Study explores if COVID-19 vaccine can help treat cancer

By Mark Waghorn via SWNS

A COVID-19 vaccine could help treat cancer, according to new research.

The jab boosted immune cells in 93 percent of patients with different forms of the disease - including leukaemia and solid lymphomas.

Named, CoVac-1, it was developed by German scientists to fuel T-cells - white blood cells that destroy invaders.

It is unlike traditional vaccines which directly target specific pathogens within the body.
This secondary response is vital for those with suppressed immune systems.

Now it has been found to be remarkably effective in fighting cancer.

Senior author Professor Juliane Walz, of University Hospital Tubingen, said: "To our knowledge, CoVac-1 is currently the only peptide-based vaccine candidate specifically developed and evaluated for immuno-compromised patients."

Approved vaccines induce a robust immune response against SARS-CoV-2 - the virus that causes COVID-19 - in most individuals.

But they have been less effective in patients blood cancers as treatments often damage healthy immune cells - in addition to malignant ones.

Prof Walz said: "In the clinic, we see many cancer patients who do not mount sufficient humoral immune responses after vaccination with available SARS-CoV-2 vaccines. These patients are thus at a high risk for a severe course of COVID-19."

Many chemotherapies and some immunotherapies destroy B cells, the immune cells responsible for antibody, or humoral, responses.

COVID-19 vaccines rely heavily on them. One way to compensate is to enhance the response from T cells, another type of immune cell.

Co-author Claudia Tandler, a graduate student in the lab, said: "T-cell immune responses against SARS-CoV-2 are of particular importance for patients with B-cell deficiencies, who develop very limited antibody responses after infection or vaccination.

"T cell-mediated immunity is indispensable for developing protective antiviral responses, and previous evidence has shown that T cells can combat COVID-19 even in the absence of neutralizing antibodies."

Designing a vaccine to stimulate T cells requires the careful selection of SARS-CoV-2 antigens - small pieces of viral proteins that can stimulate immune cells.

Current mRNA-based vaccines produce a larger piece of the spike protein which hooks onto cells - and is broken down into antigens.

Ms Tandler and colleagues chose six specific antigens from different parts of the virus to make up their vaccine.

CoVac-1 is a peptide vaccine, meaning the protein pieces are injected directly, rather than being encoded via mRNA.

Ms Tandler said: "CoVac-1-induced T-cell immunity is far more intense and broader, as it is directed to different viral components than mRNA-based or adenoviral vector-based vaccines that are limited to the spike protein and are thus prone to loss of activity due to viral mutations."

The researchers previously tested the safety and preliminary efficacy of CoVac-1 in individuals without immune deficiency.

They found all those who received the vaccine maintained robust T-cell responses three months afterwards - including against omicron and other variants of concern.

There were minimal side effects. The results provided the foundation for a phase I/II clinical trial testing its efficacy in immunocompromised patients.

In the first 14 patients with a B-cell deficiency, including 12 with leukaemia or lymphoma - were given a single dose of CoVac-1.

They were monitored for up to six months. Notably, 64 percent had previously received an approved COVID-19 vaccine that failed to elicit an immune response.

Two weeks later T-cell immune responses were observed in 71 percent of participants - rising to 93 percent after four weeks.

The potency exceeded spike-specific T-cell responses observed in B cell-deficient patients after vaccination with mRNA vaccines.

T-cell responses from CoVac-1 also exceeded those mounted by individuals who are not immuno-compromised following a COVID-19 infection.

The researchers are currently preparing a phase III clinical trial to evaluate CoVac-1 in a larger population of immuno-compromised individuals.

It is hoped the results will allow the vaccine to protect cancer patients with B-cell deficiencies from severe cases of COVID-19.

Prof Walz added: "CoVac-1 is designed to induce broad and long-lasting SARS-CoV-2 T-cell immunity, even in individuals who have impaired ability to mount sufficient immunity from a currently approved vaccine, and thus protect these high-risk patients from a severe course of COVID-19."

The findings were presented at an American Association for Cancer Research meeting in New Orleans.