One reason why cancer is so harmful is that it can trick "checkpoint" proteins found on the immune system's T cells, virtually putting the T cells to sleep. New drugs are finding a way to wake up the T cells and harness them to fight cancer, according to an article in Science News (https://www.sciencenews.org/article/new-cancer-drugs-wake-sleeping-killer-t-cells).
T cells are white blood cells that are important to the immune system and are conducive to adaptive immunity, the system that helps to control the body's immune response to specific pathogens. T cells are "like soldiers who search out and destroy the targeted invaders," explains MedicineNet. The article goes on to say, "Immature T cells, known as T-stem cells, migrate to the thymus gland in the neck, where they mature and differentiate into various types of mature T cells and become active in the immune system in response to a hormone called thymosin and other factors. T-cells that are potentially activated against the body's own tissues are normally killed or changed ("down-regulated") during this maturational process. There are several different types of mature T cells. Not all of their functions are known. T cells can produce substances called cytokines such as the interleukins which further stimulate the immune response. T-cell activation is measured as a way to assess the health of patients with HIV/AIDS and less frequently in other disorders. T cell are also known as T lymphocytes. The "T" stands for "thymus" -- the organ in which these cells mature, as opposed to B cells which mature in the bone marrow" (http://www.medicinenet.com/script/main/art.asp?articlekey=11300).
Clinical trials in 2014 offered hope for checkpoint drugs in patients who were using them as a last resort against melanoma and cancers of the kidney, bladder and lung, and new studies have demonstrated promising results against those and other cancers, according to the Science News article. Some trials are combining two "checkpoint stoppers" with good results. In one study, Postow and his team an international team gave either ipilimumab or nivolumab, or both, to people with inoperable melanoma that had spread to areas beyond the skin. Nearly 58 percent of the patients getting both drugs showed tumor shrinkage of 30 percent or more. Almost 44 percent of the patients getting just nivolumab saw a reduction in their tumors, as did 19 percent of people getting only ipilimumab, the researchers said at the American Society for Clinical Oncology (ASCO) meeting in Chicago and in the New England Journal of Medicine.
Three other studies also look promising. In a group of patients with especially hard-to-treat melanoma, 44 of 72 who got the two checkpoint drugs had a good response compared with just four out of 37 getting ipilimumab alone, researchers said at a meeting of the American Association of Cancer Research in Philadelphia. In patients who had relapsed or unresponsive Hodgkin's lymphoma, 11 out of 23 demonstrated improvement after 24 weeks on nivolumab and could stay on the drug. In 272 lung cancer patients who had a poor prognosis, nivolumab itself showed better results than the standard chemotherapy drug docetaxel; after one year, 42 percent of the patients on the checkpoint drug were still alive, as opposed to 24 percent of patients on the chemo drug. These results, which were presented at the ASCO meeting, are "pretty unheard of," according to study coauthor Julie Brahmer, an oncologist at Johns Hopkins University in Baltimore. All of the studies were published in the New England Journal of Medicine.