A personalized cancer vaccine given alongside a widely used immunotherapy drug cut the risk of patients dying or seeing their skin cancer return by 42% in a major clinical trial, researchers said this week, in results they described as a possible turning point for personalized cancer treatment. The trial also found the combination reduced the risk of the melanoma spreading by 38% over two years compared with immunotherapy alone.
In the trial, 1,137 adults who had already had their tumors surgically removed were given Keytruda, an established immunotherapy drug that helps the immune system find and attack cancer cells; about two-thirds also received an experimental vaccine called Intismeran, with the rest given a placebo. The vaccine uses the same mRNA technology as some Covid-19 shots, but is personalized to each patient using genetic information from their own tumor to train their immune system to recognize and target cancer cells if they return.
'What's to Lose?'
"Personalisation is the next step up and it's really exciting, it's a fabulous technology," said Professor Pippa Corrie, a consultant medical oncologist who helped run part of the study at Addenbrooke's Hospital in Cambridge. "The question is how much can we really demonstrate its worth, and this trial was the first proof of principle." One participant, 75-year-old Tony Chapman, was diagnosed with melanoma in 2019 and had a second operation after a lump reappeared under his arm; three years after enrolling in the trial, during which he was never told whether he received the vaccine or a placebo, he remains cancer-free with checks every six months. "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?" he said.
Independent cancer experts described the results as impressive but cautioned that longer-term data is still needed to establish whether the treatment helps most patients live longer on average, not just whether their cancer returns. Shares in Moderna and MSD (known as Merck in the US) surged earlier this year when the companies first hinted at the trial's success, but slipped again this week after analysts noted the results were not quite as strong as those from an earlier, much smaller trial. Both companies said they were now "engaging with authorities" and could seek regulatory approval as soon as next year; the same personalized-vaccine approach is already being tested against kidney, bladder and lung cancers. Wider rollout on health systems like the NHS will likely hinge on cost, since each patient's tumor must be individually sequenced to build their own vaccine.