Two American pharmaceutical companies, Moderna and Merck, reported that a trial involving a potential Moderna mRNA vaccine paired with Merck’s Keytruda cancer treatment reduced the risk of melanoma recurrence or death by approximately 50%.

According to a statement from Moderna, released on Thursday, the study involved 157 individuals with advanced stage III/IV melanoma at high risk. After undergoing complete surgical removal of the melanoma, the participants were given either a combination of the vaccine and Keytruda or Keytruda alone for a period of one year.

After a period of around three years, scientists discovered that patients who were given a combination of drugs experienced a 49% decrease in the likelihood of their cancer returning or resulting in death, compared to those who only received Keytruda.

Patients who were treated with the combination also experienced a 62% decrease in the likelihood of the cancer metastasizing to other parts of the body.

The Moderna vaccine utilizes mRNA technology, similar to their COVID vaccine, to instruct the immune system to identify and combat certain changes in cancerous cells.

Merck’s Keytruda drug is an immunotherapy that also works in the body’s immune system by increasing its ability to help detect and fight tumor cells.

Merck has announced that the U.S. Food and Drug Administration has given Breakthrough Therapy designation for the drug combination as a result of the trial. This designation is meant to speed up the development of the treatment.

The European Medicines Agency has also given the treatment a comparable designation.

According to the U.S. Centers for Disease Control and Prevention, skin cancer is the predominant type of cancer in the United States, with melanoma being the most severe form.

According to the CDC, there were 77,230 newly diagnosed cases of melanoma in 2020 and 8,214 deaths from the disease.

Reuters contributed some data for this report.