A runny nose, fever, and scratchy throat can be early signs of a cold. While it isn’t currently “cold season” which typically occurs in the fall and winter, a common viral cause of the cold, the cocksackie virus, has been recently affecting people in a different way. Although most people dread being infected by this virus, it is now being studied as a possibility to treat bladder cancer.
While viruses have the ability to cause devastating illnesses, they have recently in medicine been used to treat cancer, especially aggressive types. Oncolytic virotherapy has been an emerging treatment, with major institutions investing research and time into fine tuning this therapy. There has been a wide array of viruses that have been used, including measles, polio, herpes, and the adenovirus, but most recently the cocksackie virus.
Treatments for bladder cancer typically involve a combination of aggressive therapy and surgery that can many times be debilitating to the patient. There have been some recent advances in immunotherapy drugs known as checkpoint inhibitors (used in some other cancers as well) to treat bladder cancer. Several drugs that are approved target PD-1 and PD-L1 proteins that normally help keep the immune system “in check” from attacking other cells in the body. This inhibition of this allows T-cells to recognize and attack cancer cells in an immune response. They are approved after failure of platinum-based therapy which is still the base of first-line treatment or if it can’t be tolerated given the serious complications that can arise from this toxic regimen.
However, in addition to the arsenal of therapies to help treat this type of cancer may soon be on the horizon. In a recent study, 15 patients at the University of Surrey in England were given the cocksackie virus (CVA21) one week prior to surgery for bladder cancer through a catheter directed towards the tumor. The virus would then enter the cancer cells and trigger a protein that leads to an immune response. Once those cancer cells had died, the virus replicates and then infiltrates and attacks other cancer cells, leaving the healthy ones intact.
When the tumor samples were analyzed after surgery there was evidence that the virus had targeted and killed some of the bladder cancer cells in all 15 of the patients, with no significant side effects. In one patient all evidence of the disease had completely disappeared. All of this was following just one week of treatment, showing promise, but even greater potential for further effectiveness with increased time. This phase one clinical trial is just the beginning of possibly a promising treatment in early-stage non-invasive bladder cancer.
Bacillus Calmette-Guerin is a bacterium similar to Tuberculosis that is also is catheter-directed. It is a therapy that is currently used also to encourage the immune system to attack and destroy cancer cells. However, this has been used after transurethral resection of bladder tumor (TURBT) in an attempt to prevent the cancer from returning following the procedure. However, even after these current treatment regimens, there is a high recurrence rate of this bladder cancer.
In 2019 there will be approximately 80,000 new cases of bladder cancer and it is the fourth most common cancer in men and the eight most common cause of cancer death. Ninety percent of individuals diagnosed with bladder cancer are above the age of 55 and the average age of diagnosis of this type of cancer is 73 years old. Non-muscle invasive bladder cancer is the most common presentation of bladder cancer and very challenging to treat. The older age of onset many times can make treatment with aggressive therapy difficult for patients to tolerate. Therefore, in addition to early and effective treatment, finding a better therapy is imperative.
The plan moving forward is to use this cocksackie virus in combination with the aforementioned checkpoint inhibitor therapy prior to surgery in a future trial with even more patients.
Viruses can undoubtedly be very dangerous, there is no denying that information. With the continued viral outbreaks recently, it is refreshing to see many of these viruses now being used to treat cancer.
By Joshua Mansour, MD
Dr. Joshua Mansour is a board-certified hematologist/oncologist working and in the field of hematopoietic stem cell transplantation and cellular immunotherapy in Stanford, California. In June 2019 he was a recipient of the ‘40 Under 40 in Cancer’ award