By Donald Zuhn --
Last month, Oncolytics Biotech Inc. announced that it had been granted U.S. Patent No. 7,186,542. The '542 patent, which relates to methods of producing reovirus from a cultured cells, was the nineteenth U.S. patent to be awarded to the Calgary-based biotech company. As we reported last week, Oncolytics was recently awarded its twentieth patent, which is directed to methods of sensitizing neoplastic cells to irradiation by using reoviruses.
According to the statement released by Oncolytics, the '542 patent "expands on similar manufacturing patents secured by the Company." Oncolytics currently has an ongoing clinical program related to the use of REOLYSIN®, Oncolytics' proprietary formulation of the human reovirus, alone or in combination with radiation or chemotherapy, for the treatment of a number of human cancers, including colorectal, prostate, pancreatic, non-small cell lung, melanoma, and ovarian cancer.
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 '542 patent issued from U.S. Application No. 10/916,378 and claims the benefit of U.S. Application No. 10/097,183, filed March 14, 2002, and U.S. Provisional Application No. 60/276,734, filed March 16, 2001. Representative independent claims 1 and 2 of the '783 patent recite:
1. A method of producing reovirus from a culture of cells, comprising the steps of:
(a) providing a culture of human embryo kidney (HEK) cells which has been infected by the reovirus;
(b) extracting the reovirus from the cells by adding a detergent to the culture of HEK cells and incubating for a period of time; and
(c) collecting the reovirus.
2. A method of producing infectious reovirus, comprising:
(a) providing a culture of human embryo kidney (HEK) 293 cells which has been infected by reovirus;
(b) extracting the virus from the cells by adding octoxynol-9 to 10 to the culture and incubating at about 25ºC. to about 37ºC. for about 10 minutes; and
(c) collecting the reovirus.
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