A trial to see if vaccines can stimulate the immune system in healthy volunteers

Cancer type:

Blood cancers

Leukaemia

Lymphoma

Status:

Results

Phase:

Phase 1

This trial was done to find out if vaccines can increase the immune response Open a glossary item to certain proteins in the body. And if that can affect how well stem cell transplants work.

The first step was to find out what happens in people who don’t have cancer (healthy volunteers). Researchers then hope to give these vaccines to people who are going to donate their stem cells Open a glossary item to people with leukaemia or lymphoma.

The trial was open for people to join between 2012 and 2017. The team published the results in 2021.

More about this trial

Doctors sometimes treat leukaemia or lymphoma with a stem cell transplant using stem cells Open a glossary item from someone else. This is called an allogeneic transplant.

Different people can have slightly different forms of certain proteins. These are sometimes called alloreactive peptides Open a glossary item . Researchers think that the immune system can recognise and react differently to these peptides. And that this can affect how well stem cell transplants work.

Doctors need to match the proteins of the person donating their stem cells to the person with leukaemia or lymphoma as closely as they can. One of the proteins (peptides) they look at is HA-1.

People who have the HA-1 protein on their cells are HA-1 positive. And those who don’t are HA-1 negative.

This trial was for healthy volunteers who were HA-1 negative. They had vaccines called pDOM-HA-1 and MVA-HA-1 as an injection into a muscle. They had 3 or 4 doses in total:

2 or 3 doses of pDOM-HA-1
1 dose of MVA-HA-1

The trial team then looked for specific immune system cells. They wanted to find out if the vaccines could stimulate the immune system to make cells that would kill HA-1 positive cells.

The cells they were looking for are a type of T cell Open a glossary item . They are sometimes called HA-1 killer cells.

The idea is that these HA-1 killer cells are then given to people with leukaemia or lymphoma that is HA-1 positive. And this helps the stem cell transplant to work better.

The main aims of this trial were to find out:

if the vaccine can stimulate the immune system to produce HA1 killer cells
more about the side effects

Summary of results

A total of 9 people joined this trial. They were healthy volunteers who didn’t have cancer. They all had 3 to 4 doses of the vaccines.

The trial team took blood samples every week for 10 to 12 weeks. And then at 3 months, 6 months and 12 months. They looked for specific T cells that could target HA-1 positive cells. This is called an immune response.

The trial team found that 7 out of 9 people (78%) had an immune response to the vaccines. They also found that the immune response was highest at between 1 and 4 weeks after the MVA-HA-1 dose. It then lasted for 6 to 12 months in 6 people.

Side effects
Most people had at least one side effect from the vaccines. But they were nearly all mild or didn’t last long.

The most common side effects were:

increased blood pressure
pain, swelling or bruising at the injection site
a small temporary increase in magnesium levels in the blood

Conclusion
The trial team concluded that the vaccines in this trial could stimulate the immune system to make HA-1 killer cells. This is in healthy volunteers who don’t have cancer.

They hope these T cells will make stem cell transplants work better for people with leukaemia or lymphoma.

More detailed information
There is more information about this research in the reference below.

DNA and modified vaccinia Ankara prime–boost vaccination generates strong CD8+ T cell responses against minor histocompatibility antigen HA-1
S A Eldershaw and others
British Journal of Haematology, 2021. Volume195, issue3, pages 433-446.

Please note, the information we link to here is not in plain English. It has been written for healthcare professionals and researchers.

Where this information comes from
We have based this summary on the information in the article above. This has been reviewed by independent specialists (peer reviewed Open a glossary item ) and published in a medical journal. We have not analysed the data ourselves. As far as we are aware, the link we list above is active and the article is free and available to view.