A clinical trial shows promise for a new colorectal cancer vaccine, as it caused no serious side effects while bloodwork demonstrated immune cell activation.
These results appear in the Journal for ImmunoTherapy of Cancer and outline a phase 1 clinical trial.
The trial set out to establish if the vaccine itself was safe and whether it activated immune cells — both aspects of which were satisfactory. This success paves the way for further study.
A research team at Jefferson (Philadelphia University and Thomas Jefferson University) in the United States is the developer of the vaccine.
The group's latest scientific work involved 10 individuals who had stage 1 or 2 colon cancer.
The team administered the vaccine to the participants who returned for bloodwork at 30, 90, and 180 days after the drug delivery.
The blood samples showed evidence of killer T cell activation, a process that causes the T cells to find and destroy colon cancer cells.
The Jefferson scientists were also interested in the potential side effects of the vaccine during this trial. While the participants had some discomfort at the injection point, they reported no serious side effects.
The vaccine works by mobilizing the immune system against a specific molecule the scientists call GUCY2C. Prior research discovered that this molecule is a marker that colorectal tumors express and that helps these cancer cells stand out from healthy cells.
Researchers paired this molecule with another one that augments an immune reaction with the hope that it would target the cancer cells and kill them.
"There is an urgent need to understand what fuels colorectal cancer growth, and to harness that knowledge for developing novel therapies," says Karen E. Knudsen, Ph.D., who is the director of the Sidney Kimmel Cancer Center at Jefferson Health in Philadelphia, PA.
"This pivotal study provides some of the first evidence that it may be possible to safely direct a patient's own immune system to seek and destroy this cancer type. This is a true milestone — made possible through the scientists and clinicians in our colorectal cancer team working in synchrony."
Why colorectal cancer research is vital
Colorectal cancer includes cancers that start in the colon or the rectum. Doctors group them because they share many features of the disease and its progression.
The disease begins as one or more growths on the inner lining of the colon or rectum, and these can become cancerous over time.
Colorectal cancer is the third most common cancer in the U.S. among both men and women. The American Cancer Society (ACS) estimate that doctors will diagnose in excess of 101,000 new cases of colon cancer and more than 44,000 cases of rectal cancer this year.
As well as being the third most common cancer diagnosis, colorectal cancer is also the third leading cause of cancer-related deaths for both men and women. The ACS say the disease is expected to cause around 51,000 deaths in 2019.
Early detection of this type of cancer is crucial, as there may not be symptoms present in the preliminary stages. Colonoscopies can detect and remove polyps before they become cancerous, and there are less-invasive tests of stool that can help detect its presence.
Future research, trials, and studies
In addition to colorectal cancer, several other types of cancers express the GUCY2C molecule, including gastric, esophageal, and pancreatic. This group of diseases, including colorectal cancer, accounts for one-fifth of all cancer-related deaths.
The positive results of this new phase 1 clinical trial are promising enough that researchers say they can begin further studies in the future and will hopefully go to trial this upcoming fall.
They hope to be able to develop an even better version of the vaccine and that it could benefit even more people with different kinds of cancers.
"We are preparing for a phase II study that will begin recruiting patients this fall," says study first author Adam Snook, Ph.D., who is an assistant professor in the Department of Pharmacology and Experimental Therapeutics at Jefferson.
"We used lessons learned in the first study to modify the vaccine to hopefully make it even more effective," he concludes.