Oncolytics Biotech Inc., a Calgary-based biotechnology company, announced positive results in its UK phase II clinical trial to evaluate the objective tumour response rate of Reolysin in combination with low-dose radiation in patients with advanced cancers.

A total of 16 heavily pretreated patients with advanced cancer (melanoma (5), colorectal (4), gastric (1), pancreas (1), ovarian (1), lung (1), cholangiocarcinoma (1) sinus (1), and thyroid (1)) were enrolled in the trial. Most patients had received prior chemotherapy (13 patients) or radiation (5 patients). Of 14 patients evaluable for response, 13 patients had stable disease (SD) or better in the treated target lesions. Of these, partial responses (PR) were observed in four patients (lung, melanoma (2) and gastric) and minor responses were observed in two patients (thyroid, ovarian), for a total disease control rate (stable disease + partial response + complete response) of 93 per cent in the treated lesions. The combination was well tolerated, with only mild (Grade 1 or 2) toxicities noted.

"This is a very high disease control rate in patients who have undergone prior therapies," said Dr. Brad Thompson, president and CEO of Oncolytics. "This combination resulted in marked responses or stabilization in the treated target lesions for most of the patients. These results are expected to allow us to pursue Reolysin in combination with radical radiotherapy in future clinical trials."

The trial (REO 008) was an open-label, single-arm, multi-centre phase II study of Reolysin delivered via intratumoural injection to patients during treatment with low-dose fractionated radiotherapy. 20 Gy of radiation was given in five consecutive daily 4 Gy fractions combined with two intratumoural injections of Reolysin (1x10(10) TCID (50)) on days two and four. The primary endpoint was objective tumour response rate in treated lesions. Secondary endpoints were to evaluate viral replication, immune response, and safety. Eligible patients included those diagnosed with advanced or metastatic cancers that are refractory (have not responded) to standard therapy or for which no curative standard therapy exists. The Phase II trial followed a successful phase Ia/Ib combination Reolysin/radiation trial in which local and systemic responses were noted.

The Principal Investigator for the trial is Dr. Kevin Harrington of the Targeted Therapy Laboratory, Cancer Research UK Centre for Cell and Molecular Biology at The Institute of Cancer Research and Honorary Consultant in Clinical Oncology at The Royal Marsden NHS Foundation Trust.