Moderna shares surge after cancer vaccine works in late-stage trial
Key Points
- Moderna and Merck's personalised mRNA cancer vaccine met its goals in a late-stage melanoma trial, the first such result for an mRNA cancer treatment.
- The combination of intismeran autogene and Keytruda kept melanoma from returning for longer than Keytruda alone, and slowed its spread to other organs.
- The trial enrolled 1,137 high-risk patients who had already undergone surgery to remove the cancer.
- Moderna shares more than doubled at one point in pre-market trading; Merck rose around 7%.
- Both companies now plan to take the data to regulators and to an upcoming medical conference.
Moderna shares more than doubled in pre-market trading on Wednesday (19 August) after its personalised cancer vaccine, developed with Merck, succeeded in a late-stage melanoma trial.
The INTerpath-001 trial enrolled 1,137 patients with high-risk stage IIB to IV melanoma who had no prior systemic treatment and whose tumours surgeons had completely removed.
Volunteers received up to nine doses of the vaccine alongside Merck’s immunotherapy Keytruda for about a year.
The combination significantly extended the time patients lived without their melanoma returning and also reduced the risk of the cancer spreading to distant parts of the body. The companies reported no new safety signals.
“Today’s results represent a landmark moment for adjuvant melanoma treatment,” said Georgina Long, the study’s principal investigator and medical director of Melanoma Institute Australia.
How the vaccine works
The treatment, intismeran autogene, uses synthetic mRNA coding for up to 34 neoantigens — markers that Merck and Moderna select by sequencing the DNA of each patient’s own tumour, producing an individualised therapy designed to send T-cells after the cancer. The result marks the first late-stage success for any individualised neoantigen therapy, and the first trial of its kind to beat Keytruda on its own after melanoma surgery.
“Today, we have demonstrated the clinical benefit of this approach,” Stéphane Bancel, Moderna’s chief executive, wrote in a blog post on Wednesday.
The rise in share price took Moderna to its highest level since 2024 and a market value of roughly $50 billion, still less than a third of its 2021 peak after the launch of its Covid-19 vaccine. Moderna’s stock has fallen more than 80% from its pandemic high, and investors treated the trial as pivotal to the company’s future.
Melanoma accounts for the vast majority of skin cancer deaths despite making up a small share of overall cases, and the companies project 112,000 new US cases and more than 8,500 deaths in 2026.
Most recurrences appear in the period shortly after initial treatment. Merck and Moderna said they will keep the study running to track further measures, including overall survival, and are advancing a wider programme of nine mid- and late-stage trials covering melanoma, non-small cell lung cancer, bladder cancer and renal cell carcinoma, alongside early-stage work in pancreatic, gastric and lung cancers.
The full data goes to an international medical conference, and the companies will approach regulators about approval filings.
Moderna sought accelerated approval for the therapy in 2024 but the US Federal Drug Agency turned it down.
