Oncolytics Biotech develops REOLYSIN for patients affected by hard-to-treat cancers

A novel class of cancer therapies called live biologics is offering new hope for patients affected by hard-to-treat cancers, according to two different studies testing the therapies in patients with sarcomas and head and neck cancers.

Traditional cancer treatments such as chemotherapy and radiotherapy come with a serious disadvantage: they cannot distinguish cancer cells from normal cells. Since normal cells can be stunted by chemotherapy and destroyed by radiation along with abnormal cells, patients may experience serious health issues during a course of extended treatment.

Calgary-based Oncolytics Biotech Inc. has developed an innovative approach to cancer therapy that might help patients avoid such serious side effects. Their strategy relies on one of the human body's traditional foes: viruses. Specifically, Oncolytics is testing a live cancer biologic called REOLYSIN®, which is derived from the human reovirus.

"One of the distinguishing characteristics of the reovirus is its tendency to replicate within certain cancer cells, namely, those that possess a feature known as an activated Ras pathway," said Brad Thompson, Chairman, President and Chief Executive Officer of Oncolytics Biotech. "Approximately two-thirds of all cancers involve cells that are Ras-activated. REOLYSIN® appears to kill off these cancer cells by rupturing their walls, creating a chain reaction of 'explosions' that rip through tumors."

A team lead by Dr. Monica Mita at the Institute of Drug Development (IDD), the Cancer Therapy and Research Center at the University of Texas Health Science Center (UTHSC) in San Antonio, Texas, recently provided updated results from a Phase II study using REOLYSIN® in patients with sarcomas metastatic to the lung.

The investigators reported that the treatment has been well-tolerated to date, and that 19 of 44 patients experienced stable disease ranging from 2 to 20 months, resulting in a total clinical benefit rate (complete response + partial response + stable disease) of 43%. The response objective for the study was three or more patients having prolonged stabilization of disease (>6 months) or better, for the agent to be considered. The trial exceeded its established objective with six patients experiencing stable disease for more than six months. Two patients have experienced stable disease for more than 19 months. One of these patients has synovial cell sarcoma that relapsed following surgery, while the other has Ewing's Sarcoma and had previously progressed following multiple treatments.

"We were very happy to participate in the study," said Dr. Mita. "REOLYSIN® is a promising option for patients with sarcoma, as shown by the results of this study. As a single agent, the virus had a clinical benefit rate of 43% and it was very well-tolerated. We are contemplating further studies combining REOLYSIN® with chemotherapy in order to integrate the virus in the panoply of agents used for sarcoma treatment."

New Progress on Head and Neck Cancer

While the new viral treatment will not completely dispose of the need for chemotherapy, its ability to weaken and shrink tumors might restrict the amount of chemo that is required or help agents such as paclitaxel and carboplatin do their jobs.

The company recently provided updated results from a Phase I/II UK trial (REO 011) of REOLYSIN® combined with paclitaxel/carboplatin for patients with advanced cancers in a poster presentation at the 2009 AACR-NCI-EORTC Molecular Targets and Cancer Therapeutics conference in Boston. The investigators reported that REOLYSIN® was well-tolerated when administered intravenously in combination with paclitaxel and carboplatin. Of 19 evaluable patients with head and neck cancer, mostly SCCHN refractory to prior platinum-based chemotherapy for recurrent/metastatic disease, eight experienced partial responses and six had stable disease. The total clinical benefit rate (complete response + partial response + stable disease) observed in head and neck cancer patients in the trial was 74%. Of four patients with malignant melanoma on the trial, one experienced a partial response and one had stable disease.

"A 42% response rate and a 74% clinical benefit rate in a platinum refractory patient population that typically has a poor prognosis and limited therapeutic options is very encouraging," said Dr. Thompson. "These results further validate our decision to advance REOLYSIN® in combination with paclitaxel and carboplatin into a Phase III trial in this patient population."

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