Pancreatic cancer is one of the deadliest forms of cancer because it is usually found only after it has spread. By the time symptoms appear, treatment options are often limited.
As a result, fewer people survive this disease compared with many other common cancers. Researchers are now exploring whether preventing pancreatic cancer before it develops could save more lives.
A new Phase I clinical trial has taken an important first step in that direction. The findings were published in Cancer Discovery.
About one in ten pancreatic cancer cases are linked to inherited gene changes that are passed through families. People with these genetic mutations often develop small abnormal growths or cysts in the pancreas that can slowly become cancer over many years.
Doctors usually monitor these patients with regular scans and may recommend surgery if the lesions appear dangerous. However, surgery is a major procedure and cannot remove tiny precancerous changes that cannot yet be seen on medical imaging.
Researchers from Johns Hopkins University and collaborating institutions believed that helping the immune system destroy abnormal cells before they become cancer might offer a better solution.
They focused on KRAS, a gene that is mutated in more than 90% of pancreatic ductal adenocarcinomas. Because KRAS mutations appear early during cancer development, they are an attractive target for prevention.
The team created an experimental vaccine called mKRAS-VAX. The vaccine contains synthetic pieces of proteins representing the six most common KRAS mutations found in pancreatic cancer and many precancerous pancreatic lesions. Instead of treating existing cancer, the vaccine is designed to train immune cells to recognise and attack abnormal cells carrying these mutations.
The Phase I trial enrolled 20 adults considered to be at high risk because they had inherited cancer risk genes and pancreatic cysts seen on imaging scans. Participants received a series of injections over 13 weeks using a prime-and-boost schedule. Blood samples were collected regularly to measure immune responses, and volunteers were invited for long-term follow-up.
The results were encouraging. Ninety percent of participants developed strong KRAS-specific T-cell responses, and these immune responses remained detectable for up to two years after vaccination. Long-lasting immunity is especially important because preventing cancer requires protection over many years rather than just a short period.
The vaccine also appeared to be safe and well tolerated. During a median follow-up of 16.5 months, none of the participants developed pancreatic cancer. Researchers also observed that pancreatic cysts became smaller or disappeared more often in vaccinated participants than in a similar unvaccinated comparison group.
Despite these promising findings, the researchers emphasise that this study was designed mainly to evaluate safety rather than prove that the vaccine prevents cancer. Only 20 people participated, and the follow-up period remains relatively short. Larger clinical trials will be needed before doctors know whether the vaccine truly reduces pancreatic cancer risk.
Overall, this study provides the first human evidence that a vaccine may be able to intercept pancreatic cancer before it forms.
The long-lasting immune response and encouraging early clinical observations make this one of the most exciting developments in pancreatic cancer prevention in recent years. However, the findings should be interpreted cautiously until larger trials confirm that the vaccine can safely and effectively prevent this deadly disease over the long term.
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Source: Johns Hopkins University.
