The pharmaceutical companies Moderna and MSD (known as Merck in the US and Canada) announced on Wednesday that their experimental treatment based on messenger RNA (mRNA) technology against advanced melanoma has shown promising results in a phase III trial, the final stage of research before reaching patients.
Through a press release, instead of a scientific publication as usual, the pharmaceutical giants have revealed the success of the therapy, although without providing details on the positive results of the trial.
According to their data, the personalized treatment, called intismeran autogene, was administered in combination with pembrolizumab (Keytruda), MSD's flagship immunotherapy, to patients with advanced melanoma who had previously undergone surgery. According to both companies in a joint statement, the combination showed a statistically significant improvement in relapse-free survival compared to patients who only received immunotherapy. Specific data on the extent of the survival increase is not provided.
All the information, as the companies announced in their statement, "will be presented at an upcoming international medical meeting and shared with regulatory authorities." The announcement has already boosted the companies' stocks on Wall Street, with a 130% increase for Moderna and 10% for Merck (MSD in the US and Canada), as reported by Efe.
In June, the results of a phase IIb trial, presented at the annual meeting of the American Society of Clinical Oncology (ASCO 2026) and simultaneously published in the Journal of Clinical Oncology, showed that the treatment is effective in reducing the risk of recurrence and death from this type of skin cancer by 49% compared to treatment with pembrolizumab alone.
According to the study results, the combined therapy reduced the risk of developing distant metastases by 59%. Regarding overall survival, defined as the absence of death from any cause, it reached 92.2% in the group that received the vaccine along with immunotherapy, compared to 71.3% among patients treated only with immunotherapy.
A "tailored" tumor therapy
Without the usual peer review that should accompany any scientific advancement, this would be the first time that a cancer-fighting treatment of this kind has successfully completed a phase 3 trial.
Although it is called a vaccine, this type of therapy does not aim to prevent the disease but is designed for the patient's immune system to recognize and destroy malignant cells of an already developed tumor. The technology it is based on, messenger RNA, is the same as that used to develop the first Covid vaccines.
Unlike other vaccines, this treatment is personalized. Thus, the therapy is tailored by analyzing the specific genetic mutations of each individual's tumor. This way, the body's defenses learn to precisely recognize the biological signature of their own cancer cells to attack them.
"For many years, the idea of creating an mRNA treatment specifically designed for a person's cancer was hard to imagine. Today, we are helping to turn that vision into reality," highlighted Stéphane Bancel, CEO of Moderna, in a statement.
The Phase 3 study —the decisive clinical stage before applying for commercial approval— was conducted on a sample of over 1,100 patients. Following the positive results obtained, both pharmaceutical companies plan to present the complete scientific evidence at an upcoming medical congress and initiate formal procedures with drug regulatory agencies to request authorization and distribution.
Melanoma is one of the most aggressive and deadly variants of skin cancer. Global estimates indicate that in 2022, over 330,000 new cases were diagnosed worldwide, a trend that has been on the rise in recent years.
According to Marisol Soengas, head of the Melanoma Group at the National Center for Oncological Research, "the news is important," although she points out that "the results are not presented because there is no scientific publication," as she stated to SMC Spain.
In the scientist's opinion, the announcement is mainly interesting due to the mRNA technology. "Until now, there was no way to recognize 34 specific protein alterations in a patient, and they have combined it with this immunomodulator. The idea is to get the immune system to attack these tumor cells as much as possible."
However, she warns, "first, we have to see the final results. And what may be concerning is how generalizable it will be because this is patient-specific; and also the cost for healthcare systems, if such a personalized treatment is affordable. Perhaps in the future, common alterations may be found, but at this moment, it is personalized."
Ultimately, she concludes, the data presented "are very promising expectations, with caution, from a technologically very complex trial."