Advances in the first phase of colorectal cancer vaccine testing

The early results of the first stage of testing a unique human vaccine against colorectal cancer were promising. A recently published paper outlining the results of the first-phase tests showed that the vaccine is safe and stimulates the immune response, paving the way for larger trials in humans.

Colorectal cancer is the second largest cancer killer in the world. It is not only difficult to identify it in time, but many modern treatment methods are not very effective. Almost half of patients after surgical resection, still do not survive because of the tendency of cancer to relapse.

New vaccines are designed to stimulate the patient's immune system to attack and destroy cancer. Immunotherapy generally works by teaching the immune system to recognize foreign substances, so it is designed to identify and destroy these substances when they naturally appear in the body. Tumor cells are known to be cunning targets in this sense, since they are often very similar to normal healthy cells.

The big breakthrough that inspired scientists to this specific vaccine was the discovery that almost all colorectal cancers express the GUCY2C molecule. This molecule is also found in intestinal epithelial cells, and its presence in these cells means that any vaccine aimed at it should direct immune cells only to tumors, and not to healthy intestinal tissue.
')
This first trial of a vaccine on humans was necessary in order to establish a safety profile during treatment. Ten patients with stage I or stage II colon cancer received an injection of the vaccine, and they were monitored for six months. The results were positive, with no serious side effects. Extensive blood sampling also showed that the vaccine successfully promoted the increase in the activity of specific antitumor immune cells, suggesting that the treatment triggers the desired immune response.

“This key study provides some of the first evidence that it may be possible to safely direct a patient’s own immune system to finding and eradicating this type of cancer,” says Karen Knudsen, from Sidney Kimmel Cancer Center . "This is a real breakthrough - and it is possible thanks to the scientists and clinicians from our group on colorectal cancer, working synchronously."

The next stage of the study is the transition to a larger trial of the second phase with the participation of a larger number of patients in order to clearly evaluate the effectiveness of the vaccine. Based on the information obtained in the first phase, scientists have already changed the vaccine to make it more effective. It is also hoped that the vaccine will be effective not only in the treatment of colorectal cancer. Recent work has shown that the GUCY2C molecule is also expressed in cancer of the stomach, esophagus and pancreas, which means that this promising vaccine may be useful in combating a large number of common types of cancer.

“The goal of the trial, which will begin this fall, is to show that vaccine version 2.0 is even better and that it can benefit a much larger group of patients with cancer,” says Adam Snook, author of the new work.

Split tolerance of ad5-GUCY2C-PADRE vaccine-induced T-cell responses in colon cancer patients - Journal for ImmunoTherapy of Cancer