Personalized Vaccine and Immunotherapy Bring Bright News for Melanoma Patients

A hopeful advance in melanoma care is giving patients and researchers another reason to celebrate progress against cancer. A new study found that pairing a personalized cancer vaccine with an established immunotherapy drug reduced the risk of skin cancer returning or causing death by 49 percent five years after surgery.

The vaccine, called intismeran, was tested alongside pembrolizumab, the immunotherapy widely known as Keytruda. Together, the two treatments are designed to help the immune system recognize and attack cancer cells more effectively.

Researchers at NYU Langone Health’s Perlmutter Cancer Center led the phase 2b clinical trial, formally known as KEYNOTE-942. The findings were shared June 1 at the 2026 annual meeting of the American Society of Clinical Oncology in Chicago and published at the same time in the Journal of Clinical Oncology.

The results were encouraging. After five years, 68.8 percent of patients who received the combination therapy remained cancer free. Among patients who received pembrolizumab alone after surgery, 49.1 percent had no signs of cancer.

An NYU media release said: “This means that adding intismeran to pembrolizumab reduced the risk for recurrence or death by 49 percent. The combination therapy also reduced the risk of distant metastasis—the spread of cancer to another part of the body—by 59 percent.”

The survival numbers were also heartening. “Overall survival, meaning no death from cancer or any other cause, was 92.2 percent for the vaccine with immunotherapy group, while for the immunotherapy-alone group it was 71.3 percent.”

The trial included 107 melanoma patients who were randomly assigned to receive the vaccine plus pembrolizumab after their tumors were surgically removed. Their results were compared with those of 50 patients who received only pembrolizumab, which is already a standard treatment after melanoma surgery.

“Our study offers strong evidence to melanoma patients that intismeran vaccine therapy, when used in combination with immunotherapy, can demonstrably reduce their risk of having their cancer return and improve clinical outcomes,” said study senior investigator Janice Mehnert, MD, a professor in the Department of Medicine at NYU Grossman School of Medicine.

The promise of the approach lies in its personalization. Intismeran is made using information from each patient’s own tumor. Because all participants had undergone surgery, researchers were able to study their tumor cells and identify up to 34 neoantigens, abnormal proteins unique to each person’s melanoma. Those targets were then used to create a custom vaccine intended to train the immune system to recognize and respond to any remaining cancer cells.

The vaccine is based on messenger RNA, or mRNA, which gives cells instructions for making proteins. In cancer treatment, mRNA vaccines are designed to help immune cells distinguish cancer cells from healthy ones. In this study, the goal was to generate T cells that could recognize the melanoma-specific neoantigens and attack cancer cells if they tried to return or spread.

Pembrolizumab adds another layer of immune support. It belongs to a class of drugs called checkpoint inhibitors, which help prevent cancer cells from hiding from immune attack. These drugs block PD-1, a protein receptor that can act as a brake on T cells. By releasing that brake, pembrolizumab can make cancer cells more visible to the immune system.

This combination is especially meaningful because melanoma can be difficult to treat. While immunotherapies have transformed melanoma care, they do not work for every patient, and some tumors learn to resist them. Adding a personalized vaccine may offer a joyful step forward by giving the immune system more precise instructions.

“Our findings also serve as encouragement to cancer researchers globally that mRNA vaccines like intismeran could work well in combination with immunotherapy for other cancers whose high rates of mutations have proven difficult to target,” said Dr. Mehnert, director of the melanoma medical oncology program and a director of clinical research at Perlmutter Cancer Center.

More good news may be on the way. A phase 3 multicenter trial is already underway to see whether intismeran, combined with pembrolizumab, can help as a first-line melanoma therapy. Researchers are also studying whether the vaccine approach may help prevent recurrence in lung cancer and other cancers.

Patients in the KEYNOTE-942 trial were enrolled between 2019 and 2021 at cancer centers in Australia and the United States. Participants were men and women who had surgery to remove melanoma tumors. During follow-up, seven patients in each treatment group died, most from cancer. Reported side effects were considered manageable and included fatigue, chills, and pain at injection sites.

Skin cancer remains the most common cancer in the United States, with an estimated 112,000 new cases in 2026, including about 65,400 in men and 46,600 in women. Even so, melanoma deaths have fallen sharply over the past decade, thanks in large part to advances in treatment.

The study was funded by Moderna, the maker of intismeran, and Merck, the maker of pembrolizumab.