MSD and Moderna have reported full Phase III results for their personalised cancer vaccine, but both companies’ shares fell after some data points missed investor expectations.
Unveiled early at the European Society of Medical Oncology (ESMO) 2026 conference, which is being held in Madrid, Spain, from 23 to 27 October, due to an embargo breach, those who received intismeran autogene plus Keytruda (pembrolizumab) in the INTerpath-001 study (NCT05933577) had a 42% reduction in the risk of death or recurrence compared with those who received Keytruda alone after 24.6 months. The study enrolled patients with completely resected stage IIB-IV melanoma.
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Intismeran plus Keytruda also significantly reduced the risk of distant metastasis or death by 38% compared to the PD-1 inhibitor alone. Improvements in recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) were generally consistent across pre-specified patient subgroups.
Overall survival (OS) data are not yet mature, but there is a favourable trend in OS in the combination cohort, the companies stated.
The safety profile of intismeran plus Keytruda was generally consistent with previously reported studies of the combination, and no new safety signals were observed. Based on these data, MSD and Moderna are engaging with regulatory authorities.
Moderna and MSD shares fell on Thursday, 22 October, after disease-free metastasis survival and recurrence-free survival data came in below earlier-stage results. Moderna closed down 15.6%, while MSD fell 2.5%.
In a research note, Citi analysts said: “This is a clinically meaningful advance, with consistent efficacy across lower- and higher-risk disease. However, expectations had moved beyond a positive melanoma study, with some investors assigning value to an effective-cure narrative and success across additional solid tumours.”
The investigational mRNA-based individualised neoantigen therapy is being jointly developed by MSD and Moderna. It is also being evaluated in additional Phase II and Phase III trials across other indications, including non-small cell lung cancer.
Professor Georgina Long, the study’s principal investigator and medical director of Melanoma Institute Australia, said: “The transformative INTerpath-001 results have the potential to make a foundational shift in how we treat patients with earlier-stage melanoma in the adjuvant setting. For decades, cancer treatment has largely been defined by where a tumour originates in the body.
“The INTerpath-001 findings support a fundamentally new and individualised approach to treating resected melanoma in the adjuvant setting, one that tailors treatment to the unique mutational signature of a patient’s tumour to enhance an anti-tumour immune response. While these results are in patients with completely resected stage IIB-IV melanoma, they provide valuable insights and will help inform our understanding of intismeran as clinical research continues into other tumour types and across settings.”
The data was due to be released during the first Presidential Symposium of the conference on Saturday 24 October but was instead unveiled two days early after the data was leaked.
Speaking after the initial confirmation of the trial’s success in August, GlobalData oncology analyst Biswajit Podder touted the INTerpath-001 outcome as highly encouraging, adding that it could become the new SoC for suitable patients with high-risk resected melanoma.
GlobalData predicts sales of the cancer vaccine to surpass $1bn in 2031. GlobalData is the parent company of Clinical Trials Arena.
