Cancer is a group of diseases that hides less and less secrets from the scientific community. Although the trend in cancer treatment is to turn it into a chronic disease , the results of recent studies prove a new treatment route, through the mechanism of vaccination.
Two recent clinical trials have succeeded in preventing the reappearance and slowing the advance of tumors in people with cancer that have certain mutations , through vaccines designed to adapt to those mutations. Custom cancer vaccines have already been shown to elicit immune responses in humans, but both studies are the first to assess that these immune responses can successfully fight tumors. In addition, they suggest new forms of cancer treatment targeting the immune system, combined with immunotherapy.
How does a cancer vaccine work?
It works in a similar way to those used against infectious diseases: unique components of a foreign invader. Cancer cells , in this case, mix with agents that stimulate an immune response. The mixture is injected into the patient, hoping to unleash an immune attack strong enough to defeat the invader.
However, in cancer vaccines, the components are tailored to each patient and given after the cancer has already developed , rather than with the goal of preventing its occurrence. This personalized treatment strategy allows greater effectiveness, since each vaccine is adapted to the specific tumor mutations that each person possesses.
Pioneering studies on the effectiveness of anticancer vaccines
In the first study, led by Catherine Wu at the Dana-Farber Cancer Institute in Boston, Massachusetts, six people were treated with melanoma, a type of skin cancer. For each person, they formulated a vaccine that contained up to 20 protein fragments corresponding to the mutations in their tumors. The participants, who received surgery to remove their tumors, had been considered at high risk for cancer recurrence . Recurrence typically occurs in about half of all melanoma patients. However, two years later, four of those six patients had not seen their tumors return.
In the second group, led by Ugur Sahin from the University of Mainz in Germany, 13 patients with melanoma were treated. For this, vaccines containing RNA encoding up to 10 mutated proteins in each patient were used . The eight patients who had no visible tumors at the time of vaccination remained tumor-free more than a year later . Of the participants who had seen the tumors return, two of them experienced a remission. A third patient experienced a total remission of the tumor after immunotherapy treatment.
References:
An immunogenic personal neoantigen vaccine for patients with melanoma. DOI 10.1038 / nature22991.
Personalized RNA mutanome vaccines mobilize poly-specific therapeutic immunity against cancer. DOI 10.1038 / nature23003.
