Personalized skin cancer vaccine shows promise in new trial results

The future of cancer treatment may involve personalized vaccines designed to manage or even prevent relapses – at least if new research published Thursday continues to unfold. In a small clinical trial, high-risk melanoma patients receiving such a vaccine were able to create a lasting immune response to their cancer, scientists said. They also remained alive four years after the initial treatment, most of which were actively disease-free.

Cancer vaccines have been a much sought after goal by scientists for decades. There are two vaccines that can protect against viral diseases known to increase the risk of certain cancers, HPV and hepatitis B. But developing a widely effective vaccine that can directly prevent the onset of cancer has been a task. more difficult, due to the very nature of cancer. On the one hand, cancer cells are mutated versions of cells found in our body, so our immune system cannot recognize them as an enemy as easily as a virus. And since each cancer is unique to each person, it’s not that easy to create a vaccine that works for everyone.

In recent years, however, progress has been made in developing cancer vaccines at a more personalized level. Researchers have found that tumors carry proteins to the surface of their cells that are not found on normal cells and can make them different from our immune system. These proteins are called neoantigens. By creating vaccines that train the immune system to better recognize these neoantigens, scientists theorize, we can give our bodies a better chance at fighting a familiar cancer.

Scientists at the Dana Farber Cancer Institute in Massachusetts and elsewhere worked on one of these vaccines (called NeoVax) for melanoma skin cancer as well as glioblastoma, the most common form of brain cancer and the one that is very difficult to deal with. While their work has shown that the vaccine is well tolerated and appears to create an immune response in patients, only short-term results are available so far. Their new paper, published in Nature Medicine, suggests that their vaccine also works in the long term.

“These neo-antigens are the result of mutations found in a specific tumor – it’s something that is created on an individual level. Our vaccines must therefore be tailored to a patient’s cancer, ”said study author Patrick Ott by telephone. “But what’s new is that by using genomics and sequencing, we were able to identify these mutations much faster and more cost-effectively than before.”

They administered NeoVax to eight patients considered to be at high risk for future, possibly fatal, recurrence of advanced melanoma. Then, they followed their health over the next four years, periodically taking blood samples to study the body’s immune response to cancer, especially tumor-specific T cells.

The vaccine was given to patients about 18 weeks after surgery to remove the tumor. Ott and his team found that the volunteers continued to carry T cells specific to the neo-antigens their vaccine had taught the immune system to remember. In some people, they also saw T cells that recognized other neo-antigens specific to their tumor. This is an indication that their immune system is adapting to any persistent tumor cells in the body creating even more weapons against them. All eight patients were still alive after almost four years, with six appearing to have no disease on the last recording.

Right now, it takes at best three months from a person’s diagnosis for scientists like Ott to create a personalized vaccine. But it is possible that one day these vaccines could be created in a much shorter time, after a simple visit to the doctor. And while they may not be the ‘universal’ cancer vaccine we all hope for, Ott sees no reason why these vaccines could not possibly be made to help prevent relapse of all types of cancer. .

The vaccines can probably be combined with other treatments. Two study patients with cancer that had spread elsewhere received immune checkpoint inhibitors, drugs that allow the immune system to better target tumor cells. In these patients, the group found evidence that tumor-specific T cells had found their way to the metastasized tumors.

In the future, Ott and his team hope to refine their vaccine technology to create even more potent immune responses that, combined with drugs like immune checkpoint inhibitors, can manage advanced cancer cases. They are also now testing their vaccine with other cancers, while continuing to monitor their existing patients.