Activity of intravesical CG0070 in Rb-inactive superficial bladder cancer after BCG failure: Updated results of a phase I/II trial.

4593 Background: Loss of retinoblastoma (Rb) tumor suppressor activity occurs commonly in bladder cancer and leads to upregulation of the E2F-1 transcription factor. CG0070 is a replication-competent oncolytic adenovirus genetically modified to express GMCSF under control of the human E2F-1 promoter. Updated results from a phase I study of CG0070 in patients with recurrent superficial bladder cancer (T1, Ta, Tcis) after BCG treatment are presented here. Methods: The V-0046 phase I/II study previously reported the safety and evidence of efficacy of single and multiple doses of intravesical CG0070. Efficacy was determined using quarterly cystoscopy, biopsy, and/or urine cytology. Tumor Rb status was assessed immunohistochemically in 18 tumors. Results: 35 patients were treated with either a single dose (n=13) of CG0070 ranging from 1x1012 to 3x1013 viral particles (vp) or with weekly x 6 (n=9) or every 4 week x 3-6 doses (n=13) ranging from 1x1012 to 1x1013 vp per dose. The most common adverse events regard...