Preliminary results from an ongoing patient study in the UK have demonstrated that Reolysin was well-tolerated by patients and there was evidence of virus replication within several types of tumors in patients who had failed all previous treatments. Of 12 patients who received doses of Reolysin on five consecutive days, at least four patients had stabilization of the measured tumor. Patients who experienced tumor activity included those with colorectal, prostate, non-small-cell lung and bladder cancers.

The reovirus, when delivered intravenously, enters cancer cells, replicates within them and ultimately kills them. It works by replicating within cancer cells that have an activated Ras pathway, a common mutation that is shared by approximately two-thirds of all human cancers.

Oncolytics has also started patient enrolment in a similar intravenous trial in the U.S. at the Montefiore Medical Center in New York City. This clinical trial is an open-label, dose-escalation Phase I study in which a single dose of Reolysin is administered intravenously to patients with advanced and/or metastatic solid tumors.