What You Need to Know about Cancer Immunotherapy
Efficiency, risks and price
Many promising cancer treatments have gone the distance at the stage of clinical trials. But immunotherapy has every chance of avoiding such a fate: its significance for medicine is already being compared with the discovery of antibiotics and chemotherapy. We tell you what you need to know about the most promising direction in oncology.
What is cancer immunotherapy?
Most cancer cells have tumor antigens on the surface – proteins or carbohydrates that can be detected and destroyed by the vigilant immune system. Immunotherapy activates the immune system, turning it into a formidable weapon against many types of cancer.
The greatest interest of scientists, doctors and investors is attracted by two types of immunotherapy:
- immune response checkpoint inhibitors that take the immune system off the brakes, allowing it to see and destroy cancer;
- CAR is a T-cell therapy that makes a more targeted attack on cancer cells.
Immune response checkpoint inhibitors block the ability of certain proteins to blunt or weaken the immune system's response to tumor antigens. In normal times, such proteins restrain the immune system from behaving too aggressively, preventing it from damaging the body. But cancer can intercept them, using them to suppress immune reactions (the tumor becomes "invisible" to the immune system).
For the treatment of malignant tumors (including melanoma, Hodgkin's lymphoma, lung cancer, kidney cancer and bladder cancer), 4 drugs that activate the immune system have already been approved: ipilimumab (Ipilimumab, MDX-010, MDX-101), pembrolizumab (Keytruda), nivolumab (Opdivo) and atezolizumab (Tecentric).
Jimmy Carter, the former US president, cured inoperable melanoma with pembrolizumab last year. In December 2015, the politician announced that all signs of cancer had disappeared.
CAR T Cell therapy uses T cells, a key part of the body's immune system, to treat cancer. They are extracted from the patient's blood, genetically modified in the laboratory, "targeting" a specific type of cancer, and injected back into the body. This procedure, available only in clinical trials, is currently used to treat leukemia and lymphoma. The U.S. Food and Drug Administration is likely to approve T-cell therapy in 2017 or 2018. When this technology will reach Ukrainian clinics is a rhetorical question.
Current problems of immunotherapy
Inhibitors of immune response control points cause tumor shrinkage and stabilization of the tumor process in an average of 20% of patients. Researchers do not yet understand why some cancers do not respond to treatment. For example, immunotherapy is effective for patients with melanoma, but useless for the treatment of pancreatic cancer.
It is believed that the key to improving the effectiveness of immunotherapy will be its combination with other treatments. Scientists want to combine checkpoint inhibitors with T-cell therapy, radiation and chemotherapy. But such a combination can increase the risk of side effects, dealing a crushing blow to healthy cells of the body.
The main disadvantages of cancer immunotherapy
By "rocking" the immune system, immunotherapy can cause serious damage to healthy tissues and organs. Researchers are working on ways to reduce its potential toxicity, but there is still a lot of work ahead.
Today, there are two types of risks associated with immunotherapy:
- Almost all patients experience flu-like symptoms after treatment, including fever, headache and muscle pain; some end up in the intensive care unit.
- Treatment can cause brain swelling and death.
Standard cancer treatments also have dangerous side effects. For example, chemotherapy and radiation therapy for the treatment of leukemia in children can cause secondary cancers, infertility and heart damage, but doctors often have to take risks to save lives.
Another significant drawback of immunotherapy is its high cost:
- an annual supply of Keytruda will cost the patient 150 thousand dollars a year;
- the cost of 40 ml of ipilirumab exceeds 29 thousand dollars;
- more than $ 2,500 will have to be spent on 100 mg of nivolumab.
So far, such sky–high figures do not inspire patients with optimism, but immunotherapy is a young direction in oncology, and the more new drugs appear on the global pharmaceutical market, the lower prices will fall.
Portal "Eternal youth" http://vechnayamolodost.ru 04.10.2016