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The discovery of the drug nitazoxanide, touted as “effective” against the coronavirus by metior (Ministry of Science, Technology and Innovations) in an announcement this Monday (19), without disclosure of the study data, involved a large national research center and a search for “needle in a haystack” to find a treatment for disease .
It is not yet clear how effective treatment with the dewormer is – Dr. Patricia Rocco, head of the Pulmonary Research Laboratory of the IBCCF (Instituto de Biophísica Carlos Chagas Filho) of the UFRJ (Federal University of Rio de Janeiro), participated in the interview later led the drug tests and spoke of “decreased viral load.”
“Nitazoxanide, compared to the group that took the placebo, generated a significant reduction in viral load, with a greater number of patients testing negative for Sars-Cov-2. The reduction in viral load alone already generates a lower transmissibility of the virus I cannot give more details, because the study was sent to an international journal ”, he pointed out.
Rocco explained that the prior disclosure of effectiveness, without opening data, was produced by the emergency caused by the pandemic. It is not clear, for example, whether the drug is in fact “effective” only in the early stages and in mild cases of the disease or also in more severe cases with hospitalizations. So far, no percentages or data have been published on the drug’s supposed effectiveness.
The search for a remedy against the disease is the main short-term solution to the pandemic, before the vaccine arrives. No treatment has been shown to be completely effective.
According to Minister Marcos Pontes, the drug should not be taken as a form of prevention, but only after the presence of the virus in the body has been verified. The minister himself says that he was one of the volunteers in the test, since he was infected with the coronavirus. Studies with the drug will continue, but now at the Ministry of Health.
The search for medicine
It all started in January, long before the first official case of coronavirus in Brazil. At that time, researchers from the Cnpem (National Center for Investigations in Energies and Materials), in Campinas (SP), began to look for drugs that were already on the market and that could act against the covid, the technique is called “drug repositioning “. “.
Less than two months after the start of the trials, which involved more than 2,000 treatment candidates, five options remained, considered the most promising.
The Cnpem, where the initial research was conducted and the drug was selected, is an independent research center, but supervised by the MCTI. It has national laboratories for nanotechnology, biosciences, bio-renewables and synchrotron light, the latter being responsible for Sirius, one of the most advanced particle accelerators in the world.
Use a computer to understand interactions
Of the 2,000 initial medications, pain relievers, antihypertensives, antibiotics and diuretics, among others, the number dropped to 16 after computer analysis. Then it was narrowed down to five more promising, cheaper and available drugs in the Brazilian market.
The intention was to see if any of the thousands of selected drugs could interact with protease. [um tipo de enzima] of the coronavirus to prevent its replication in the human body.
In this phase of the research, computer simulations and analyzes with artificial intelligence were performed to understand which drugs could inhibit the enzyme and function as an antiviral.
“This adjustment doesn’t happen easily. It’s like looking for a key [medicamento] on a keychain full of them [muitos compostos]. This key must fit snugly into the virus lock [locais específicos das proteínas dos vírus capazes de bloquear sua atividade]”he said at the time to Inclination Daniela Trivella, scientific coordinator of LNBio (National Laboratory of Biosciences) of Cnpem.
“These specific regions of viral proteins are important for carrying out chemical reactions, infecting human cells and spreading viral genetic material, fundamental stages of an infection. That is why we are targeting these blockades, ”says Trivella.
Cell tests
After computational analysis, the research passed tests. in vitro Of medicine. In this phase, the selected drugs were tested in cells infected with the coronavirus. The intention was to check if the tests identified by the computers were being realized in the laboratories.
Nitazoxanide has been identified as the most promising of the drugs selected by Cnpem. In laboratory tests, it showed 94% effectiveness after 48 hours in tests in vitro against the coronavirus, a number similar to that of chloroquine, which was subsequently not shown to be effective in human trials.
The pompous announcement by the ministry drew criticism from experts at the time, who said the test in vitro it didn’t have much meaning. Clinical tests were lacking, which began to be developed between the end of April and the beginning of May.
Clinical trials
According to Patrícia Rocco, the tests involved several Brazilian cities such as São Caetano do Sul (SP), Barueri (SP), Juiz de Fora (MG), Sorocaba (SP), Bauru (SP), Guarulhos (SP) and the Federal District .
The clinical study was approved by organizations such as Conep (National Council for Research Ethics) and was followed for four months. In all, 1,575 admitted volunteers with up to three days of covid symptoms took part in the tests: one group took the drug and the other, a control group, took a placebo.
In the group that took nitazoxanide, 500 milligrams of the drug were prescribed three times a day. The published results point to the drug’s efficacy in reducing viral load, but without details of the size of this efficacy or data proving potential treatment.
