Oncolytics Biotech Inc. has commenced patient enrolment in its phase Ib UK clinical trial investigating Reolysin in combination with radiation therapy as a treatment for patients with advanced cancers.

The phase Ib trial will treat patients with a range of two to six intratumoural doses of Reolysin at 1x10(10) TCID(50) with a constant radiation dose of 36 Gy in 12 fractions.

Patient enrolment in the Ia combination Reolysin/radiation trial was completed in June 2006. The phase Ia trial tested two intratumoural treatments of Reolysin at dosages of 1x10(8), 1x10(9), or 1x10(10) TCID(50) with a constant localized radiation dose of 20 Gy given in five fractions. A maximum tolerated dose (MTD) was not reached and the combination treatment appears to have been well tolerated by the patients.

Interim results of the Ia trial were presented at the American Association for Cancer Research (AACR) Annual Meeting in Washington, D.C. in April 2006. Preliminary analysis has demonstrated evidence of both local and systemic response.

The primary objective of the phase Ib trial is to determine the MTD, dose limiting toxicity (DLT), and safety profile of Reolysin when administered intratumourally to patients receiving radiation treatment. A secondary objective is to examine any evidence of anti-tumour activity. Eligible patients include those who have been diagnosed with advanced or metastatic solid tumours that are refractory (have not responded) to standard therapy or for which no curative standard therapy exists. An additional group of patients is planned to be treated at the maximum dose regimen reached in the Ib trial.

The principal investigators for the trial are Dr. Kevin Harrington of the Targeted Therapy Laboratory, The Institute of Cancer Research, Cancer Research UK Centre for Cell and Molecular Biology and Honorary Consultant in Clinical Oncology at The Royal Marsden NHS Foundation Trust, London, UK, and Dr. Alan Melcher of the Cancer Research U.K. Clinical Centre at St. James's University Hospital in Leeds. The trial is enrolling patients at the Royal Marsden and St. James's Hospitals in the U.K.