Oncolytics Biotech reports positive interim results of UK phase Ia/Ib trials

Oncolytics Biotech Inc. has announced that an oral presentation covering interim results from a U.K. Phase Ia/Ib combination REOLYSIN and radiation clinical trial for patients with advanced or metastatic cancers is scheduled to be presented at the National Cancer Research Institute (NCRI) conference on October 2, 2007 in Birmingham, U.K.

The presentation, entitled “Biological Approaches to Radiosensitisation: Viruses, Gene Therapy and Novel Radiosensitisers” will be presented by Dr. Kevin Harrington of The Institute of Cancer Research, London and one of the principal investigators for the trial. The conference runs from September 30 through October 3, 2007 in Birmingham, U.K.

“We are very pleased with the results of this trial to date,” said Dr. Brad Thompson, President and CEO of Oncolytics. “We continue to evaluate the data and look forward to announcing final results.”

To date, 22 patients have been treated with 15 having completed the study. Five patients withdrew from the study, and two patients are still on study.

A total of 11 patients in the Ia portion of the trial received two intratumoural treatments of REOLYSIN® at dosages of 1x108, 1x109, or 1x1010 TCID50 with a constant localized radiation dose of 20 Gy given in five fractions. Of these 11 patients, three patients (oesophageal, squamous skin carcinoma and squamous cell scalp) experienced significant partial responses.

One month following treatment, the oesophageal patient experienced a 28.5% reduction in the target tumour, with stable disease noted in four, non-treated tumours. At two and three months, the target tumour had shrunk 64%, with stable disease continuing in the four non-treated tumours, including a 15% volume reduction in non-treated mediastinal disease that was maintained for more than six months. The squamous skin cancer patient experienced a 50% reduction in the target tumour, as well as stable disease in two, non-treated tumours at one, two and three months post treatment.

The squamous cell scalp patient experienced stable disease in the target tumour for two months which then became a partial response at three months. This patient also experienced stable disease in one non-treated tumour measured at three months post-treatment. Patients in the Ib portion received either two, four or six intratumoural doses of REOLYSIN® at 1x1010 TCID50 with a constant localized radiation dose of 36 Gy given in 12 fractions. Of the six patients who have completed the study to date, three patients (colorectal, melanoma and lung cancer) experienced tumour regression in the target tumour, as well as stable disease in non-treated tumours.

The colorectal patient experienced a partial response with a more than 50% regression in the target tumour as well as stable disease in four, non-treated tumours measured at one month following treatment. A melanoma patient experienced minor regression in the target tumour as well as stable disease in two, non-treated tumours at one and two months following treatment. A lung cancer patient experienced minor regression in the target tumour, as well as stable disease in three, non-treated tumours at two months following treatment.

The treatment has been well tolerated, with mostly Grade 1 or 2 toxicities noted including fatigue, lymphopenia, fever, and neutropenia. Grade 3 toxicities including cellulitis, dysphasia and diarrhoea were related to disease progression and not to the combination treatment. Viral replication was unaffected by cellular irradiation.

The primary objective of the Phase Ia/Ib trial is to determine the maximum tolerated dose (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.