Cancer vaccine: how the ‘personalized’ vaccine against melanoma works, which promises to revolutionize the treatment of a more lethal form of skin cancer

It is an important and pioneering trial that could represent a significant advance in the fight against cancer.

Researchers in London are testing the first “personalized” messenger RNA (mRNA) vaccine designed to combat melanoma, the deadliest form of skin cancer.

The vaccine, technically called mRNA-4157 (V940), uses the same technology as the most recent Covid-19 vaccines and is being tested in phase III trials, the last phase of testing before final evaluation for approval and release for use. on a large scale.

The United States and Australia also participate in the testing program, however, the United Kingdom was the first of the three countries to begin phase III, after a positive assessment of the results in the previous two phases.

One of the first patients to test this vaccine in phase III is Steve Young, 52, who had a melanoma removed from his scalp in August last year.

The goal is to help his immune system recognize and eliminate any cancer cells that may remain in his body. If all goes well, this will prevent the cancer from returning.

Doctors at University College London Hospitals (UCLH) are administering the vaccine in conjunction with another medicine, pembrolizumab or Keytruda, which also helps the immune system destroy cancer cells.

Treatment with the vaccine and medicine, manufactured by the companies Moderna and Merck Sharp and Dohme (MSD), is not yet available outside of clinical trials. Experts in other countries, including Australia, are also testing it on patients to gather more evidence and determine whether it should be widespread.

It is called a personalized vaccine because its composition is modified to suit each patient. It is generated specifically to match the unique genetic signature of the patient’s own tumor and works by instructing the body to produce proteins or antibodies that attack markers or antigens found only on these cancer cells.

Dr Heather Shaw, a researcher at UCLH, explained that the vaccine has the potential to cure patients with melanoma and is being tested in other types of cancer, such as lung, bladder and kidney. “

It’s one of the most exciting things we’ve seen in a long time,” he said. “Because it’s personalized, it couldn’t be given to another patient because it wouldn’t be expected to work.”

“It’s truly personalized. These things are very technical and are designed for the patient”, he adds.

The aim of the international trial in the UK is to recruit between 60 and 70 patients across eight clinics in the cities of London, Manchester, Edinburgh and Leeds.

Patients in the trial must have undergone surgical removal of high-risk melanoma within the last 12 weeks to ensure the best outcome. Some of them will receive a dummy or placebo shot instead of the vaccine. However, none of them know which one they will receive.

“[O ensaio] It gave me the opportunity to feel like I was actually doing something to fight a potentially invisible enemy,” Young told BBC Radio 4.

“The scans showed that I was radiologically clean, but obviously there was still the possibility of cancer cells floating around undetected. So instead of sitting around hoping it wouldn’t show up again, I had the opportunity to put on the boxing gloves and face it”.

Young, who is a musician by profession, had a lump on his scalp for many years before realizing it was cancer. He said the diagnosis had a “huge impact” on him.

“I literally spent two weeks thinking ‘this is the end’,” he explains. “My father died of emphysema at 57 and I thought ‘I’m going to die younger than my father’.”

The most common signs of melanoma that people should look out for are:

• A new abnormal mole (such as a mole, blemish or wart)
• An existing mole that appears to be growing or changing
• A change (in color or texture, for example) in an area of ​​skin that was normal.

A change in appearance of a mole, as in these four images, could be a sign of melanoma. The ABCDE checklist can help identify whether a mole is abnormal:

A – asymmetrical (does the sign have an irregular shape?)

B – edge (are the edges irregular or uneven?)

C – color (does the signal have an irregular color with different tones?)

D – diameter (is the sign larger than the others?)

E – evolution (is it changing? Has it started, for example, to itch, bleed or form crusts?)

These changes are not always cancerous, but it is important to have them checked. The earlier a melanoma is detected, the easier it is to treat and the greater the chances of success.

Data from the phase II trial, published in December, revealed that people with severe, high-risk melanomas who received the shot along with the Keytruda immunotherapy had almost half (49%) the chance of dying or having their cancer come back after three years compared to those who only received the medicine.

Shaw said there was real hope that the therapy could “change the rules of the game”, especially as it appeared to have “relatively tolerable side effects”.

These include tiredness and arm pain when the shot is administered, and he adds that for most patients it appears to be no worse than the flu or Covid-19 vaccine.