What are cancer vaccines used for? How do these vaccines work? Will they become the norm for treating cancer? Prof. Lana Kandalaft gives us some answers.

When it’s working as it should, our immune system is incredible. It constantly surveys the body to defend it from illness or infection. What happens, for instance, when a potentially cancerous mutation occurs in our cells? Our dendritic cells, which I like to think of as the spies of our immune system, identify it as a threat. They prime our T cells – the soldiers – to attack and destroy cancerous cells. This is what we call the ‘cancer immunity cycle’. Mutations are perfectly normal and occur on a daily basis in our bodies. When all goes well, they are promptly detected and eradicated.

But sometimes, a mutation goes undetected and cancer can develop. As well as chemotherapy, radiotherapy and surgery, another pillar of cancer treatment is immunotherapy, which helps the immune system recognise and fight cancer cells. Our job as immunotherapists is to boost this immunity cycle when it’s not working properly.

My work at the Center of Experimental Therapeutics at the Department of oncology UNIL-CHUV involves developing vaccines to treat different types of cancer. Currently, cancer vaccines are therapeutic – their aim is to cure disease rather than prevent it – and this is the focus of our work.

My team and I use a cellular approach to vaccination: instead of relying on the dendritic cells to do their job and prime T cells to attack cancer cells, we vaccinate the patient with cells that recognise the tumour. This process mimics what happens in the body and aims to boost the immunity cycle. We recently launched trials for vaccines to treat lung cancer, pancreatic cancer and ovarian cancer.

Personalised vaccines: the way forward?

Unlike with a disease like COVID-19, where the antigens are the same for all of us, every cancer tumour is unique. If 100 patients have ovarian cancer, each will have a different mutation. The best way to address this is through personalised vaccines that target specific mutations. Research has shown that personalised vaccines induce a powerful immune response and create T cells that attack all the antigens in the tumour.

With a personalised vaccine, a batch is created and a patient is vaccinated at regular intervals. My team and I are working with 60 ovarian cancer patients in this way – with what’s called a whole tumour immunising vaccine – and the responses so far have been very promising. The downside to this tailor-made approach is that it’s cumbersome, expensive and therefore difficult to perform for every patient. So the question is: can we make personalised vaccines faster, cheaper and available to all patients?

Progress has been slow so far. Only one therapeutic vaccine – for prostate cancer – has become standard care. But we have good reason to believe developments will accelerate. For one, advances in technology, such as combining bioengineering with robotic technology, mean the field is progressing fast. Biotech companies are already creating libraries of shared antigens and can (to a certain extent) tailor vaccines by matching the antigens they have in stock with those closest to the patients’ needs.

With cancer causing nearly one in six deaths worldwide, the stakes could hardly be higher. And that’s why, although there are challenges ahead and we’re unsure how quick progress will be, I’m hopeful that cancer vaccines will become a standard treatment for all.

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