Against cancer and AIDS
Cancer drug cures HIV, doctors found
The medicine that doctors used to treat an HIV-infected patient for lung cancer caused a sharp decrease in the number of cells infected with the virus, according to French doctors in a report published in the journal Annals of Oncology (Guihot et al., Drastic decline of the HIV reservoir in a patient treated with nivolumab for lung cancer).
Doctors of the oncology department of the Piti-Salpetriere Hospital in Paris (France) observe a 51-year-old patient who was recognized as HIV-positive in 1995. He was diagnosed with lung cancer in May 2015. The patient underwent surgery and chemotherapy, but less than six months later he relapsed. He was treated with a new generation drug – nivolumab (nivolumab). Since December 2016, the patient has been injected with medication every day. In total, he received 31 injections.
At the beginning of treatment, HIV was not detected in blood samples. Then, within 45 days, the number of cells with HIV increased. At the same time, the activity of T cells - cells of the immune system – increased, CD8 T cells were especially noticeably activated, which indicated the body's response to HIV. According to the authors of the article, on the 120th day of treatment, the source of HIV-infected cells showed a "sharp and constant reduction".
A carrier of HIV infection does not always get sick immediately. Suppressed by the immune system, the virus in a dormant state hides in the cells of the brain and bone marrow, in the genital tract. Neither antiviral therapy nor the weakened immune system of the patient can remove it from there. That's why if you stop taking drugs against HIV, it will begin to multiply and infect other cells. Scientists have been looking for ways to purify these reservoirs of HIV-infected cells for a long time. But so far without much success.
HIV first attacks the cells of the immune system – CD4 T-lymphocytes. Under the pressure of infection, they die en masse, not allowing the immune system to fight the disease. Actually, that's why it is called immunodeficiency syndrome, or AIDS. In the reservoir, infected CD4 T cells sleep and HIV is not produced. They are prevented from waking up by special molecules, the so–called immune control points - "killers" of T cells. Some of them – PD-1 program cells for early death. Scientists have long been looking for drugs that could activate these dormant infected cells and thus expose them to the attacks of the immune system. If successful, HIV-infected people could be completely cured.
"It is well known in oncology that drugs that block immune checkpoints, such as PD-1, effectively restore immune defenses to resist cancer. It was also believed, but it has not yet been experimentally shown that these same blockers can also awaken HIV-infected cells, which means that they raise immunity against them," he said the head of the study, the head of the oncology department, Professor Jean-Philippe Spano (Jean-Philippe Spano).
Now scientists have shown for the first time that this hypothetical mechanism works on humans. "The treatment can be applied to HIV patients regardless of whether they have cancer, since the drug works on both HIV reservoirs and tumor cells," says Spano.
Despite the absence of side effects, the authors of the work warn that this is the only positive case of cure so far. The previous similar experience was unsuccessful. Scientists have yet to evaluate the results of their clinical studies, as well as trials on 50 French patients. We need to understand how toxic the drug is for people. In addition, if you identify markers that show whether the patient's immune system will respond to the drug, then treatment can be personalized.
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