Combination of a MDR1-targeted replicative adenovirus and chemotherapy for the therapy of pretreated ovarian cancer.

Purpose: Targeted oncolytic adenoviruses capable of replication selectively in cancer cells are an appealing approach for the treatment of various cancer types refractory to conventional therapies. The aim of this study was to evaluate the effect of Ad5/3MDR1E1, a multidrug resistance gene 1 (MDR1)-targeted fiber-modified replication-competent adenovirus for the therapy of platinum-pretreated ovarian cancer in combination with cytostatic agents.

Methods: MDR1-specific tumor cell killing of Ad5/3MDR1E1 was systematically evaluated in chemotherapy naïve and pretreated ovarian cancer cells in vitro. Combinations of Ad5/3MDR1E1 and cytostatic agents were studied in vivo and in vitro. An in vivo hepatotoxicity model was used to evaluate liver toxicity.

Results: We demonstrate efficient oncolysis of Ad5/3MDR1E1 in chemotherapy-resistant ovarian cancer cells as well as therapeutic efficacy in an orthotopic mouse model. Further, combining Ad5/3MDR1E1 with paclitaxel resulted in greater therapeutic benefit than either agent alone.

Conclusion: These preclinical data suggest that a fiber-modified adenovirus vector under the control of the MDR1 promoter represents a promising treatment strategy for platinum-pretreated ovarian cancer as a single agent or in combination with conventional anticancer drugs.