Moderna's personalized cancer vaccine clears phase 3 melanoma trial

Stock nearly triples on news, adding $44 billion in market value

Moderna announced Wednesday that its personalized mRNA cancer vaccine, given alongside Merck’s immunotherapy drug Keytruda, met both primary and secondary goals in a phase 3 melanoma trial. At the company’s Cambridge, Massachusetts, headquarters, meetings were canceled and roughly 4,500 employees crowded into the company cafeteria as Chief Executive Stéphane Bancel took the stage. According to The Wall Street Journal, Bancel, who normally speaks off the cuff at such gatherings, was too emotional to trust his memory and relied on a notecard instead. Moderna’s stock nearly tripled on the announcement, adding $44 billion to market value.

“It is part of our responsibility to try to go after big bets that are hard,” Bancel told the crowd, comparing the morning to the day Moderna announced its COVID-19 vaccine data at the depths of the pandemic. “Remember to tell your grandchildren one day, Aug. 19, 2026, was the day a new chapter started.” Employees toasted with sparkling wine and hugged. Some cried.

Moderna’s shares, among the most shorted in the S&P 500 in June, nearly tripled on Wednesday’s news, adding $44 billion to the company’s market value. Earlier this year, short interest in Moderna had reached 20%, a level signaling intense investor pessimism about a stock that had lost more than 90% of its value from its pandemic-era peak.

The phase 3 trial had accrued enough data to reach statistical significance, the company said, and met its primary goal of preventing cancer recurrence while also clearing a secondary goal of preventing the disease from spreading throughout the body. Moderna and Merck said the combination significantly extended the time patients remained cancer-free compared with Keytruda alone. The companies cautioned that detailed efficacy data have not yet been disclosed. Full findings are scheduled for presentation at a medical conference later this year, and the companies are hoping for U.S. approval next year.

Several outside researchers urged patience. Dr. Drew Weissman, a University of Pennsylvania professor who won a Nobel Prize for his work on mRNA technology, said the announcement represented an important milestone but stressed that complete data remained to be seen. “We don’t have all of the data yet, and I think that’s really needed,” Weissman said. “We don’t know how long it’s going to last. So it certainly is a major milestone to cross, but the game isn’t over yet.”

The treatment works by sequencing a sample of each patient’s surgically removed tumor, identifying the specific mutations in the cancer cells, and producing a personalized mRNA vaccine designed to direct the immune system against those mutations. The vaccine, packaged in lipid nanoparticles, instructs the patient’s cells to produce proteins that train the immune system to attack any remaining cancer cells carrying the same targets. Moderna and Merck are also testing similar vaccines against lung, kidney, and pancreatic cancers.

The Merck partnership dates to the spring of 2016, when Bancel and Stephen Hoge, who leads Moderna’s drug development, traveled to New Jersey to pitch Roger Perlmutter, then in charge of research at Merck. Perlmutter, who said he and his colleagues had “considerable skepticism,” agreed to fund initial research with a $200 million payment to Moderna. Jeff Coller, an RNA biologist and Johns Hopkins University professor not involved in the project, called the platform a “convergence of a lot of technology all at once.”

In 2022, after a smaller study showed a 44% reduction in the risk of melanoma recurrence or death compared with Keytruda alone, Merck committed to jointly developing the vaccine and splitting any profits. “It was like, ‘Holy cow guys, this worked — like, it worked,’” Hoge recalled. “I almost don’t believe it.” Perlmutter, describing his decision to back the program a decade ago, said, “I’m an immunologist. Stéphane is an engineer. So we come from quite different backgrounds. But the idea of tumor immunology was something that I’d been working on for a very long time.”

Moderna’s oncology program began in 2013 with a personal check. Patrick Degorce, an early Moderna investor and hedge-fund manager whose wife had died of lung cancer, sent Bancel an envelope containing $500,000 to fund two cancer scientists after Bancel had told him the company could not afford to pursue the work. Days later, the envelope arrived. The fledgling biotech had an oncology program.

The COVID-19 pandemic transformed Moderna. The company’s mRNA vaccine, developed with more than $1 billion in Trump administration funding, was authorized for emergency use in December 2020 and generated roughly $36 billion in sales in its first two years. The stock peaked near $500 a share. But as the pandemic subsided, COVID vaccine sales collapsed — 2023 sales fell by nearly two-thirds — and Moderna announced job cuts and the end of research programs including a pediatric RSV vaccine.

Federal mRNA funding has also been reduced. Health Secretary Robert F. Kennedy Jr. canceled Moderna’s contract to develop mRNA-based vaccines for pandemic influenza viruses, telling reporters at the time, “We’re moving beyond the limitations of mRNA and investing in better solutions.” Approval of Moderna’s cancer vaccine, if it comes, would require navigating a federal health apparatus that has halted hundreds of millions of dollars in mRNA funding.

Among those who have already benefited from earlier trials is Greg Byrne, an 87-year-old Arizona resident who has had two bouts of melanoma. After surgery, Byrne enrolled in an earlier Moderna study and said he has been melanoma-free for two years. “The day the news about the vaccine’s success came out was a great day for me,” Byrne said. “I have a vested interest.” The 87-year-old said he is still able to play golf and bought Moderna stock when he started the trial two years ago.

Tommy Hill, managing partner of a hedge fund that focuses on distressed companies, said his firm took a small position earlier this year on the view that Moderna’s vaccine business was worth more than Wall Street was giving it credit for. “There are a lot of smart people up in Boston working damn hard and they were able to come up with a Covid vaccine within six or nine months,” Hill said. “They’re not dummies.” The firm made more than $25 million on the day of the stock surge, according to an analysis of its latest quarterly filing.

Despite Wednesday’s results, the path to approval and commercial success remains steep. Ira Mellman, president of research at the Parker Institute for Cancer Immunotherapy, said the vaccine’s costs would likely be “on the high end of even a cancer drug.” Bancel has said the treatment, if approved, would be priced less than CAR-T therapies, which can run up to $500,000 for a single patient, but the companies have not disclosed specific pricing plans. The personalized nature of the vaccine — each dose must be manufactured individually from a patient’s tumor sample — poses manufacturing and cost challenges that traditional vaccines do not face.

Bancel, who has been CEO of Moderna for nearly 15 years, said in an interview the day after the announcement that he has no intention of leaving the company. “There’s no job after Moderna,” he said. “Doing a traditional company would have no taste. It would have no challenge.”

MSI previously reported on the initial announcement of the trial results and the stock reaction, followed by coverage of the trial’s interim findings and design earlier in the week.