New corona vaccine developed for cancer patients

"Researchers from Tübingen have developed a novel peptide-based vaccine against corona. The preparation CoVac-1 is to be used primarily in cancer patients and people with an immune deficiency. .

A novel corona vaccine is intended to protect cancer patients and people with congenital immune defects from Covid-19 in particular. In a small clinical study, the CoVac-1 preparation developed by Tübingen researchers showed the desired effect in 93 percent of the vaccinated subjects: activation of the T-cell immune response. This was reported by the scientists at the annual meeting of the American Association for Cancer Research (AACR) in New Orleans. The extent to which the 14 patients in the study were actually protected from infection or severe symptoms with the vaccination was not examined.

 

The current corona vaccines primarily trigger a so-called humoral immune response in the body, i.e. the formation of antibodies by the B cells. However, many chemotherapies and some immunotherapies destroy the B cells, so the vaccines do not work well in these patients. The formation of antibodies is also disturbed in people with certain congenital immune defects. CoVac-1 should therefore above all build up cellular immunity, which is triggered by T cells.

 

Peptide-based vaccine

"T cell-mediated immunity is essential for the development of a protective antiviral response, and previous studies have shown that T cells can fight Covid-19 even in the absence of neutralizing antibodies," explains Claudia Tandler from the University of Tübingen on the occasion of the presentation of the results.

These refer to vaccinations of 14 patients with a B cell defect, including 12 patients with leukemia or lymph node cancer. About two thirds of the patients had already been vaccinated with an approved corona vaccine, but their immune system had not built up a sufficient antibody response. 28 days after the CoVac-1 vaccination, the researchers registered a robust T-cell response in 13 patients. A clinical study with more patients is currently being prepared.

The preparation of the Tübingen researchers is a so-called peptide-based vaccine. This contains six different protein components (peptides) from Sars-CoV-2 as antigens against which the immune system builds a T cell response after vaccination. Among them is the spike protein, against which the previously available vaccines are also directed. 

The combination of several virus proteins in one vaccine is intended to trigger the broadest possible T-cell immune response, so that the protective effect is retained even in the event of mutations in the virus.

"As far as we know, CoVac-1 is currently the only peptide-based vaccine candidate that is being developed and evaluated specifically for people with immunodeficiency," says Juliane Walz from the University Hospital in Tübingen, Head of Vaccine Development. It is hoped that this will protect high-risk patients from a severe course of Covid 19."

 

 Cellular immunity is much more difficult to measure than the formation of antibodies.