Optimism around ‘personalised’ melanoma treatment

A therapeutic cancer vaccine tailored to individual melanoma tumours and used with existing immunotherapy leads to a ‘statistically significant’ reduction in recurrence, a new clinical trial suggests.
 
In an announcement this month, pharmaceutical companies Moderna and MSD said a Phase 3 trial using intismeran, an mRNA-based individualised neoantigen therapy, alongside pembrolizumab (sold as Keytruda), brought ‘clinically meaningful improvements’.
 
Recruiting 1137 participants with resected Stages 2B to 4 cutaneous melanoma, the randomised controlled trial split the patients between an intismeran and pembrolizumab combination treatment group and a control group treated with pembrolizumab alone.
 
The specific results have not yet been made public, nor have they been peer reviewed for publication.
 
However, the companies’ announcement said the result ‘builds on’ earlier Phase 2b trials, which show a 49% reduction in the risk of recurrence or death, and the risk of metastasis or death going down by 59%.
 
Professor Georgina Long, who was Australian of the Year 2024 alongside Professor Richard Scolyer, is the lead investigator for the Phase 3 clinical trial.
 
As Medical Director of the Melanoma Institute Australia, she describes the results as ‘a landmark moment for adjuvant melanoma treatment’.
 
‘This is the first Phase 3 study to show that intismeran, a treatment designed based on the unique mutational “fingerprint” of a patient’s own tumour, given in combination with pembrolizumab can reduce the risk of recurrence or death in patients with completely resected stage IIB-IV melanoma compared to Keytruda alone,’ Professor Long said.
 
‘Intismeran in combination with pembrolizumab has the potential to establish a new treatment paradigm in the adjuvant melanoma setting, helping patients remain cancer-free for longer.’
 
Associate Professor Joel Rhee, RACGP Specific Interests Cancer and Palliative Care Chair, said he will be following the detailed results with interest when they are presented at an upcoming international conference.
 
‘From what I can see, it’s exciting progress when it comes to the treatment of melanoma, which is extremely important in the Australian context because of its prevalence,’ he told newsGP.
 
‘It’s always been a challenge in managing patients with more advanced versions of melanoma, so it’d be really interesting to see what it shows.
 
‘We can be cautiously optimistic at this point.’
 
Associate Professor Seth Cheetham, Deputy Director of the BASE mRNA facility at The University of Queensland, said the Phase 3 trial results are ‘critical as they demonstrate that a new medicine works in a large number of patients’.
 
‘These large studies are used by regulatory agencies to approve new medicines for widespread use in the community, and these results are likely to support the future approval of Moderna and Merck’s personalised cancer vaccine for melanoma within one to two years,’ he said.
 
‘The greatest challenge now will be to deliver this new type of medicine at the scale that it can reach patients throughout the community.
 
‘While previous personalised medicines match patients to the right drug, this is the first to create an entirely new drug for each patient.
 
‘The trial represents a landmark in personalised cancer medicine and is the start of a wave of new studies to bring this technology to patients with other diverse types of cancer.’
 
Federal Health and Ageing Minister Mark Butler called the trial results ‘incredibly exciting’ given the disease’s prevalence in Australia.
 
There were around 17,400 new cases diagnosed in the country in 2025 according to the Australian Institute of Health and Welfare, and it caused an estimated 1455 deaths in the same year.
 
Keytruda was first listed on the Pharmaceutical Benefits Scheme to treat melanoma in 2015, with its listing since expanded to include several other cancers.
 
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