A 42% cut in the risk of melanoma returning or killing patients: that is the headline number from a major clinical trial of a personalised cancer vaccine developed by MSD and Moderna, a result that could reshape the commercial and clinical economics of cancer treatment. The findings, reported in detail by the BBC at https://www.bbc.co.uk/news/articles/cq0ld9g9e913o, sent shares in both drugmakers sharply higher earlier this year after they first hinted at the vaccine’s success in the summer. By contrast, investors sold off stock on Thursday when financial analysts judged the results not quite as strong as those from an earlier, much smaller trial.
The trial involved 1,137 adults, all of whom had already had their tumours removed through surgery. Every participant received Keytruda, an established immunotherapy drug sold by MSD that helps the body’s immune system find and attack cancer cells. About two-thirds also received the experimental vaccine, called Intismeran, while the rest were given a placebo or dummy drug. Two years after starting treatment, those who received the jab were far less likely to have had their melanoma come back or spread across the body, with the combination reducing the risk of spread by 38% over two years.
Intismeran uses the same mRNA technology as some Covid jabs, but with a crucial commercial and logistical difference: it is personalised to each patient. Information from a patient’s own tumour is used to train their immune system to recognise cancer cells and target them if they return. That bespoke manufacturing model is central to the cost question that will determine whether the treatment reaches a wide market. Widespread use in the NHS, in particular, will depend on price, given that each individual patient will need to have their tumour genetically analysed and a personalised vaccine made for them.
Both companies said they are now “engaging with authorities”, suggesting they could file for approval from medicine regulators as soon as next year. They added that the same approach is already being tested against other tumours, including kidney, bladder and lung cancer, signalling an ambition to build a broader personalised oncology franchise rather than a single-product play.
Market reaction aside, independent cancer experts urged caution on the evidence. Professor Alan Melcher from the Institute of Cancer Research in London, who was not involved in the research, described the results as “very impressive” but added: “It is an important proof of principle for the field, although we shouldn’t get ahead of the evidence.” He noted that the same approach cannot be assumed to work across all cancers from one melanoma trial, and that longer follow-up will be important to understand the effect on overall survival. Other experts described the results as impressive while stressing that longer-term studies are still needed to establish whether the treatment really helps most patients live longer, on average.
The trial will continue so that patients can be monitored, both to see whether the cancer returns over time and to assess whether the drug ultimately helps them live longer. That follow-up data will matter as much to investors and regulators as to clinicians, since overall survival is the benchmark on which pricing and reimbursement decisions typically rest.
Prof Pippa Corrie, a consultant medical oncologist who helped run part of the study with patients at Addenbrooke’s Hospital in Cambridge, was enthusiastic about the technology’s direction. “Personalisation is the next step up and it’s really exciting, it’s a fabulous technology,” she said, adding: “The question is how much can we really demonstrate it’s worth and this trial was the first proof of principle.”
For patients, the trial has already delivered personal outcomes. Tony Chapman, a 75-year-old diagnosed with melanoma in 2019, had a tumour removed from his chest before a lump appeared under his arm and he was told the cancer had returned and he needed a second operation. He volunteered for the study, though like all participants he still does not know whether he received the vaccine or a placebo. “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. Three years on, he has checks every six months and remains cancer-free.
What remains open is the price tag: whether a bespoke vaccine for every patient can be manufactured and reimbursed at a scale that turns a striking trial result into a viable oncology business.