By Donald Zuhn ---
On April 3, 2007, Oncolytics Biotech Inc. announced that it had been granted U.S. Patent No. 7,198,783. The '783 patent, which relates to methods of sensitizing neoplastic cells to irradiation by using reoviruses, is the twentieth U.S. patent to be awarded to the Calgary-based biotech company.
According to the statement released by Oncolytics Biotech, the allowed claims "describe a method of using reovirus to sensitize Ras-activated cancer cells that are resistant to radiation therapy." Chief Scientific Officer Dr. Matt Coffey characterized the '783 patent as "an important piece of intellectual property that supports our ongoing Phase II clinical program" using REOLYSIN®, Oncolytics' proprietary formulation of the human reovirus, in combination with radiation.
Reovirus (Respiratory Enteric Orphan virus) is found naturally in sewage and water supplies and inhabits human respiratory and bowel systems. Because tumor cells bearing an activated Ras pathway lack dsRNA-activated protein kinase (PKR - protein kinase dsRNA), they are unable to activate a PKR-mediated anti-viral response. As a result, such cells are susceptible to reovirus infection and subsequent cell death. Normal cells, however, do not possess activating mutations of Ras, and thus, are able to terminate reovirus infection through normal PKR activity.
The '783 patent issued from U.S. Application No. 10/431,579 and claims the benefit of U.S. Provisional Application Nos. 60/378,948, filed May 10, 2002, and 60/443,189, filed January 29, 2003. Representative independent claims 1 and 23 of the '783 patent recite:
1. A method of sensitizing a ras-activated neoplastic cell to irradiation, wherein the neoplastic cell is resistant to an irradiating agent in the absence of reovirus, comprising:
(a) determining whether the neoplastic cell is resistant to an irradiating agent in the absence of reovirus, wherein the determination indicates that the neoplastic cell is resistant to the irradiating agent in the absence of reovirus;
(b) administering to said neoplastic cell an effective amount of a reovirus under conditions that result in infection of the cells by the reovirus; and
(c) then subjecting said cell to an effective dose of the irradiating agent, whereby the sensitivity of the neoplastic cell to the irradiating agent is increased by the reovirus.23. A method of treating or ameliorating a tumor comprising ras-activated cells in a subject, comprising:
(a) determining whether the tumor is resistant to an irradiating agent in the absence of reovirus, wherein the determination indicates that the tumor is resistant to the irradiating agent in the absence of reovirus;
(b) administering to the subject an effective amount of a reovirus under conditions that result in infection of cells of the tumor by the reovirus; and
(c) then irradiating the subject with an effective dose of an irradiating agent.
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