Evaluation of E1-mutant adenoviruses as conditionally replicating agents for cancer therapy

The oncolytic effect of adenoviruses may provide an efficient means to dest roy tumor tissue if viruses could be developed with sufficient selectivity and efficacy. In this report we have characterized several adenoviruses, ea ch with different mutations in the El region, for selective cytopathic effe ct in tumor cells in vitro and for their ability to inhibit tumor growth in vivo. Of the El mutants tested, we have identified one, E1Ad/01/07, which preferentially induces cytopathic effects in a range of tumor cells versus primary cells. In addition, E1Ad/01/07 significantly inhibited tumor growth and increased survival of mice in several models of human cancer. These re sults suggest that E1Ad/01/07 might serve as an effective cancer therapeuti c, combining both selectivity and efficacy.