Reovirus: Rationale and clinical trial update.

Early clinical trials of reovirus administered via the intratumoral or intravenous routes in patients with advanced cancers established the safety profile and MTD of these agents. Reovirus is an orphan virus and is the cause of a well-documented subclinical syndrome. Preclinical evidence of the novel mechanisms of anticancer activity of reovirus provided the rationale for advancing this agent into clinical trials. Preclinical studies have also defined the specificity of the antitumor activity of reovirus, and also its efficacy in combination with cytotoxic chemotherapies and immunosuppressants. Early clinical trials of combinations of the injectable oncolytic reovirus therapy Reolysin (Oncolytics Biotech Inc) plus cytotoxic chemotherapies are ongoing, as are phase II trials of Reolysin as a single agent for the treatment of specific tumor types.