganciclovir for 14 days. Toxicity and clinical efficacy were assessed using Common Toxicity Criteria (CTC) Adverse Events grading and Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Imaging using In-111 pentetreotide was obtained before and after treatment. Tissue samples were obtained to evaluate for gene transfer, generation of wild-type virus, viral shedding, and antibody response. Results: Twelve patients were treated in three cohorts. The most common vector-related clinical toxicities were grade I/II constitutional or pain symptoms, experienced most often in patients treated at the highest dose. MTD was not identified. Five patients showed stable disease; all others experienced progressive disease. One patient with stable disease experienced complete resolution of disease and normalization of CA125 on further follow-up. Imaging detected increased In-111 pentetreotide retention in patients treated at the highest dose. Ancillary studies showed presence of Ad5.SSTR/TK.RGD virus and HSV1-tk expression in ascites samples collected at various time points in most patients treated within the higher dose cohorts. Conclusions: This study shows the safety, potential efficacy, and possible gene transfer imaging capacity of Ad5.SSTR/TK.RGD in patients with recurrent gynecologic cancer. Further development of this novel gene therapeutic appears to be warranted. ©2012 AACR.