Study: Early trial of new vaccine shows promise for treating KRAS-mutated pancreatic and colon cancers

RELEVANCE

Most relevant for: People with a high risk for pancreatic or colon cancer.

It may also be relevant for:

• people newly diagnosed with cancer
• people with pancreatic cancer
• people with colorectal cancer

Relevance: Medium-High

Strength of Science: High

Research Timeline: Human Research

More rating details

What is this study about?

This study looked at an experimental vaccine for cancer treatment in people with pancreatic or colorectal cancer who had a specific biomarker known as a KRAS mutation. Early results were encouraging. The vaccine produced a strong immune response in most participants, suggesting that it may help reduce the chance of cancer returning.

Participants in this small, early study who had stronger immune responses to the vaccine tended to live longer than those with weaker immune responses. While these early results are promising, more research is needed to confirm these findings and understand how well the vaccine delays the return of cancer and how safe the vaccine may be when tested among more participants.

Why is this study important?

People often think of vaccines as a way to prevent different types of infections. Prevention is one important role for vaccines, but they can also treat disease. In fact, vaccines have been used since 1990 to treat early bladder cancer, and a vaccine for prostate cancer was approved by the FDA in 2010.

This study focuses on a new vaccine that is being evaluated as a treatment for pancreatic cancer (specifically pancreatic ductal adenocarcinoma or PDAC), a cancer with few effective treatment options. A small number of participants with colon cancer were also included in this study.

This vaccine focuses on the KRAS gene, which is often involved in cancer growth. Mutations in the KRAS gene occur in 90% of pancreatic cancer patients and 50% of colon cancer patients. These cancers often return after surgery and chemotherapy/radiation. Fewer than 20% of people with these diagnoses are alive five years after their diagnosis.

Researchers want to find new, effective treatments to target KRAS-related cancers, and vaccines may be a helpful approach.

Study findings

This small phase 1 trial, called AMPLIFY-201, tested whether a vaccine given to people treated for colon and pancreatic cancers produced an immune response that kept the cancers from returning. This phase 1 study is the first step to determine whether the treatment is safe and effective, and identify the right dose with a small number of participants.

This study included 25 people with KRAS-mutated cancers: 20 with pancreatic cancer and 5 with colon cancer. All participants had surgery and prior chemotherapy, and some also had radiation treatment. The study did not report whether any participants had inherited mutations in hereditary cancer genes.

Although participants’ imaging tests showed no visible signs of cancer at the start of the study, blood tests showed small traces of cancer-related DNA in their blood, suggesting that some cancer remained, and participants were at high risk for their cancer returning.

Participants received a vaccine containing several small portions of the KRAS protein. The vaccine was designed to trigger the immune system to produce antibodies that target and destroy cancer cells containing KRAS. To understand whether the vaccine worked as intended, researchers studied participants’ immune system responses, the presence of tumor biomarkers, whether the cancer returned and how long participants lived (survival).

Study findings

• Immune system response to the vaccine: The vaccine successfully activated an immune response in most participants.
  • 84% of participants had a response to at least some portion of the vaccine; 57% responded to all portions of the vaccine.
  • 71% of participants had an immune response involving multiple types of T cells, including immune cells that can detect and destroy cancer cells and immune cells that coordinate longer immune system memory.  
  • 17 participants had a strong immune response and 8 had a relatively weak immune response. Those with stronger immune responses lived longer and had lower chances of their cancer returning.
  • Many participants had an immune response that lasted for a long time after the initial vaccine treatment (over a year at the time of publication).
  • Two-thirds of participants had an immune system response that included parts of KRAS that were not included in the vaccine.
  • Variable response to vaccines is common. It is unknown why some people respond to vaccines better than others.
• Impact on tumor biomarkers: Before vaccination, all participants had detectable tumor biomarkers in their blood. After vaccination, researchers looked at whether the level of these tumor biomarkers was the same, lower or absent.
  Of the 25 participants:
  • 3 did not have a change in tumor biomarkers (no response).
  • 16 had lower tumor biomarker levels (partial response).
  • 6 had no evidence of tumor biomarkers (complete response), no longer showing any signs of cancer.
  • Participants with stronger immune system responses had either a larger decrease or a complete absence of tumor biomarkers.
• Time before cancer returned: The average time before cancer returned (relapse-free survival) among all participants was over 16 months.
  • 11 of the 17 participants with a strong immune response were alive and cancer-free at the time of publication; 5 of the 11 needed no other treatment after their vaccination.
  • The 8 participants with weaker or no immune response had a recurrence within about 3 months after they began the study; 7 died by the end of the follow-up period.
• Overall survival: On average, participants lived nearly 29 months after receiving the vaccine.
  • All participants received the vaccine, so whether this improves survival compared to a person who did not get the vaccine is unknown. However, participants with a stronger immune response to the vaccine lived longer than participants with a weaker immune response, suggesting that the vaccine may improve survival.
• Safety: The vaccine seemed to be safe for use and was well tolerated.
  • No participants dropped out of the study due to side effects. Some people experienced mild side effects, with fatigue being the most common, followed by injection site reactions and muscle pain.

Participants with a strong immune response had changes in tumor biomarkers, a longer time before their cancer returned and lived longer compared to participants with a weak immune response. These results suggest that the vaccine triggered the immune system to kill remaining cancer cells. However, it is possible that this immune response would have happened without the vaccine. Additional research is needed to compare the responses of vaccinated people to unvaccinated  people to clarify whether the vaccine causes the immune response.

Given the promising results from this phase 1 trial, the researchers started a phase 2 trial that will include a larger number of pancreatic cancer patients, compare vaccinated and unvaccinated participants and provide a better understanding of safety and side effects. (The study is no longer enrolling participants.) All participants will be followed for a prolonged time after vaccination to understand the longer-term effects of this vaccine. Patients with colon cancer were not included in the phase 2 trial.

What does this mean for me?

This research offers hope that vaccines can be used to treat KRAS-mutated cancers.

This vaccine is still in the early phases of study and is not yet available to the public outside of the clinical trials. Unlike some vaccines that must be tailored to an individual, this vaccine is an “off-the-shelf” product, meaning it can be given to many patients without customization. It could be a more accessible treatment option if these results are confirmed. While the current results are promising, more research is needed before the vaccine can be considered for FDA approval. Additionally there are several other trials underway for treating pancreatic cancer.

If you have pancreatic or colon cancer, especially those with a KRAS mutation, ask your doctor about current or upcoming clinical trials.

Reference

Wainberg ZA, Weekes CD, Furqan M, et al. Lymph node-targeted, mKRAS-specific amphiphile vaccine in pancreatic and colorectal cancer: phase 1 AMPLIFY-201 trial final results. Nature Medicine. 2025.

Pant S, Wainberg ZA, Weekes CD et al. Lymph-node-targeted, mKRAS-specific amphiphile vaccine in pancreatic and colorectal cancer: the phase 1 AMPLIFY-201 trial. Nature Medicine. 2024; 30:531–542.

Elicio Therapeutics announces publication of ELI-002 updated AMPLIFY-201 phase 1 follow-up data in Nature Medicine for minimal residual disease (“MRD”) positive, adjuvant-stage patients. Press Release. August 12, 2025.

Disclosure: FORCE receives funding from industry sponsors, including companies that manufacture cancer drugs, tests and devices. All XRAYS articles are written independently of any sponsor and are reviewed by members of our Scientific Advisory Board prior to publication to assure scientific integrity.

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posted 12/9/25