0729 GMT April 23, 2021
The vaccine, called NeoVax, works by targeting specific proteins on an individual patient's tumor cells, the researchers said, UPI reported.
Nearly four years after vaccination, patients' immune system cells were active against tumor cells with those distinctive proteins, as well other proteins found in their tumor cells, the data showed.
The findings demonstrate the lasting immunity generated by the vaccine, which spurs the body's immune system to keep cancer cells from growing, the researchers said.
"These findings demonstrate that a personal ... vaccine can stimulate a durable immune response in patients with melanoma," study coauthor Dr. Catherine J. Wu said in a press release.
"We found evidence that the initial, targeted immune response has broadened over the years to provide patients with continued protection from the disease," said Wu, an oncologist at the Dana-Farber Cancer Institute in Boston.
More than 100,000 people in the United States are diagnosed with melanoma annually, according to the American Cancer Society.
Unlike vaccines against viruses such as the flu or even COVID-19, melanoma vaccines don't prevent the disease, Wu and her colleagues said.
Instead, they prevent the disease from returning in those considered at high risk for recurrence after surgery, they said.
Although such vaccines have been in development for decades, NeoVax is a relatively new option created by researchers at Dana-Farber.
It's currently being evaluated in clinical trials for use in patients with melanoma, as well as other cancers, including kidney cancer, according to the institute.
For this study, Wu and her colleagues evaluated the vaccine in eight patients who had undergone surgery for advanced melanoma and were considered at high risk for recurrence.
All eight patients were treated with NeoVax roughly four months after surgery.
Each dose of the vaccine is made using a sequence of DNA from the patient's tumor, which is then used to generate immune system response against any melanoma cell that displays certain proteins, according to the researchers.
Roughly four years after NeoVax treatment, all eight patients were alive, with six showing no signs of active disease, the researchers said.
"We found evidence of everything we look for in a trong, sustained immune response," said study coauthor Dr. Patrick A. Ott.
"[These findings are] a strong indication that personal neoantigen peptide vaccines can help control metastatic tumors, particularly when combined with immune checkpoint inhibition," said Ott, a medical oncologist at Dana-Farber.