Immunotherapy aids your immune system to fight off cancer. There are five types of immunotherapy: treatment vaccines, immune checkpoint inhibitors, T-cell transfer therapy, monoclonal antibodies, and immune system modulators. While there have been no treatment vaccines approved for colorectal cancer (CRC) yet, BioNTech’s mRNA-based treatment vaccine has recently reached phase 2 clinical trials for CRC. The vaccine, individualized to each patient, is being developed as a treatment for CRC as well as to prevent relapse in those who have undergone CRC surgery. 

How Does Immunotherapy Work?

The immune system is built to detect and destroy abnormal/mutated cells. Tumor-infiltrating lymphocytes are often found around tumors and they are an indication that the immune system is working to eliminate the tumor. Cancer cells typically undergo genetic changes that allow them to escape the immune system—they often have proteins on their surface that inactivate immune cells, and they can even change cells surrounding them to interfere with the immune system. Therefore, a therapy that can train the immune system to identify and destroy cancer cells capable of defying the immune system is important.

Cancer Treatment Vaccines

Cancer treatment vaccines are designed for people who already have cancer, and trains their body’s immune system to find well-hidden cancer cells. These vaccines can be made in three different ways. 

  1. From the patient’s own cancer cells to cause an immune response against features that are unique to their cancer.
  2. From tumor-associated antigens that are found on cancer cells. These are made for cancer subtypes.
  3. From dendritic cells, which are a type of immune cell that respond to an antigen on tumor cells. This type of a vaccine is already being used for treating prostate cancer.

Matias Riihimäki et al. in their 2016 epidemiologic study published in Scientific Reports found that up to 18% of all CRC patients have recurrence and up to 25% have metastasis. A treatment vaccine would be able to help prevent recurrence and help patients with metastasis suppress small tumors that are often difficult to remove surgically.

BioNTech Chief Medical Officer and Co-founder Özlem Türeci, M.D., noted in a press release, “This trial is an important milestone in our efforts to bringing individualized immunotherapies to patients. Many cancers progress in such a way that the patient initially appears tumor-free after surgery, but after some time tumor foci that were initially invisible grow and form metastases. In this clinical trial in patients with colorectal cancer, we aim to identify high-risk patients with a blood test and investigate whether an individualized mRNA vaccine can prevent such relapses.”

Gargi Patel is a Colon Cancer Prevention Intern at the Colon Cancer Foundation.

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