The early data collected from a clinical trial at Washington University School of Medicine in St. Louis has found that a new personalized melanoma vaccine can help in marshalling a powerful immune response against unique mutations in tumors of patients.

The vaccines were given to three patients with advanced melanoma and they appeared to increase the number and diversity of cancer-fighting T cells responding to the tumors.

The research was published in Science Express, in a special issue devoted to cancer immunology and immunotherapy.

During the trial, the vaccines were given to melanoma patients who had had surgery to remove their tumors but whose cancer cells had spread to the lymph nodes.

The paper contains details of the data on the immune response seen in the first three patients.

"This proof-of-principle study shows that these custom-designed vaccines can elicit a very strong immune response," said senior author Gerald Linette, MD, PhD, a Washington University medical oncologist leading the clinical trial at Siteman Cancer Center and Barnes-Jewish Hospital. "The tumor antigens we inserted into the vaccines provoked a broad response among the immune system's killer T cells responsible for destroying tumors. Our results are preliminary, but we think the vaccines have therapeutic potential based on the breadth and remarkable diversity of the T-cell response."

The researchers, however, cautioned that it is too early to say whether the vaccines will be effective in the long term. The study was designed to evaluate safety and immune response and researchers noted that none of the patients has experienced adverse side effects.

"This is about as personalized as vaccines can get," said co-author Elaine Mardis, PhD, co-director of the McDonnell Genome Institute at Washington University, where the cancer genome sequencing, analysis and neoantigen prediction were performed. "The approach we describe is fundamentally different from conventional mutation discovery, which focuses on identifying mutated genes that drive cancer development. Instead, we're looking for a unique set of mutated proteins in a patient's tumor that would be most likely to be recognized by the immune system as foreign."