An experimental vaccine could open a new front against pancreatic cancer by stopping the disease before it becomes invasive, offering hope to people born with an elevated genetic risk.
The shot is designed to target mutations in the KRAS gene, which are found in more than 90 percent of pancreatic cancers — about 60,000 of the more than 67,000 cases diagnosed in the US each year.
Researchers say the vaccine works by teaching the immune system to recognize and attack cells carrying the KRAS mutation. The goal is to eliminate dangerous cells while they are still precancerous, years before they can develop into an aggressive and often fatal tumor.
In an early trial involving 20 people considered at high risk because of a KRAS mutation or a strong family history of pancreatic cancer, 90 percent developed an immune response after vaccination. No participant was diagnosed with pancreatic cancer during the follow-up period.
The findings represent the first human test of a KRAS-targeting vaccine in people with an inherited predisposition to pancreatic cancer.
Pancreatic cancer remains among the most lethal forms of the disease, with a five-year survival rate of only 13 percent. It is frequently caught late because early warning signs can be subtle and resemble far less serious conditions, allowing the cancer to spread before it is detected.
During a median follow-up of 16.5 months in the 20-patient study, none of the high-risk participants developed pancreatic cancer, and some experienced shrinkage of precancerous cysts.
The research comes as pancreatic cancer rates continue to rise. Over the past three decades, incidence has increased by nearly 20 percent, climbing from 10.6 to 11.9 cases per 100,000 people since 1995, with women experiencing a steeper rise than men.
Holly Shawyer of North Carolina was diagnosed with pancreatic cancer in her 30s despite being a marathon runner. Her main symptom was a stomach ache. ‘I was in great health before this,’ she said
The trial, published in the journal Cancer Discovery, enrolled 20 people considered at high risk for pancreatic cancer. Some had a strong family history of the disease, meaning multiple close relatives had been diagnosed.
Others carried a specific genetic mutation, such as BRCA2, that is known to increase risk. All of them had small cysts on their pancreas – the kind of growths that can sometimes turn into cancer over time.
The vaccine, called mKRAS-VAX, contains six lab-made peptides, or short chains of amino acids designed to resemble fragments of the mutant KRAS protein found in cancer cells.
When injected, the immune system recognizes these peptides as foreign and learns to attack any cell carrying the KRAS mutation.
The vaccine also includes an adjuvant called poly-ICLC, which helps boost the immune response.
Patients received five injections over several months: three initial priming doses, followed by a booster.
The goal was to train the immune system to recognize the KRAS mutation and then reinforce that training to sustain the response.
To measure whether the vaccine worked, researchers took blood samples before and after vaccination.
They looked for T cells, a type of white blood cell that fights disease, that could specifically recognize the KRAS mutation. A strong increase in these T cells was considered a successful immune response.
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Ryan Dwars of Iowa with his family. He was diagnosed with stage four pancreatic cancer at 36
They also compared MRI scans taken before and after vaccination to see if any cysts had shrunk or disappeared and tracked whether any patients developed pancreatic cancer during follow-up.
In 18 out of 20 patients, the immune system produced T-cells specifically trained to recognize and attack cells carrying the KRAS mutation. This was not a fleeting effect. In many patients, the response persisted for up to two years.
The vaccine also appeared to affect pancreatic cysts. Among 16 patients whose cysts could be evaluated, three saw their cysts disappear entirely.
Three others had partial shrinkage and the rest remained stable.
When researchers compared the vaccinated group to a similar group of unvaccinated patients, they found that 37.5 percent of vaccinated patients saw their cysts shrink or resolve compared to just 6.8 percent of those who did not receive the vaccine.
Over a median follow-up of 16.5 months, none of the vaccinated patients developed pancreatic cancer.
The vaccine also proved to be safe. None of the 20 patients experienced serious side effects.
Each year, pancreatic cancer is diagnosed in 13.9 per 100,000 people and claims 11.3 per 100,000. Rates are age-adjusted based on recent data
The most common reactions were mild, including injection site pain, fatigue, chills and flu-like symptoms, and all resolved on their own.
Currently, high-risk patients undergo routine imaging to monitor for suspicious growths, but these scans often detect only a fraction of the precursor lesions that can turn into cancer – and when worrisome cysts are found, surgery can carry serious risks.
The vaccine offers a different approach. Instead of waiting for cancer to appear and then treating it, the goal is to intercept it early using the body’s own immune system to keep precancerous cells in check.
If larger studies confirm these early findings, the vaccine could one day offer a simple, non-invasive way to protect people at the highest risk, offering the chance to stop pancreatic cancer before it starts.
The results are still preliminary. This was a small study, and larger trials will be needed to confirm whether the vaccine truly prevents cancer.
But the findings offer promising proof that a vaccine can train the immune system to recognize and potentially intercept pancreatic cancer in people at the highest risk.
