World first personalised cancer vaccine stops disease returning in major trial

A new personalised cancer vaccine given alongside a widely used immunotherapy drug has cut the risk of patients dying or their skin cancer returning by 42% in a major clinical trial.

The researchers involved say the results could mark a turning point in cancer treatment, bringing personalised medicine a step closer.

The trial, involving more than 1,100 patients, also found that the new drug combination reduced the risk of melanoma, a type of skin cancer, spreading by 38% over two years.

The drug manufacturers MSD and Moderna say the same approach is already being tested against other tumours, including kidney, bladder and lung cancer.

Independent cancer experts described the results as impressive but said longer-term studies were still needed to establish whether the treatment really helps most patients live longer, on average.

The new approach is aimed at cancer patients who have already had their tumour removed through surgery.

In the trial, 1,137 adults were given Keytruda, an established immunotherapy drug which helps the body's immune system find and attack cancer cells.

About two-thirds also received an experimental vaccine based on the same mRNA technology used in some Covid jabs, with the rest being given a placebo or dummy drug.

The vaccine, called Intismeran, uses the same mRNA technology as some Covid jabs.

It is personalised to each patient, using information from their own tumour to help train their immune system to recognise cancer cells and target them if they return.

Two years after starting the treatment, the patients who received the jab were far less likely to have had melanoma come back or see it spread across the body.

"Personalisation is the next step up and it's really exciting, it's a fabulous technology," says Prof Pippa Corrie, a consultant medical oncologist who helped run part of the study with patients at Addenbrooke's Hospital in Cambridge.

"The question is how much can we really demonstrate it's worth and this trial was the first proof of principle."

Prof Corrie worked with patients enrolled in the trial including 75-year old Tony Chapman, who was diagnosed with melanoma in 2019.

He had the tumour removed from his chest but a lump later appeared under his arm and he was told his cancer had returned and he needed a second operation.

He then volunteered to take part in the study but, like all the other participants, he still doesn't know whether he was given the experimental vaccine or a placebo alongside his immunotherapy treatment.

"This just seemed like a really good example of moving science forward, as well as getting some benefit for yourself, so what's to lose?" Tony said.

Three years on he is now having checks every six months and remains cancer-free.

Shares in the drugmakers MSD (known as Merck in the US) and Moderna have surged since both companies first hinted at the success of the vaccine in the summer.

But investors sold off stock on Thursday after financial analysts said the results were not quite as strong as those seen in an earlier, much smaller trial.

Both companies said they were now "engaging with authorities" suggesting they could file for approval from medicine regulators as soon as next year.

Widespread NHS use will also depend on cost, given that each individual patient will need to have their tumour genetically analysed and a personalised vaccine made for them.

The trial will continue so that the patients involved can be monitored – both to see if the cancer returns over time and to assess whether the drug ultimately helps them live longer.

Professor Alan Melcher from the Institute of Cancer Research in London, who wasn't involved in the research, described the results as "very impressive".

"It is an important proof of principle for the field, although we shouldn't get ahead of the evidence," he said.

"We can't assume from one melanoma trial that the same approach will work across all cancers, and longer follow-up will be important to understand the effect on overall survival."