Calgary, AB (RPRN) 7/28/2009–According to the American Cancer Society, about 150,000 Americans will be diagnosed with colorectal cancer in 2009.  These patients are widely treated with a drug regimen that includes a class of drugs called anti-EGFR monoclonal antibodies. The product labels on this class of drugs known as anti-EGFR monoclonal antibodies, specifically cetuximab (Erbitux®) and panitumumab (Vectibix®) have just been changed so that they will no longer be recommended for the treatment of patients with colorectal cancers having a specific mutation (KRAS).

Retrospective subset analysis of seven separate randomized trials in patients with colorectal cancers having KRAS mutations, noted a lack of benefit associated with these monoclonal antibodies. The percentage of study populations for which KRAS status was assessed range from 23 to 92%.
Patients can now be screened for EGFR and KRAS status, and patients with KRAS mutations will not be treated with therapies that are unlikely to provide benefit. Patients with just EGFR mutations or overexpression will now be treated with anti-EGFR antibodies with a higher certainty of response.  For patients with mutations in KRAS, the good news is that an alternative therapy is currently being developed for them. An oncolytic virus being developed by Oncolytics Biotech Inc. can kill cancer cells with this particular mutation and with EGFR mutations as well, and is already well-advanced into clinical trials in the U.S. and the U.K.

REOLYSIN, Oncolytics’ proprietary formulation of the reovirus, preferentially replicates in cancer cells that have an activated RAS pathway.  Approximately two-thirds of all cancers have an activated RAS pathway, including most metastatic disease.  A large number of mutations, including mutations in EGFR, Her2 or KRAS along the RAS pathway lead to RAS pathway activation.
REOLYSIN works by exploiting any mutation that leads to an activated RAS pathway. These mutations allow the virus to replicate inside tumor cells, producing thousands of copies of itself.  Eventually, the cancer cells die, releasing the virus particles, which in turn infect other cancer cells. To date, more than 280 patients with various forms of cancer have been treated with REOLYSIN in various trials in Canada, the U.S., and the U.K.  Side effects of oncolytic virus treatment are mild compared with those of chemotherapy or radiation. Some patients report a combination of mild, flu-like symptoms, which usually resolve rapidly.

While REOLYSIN is not yet available to the public, the Company has submitted a protocol to the U.S. FDA for a Phase III trial, the last step before applying for product approval.
Already underway is a U.S. Phase II clinical study using REOLYSIN in combination with paclitaxel and carboplatin in patients with non-small cell lung cancer (NSCLC) with KRAS or EGFR-activated tumors.  Like colorectal cancer patients, those with mutant KRAS, or up to 20 per cent of the more than 180,000 patients diagnosed every year in the U.S. with NSCLC, do not derive benefit from EGFR-based therapies.

Together, KRAS mutated lung and colorectal cancers account for close to 100,000 newly diagnosed cases of cancer every year in the U.S.  KRAS mutated cancers are also found at high rates in leukemias and pancreatic cancers.  Advances in screening and treatment offer a prime example of the way personalized medicine can be used to tailor therapies to individuals with these cancers, possibly improving or extending life, while avoiding costly treatments that offer little to no benefit. For more information, log on to www.oncolyticsbiotech.com.

Media contact: Janet Vasquez, The Investor Relations Group, 212-825-3210 jvasquez@investorrelationsgroup.com