Personalized cancer vaccine cuts risk of recurrence and death by 42%

A large clinical trial has shown that a new cancer vaccine, tailored for each patient, reduced the risk of death or melanoma recurrence by 42% when given alongside a common immunotherapy drug.

According to researchers cited by the BBC, these results could mark a turning point in cancer treatment and bring personalized medicine closer to wider use.

The trial indicated that combining the vaccine with immunotherapy lowered the risk of melanoma spreading by 38% over two years, compared to immunotherapy alone.

The same approach is now being tested for other cancers, including kidney, bladder, and lung cancer, according to developers MSD and Moderna.

Independent cancer experts described the results as "impressive," but stressed the need for longer studies to determine whether the treatment truly extends patients' lives.

The new treatment targets cancer patients who have undergone surgery to remove their tumors. The trial involved 1,137 adults, all of whom received Keytruda, an approved immunotherapy drug.

About two-thirds of participants received the experimental vaccine in addition to immunotherapy, while the rest were given a placebo.

The vaccine, called Intisemeran, uses messenger RNA (mRNA) technology similar to some COVID-19 vaccines. It is custom-made for each patient using information from their tumor, aiming to train the immune system to recognize and target cancer cells if they return.

After two years of treatment, patients who received the vaccine were less likely to experience melanoma recurrence or spread.

Professor Pippa Corrie, an oncology consultant who led part of the study at Addenbrooke's Hospital in Cambridge, said: "Designing treatment to fit each patient is the next step, and that's very exciting. It's a truly remarkable technology."

She added: "The key question is how much real benefit we can prove. This trial has provided the first practical evidence for this approach."

Among Corrie's trial participants was Tony Chapman, 75, who was diagnosed with melanoma in 2019.

Tony underwent surgery to remove a tumor from his chest, but later developed a lump under his arm. Doctors told him the cancer had returned and he needed a second operation. He decided to join the trial, though he does not know whether he received the experimental vaccine or a placebo.

He said: "I saw it as a very good opportunity to contribute to science and perhaps benefit personally as well. What did I have to lose?" Three years later, Tony remains cancer-free and has check-ups every six months.

Shares in MSD (known as Merck in the US) and Moderna surged after the companies announced the vaccine's success in the summer, but investors sold shares on Thursday after financial analysts noted the results were not as strong as those from a previous, smaller trial.

The companies said they are "in discussions with regulatory authorities," which could pave the way for a drug approval application as early as next year.

The cost of the treatment will affect its potential for widespread use within the UK's National Health Service, as preparing the vaccine requires genetic analysis of each patient's tumor and manufacturing a personalized dose.

Patients in the trial will continue to be monitored to track cancer recurrence and assess whether the treatment helps extend survival.

Professor Alan Melcher of the Institute of Cancer Research in London, who was not involved in the study, described the results as "extremely impressive," emphasizing the importance of long-term follow-up to understand the impact on survival rates and cautioning against generalizing the findings to all cancers without further evidence.

The full trial results are due to be presented Saturday at the European Society for Medical Oncology (ESMO) conference in Madrid. The findings have not yet been published in a peer-reviewed journal, where they would undergo further scrutiny by independent experts.