Viruses, often thought of as disease agents, are now the ground troops in the war on cancer. Oncolytic viruses, [OV] are first synthesized to remove disease elements and, once inserted back into the body, move rapidly to the tumor, where the immune system recognizes the threat and attacks cancer cells.
This revolutionary gene therapy produces few side effects or damage to other parts of the body. The FDA has recently approved OV for blood cancer, and pharmaceutical companies in the US, Europe and Asia are stepping up development of viral therapies for lung, breast, colorectal, prostate, pancreatic, ovarian, liver, bladder, brain, and head & neck cancers.
ACGT Scientific Advisory Council member Dr. Stephen Russell, a researcher at the Mayo Clinic who specializes in viral oncology as these treatments are known, hopes that the FDA’s clearance of Imlygic [or T-VEC] represents “a huge milestone” in cancer treatment development.
Dr. John Bell, ACGT Scientific Advisory Council member and current ACGT Research Fellow, Ottawa Hospital Research Institute, said that while T-VEC was designed to be directly injected into a tumor, as opposed to being delivered to the whole body, some results showed systemic effects, “waking up” the body’s immune system to the presence of other tumors, even those not injected with the virus.
A specially modified form of the virus replicates inside cancer cells and causes the cells to rupture and die. Then, it triggers the body’s immune system to attack the rogue cells too, upon detecting the presence of the virus.
Russell hopes that Imlygic represents “a first step in the direction of a complete change in the game” in how we treat cancer. “This really is a single step along that path…but it’s a very important and very significant step.”
If cancer-killing viruses could be delivered to their targets through the bloodstream, rather than injection into the tumor, they could be used to treat a greater range of cancers.