Genetically modified viruses against cancer
Smallpox virus has prolonged the life of cancer patients
A weakened and genetically modified cowpox virus – an oncolytic viral vaccine called Pexa-Vec or JX-594 was received by 30 patients with progressive hepatocellular carcinoma. The JX-594 virus comes from a vaccine strain of the virus that has been widely used as a live smallpox vaccine. The genetic engineering transformations of this virus have led to the fact that it has become capable of killing cancer cells in three different ways. Firstly, it exposes them to lysis – as a result of intracellular reproduction of viral particles, the cell wall is destroyed, secondly, the virus affects the blood vessels that feed the tumor, and finally, the virus stimulates the immune response of the body due to the fact that it received the gene of the cytokine immunostimulator GM-CSF, which acts as a leukocyte growth factor.
16 patients who received a high dose of oncolytic viral vaccine lived an average of 14.1 months, while 14 patients who received a low dose of the same viral drug lived an average of 6.7 months.
The test results are presented in the journal Nature Medicine (Heo et al., Randomized dose-finding clinical trial of oncolytic immunotherapeutic vaccinia JX-594 in liver cancer l).
In patients with a progressive liver tumor, hepatocellular carcinoma, there was a reduction in the size of the malignant formation, as well as a decrease in the blood supply to the tumor, regardless of whether they received a high or low dose of the drug.
Regardless of the dose, the side effects of treatment were also moderate: all participants in the trials had cold symptoms for one or two days, and only one patient had severe nausea and vomiting.
The results obtained require confirmation in a larger trial, but experts from the British charity supporting research in the field of oncology, Cancer Research UK, note that "an encouraging step forward has already been made."
According to one of the authors of the study, Alan Melcher from the University of Leeds, now "it has been possible to show the potential of viruses in the fight against cancer, and that viral therapy has minor side effects compared to traditional methods of treating cancer, such as chemo and radiation therapy. If the use of oncolytic viral drugs proves effective in the future, in broader trials, they will become available to patients within five years," the scientist believes.
Melcher's co-author, David Kirn, a researcher at Jennerex Biotherapeutics in San Francisco, emphasizes that the presented results represent "the first case in the history of medicine when a genetically modified virus improved the quality of life of cancer patients."
Portal "Eternal youth" http://vechnayamolodost.ru12.02.2013