An experimental vaccine has shown early promise in preventing pancreatic cancer by training the immune system to target a KRAS mutation, which is present in over 90 percent of pancreatic cancers. The vaccine, mKRAS-VAX, aims to intercept the disease at its precancerous stage.
In a preliminary trial involving 20 individuals at high risk for pancreatic cancer, 90 percent developed immune responses. Over a median follow-up period of 16.5 months, none of the participants developed pancreatic cancer. Additionally, some participants experienced shrinkage of precancerous cysts on their pancreas.
Pancreatic cancer is notoriously deadly, with a five-year survival rate of just 13 percent. It is often diagnosed late due to vague early symptoms, by which time the disease has frequently spread. Rates of pancreatic cancer have been increasing, with a nearly 20 percent rise in overall incidence since 1995.
The trial, published in the journal Cancer Discovery, included individuals with a strong family history of the disease or specific genetic mutations like BRCA2 known to increase risk. All participants had small pancreatic cysts, which can potentially develop into cancer.
The mKRAS-VAX vaccine consists of six synthetic peptides designed to mimic fragments of the mutant KRAS protein. When administered, it prompts the immune system to identify and attack cells bearing this mutation. An adjuvant, poly-ICLC, was included to enhance the immune response.
Participants received five injections over several months, including initial doses and a booster. Researchers monitored the immune system by analyzing blood samples for T cells capable of recognizing the KRAS mutation and by comparing MRI scans taken before and after vaccination to assess changes in pancreatic cysts. They also tracked the development of cancer in participants.
Among the 18 participants who showed a T-cell response, the reaction was sustained, persisting for up to two years in many cases. Of the 16 patients whose cysts could be evaluated, three saw their cysts disappear, three experienced partial shrinkage, and the rest remained stable. Compared to a control group of unvaccinated patients, a significantly higher percentage of vaccinated patients (37.5 percent) showed cyst shrinkage or resolution compared to 6.8 percent in the unvaccinated group.
The vaccine was found to be safe, with no serious side effects reported among the 20 participants. Mild reactions, such as injection site pain, fatigue, chills, and flu-like symptoms, were common but resolved on their own.
This vaccine approach differs from current methods, which typically involve monitoring for suspicious growths or surgically removing identified cysts, procedures that carry significant risks. The goal of mKRAS-VAX is to leverage the body's immune system to manage precancerous cells before they can become invasive.
While these initial findings are encouraging, larger studies are necessary to confirm the vaccine's efficacy in preventing pancreatic cancer. However, the trial provides promising evidence that a vaccine can effectively train the immune system to recognize and potentially intercept this aggressive cancer in high-risk individuals.