Moderna shares surged as much as 90 percent in premarket trading Wednesday after the company and Merck announced that their personalized mRNA cancer vaccine had succeeded in a major late-stage trial for melanoma, a result researchers are calling a milestone for cancer treatment. Merck's stock climbed more than 8 percent on the same news.
The Phase 3 trial, known as INTerpath-001, enrolled 1,137 patients with high-risk, surgically removed melanoma. Participants either received the experimental vaccine, called intismeran autogene, alongside Merck's immunotherapy Keytruda, or Keytruda by itself for about a year. The combination met its main goal of significantly extending the time patients lived without their cancer returning, and also hit a key secondary target of slowing the disease's spread to other parts of the body.
A First For The Field
Researchers have chased the promise of so-called neoantigen vaccines, shots built from the specific mutations found in a patient's own tumor, for years. This is the first randomized Phase 3 trial to definitively demonstrate that kind of personalized approach can work, and the first positive late-stage result for any mRNA-based cancer treatment. Jedd Wolchok, director of the Meyer Cancer Center at Weill Cornell Medicine, called it proof that something once dismissed as science fiction can now delay the progression of a deadly cancer.
Each dose of the vaccine is manufactured individually. Scientists sequence a patient's tumor after surgery, identify its unique mutations, and build a shot designed to train the immune system to recognize and attack any cancer cells that share those same mutations. Moderna and Merck said no new safety concerns emerged in the trial, with side effects similar to those seen with other common vaccines.
What It Means For Both Companies
For Moderna, the results are a badly needed catalyst. The company has leaned almost entirely on its COVID-19 vaccine for revenue since the pandemic eased, and Wednesday's stock move reflects how much investors have been waiting for a credible path to diversification. Analysts at William Blair upgraded the stock following the announcement, while Barclays had previously estimated the therapy could generate roughly $3 billion a year in melanoma treatment alone by 2035.
For Merck, the timing matters just as much. Keytruda remains the pharmaceutical industry's best-selling drug, bringing in over $32 billion last year, but it faces patent expiration in the coming years. A successful combination therapy gives Merck a plausible way to extend Keytruda's commercial life well beyond that cliff. Both companies say they plan to present full trial data at an upcoming medical conference and begin discussions with regulators, with an estimated 112,000 new melanoma cases and more than 8,500 deaths expected in the US alone this year.