First of its Kind Trial Uses Viruses to Treat Bladder Cancer

By Sara Bondell - November 09, 2020

For decades, chemotherapy was the only option to treat bladder cancer. Only in the last few years has there been a flurry of activity to develop new treatments, like the approval of immunotherapy drugs for certain types of bladder cancer.

However, about 25% of bladder cancer patients with muscle invasive disease—cancer invading into the deeper layer of the bladder—are presumed to harbor tiny metastases in addition to the tumor within the bladder. For this group of patients, chemotherapy remains the gold standard prior to surgical removal of the bladder in order to sweep up the cancer cells already spread outside of the bladder. However, if patients are ineligible for chemotherapy, there is currently no good alternative treatment.

To offer hope to these patients, a new clinical trial at Moffitt Cancer Center was launched combining immune checkpoint inhibitors, a type of immunotherapy, with an oncolytic virus that is genetically engineered to attack cancer cells.

Roger Li, MD, urologic surgeon
Roger Li, MD, urologic surgeon

“The thought behind this trial is that we are going to insert the oncolytic virus inside the bladder and use it to spark the fire that wakes up the body’s immune system to attack the cancer,” said Dr. Roger Li, a urologic surgeon in Moffitt’s Genitourinary Oncology Program and lead investigator for the trial. “On top of that, we will use immune checkpoint therapy to further add fuel to the fire.”

A patient’s immune system is an ally in fighting cancer, but turning it on to fight cancer cells can be a very tricky process. Oftentimes, cancer cells can evade an immune attack and fly under the radar even when the immune system is ramped up. Immune checkpoint inhibitors can release the brakes on the immune system and allow it to seek out and attack cancer cells and other threats. Li says using an oncolytic virus first to engage an immune response and then amplifying that response with immunotherapy can trigger a cancer-specific immune attack.

The trial will combine an immune checkpoint inhibitor with an oncolytic virus to ramp up the immune system to attack cancer cells.
The trial will combine an immune checkpoint inhibitor with an oncolytic virus to ramp up the immune system to attack cancer cells. Courtesy: CG Oncology, Inc.

Patients on the trial will be given six weekly infusions of the virus inside the bladder. In two of those six weeks, they will also receive the immune checkpoint inhibitor, Opdivo. Samples of the cancer will be taken before and after treatment to further understand the effect of the treatment on the bladder.

The first patient is scheduled to begin the trial this month. Moffitt will also be opening another trial that will combine the same oncolytic virus with a different immunotherapy agent for patients with a recurrent non-muscle invasive bladder cancer following Bacillus Calmette-Guerin (BCG) treatment, the most common intravesical immunotherapy for treating early-stage bladder cancer.

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