A phase II clinical trial for a skin cancer vaccine has delivered very promising results.

Developed by Moderna, the vaccine is designed to work alongside another immunotherapy treatment called KEYTRUDA, which also helps the body fight cancer.

KEYTRUDA is owned by Merck (also known as MSD), and the ongoing clinical trial is a collaboration between both pharmaceutical companies to treat patients who have had high-risk melanoma cut out of their skin.

Compared to KEYTRUDA on its own, initial data shows that both medicines in combination reduce the risk of recurrence or death in the next three years by 49 percent.

Meanwhile, the risk of the cancer spreading or turning fatal was reduced by 62 percent compared to KEYTRUDA on its own.

Kyle Holen, Moderna's senior vice president, says in a recent press release he is very excited to see "such a robust clinical benefit".

It is the first therapy to show a significant benefit over KEYTRUDA on its own.

"We are committed to driving research forward for innovative modalities in earlier stages of cancer, where we can make the most meaningful impact for patients, by combining Merck's expertise in immuno-oncology with Moderna's innovative mRNA technology," says Marjorie Green, senior vice president at Merck Research Laboratories.

Moderna's technology is what underpins the company's COVID-19 vaccine. Messenger RNA (mRNA) can enter cells easily and provide instructions for certain proteins that help fight against pathogens.

Scientists at Moderna explain that they are now using this concept to "harness the body's immune system to identify and kill cancer cells in the same way the immune system identifies and targets infections."

The mRNA vaccine designed for stage III and stage IV melanoma is called mRNA-4157 (or V940). It consists of a synthetic mRNA code that holds the key to producing up to 34 antigens, which train and activate a patient's antitumor immune response.

KEYTRUDA, meanwhile, works by boosting the immune system's ability to detect and fight tumor cells.

A phase IIb clinical trial on both medicines enrolled 157 patients who had their high-risk melanoma surgically removed. Patients were given either the combined treatment or KEYTRUDA on its own once every three weeks for roughly a year.

Side effects of the combined treatment were not too different from KEYTRUDA on its own. The most common symptoms, which impacted roughly 50 percent of patients, included fatigue, injection site pain, and chills.

The combined treatment has proved so effective, the US Food and Drug Administration and the European Medicines Agency have both agreed to fast-track the medicine for future approval. The timeline of that approval is unclear, but scientists are already going ahead with a phase III clinical trial. It should produce results by 2029.

Moderna isn't the only company working on specialized mRNA vaccines for cancer. Pfizer has similar goals, and BioNTech has recently made headlines for its development of a personalized mRNA vaccine for pancreatic cancer.

To date, the US FDA has only approved one anti-cancer vaccine for prostate cancer, and it achieves only minimal survival benefits.

The future of this technology remains uncertain yet hopeful.