Researchers in the United States have reported encouraging early findings from a clinical trial testing an experimental vaccine designed to target mutations associated with pancreatic cancer.
The vaccine, known as mKRAS-VAX, is being investigated as a form of cancer interception. Instead of waiting for an established tumour to develop, the strategy aims to stimulate the immune system against abnormal cells carrying specific KRAS mutations.
KRAS mutations are found in most pancreatic cancers and also occur in many precursor lesions. This makes the protein an attractive target for researchers seeking to intervene earlier in the development of the disease.
The phase 1 study involved 20 people with a hereditary predisposition to pancreatic cancer who also had a pancreatic abnormality identified through imaging. Participants received four doses over a 13-week period and were monitored for safety and immune responses.
Eighteen of the 20 participants developed a significant immune response to the vaccine. Researchers reported a median 18.2-fold increase in T-cell responses directed against mutant KRAS.
The immune response involved both CD4-positive and CD8-positive T cells, while memory T-cell responses remained detectable in some participants for as long as two years. These findings suggest that vaccination can generate an immune response capable of recognising cells carrying cancer-associated mutations.
After a median follow-up of 16.5 months, none of the participants had developed pancreatic cancer or a high-risk pancreatic lesion requiring surgical removal. However, the researchers caution that the study was small and was primarily designed to assess safety and immune response rather than prove that the vaccine prevents cancer.
The treatment was considered safe in this early study, with reported adverse effects generally mild to moderate. Injection-site reactions, fatigue, chills and flu-like symptoms were among the most common effects.
Larger and longer studies will be needed to determine whether the immune response ultimately translates into reduced cancer development. Nevertheless, the findings support growing interest in treating cancer at its earliest stages, before abnormal cells progress to invasive disease.