Moderna and Merck soar on stock market after announcing "positive results" of a melanoma vaccine
The companies assure that the drug "can reduce the risk of relapse or death", but they have not made the trial data public
BarcelonaAt 5:20 PM this Wednesday, the pharmaceutical companies Moderna and Merck saw their stock prices soar by 119% and 11.10%, respectively. The increase in share prices occurred after the two giants announced, in a joint press release, the achievement of "positive results" in the clinical trial of an experimental and pioneering therapy for melanoma, the most common skin cancer. Specifically, it is a vaccine (autogene intismere) that, in combination with an immunotherapy called Keytruda (pembrolizumab), is being evaluated as an adjuvant treatment to reduce the risk of melanoma recurring or spreading after tumor removal.
As soon as they reported this breakthrough, the shares of the American biotechnology laboratory Moderna soared. During the afternoon, the nearly 120% increase on the New York Stock Exchange led the shares to reach $139, compared to the $62.96 they marked at the last closing. The boost in the shares of the German pharmaceutical company Merck was slightly more moderate, marking an 11% increase on the American stock market, reaching $150.17 per share, up from the $135.17 recorded at the end of the previous trading day.
Both companies have made public that the phase 3 clinical trial has met its two primary endpoints – relapse-free survival and distant metastasis-free survival – and that the combination can reduce the risk of relapse or death in patients with high-risk cutaneous melanoma who have undergone complete tumor removal. The companies emphasize that the results "have the potential to establish a new treatment paradigm" in this cancer. However, this statement does not yet detail the specific figures for improvement in survival or relapse risk, and data previously published by the two pharmaceutical companies need to be reviewed.
Previous results
Intismeran autogene is an individualized experimental therapy based on messenger RNA –the same technology on which COVID vaccines are based– which is designed and produced from a sample of the patient's tumor. The objective is to identify its mutational profile and generate a specific immune response against cancer cells. The vaccine encodes up to 34 neoantigens and adapts to the unique biology of each patient's tumor to teach the immune system to recognize and attack tumor cells in case they reappear, according to its proponents.
In December 2022, Moderna and Merck announced that the combination of the vaccine, then named mRNA-4157/V940, with Keytruda –an immune checkpoint inhibitor– had reduced the risk of relapse or death by 44% in patients with melanoma. In 2024, the companies presented updated trial data at the American Society of Clinical Oncology (ASCO) showing a 49% reduction in the risk of relapse or death and a 62% reduction in the risk of distant metastasis or death compared to treatment with Keytruda alone. More recently, in June 2026, after five years of follow-up, data confirmed a 49% reduction in the risk of relapse or death and a 59% reduction in the risk of distant metastasis or death.
"For many years, the idea of creating an RNA treatment specifically designed for a person's cancer was difficult to imagine; now we are helping to turn this vision into a reality," said Moderna's CEO, Stéphane Bancel. The phase 3 clinical trial of this vaccine was conducted with 1,137 people with high-risk cutaneous melanoma, stages IIB to IV, after complete tumor removal.