The announcement by Moderna and Merck (MSD) of a therapeutic vaccine to prevent metastasis of melanoma, the most aggressive skin cancer, came as a surprise on Wednesday and sent shares of these pharmaceutical giants soaring. In a joint statement, the companies claimed to have obtained "positive results" in the phase 3 trial – the stage at which efficacy and safety are reviewed in patients before applying for marketing authorization. In the statement, they claimed to have achieved relapse-free survival and distant metastasis-free survival – to other organs or lymph nodes – in patients who had already undergone complete tumor removal. However, they did not provide any specific data on the vaccine. Nor is there, at the moment, an associated scientific publication.

At 5:20 PM this Wednesday, pharmaceutical companies Moderna and Merck (MSD) saw their stock prices soar by 119% and 11.10%, respectively. The increase in share price 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 intismetan) 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.