Study included patients with a previous history of advanced adenoma
In the quest to prevent colon cancer, University of Pittsburgh Cancer Institute (UPCI) researchers developed a vaccine that effectively stimulated the immune system to respond to early indications of colon cancer in patients at high risk for the disease.
“This prophylactic colon cancer vaccine boosts the patient’s natural immune surveillance, which potentially could lead to the elimination of premalignant lesions before their progression to cancer,” said Olivera Finn, PhD, distinguished professor and chair of the Department of Immunology at Pitt’s School of Medicine, and developer of the vaccine. “This might spare patients the risk and inconvenience of repeated invasive surveillance tests, such as colonoscopy, that currently are used to spot and remove precancerous polyps.”
The vaccine works by targeting an abnormal variant of a self-made cell protein, MUC1. In advanced adenomas and cancer, this protein is altered and produced in excess.
Researchers tested the vaccine in 39 patients aged 40 to 70 years without cancer but with a history of advanced adenomas, which placed them at higher risk for subsequent colorectal cancer. For each patient, an initial dose of the vaccine was given, and then additional shots were administered 2 and 10 weeks later. During the study, blood samples were drawn to measure immune response at 2 weeks, 10 weeks, 12 weeks, 28 weeks, and 1 year later. To confirm the persistence of the immune response, a booster injection was given at 1 year.
In 17 (44%) of the patients, a protective response was produced. As for the other 22 patients, researchers believe the lack of response may be attributed to already high levels of cells that suppress the immune system.
Finn, coleader of UPCI’s immunology program said, “This suggests that it might be better to vaccinate people against colon cancer at an even earlier stage, or vaccinate only people who do not already have suppressed immune systems.”
Side effects of the vaccine included red skin and discomfort at the injection site and flu-like symptoms after the first injection. However, the vaccine was well tolerated and safe.
Trial results are available online and reported in the January issue of the journal Cancer Prevention Research.
Source: UPMC.