Does this vaccine prevent cancer?
Vaccines against measles, diphtheria, COVID-19 and other infections are given to healthy people to prevent disease. Cancer vaccines work in a different way. They are administered to people who have already contracted cancer in order to strengthen the fight of their immunity against the tumor. This vaccination is a form of immunotherapy. The cancer vaccine teaches T cells of the immune system to better recognize cancer cells and attack them to prevent them from spreading throughout the body. The new vaccine helps T cells recognize certain proteins in melanoma, the most dangerous skin tumor.
The vaccine is made individually. Doctors take cells from a patient’s surgically removed tumor. The study of the RNA of these cells provides information about which unique proteins (neoantigens) recognized for the immune system are synthesized by this cell. The vaccine contains these individual neoantigens, to which an immune response must be generated.
The new study involved eight patients who underwent surgery for advanced melanoma (that is, at least in local lymph nodes). Each of them received the vaccination approximately four months after the operation. The side effects of the injection were mild – weakness and flu-like symptoms. During the study, the scientist took blood from study participants to analyze the immune response to the tumor.
By the end of the fourth year, all participants were alive, six of them showed no signs of active illness. Two had cancer recurrence, lung metastases – they received additional treatment.
“We found evidence of what we had hoped for, a sustained immune response. T cells continued to attack melanoma cells and retained memory for the proteins they initially responded to, ”said Patrick Ott of Harvard Medical School, co-author of the study.
Tests showed that the patients’ T cells not only retained their memory, but also “expanded” it. By the end of the study, they were responding to more tumor proteins than the vaccine had taught them at the start of the study.
This study had certain limitations, such as small size and no control group. “The data presented in this study is very interesting, but applied to the relatively small number of patients whose tumors were completely removed by surgery,” says Pawel Kalinski of the Rose Park Cancer Center in Buffalo. He pointed out that future studies will need to include a control group whose participants will only undergo surgery. In addition, in his opinion, what kind of T-cell reactions ensure long-term remission of the disease.