In 2018, the Nobel Prize in medicine was awarded for the discoveries in the field of cancer immunotherapy. The immunotherapy drugs "train" the patient’s immune system to recognize and destroy cancer cells. At the same time, the healthy tissues of the body are not exposed to an immune attack, which makes the treatment sparing and minimizes the side effects that are typical for an anticancer therapy.
Immunotherapy affects different components of the immune system. This is determined by the physiology of the tumor and its molecular characteristics. In addition to active cancer treatment, immunotherapy techniques include prophylactic vaccination against HPV (a risk factor for cancer of the genitals, anal area and throat), hepatitis B (a risk factor for liver cancer) and prostate cancer.
Immune checkpoint inhibitors
To distinguish healthy cells from atypical ones, the immune system uses "checkpoints". These are specific molecules on the surface of the immune cells whose activation or inactivation triggers an immune response. The mutating cancerous tumors are able to act on the "checkpoints" and elude the patient’s immunity. The preparations of immune checkpoint inhibitors restore this mechanism.
The clinical practice involves the use of drugs which targetedly impact PD-1 or PD-L1. PD-1 is a protein located on the surface of T-cells (T-killers). PD-L1 is located on the surface of normal cells. When a killer T-cell sees the PD-L1 protein on the surface of another cell, it automatically considers such a cell to be healthy. However, some tumors actively synthesize PD-L1, and thus mask themselves from killer T-cells. Pembrolizumab (Keitruda), nivolumab (Opdivo) and atesolizumab (Tecentric) drugs block PD-1 or PD-L1, thereby making the tumor visible to killer T-cells.
Immune checkpoint inhibitors can be used in non-small cell lung cancer, kidney and bladder cancer, head and neck cancer, melanoma and Hodgkin’s lymphoma. Their role in the treatment of chronic myelogenous leukemia and other hematological pathologies is also being studied.
Antibodies are protein molecules that recognize antigens that enter the body and reliably connect with them. The antigen-antibody complex becomes visible to immune killer cells and is attacked. The research has discovered antigens that can be found exclusively on cancer cells. They are specific to each type of cancer. This allows antibodies to target the tumor specifically.
The monoclonal antibodies can show the pronounced antitumor activity in the following diseases:
- Brain cancer
- Breast and ovarian cancer
- Chronic lymphoblastic leukemia
- Colorectal tumors
- Stomach cancer
- Hodgkin's lymphoma and non-Hodgkin's lymphoma
- Lung cancer
- Prostate cancer
In modern oncology, including immunotherapy for chronic leukemia in children, several types of monoclonal antibodies can be used. These are alemtuzumab (Campath), trastuzumab (Herceptin), blinatumomab (Blincyto) and others.
In addition to the conventional monoclonal antibodies, doctors can also use conjugated ones. They include an additional component – a radionuclide or a molecule of a chemotherapy drug. Due to this, cancer cells are not only exposed to an immune attack, but are also destroyed due to radioactive irradiation or exposure to a chemotherapy agent.
CAR T-cell therapy
The immune system stores the memory of all antigens normally found in the human body. When a new antigen enters the body, the immune system recognizes it, attacks and "remembers" it. If such an antigen enters the body again, it will be met by trained, specific cells of the immune system.
CAR T-cells are a genetically modified type of white blood cells that can recognize cancer antigens and targetedly destroy tumor cells in a particular patient. This is possible due to the attachment to a T-cell of a specific chimeric receptor (chimeric antigen receptor or CAR) created in the laboratory conditions.
The creation of T-leukocytes with CAR takes place in high-tech laboratories and includes several stages:
- Leukapheresis, which involves the patient’s blood filtering and obtaining white blood cells
- Isolation of T-cells from the total leukocyte mass
- Stimulation of T-cell growth and reproduction
- Introduction into the T-cells of the gene responsible for the synthesis of the chimeric receptor
- CAR T-cells infusion to patient
Given the complexity of creating chimeric receptors, CAR T-cell therapy is currently used exclusively in patients with acute lymphoblastic leukemia and large B-cell lymphomas.
Immunotherapy in the world's leading clinics with Booking Health
Over the past year, the FDA has approved the use of more than 10 drugs for immunotherapy and targeted therapy. Before using innovative drugs in a particular country, they undergo a legalization procedure at the local level. Unfortunately, this process can take from several months to several years. The patients who want to start immunotherapy according to new protocols immediately often need to travel abroad, to countries with more developed medical systems.
The patients can be treated in foreign clinics with services of Booking Health, a certified international medical tourism operator. The Booking Health specialists help with the following important issues:
- Selection of the right clinic based on the annual qualification profile
- Direct communication with the attending physician
- Preparation of a preliminary treatment program without repeating previous tests
- Provision of the favorable cost of medical services, without overpricing for foreigners (saving up to 50%)
- Making an appointment with a doctor
- Monitoring of the implementation of a medical program at all its stages
- Insurance against the cost of treatment increase in case of complications (а coverage of 200,000 EUR, valid for 4 years)
- Assistance in buying and forwarding medicines
- Communication with the clinic after a treatment completion, receiving and translating medical records
- Control of invoices and return of unspent funds
- Organization of additional diagnostic tests and consultations
- Top-class services: interpreting services, booking hotels, airline tickets, transfer
Choose treatment abroad and you will for sure get the best results!
Author: Dr. Nadezhda Ivanisova