'Main approaches to COVID-19 treatment summarised'

And, of course, most of them are associated with the use of previously known drugs used in the treatment of other diseases," said Anastasia Shpichka, a co-author of the study from Sechenov University. Analogues of the molecule ACE2, which the virus uses to enter host tissue, may also bind to viral particles and 'distract' them from the patient's cells, the researchers noted.

Scientists have assessed currently known approaches to the treatment of novel coronavirus infection in a study that sheds light on the different groups of drugs used against COVID-19 across the world. The researchers, including those from Sechenov University in Russia, noted that most symptoms of COVID-19 such as fever, dry cough, increased fatigue, and loss of taste and smell, are associated with an overreaction of the patient's immune system, which, in severe cases, causes damage to lung tissue and systemic inflammation.

In the review research, published in the Journal of Molecular Medicine, they aid the immune system's antibody proteins contained in the serum of people who have had the viral disease can speed up the recovery of other patients. However, they said the method has several limitations, including that the number of potential donors of antibody-containing blood plasma is still small. According to the researchers, the activity of antibodies decreases over time, and the proteins may also help the virus spread in the body -- a phenomenon known as an antibody-dependent enhancement of infection. They mentioned that another component of the immune system, the T-lymphocyte cells which destroy damaged or infected cells of the body, may also be used. Citing previous research, the scientists said the number of T-cells of the CD8+ subpopulation is significantly reduced in patients with COVID-19, with the more severe the disease the lower this number. "T-cells directed against a specific virus can be produced in vitro and offered to patients as therapy," they noted in a statement.

Suppression of some molecules such as AAK1 and GAK, which are needed for the virus to enter a cell, has also been attempted, the scientists said, adding that some of these inhibiting drugs have already been tested and used for another purpose such as for the treatment of rheumatoid arthritis. "Analysis of clinical trials registered in ClinicalTrials.gov has shown a wide variety of therapeutic agents offered for the treatment of COVID-19. And, of course, most of them are associated with the use of previously known drugs used in the treatment of other diseases," said Anastasia Shpichka, a co-author of the study from Sechenov University.

Analogs of the molecule ACE2, which the virus uses to enter host tissue, may also bind to viral particles and 'distract' them from the patient's cells, the researchers noted. They said such ACE2 receptor analogs have already been developed, tested, and shown to slow down the spread of the virus in the body, but not stop it, indicating the presence of other entry points into human cells. With respect to antiviral drugs, the scientists said the results have been contradictory. According to the study, Remdesivir, which showed good efficacy against SARS-CoV-2 in some studies, did not bring noticeable benefits in others.

Attempts to use HIV medications against SARS-CoV-2 also yield mixed results, the scientists added. They said another area of research is the suppression of excessive immune system reaction, which especially affects the lung tissue. A treatment option involving the use of unspecialized cells in the body called mesenchymal stem cells, used in the treatment of inflammatory and autoimmune diseases, is currently being studied for its effectiveness against COVID-19, the scientists noted. They added that a class of drugs that limit inflammatory response called corticosteroids can reduce mortality among patients with severe disease.

"Despite the efforts of scientists from all over the world, aimed at finding an effective COVID-19 treatment, the optimal algorithm has not yet been found," the researchers said. They believe the key to creating a drug can be either a discovery as part of one of these approaches or a new solution at the intersection of scientific disciplines or borrowed from the experience of treating other diseases.