In many cases, Pancreatic cancer develops silently, without early symptoms, making it difficult to detect in its initial stages. (Photo: Freepik)
A new experimental vaccine designed to prevent pancreatic cancer has shown promising results in an early‑stage clinical trial, offering fresh hope for people at high risk of developing one of the deadliest forms of the disease.
The findings, published in Cancer Discovery, a journal of the American Association for Cancer Research (AACR), showed that the vaccine was safe and triggered a strong immune response in 90 per cent of participants at high risk of pancreatic ductal adenocarcinoma (PDAC), the most common and aggressive type of pancreatic cancer.
Researchers also found that none of the 20 participants developed pancreatic cancer during a median follow‑up of 16.5 months. In addition, 37.5 per cent of those who received the vaccine experienced a reduction or complete disappearance of pancreatic cysts, compared with just 6.8 per cent in a similar unvaccinated group.
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While the study was not designed to prove the vaccine prevents cancer, scientists say the findings provide the first evidence that vaccination could help stop pancreatic cancer before it develops.
Pancreatic cancer remains one of the most difficult cancers to treat because it is often diagnosed only after it has spread. The disease rarely causes symptoms in its early stages, leaving patients with limited treatment options once detected. It also has one of the lowest five‑year survival rates among all cancers.
About one in 10 pancreatic cancer cases is linked to inherited genetic mutations. These individuals face a much greater lifetime risk. In most cases, pancreatic cancer develops gradually from tiny abnormal growths or cysts in the pancreas that can eventually become cancerous.
People at high risk are usually placed under regular surveillance using imaging scans. If doctors believe a lesion is likely to become cancerous, or if early cancer is detected, surgery is often recommended.
However, this approach has limitations because many precancerous lesions are microscopic and cannot be detected through current imaging technologies. Even after surgery, pancreatic cancer returns in up to 80 per cent of patients.
The study was conducted by scientists from the Sidney Kimmel Comprehensive Cancer Centre at Johns Hopkins University, who investigated whether the immune system could be trained to stop pancreatic cancer before it develops.
“Prevention and interception save lives and reduce the morbidity associated with cancer development and progression. This is especially important for cancers whose early‑onset frequency is increasing and for which we do not have effective methods for early detection,” the researchers said.
To overcome these challenges, the team developed an experimental vaccine known as mKRAS‑VAX. The vaccine targets mutations in the KRAS gene, found in more than 90 per cent of pancreatic cancers and many precancerous lesions. Rather than treating existing cancer, it is designed to train the immune system to recognise and destroy abnormal cells carrying KRAS mutations before they become cancerous.
The phase I trial enrolled 20 people at high risk because they had inherited cancer‑related mutations and small pancreatic cysts detected during routine screening. Participants received a series of injections under the skin over 13 weeks, after which researchers monitored immune responses through regular blood tests.
The results exceeded expectations. The vaccine stimulated KRAS‑specific T‑cell responses in 90 per cent of participants. These immune cells remained detectable in blood for up to two years, suggesting the vaccine may provide long‑lasting protection.
“This long‑lasting response is particularly noteworthy when assessing possible interception of cancer, which requires long‑lasting immunity,” the researchers said, adding that the vaccine was safe and well‑tolerated, with no major safety concerns reported.
Beyond stimulating the immune system, researchers observed encouraging signs that the vaccine could slow the earliest stages of disease. More than one‑third of vaccinated participants experienced shrinking or complete disappearance of pancreatic cysts, a much higher proportion than among comparable unvaccinated individuals.
“Overall, this study represents the first proof of concept for the use of vaccines for interception of pancreatic cancer in human patients,” the researchers said.
Despite the promising findings, the researchers cautioned that larger trials are needed before the vaccine can become part of routine care. The current study involved only 20 participants and was designed primarily to evaluate safety and immune response rather than to prove prevention.
They also noted that immune responses were measured only in blood samples. An ongoing trial will examine whether vaccine‑generated T cells can enter precancerous pancreatic tissue and destroy abnormal cells at the site where cancer begins.
“Successful interception that could reduce the occurrence of pancreatic cancer would be a major achievement,” they noted.
The team believes further studies will help determine the best time to administer the vaccine, identify those most likely to benefit, and establish whether it can significantly reduce pancreatic cancer cases. If confirmed in larger trials, the vaccine could become the first preventive immunotherapy for pancreatic cancer, offering a new strategy to stop one of the world’s deadliest cancers before it starts.
