Novel Approach Using Reovirus Therapy May Give New Hope to Incurable Cancer

Multiple myeloma is characterized by malignant plasma cells that form tumors in bone marrow and is the second most common blood-based cancer.

The American Cancer Society estimates that more than 80,000 people in the U.S. are currently living with multiple myeloma and more than 20,000 new cases are diagnosed each year. Approximately 10,000 Americans die annually from multiple myeloma.

The plasma cell tumors involved in multiple myeloma can spread throughout bone marrow, thereby disrupting the production of red blood cells and platelets that normally are found in the marrow. Excessive numbers of malignant plasma cells also may decrease the number of white blood cells, which are important in fighting off infections.

Stem cell rescue following high-dose chemotherapy with autologous or allogenic transplantation has become standard therapy for a subset of good-performance patients. Dr. Chandini M. Thirukkumaran and a team of researchers at the Tom Baker Cancer Center in Calgary, Alberta tested a novel biologic called REOLYSIN and found that it successfully kills multiple myeloma cancer cells without killing or affecting the (non-cancerous) stem cells in early models.

This finding was the basis of a recent poster presented at this year’s annual meeting of the American Association for Cancer Research. The poster, titled "Reovirus successfully purges multiple myeloma ex vivo and does not affect human CD34+ cell engraftment in a murine transplantation model," covers the utility of reovirus in treating hematological malignancies such as multiple myeloma.

Dr. Thirukkumaran’s team discovered that after REOLYSIN was used as a  purging agent to clean the multiple myeloma cells, the mice in the experiment went on to regrow their human stem cells in bone marrow without incident. Follow-up tests concluded that the mice were devoid of multiple myeloma cells.

The investigators concluded that the sensitivity of reovirus toward multiple myeloma, and its lack of effect on human stem cells, highlight the potential of reovirus as an ex vivo purging agent during autologous hematopoietic stem cell transplants for multiple myeloma. They went on to suggest that their results merit the further investigation of the agent in a future Phase I trial in humans.

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