Moderna, Merck Vaccine Succeeds in Preventing Melanoma from Returning

An experimental mRNA-based vaccine succeeded in preventing cancer from coming back or spreading in a study of high-risk melanoma patients, Moderna and its partner Merck said Wednesday, paving the way for a potentially new life-extending treatment for the thousands of people diagnosed with the deadly skin cancer each year.

The study looked at people who had surgery to remove a melanoma—the point of the treatment was to reduce the risk of it coming back.

The companies said the late-stage study, which tested the personalized cancer vaccine intismeran in combination with Merck’s blockbuster cancer immunotherapy Keytruda, met its main goal of extending the time before cancer returns in high-risk patients. The study also met a secondary goal of preventing the disease from spreading to different organs.

“I have a feeling that this is just the beginning of a new field,” said Jane Healy, a vice president of oncology at Merck, adding the goal for patients is “to give them longer without having to worry about treatments for cancer.”

Moderna shares surged more than 60% in early trading Wednesday, while Merck’s stock rose 7.3%.

The companies didn’t provide specific details about how long patients taking the Moderna-Merck combination lived without their cancer progressing or how long they lived on average. The companies will present more details at a medical conference later this year.

Investors and researchers will be watching closely to see how effective and tolerable the vaccine proves to be, as that has the potential to dictate its chances for approval and how widely it is used.

The results mark the first successful late-stage trial for a personalized mRNA cancer therapy, validating decades of research into custom treatments engineered specifically for an individual’s tumor mutations.

For Moderna, these results could pave the way for its entry into the $240-plus-billion cancer-drug market, a boon for a company that has been dependent Covid-19 vaccine sales, which have been falling. For Merck, this could bring a new drug into its arsenal to help offset the impending patent loss for Keytruda, one of the top-selling drugs in the world.

Moderna has been trying to regain financial ground after years of consecutive losses since the Covid-19 pandemic started to wane.

“We are now an oncology company,” said Moderna Chief Executive Stéphane Bancel. “By Christmas, you could have a company that’s going back into sales growth for the first time in four years.”

The melanoma study followed more than 1,000 patients who were randomized to either receive a combination of intismeran and Keytruda or Keytruda alone for about a year.

Unlike traditional vaccines designed to prevent infections, intismeran is a personalized therapeutic vaccine built for a single person. The process begins after a patient undergoes surgery to remove a high-risk melanoma tumor. Doctors send a blood sample and biopsy of the tumor, where the cancer’s genetic profile is analyzed.

Scientists home in on unique mutations on the cancer cells that are likely to alert the immune system. Those mutation targets are encoded into mRNA and manufactured into a vaccine—a process that takes about six weeks from the date of the biopsy.

Meanwhile, patients recover from their surgery and start a regimen of Keytruda to keep the disease in check while their personalized shot is prepared.

Moderna and Merck teamed up in 2016 to jointly develop personalized mRNA cancer vaccines and expanded that partnership over time. The researchers began by studying the vaccine in melanoma because those tumors are typically highly mutated. There are other studies under way in different types of cancer, including bladder cancer, a common form of lung cancer and kidney cancer.

Ahead of the news, Citi analyst Geoff Meacham said the study could be a “defining catalyst” for Moderna’s cancer drug business and that strong results could speed FDA review. Bancel said the company hopes to have the drug on the market in 2027.

Earlier trial readouts showed that the vaccine in combination with Keytruda reduced the risk of melanoma recurrence or death by 49% compared with Keytruda alone.

Moderna recently won approval for its mRNA-based flu vaccine, though analysts said this was more likely to be a long-term growth driver than an immediate financial windfall.

Personalized cancer vaccines are complicated and expensive to produce. Questions remain as to how accessible the vaccines will be if they are approved. The only FDA-approved therapeutic cancer vaccine to date is Provenge, a personalized immunotherapy for prostate cancer.