Vaccine, virus, neutron beam
Science is changing the approach to cancer treatment
RIA Novosti, Nikolay Guryanov
Thanks to discoveries in various fields of science, cancer treatment is becoming more effective and safer. At the same time, Russia has its own promising developments. About the new weapon against malignant tumors — in the material of RIA Novosti.
Hit the mole
It is well known that the earlier an oncological disease is detected, the more effective therapy is and the longer a person will remain healthy.
"Both methods of early diagnosis and methods of treatment of manifest stages of cancer have seriously improved in 15-20 years. Of course, this is not the same as it was in the 1990s. Such a parallel movement is arranged differently in different parts of the world, and we must understand that access to medical care is not the same in the world, including to diagnostic systems, and even more so to therapeutic ones," says Igor Samoylenko, senior researcher at the Blokhin Institute of Oncology.
The tumor is difficult to kill — it is able to change and hide from treatment. It's like a child's game when a mole appears from different holes and has to be beaten with a sledgehammer. Thanks to the achievements of molecular biology, today there are ways to detect in advance the attempts of malignant formations to evade the blow. Medicine has learned to reliably predict tumor changes for such dangerous types of oncopathology as lung and colon cancer.
"First of all, this is a so-called liquid biopsy: microscopic changes are detected in blood plasma samples, indicating that the drug has stopped working. Although the patient's well—being remains the same and even instrumental studies — for example, tomography - show nothing. After that, you can choose a drug without waiting for the rapid progression of the disease," explains Samoylenko.
Even 20 years ago, hematologists learned how to use a liquid biopsy to establish molecular biological relapses for blood cancer. And now the same method will be used for solid tumors — that is, for those that have a tangible, visible manifestation.
Cancer vaccine
Any tumor, as a rule, develops from a normal cell and in the course of evolution gains additional damage, which doctors have recently learned to notice. These mutations are very individual for each individual. Having determined how exactly the cancer cells differ from the original one, you can act in two ways.
Firstly, to detect the return of the disease at an early stage. This is how several companies work, including the American Natera, which made the Signatera test for early diagnosis of tumor relapses. Samoylenko calls this an important step forward for the entire direction of liquid biopsy.
"There is a possibility that this will replace such heavy examinations as mammography or colonoscopy — a blood test will be enough instead. In Russia, a similar system is at the final stage of creation, which scientists from the Blokhin Institute and the Novosibirsk Institute of Molecular Biology are working on. These tests may change our practice in the near future," the specialist says.
The second way to dispose of information about how exactly the tumor differs from normal tissue is to make a specialized medicine: the so-called peptide vaccine.
"The most superficial story is when they take altered pieces of proteins that distinguish a tumor from a normal cell and isolate fragments that the immune system is able to recognize. Immune constructs such as chimeric antigenic receptors can be constructed. They activate T-cells against peptides that distinguish a tumor from healthy tissue in a particular Ivanov, Petrov, Sidorov," the expert explains.
Although intensive work is underway in this direction, so far the results have been different, including failures. But there is hope for success.
"Now there are no large phase III studies (preliminary to the registration of the drug — Ed.) that have demonstrated success, but small steps within the framework of phases I and II are being done for different localizations — for lung cancer, melanoma, colon cancer. There are signals that this may work well," says Samoylenko.
A life-saving virus
Cancer can be killed by a virus, because intracellular antiviral protection in the tumor works poorly or does not function at all. This discovery led to the creation of oncolytic viruses — both on the basis of natural and completely artificial. They infect only tumor cells, and ignore healthy ones. Some drugs are already certified for treatment. Similar developments were carried out in the USSR, but after its collapse, the production of the drug remained in Latvia, where a medicine called Rigvir was registered. In the United States and several European countries, a drug based on the Imlygic herpes virus produced by Amgen was allowed to be used. It is used in the treatment of malignant melanoma, skin cancer. There is also a similar drug in China — for the treatment of tumors of the oropharyngeal zone (head and neck), but it has no registration in other parts of the world.
"This is not a super effective remedy. But patients who have few other treatment options can sometimes be helped. The direction is developing quite rapidly. Today there are a dozen developments with viruses similar in meaning to the action. They are now in the second phase of the study and are even being launched in the third," says the oncologist.
Wake up the immune system
A big breakthrough has occurred in the field of molecular and immune biology: researchers have learned how to modify immune cells. This is a medicine that can be designed for any task. It has a fairly wide spectrum of action, unlike, for example, chemotherapy drugs.
"Today there is a large set of commercially available drugs for the treatment of hematological diseases based on chimeric antigenic receptors. In Russia, they are also individually provided to those in need of therapy. At the Rogachev Institute, they were made on the spot for their patients," the doctor explains.
"At the Blokhin Institute of Oncology, this technology for solid tumors is slowly approaching the final stage of testing — Professor Mikhail Kisilevsky is doing this here. We made CAR-T (a genetically modified immune T-cell, whose action is directed specifically against certain pathogens) against the her2 receptor, a therapeutic target for common types of malignancies. Preclinical studies have shown that it is safe, animal tests have had an effect. If everything goes well, then clinical trials are just around the corner," Samoylenko believes.
Nuclear reactions in you
Radiation therapy also does not stand still. "Advances in the field of radiobiology and engineering of radiation devices make it possible to bring a high dose of radiation to a pathological area — metastasis or tumor with surgical precision. This was not done twenty, maybe even ten years ago. Today, the devices are safe enough for healthy tissues and reliable," says Samoylenko.
New types of energy for cancer treatment are also gaining popularity. This is primarily about proton therapy. Its advantages are that it is devoid of toxicity and side effects that conventional radiation therapy can still give, the doctor notes.
The technique of boron-neutron capture therapy is being developed. The place to be irradiated is saturated with a special substance with a high content of boron atoms, after which a harmless neutron beam is passed through the human body. Where there is boron, tissue damage occurs due to nuclear reactions. Boron captures neutrons, holds them, and as a result, radiation occurs that damages the tumor at a very short distance of a few millimeters. According to the expert, for some localizations — for example, the neck and head areas — this is a very promising, reliable technique. It is most actively developed in Japan and Korea.
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