June 7 (Reuters) - Patients who received an experimental messenger RNA vaccine from Moderna, along with Merck's Keytruda immunotherapy, after surgery for skin cancer had a lower risk of recurrence five years later than those who received the drug alone, researchers told the American Society of Clinical Oncology conference.

Researchers tested the vaccine (Entesmiran) in a mid-stage trial alongside (Keytruda) on 107 patients. Another 50 patients received only Keytruda, the world's best-selling prescription drug.

Entesmiran is a personalized immunotherapy that is prepared based on information derived from each patient's individual tumors and aims to stimulate an immune response to abnormal proteins, known as neoantigens, produced by cancer cells.

The study report, which was also published in the Journal of Clinical Oncology, showed that after five years there were no signs of cancer recurrence in 68.8 percent of patients who received the combination therapy, compared to 49.1 percent of those who received Keytruda alone, chemically known as pembrolizumab.

The overall survival rate was 92.2 percent among those who received the vaccine, compared to 71.3 percent among those who did not receive it.

The researchers noted that the combination therapy reduced the risk of disease recurrence by 49 percent and the risk of distant spread by 59 percent.

"Our study provides strong evidence for skin cancer patients that entesmiran vaccine treatment, when used in conjunction with immunotherapy, can substantially reduce the risk of cancer recurrence and improve their clinical outcomes," said study leader Dr. Janice Mehnert of the Grossman School of Medicine at New York University in a statement.