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What is immunotherapy?

Cancer immunotherapy treatments are often in the news. These innovative treatments really do look set to change the way we treat cancer. But they are also complex, and there is still a whole lot that we do not know. Only more research will unlock their full potential. So what exactly is immunotherapy? How does it work? And where does the research need to go next? Here’s our explainer on the basics of cancer immunotherapy.

Immunotherapy is a powerful type of targeted cancer treatment that works alongside our own immune system. Each type of immunotherapy works differently, but they all ultimately have one aim: to harness the ability of our own immune system to target and kill cancer cells.

Our immune system is usually very good at spotting and clearing away old or damaged cells which have the potential to turn into cancer. But sometimes the cancer can ‘hide’, and is left to grow undetected. Or sometimes the immune system detects the cancer, but it is not powerful enough to clear the cancer away. It needs a little help. This is where immunotherapy comes in.

There are lots of different types of immunotherapy. Some immunotherapies are designed to be used on their own, while others can be used alongside other cancer treatments, including chemotherapy, radiotherapy, and surgery. A few are already available for patients. Many are still in development and may only be available as part of research trials.

The main types of cancer immunotherapy treatment:

Adoptive cell therapy

Adoptive cell therapies work by boosting the power of specific immune cells, called T cells, to recognize and attack cancer. With this type of therapy, doctors take a sample of the patient’s own T cells and study them in the lab.

They then use special technology to select or alter the cells and enhance the cell’s ability to attack the cancer. Finally, these new ‘souped-up’ immune cells are grown in large numbers in the lab, before being infused back into the patient to fight the cancer. CAR T-cell therapy is a type of adoptive cell therapy. It involves genetically changing patient T-cells so they can fight cancer.

Cancer treatment vaccines

All vaccines work by training our immune system to effectively recognise and clear a disease. Cancer treatment vaccines are designed to work in a similar way with cancer.

Most cancer treatment vaccines are at the research stage, and scientists are still investigating which methods might work best. Many of these types of vaccines aim to teach the immune system to better recognise certain proteins or other molecules that the cancer cell produces, called antigens. Once the immune system can easily recognise a specific antigen, it will know to attack that antigen and the cancer cell it is attached to in the body.

Virus and bacteria cancer vaccines

Other cancer vaccines use weakened or altered versions of bacteria or viruses to stimulate the immune system against the cancer. For example, bladder cancer is sometimes treated with the BCG (Bacillus Calmette-Guérin) vaccine, which was originally developed to protect the body against tuberculosis. The BCG vaccine contains weakened bacteria, and when it is given directly into the bladder, it can stimulate an immune response that helps to target cancer cells in that area.

A different method aims to use viruses to directly infect and kill cancer cells. The virus has been made or altered so it does not infect healthy cells. The immune system then also recognises the infection and destroys the cancer cell.

These cancer treatment vaccines are different from cancer prevention vaccines, such as the HPV vaccine. This vaccine is used to prevent infection with human papillomavirus, and reduce a person’s risk of developing certain cancers, like cervical cancer.

Monoclonal antibodies

Monoclonal antibodies are special lab-generated proteins. They each work in different ways to help the immune system target the cancer cell. For example, some monoclonal antibodies are designed to stick to the tumour. They can act as flags that help the immune system to recognise that the cancer cell is dangerous, and needs destroying.

One way that cancer cells can ‘hide’ from the immune system is by developing ways to dampen down its cancer-seeking activity. Immune checkpoint inhibitors are a type of monoclonal antibody that work by blocking the signals a cancer cell (and other cells) produce when they are trying to do this. By switching off these signals, immune checkpoint inhibitors help to take the brakes off the immune system, allowing it to attack cancer cells with more power.

Cytokine treatments

Cytokines are proteins that naturally form part of our immune system. They can help stimulate the whole system into action. Inteferon and interleukin are two different types of cytokines, and researchers have made synthetic versions of these proteins which are sometimes used to treat some specific cancers, such as kidney cancer, and certain types of leukaemia.

What is next for immunotherapy?

Immunotherapies are beginning to make a real difference to the lives of people with cancer. But this is just the start of the story. Improving the effectiveness of immunotherapies is a real priority area of research. If researchers can figure out why immunotherapies do not work so well for some people, they can begin to find ways to overcome this.

This is one area of research where, thanks to your help, Worldwide Cancer Research scientists have already started to make a real difference:

In 2020 a team part-funded by Worldwide Cancer Research produced promising early data suggesting that combining immunotherapy with another drug called tumour necrosis factor, might help eradicate medulloblastoma brain tumours that are not treatable by immunotherapy alone.

And in a different project, researchers in the Netherlands found evidence from an early clinical trial that combining two types of immunotherapy prior to surgery in bladder cancer patients could be an effective way to stop the cancer coming back.

With your help we can better understand immunotherapy.

For example, we need to better understand just how cancer cells manipulate or hide from our immune system. This kind of early-stage discovery research underpins everything we know about immunotherapy and more knowledge like this will lead to even better treatments.

This is why we are proud to be able to support scientists in the UK, who are working to identify cancer cell characteristics that make them more likely to respond to immunotherapy. And researchers in Italy, who are investigating how microbes in our gut influence the ability of our immune system to fight cancer.

But it is not just the scientists who are making this happen. We cannot fund vital research like this without the support of Curestarters like you. Together we can save lives by discovering the next cure for cancer. Will you join us today?