New York: Moderna and Merck said a personalised mRNA cancer vaccine reduced the risk of recurrence and spread of melanoma in a late-stage trial, a major success in a new field of cancer treatment that sent Moderna’s shares surging more than 170 per cent.

The companies tested the vaccine together with Merck’s immunotherapy drug Keytruda, a widely used melanoma treatment. Thousands of patients who have undergone surgery to remove high-risk melanoma tumours could benefit as soon as next year if regulators approve the vaccine, Moderna president Stephen Hoge said in an interview on Wednesday (US time).

This is the first positive late-stage trial result for an mRNA cancer vaccine, which trains a patient’s immune system to fight tumours by targeting specific mutations in those cells, and the first such study to show that adding a treatment to Keytruda worked better than that therapy alone. Merck, Moderna and other companies are testing similar approaches against lung, breast and pancreatic cancers.

Karen Knudsen, CEO of the Parker Institute for Cancer Immunotherapy, said the Moderna results could signal a new era for treating solid-tumour cancers.

“The positive hit here leads us into truly this next phase in immunotherapy,” Knudsen said. “This is an auspicious start – this is where things begin.”

The results signalled a reversal of fortune for Moderna, which has struggled to generate new products beyond its COVID-19 vaccine and faced pushback over its mRNA technology from US President Donald Trump’s administration.

US Health and Human Services Secretary Robert F. Kennedy Jr has criticised the safety and efficacy of mRNA vaccines and cut $US500 million ($702 million) in mRNA vaccine projects. Still, the National Cancer Institute has continued to fund trials of cancer vaccines, including those based on mRNA.

Moderna shares surged to multiyear highs, adding about $US40 billion to the company’s market capitalisation. Merck climbed 12 per cent on hopes the vaccine would expand its prospects in cancer as Keytruda, once the world’s best-selling drug, faces patent expiration later this decade.

The vaccine – which is a personalised treatment – could be difficult to make and scale up commercially, although Hoge said Moderna was confident it could meet demand over the next few years.

The companies did not provide detailed results, which they said they would share at an upcoming medical meeting. They do not yet have results on overall survival, a secondary endpoint in the trial that measures whether patients who receive a treatment live longer than those who do not.

Melanoma is the deadliest form of skin cancer.

Interim results of the ongoing study, released on Wednesday, found the treatment, Intismeran, met both its primary target of reducing cancer recurrence and its secondary goal of preventing tumours from spreading to other parts of the body, compared with Keytruda alone.

When the vaccine is injected into a patient, the patient’s cells produce copies of mutations for the immune system to recognise and destroy.

“This is the first time that we’ve seen really clinically significant, statistically significant improvements over checkpoints like Keytruda in this population, and it is the first time we’ve done that with an individualised treatment,” Hoge said.

Merck said the companies were already in talks with regulators about the treatment. Hoge said, given the vaccine’s breakthrough therapy designation, it could be available as soon as next year. He called the result a landmark.

The cancer treatment combines Merck’s Keytruda with a made-to-order mRNA vaccine from Moderna that is based on an analysis of mutations found in the patients’ own tumours.

The trial enrolled 1137 high-risk patients with stage IIB-IV melanoma that had been surgically removed.

Volunteers were randomised to receive up to nine doses of Keytruda plus the personalised vaccine or Keytruda alone for about one year.

The companies said no new safety signals have emerged in the trial. In January, the companies announced results of a mid-stage trial of the treatment showing that it reduced the risk of recurrence or death by 49 per cent after five years.

Moderna CEO Stephane Bancel said on CNBC the companies had not decided on pricing, saying the data had only become available a couple of days ago.

William Blair analyst Myles Minter said the interim results position both companies well to seek regulatory approval, while also reading positively for the vaccine’s studies in other types of cancer.

Last month, Barclays analysts said they expected the therapy could generate annual sales of about $US3 billion for treating melanoma by 2035.

Reuters