The myxoma virus can be lethal to rabbits but it does not affect humans when they are exposed to it.
In their study, published in Blood, the scientists found that the myxoma virus simultaneously killed cancer cells and prevented graft-versus-host disease, one of the most dangerous complications of bone marrow transplants.
Bone marrow transplants are an important form of treatment for patients with blood cancers, such as leukemia and multiple myeloma. If a patient's bone marrow is not producing enough healthy stem cells, healthy cells can be infused into their body to replace damaged or diseased bone marrow.
There is a risk, however, with the procedure in that newly transplanted white blood cells can attack the recipient's body - a condition referred to as graft-versus-host disease that can lead to shortness of breath, abdominal pain and, in severe cases, death.
Myxoma virus is typically found among rabbits in Australia and Europe. In rabbits, the virus can lead to the highly lethal condition myxomatosis, but in humans, the myxoma virus is benign.
The researchers tested the virus on human cells in the laboratory, attaching the myxoma virus to white blood cells known as T cells before delivering them as part of a bone marrow transplant. Once transplanted, the virus not only blocked graft-versus-host disease but was delivered to cancer cells that were present and killed them.
Process may benefit those at higher risk of graft-versus-host disease most
Dr. Christopher R. Cogle, lead investigator for the study and an associate professor at the University of Florida (UF) College of Medicine, believes that the application of the virus may be particularly useful for patients who have a higher risk of graft-versus-host disease, namely those who have difficulty finding suitable donors.
If a bone marrow donor is only a partial match for the recipient, the risk of graft-versus-host disease is around 80%. According to Dr. Cogle, African-American patients and older adults are least likely to find fully-matched bone marrow donors.
Following successful testing of the myxoma virus on human cells, the team is now looking to test its efficacy using a mouse model. They hope that a full clinical trial can commence within the next year, although there is a lot of work to be done before one can begin.
A clinical grade virus will need to be developed, and safety testing will need to be conducted. Dr. Cogle states that the patent on the myxoma process has been licensed to a company who will now aim to raise money for future trials.
According to Grant McFadden, a professor in the UF College of Medicine Department of Molecular Genetics and Microbiology, the study marks the first time that a virus has been shown to simultaneously prevent graft-versus-host disease and kill cancer cells in the laboratory.
While the myxoma process has only been found to work on blood-related disorders such as leukemia and multiple myeloma, Prof. McFadden is hopeful that in the future, the process will have broader application for other forms of cancer.
"Myxoma is one of the best strategies because it is effective but doesn't affect normal stem cells," concludes Dr. Cogle.
Previously, Medical News Today reported on a study that identified a gene mutation that increases the risk of acute lymphoblastic leukemia.