In the worldwide race to develop a treatment for the new coronavirus, there is much talk of repositioning drugs known to have other effects, and the effectiveness of which is being tested against SARS-CoV-2. This is the case of antivirals against HIV, the antimalarial chloroquine, but also favipiravir, usually prescribed for influenza in the countries of East Asia (China, Japan, etc.). On March 18, 2020, Chinese authorities, including Zhang Xinmin, director of the National Center for Biotechnology Development, announced that the latter drug would be effective against SARS-CoV-2. A clinical trial conducted with 320 patients, in Wuhan and Shenzhen, would have given good results.
In an article published on March 18, Lei Liu, of the University of Science and Technology of Shenzen, indicates that the patients who received favipiravir were cleared of the virus in four days (a median value), against eleven days. in the control group receiving lopinavir / ritonavir, two other antivirals whose repositioning against SARS-CoV-2 is being studied. Lung scans confirmed this positive development: after fourteen days, patients treated with favipiravir had significantly better recovery from the use of their lungs than patients in the control group.
Favipiravir is an organofluorinated pyrazine that is said to inhibit an enzyme in RNA viruses such as SARS-CoV-2, the so-called “RNA-dependent” RNA polymerase, which is involved in the duplication of RNA in the virus. However, it would have no effect on the RNA polymerases of our own cells (which work differently), which explains the few side effects encountered in different tests, except in pregnant women, because the compound would be teratogenic. In fact, favipiravir was successfully tested in mice against the Ebola virus in 2014. A French nurse from Doctors Without Borders is said to have cured hemorrhagic fever thanks to this molecule … but trials in humans have not not been conclusive.
The results obtained on SARS-CoV-2 have decided several countries and institutions to include favipiravir in the list of potential drugs to be tested on a large scale. This is the case of Italy, where the Italian Agency has authorized tests in hospitals in the three regions most affected, Lombardy, Veneto and Emilia-Romagna, while recalling that there is no today only very preliminary results.
The World Health Organization is also considering adding favipiravir to the list of molecules tested in Solidarity, a very large-scale trial in which ten countries (Argentina, Iran, South Africa, etc.) would participate, and would cover several thousand patients, alongside remdesivir, chloroquine (and hydroxychloroquine), the combination of lopinavir / ritonavir alone or with interferon beta. Solidarity is the global version of the Discovery test, carried out by Inserm on a European scale (France, Belgium, Germany, Netherlands, Luxembourg, etc.). We cannot stress this enough, it will take time to develop a vaccine, at least a year at best. In the meantime, to limit the spread of Covid-19, respect for barrier gestures is essential.