Recent advances in peptide cancer vaccines

In the field of cancer treatment, a number of achievements in immunotherapy have emerged. Cancer vaccines, as one of them, have emerged as a research hotspot. Compared to conventional vaccines, cancer vaccines, such as cervical cancer vaccines, not only have the preventive effects, but also can be used as therapeutic vaccines to activate the human immune system and kill tumor cells.

There are many types of cancer vaccines, including cell vaccines, nucleic acid vaccines, protein peptide vaccines, and genetically engineered vaccines. No matter what kind of vaccine, tumor antigens are presented to immune cells to activate the immune response, thereby achieving anti-cancer effects. Here is a list of recent advances in cancer vaccines.

Peptide vaccine

Polypeptide vaccine is a vaccine prepared by chemical synthesis technology according to the amino acid sequence of a certain antigen epitope in a pathogen antigen gene. If a specific antigen in a tumor cell can be found and a cancer vaccine can be developed based on this amino acid sequence, the relevant immune cells can be activated to kill tumor cells of the same specific antigen.

ASCO has two researches on peptide cancer vaccines: the first is the application of multiple peptide vaccines in aggressive tumors; the second is the clinical efficacy of peptide vaccines based on new antigens.

In the first study, there was not much research on tumor and lymph node microenvironment in patients with aggressive cancer, and there was no effective way to regulate it. However, multiple peptide vaccine treatments may be able to solve this problem, and can also be guaranteed in clinical safety.

The study recruited a total of 11 patients and identified numerous targets through various methods. Patients were vaccinated subcutaneously at the lymph nodes every other week for a total of 8 times. The vaccine was then injected subcutaneously in the active site of the tumor by CT or PET for a total of 10 times.

The results of the study showed that 100% of patients responded to treatment regardless of disease progression, 80% of them reached CR, and 20% of them with pseudo-progression later developed CR.

Granzyme B levels were increased in 100% of patients targeting Bcl-2 (p = 0.001), VCP (p = 0.0001), Ape-1 (p = 0.005) and RCAS1 (P = 0.0001), and scan data were similar after treatment result.

Patients showed more CD8 T cell infiltration at tumor sites (p = 0.002) than non-tumor sites (p = 0.01). The number of disappearance of lung (p = 0.004) and liver (p = 0.001) metastases in patients was significantly related to the increase of IL-12.

This study shows that injection of multiple peptide vaccines into the lymph nodes and tumor sites of multiple solid tumors is not only safe and reliable, but also can improve the clinical benefit of advanced patients.

In the second study, neoantigen vaccines can activate T cells and kill tumor cells. However, most peptide vaccines either choose HLA-binding epitopes or HLA-presenting epitopes, and neither can induce a personalized T cell response. This study suggests that personalized epitopes that bind to multiple autologous HLA alleles can induce T-cell responses.

The researchers injected patients with synthetic long-chain polypeptide (SLP) vaccines in two clinical trials, identified epitopes of the single HLA and 3 HLA alleles, and validated them with CD8 and CD4 T cell responses. Ultimately, they developed a personalized vaccine that binds 14 HLA alleles from 12 tumor antigen sources.

The results showed that there was no correlation between single HLA-binding epitopes and HPV-specific T cell responses. In contrast, the consistency of the first-type HLA epitope and CD8 T cell response was 90% (p <0.001), and the response of the second-type HLA personalized epitope and CD4 T cell response was 69% (p = 0.005).

The value of the individualized epitope can predict the T cell response rate in clinical trials of SLP vaccines. It is predicted that 91% and 100% of peptide vaccines can induce CD8 and CD4 T cell responses, respective.