This weekend, the European Society for Medical Oncology (ESMO) is hosting its annual conference. Cancer scientists from around the world are gathering to share their latest research, and Cancer Research UK’s experts are on hand to help make sense of it.

We’ll keep updating this article through ESMO 2026.

A personalised cancer vaccine lowers the risk of melanoma coming back

ESMO weekend kicked off with a bang, with one of the most anticipated stories breaking before the conference had even started. Full results are still to come, but we now have the clearest sign yet that personalised vaccines could help shape the future of cancer treatment.

In the first phase 3 trial of its kind, researchers tested Intismeran, which uses the same mRNA technology as some COVID vaccines, alongside a common immunotherapy drug. Together, they cut the risk of patients dying or seeing their skin cancer return in two years by 42% compared with the immunotherapy alone.

Unlike traditional vaccines, Intismeran is designed as a treatment, rather than a prevention tool. Researchers gave it to people with advanced melanoma that had been surgically removed but had a high risk of coming back.

“The science that helped protect us against COVID-19 is now showing promise in treating cancer,” said Dr Catherine Elliott, Cancer Research UK’s director of research. “These results are encouraging for people with melanoma, a cancer that can come back aggressively after surgery.”

The next steps for Intismeran

Despite the shared name, no two Intismeran vaccines are the same. Scientists make them by testing each patient’s cancer cells for unique features the immune system can learn to recognise. Then they use this information to generate bespoke mRNA instructions that can be loaded into a vaccine.

Patients receive their personalised vaccine alongside an off-the-shelf immunotherapy drug called pembrolizumab, which is often described as a way of “taking the handbrake off” cancer-stopping immune cells. It’s as if the immune system were a rally car, with pembrolizumab as the driver and Intismeran navigating.

Encouraging as these results are, we’re still some way from personalised cancer vaccines becoming a common part of standard care. Making them is difficult, expensive and time-consuming, and success in melanoma won’t necessarily translate to trials for other cancer types.

This trial will also need to continue so researchers can see how well the treatment works over time and if it improves overall survival. Regulators will then need to review the final results, which may take several years.

“Cancers differ from person to person, so research into tailored treatments is vital,” said Elliott. “Continued investment will help us understand who benefits most from approaches like this, and how we can make them available to the people who need them.”

We spoke to Dr Heather Shaw, who coordinates the trial in the UK, for an episode of That Cancer Conversation. Check it out to find out more about how the vaccine works: