Experts caution that while results are promising, applicability to other cancers remains under investigation, though the potential impact on oncology is strong.

Irish stakeholders welcomed the breakthrough but pressed for faster access and clearer paths to approval and reimbursement within Ireland, warning of delays before routine care benefit.

Skin cancer remains the most common cancer in the U.S., with substantial incidence and mortality anticipated this year by the American Cancer Society.

The findings involve 107 U.S. patients and international sites, with five-year follow-up data presented after long-term observation.

A trial involving 157 patients with stage 3+ melanoma shows that after five years about 70% of those treated with the personalized mRNA vaccine remained cancer-free, versus 49% on standard therapy, with the vaccine cutting the risk of metastasis by nearly 60%.

The vaccine is tailored to each patient by sequencing the tumor and selecting typically 20–34 neoantigens, with Moderna manufacturing the patient-specific vaccine.

During follow-up, 71 deaths occurred across groups (mostly cancer-related); side effects were generally manageable, including fatigue, injection-site pain, and chills.

Experts warn results do not prove survival benefit yet and highlight questions about real-world applicability, manufacturing logistics, and cost, with prices discussed around €300,000 per patient for personalized vaccines.

Vaccine recipients reported better quality of life during treatment, with mild, short-lived side effects similar to a COVID-19 vaccine.

Results were shared at a Chicago conference and in the Journal of Clinical Oncology, showing lasting tumor control after five years but no clear overall survival benefit due to small sample size and non-blinded design.

If validated, this personalized mRNA approach could extend beyond melanoma to cancers like pancreatic and lung cancer, leveraging advances in immunotherapy and broader mRNA use.

The study was led by NYU Langone Health and presented at the ASCO meeting, with results destined for publication in the Journal of Clinical Oncology.