mRNA Cancer Vaccine Milestone! Moderna (MRNA.US) teams up with Merck (MRK.US) for successful melanoma trial, pre-market stock price surges 80%

According to Jinse Finance, Moderna Inc. (MRNA.US) and Merck & Co. (MRK.US) have announced that their personalized cancer vaccine successfully reduced the risk of melanoma recurrence in a large-scale late-stage trial, marking a significant milestone for mRNA-based cancer therapy. The trial met its primary endpoint—data show that the vaccine, in combination with Merck's immunotherapy drug Keytruda, reduces the rate of melanoma recurrence compared to Keytruda alone. In a joint statement released Wednesday, the two companies stated that the study also met a key secondary endpoint by demonstrating that the vaccine helps prevent the spread of tumors to other parts of the body.

The companies said this is the first time any mRNA-based cancer therapy has achieved positive results in a late-stage clinical trial. Boosted by the news, Moderna's stock price surged more than 100% in New York premarket trading. At the time of writing, it was up 80% premarket, with Merck’s share price rising about 7.2%.

Detailed data on the exact degree of improvement in recurrence-free survival (the length of time patients remain free from cancer recurrence) have not yet been disclosed. The trial is ongoing to assess whether vaccinated patients can achieve a longer overall survival period.

Melanoma is the most serious type of skin cancer. According to the American Cancer Society, about 112,000 people are diagnosed with melanoma each year in the U.S., and around 8,500 people die from the disease annually.

The companies said in their statement that they will discuss submitting a marketing application to regulators and will present related data at an upcoming medical conference. In an interview, Moderna CEO Stéphane Bancel said that, depending on the regulatory review, the product could be approved for market as early as 2027.

Bancel stated: "This is an extraordinary milestone for mRNA science."

The underlying science behind the vaccine (named intismeran autogene), co-developed by the two companies, has been over a decade in the making. The vaccine uses the same messenger RNA technology as Moderna’s COVID-19 vaccine and is personalized to match the unique tumor mutations of each patient.

In the trial, patients were given the mRNA vaccine in combination with Merck’s Keytruda after undergoing tumor-removal surgery. Patients in the control group received only Keytruda—a standard treatment used to prevent recurrence in high-risk patients.

The goal is for the two drugs to work together to train the immune system to attack any remaining cancer cells in the body.

Thanks to the cancer vaccine's prospects, Moderna's stock price has gained 113% from the start of the year through Tuesday's close. The melanoma trial is considered a key early test of the method’s efficacy. Merck and Moderna are conducting trials in other types of cancer (including lung cancer), but the melanoma studies are the most advanced.

Scientists have long pursued the idea that vaccines could enable the body’s own defense system to combat cancer by training the immune system to recognize the molecular fingerprint of tumors and destroy any lingering cells. However, until now, it has been extremely difficult to make such vaccines work.

Janet Healy, head of early oncology development at Merck, said in an interview weeks ahead of the data release: “Therapeutic vaccines have always been the ‘holy grail’ in the cancer field. People have been pursuing this in various ways for over a century.” She pointed out that one potential advantage of such vaccines is prolonging survival without significantly increasing side effects.

Earlier this year, the two companies reported that a mid-stage trial showed the risk of death or cancer recurrence five years after receiving the mRNA vaccine and Keytruda therapy for skin cancer was 49% lower compared to patients treated with Keytruda alone.