Regen-cov: the first antiviral treatment that proves to save the lives of seriously ill patients with covid

2021-06-19T19:57:24.339Z

An expensive cocktail of foreign antibodies prevents one death for every 17 patients treated, according to the results of the world's largest clinical trial

Humanity developed vaccines to prevent covid in record time, but has accumulated failures in the race to find an effective treatment for people who already have the disease. Around 80,000 infected people continue to die in the world every week. After a year and a half of pandemic, at last, antiviral therapy has shown for the first time that it can save the lives of hospitalized patients with coronavirus. The treatment, developed by the American company Regeneron, is effective only in seriously ill patients who lack their own defenses against the virus. In these patients, for every 100 treated, six deaths would be avoided, according to the preliminary results of the largest clinical trial in the world, Recovery, coordinated by researchers from the University of Oxford (United Kingdom).

The treatment, called Regen-cov in the United States, is a cocktail of two experimental drugs - imdevimab and casirivimab - given together intravenously, in a single dose. They are two types of powerful virus neutralizing antibodies, selected and multiplied after an analysis of thousands of natural antibodies from people recovered from covid or from mice genetically modified to mimic a human immune system. This experimental therapy became famous in October 2020, when then-US President Donald Trump affirmed that it was "a cure", after having mild symptoms of covid and being treated with it.

Some 9,800 hospitalized patients in the United Kingdom participated in the clinical trial, all with the same standard treatment, but half of them also with the antibody cocktail.

The study has only observed significant effects in critically ill patients without their own antibodies against the coronavirus.

In this type of affected, mortality reached 30% in the group with the usual therapy, compared to 24% in the patients who also received the Regeneron cocktail.

It is a reduction in mortality of 20%.

The length of stay in the hospital also fell from the usual average of 17 days to 13 days, a decrease of 24%.

Oxford University epidemiologist Martin Landray thinks this is "great news"

The epidemiologist Martin Landray, from the University of Oxford, stressed this Wednesday in a statement that "it is the first time that an antiviral treatment has proven to save lives in hospitalized patients with covid." Landray thinks this is "great news." His colleague Peter Horby recalled that there were many doubts about the efficacy of antiviral treatments against severe disease, with the virus already rampant. "It is wonderful to know that even in advanced COVID, attacking the virus can reduce mortality in patients who have failed to generate an antibody response of their own," said Horby.

The Recovery trial, involving nearly 180 UK hospitals, has been essential during the pandemic to distinguish truly effective treatments and rule out useless therapies. The project, coordinated by Landray and Horby, showed just a year ago that an anti-inflammatory drug synthesized in 1957, dexamethasone, reduces the risk of death of the most seriously ill by a third. It is a very cheap drug that has saved hundreds of thousands of lives. According to calculations by the Oxford researchers, for every eight seriously ill patients treated with dexamethasone, one death is prevented. And the treatment only costs a few euros. For every 17 patients treated with the Regeneron cocktail, one death is prevented, but the therapy costs more than 1,700 euros per person, according to a US agreement with the manufacturer.With this price it will only be an option in rich countries. The US authorities already injected 450 million dollars into Regeneron in July 2020, to promote the development of this experimental treatment.

Regen-cov is not the solution to covid, but it is a new addition to the limited medical arsenal against the disease. The virologist Isabel Sola, from the CSIC, applauds the apparent reduction in mortality and hospitalization time, but is cautious. "Welcome to that effect, although we will have to see how it works with the variants of the virus," he warns. Sola participates in the European project Manco, which is also looking for effective monoclonal antibodies against the coronavirus.

Scientist Fiona Watt, Executive Director of the UK Medical Research Council, has welcomed the results of the trial. “It is a very important finding. It means that hospitalized patients with covid can be divided into two groups, based on whether they have produced antibodies against the virus or not, ”explained Watt. If patients do not have natural antibodies, the researcher has argued, a cocktail of foreign antibodies can reduce the risk of dying and the length of stay in the hospital. And, if patients already have their own antibodies, doctors can save themselves the very expensive Regeneron treatment, because with these people it does not work.

The two Regen-cov antibodies adhere to the spicules of the coronavirus, reducing their ability to infect human cells. Previous trials had shown promising results in mild, non-hospitalized patients, but it was unknown whether Regeneron's cocktail was capable of saving the lives of critically ill patients. Recovery is the first trial large enough to demonstrate efficacy in some patients, according to the Oxford statement.

Basel, Switzerland-based biotech company Roche has partnered with Regeneron to manufacture and supply Regen-cov. The drug regulatory agency in the United States, the FDA, in November authorized the emergency use of this cocktail of antibodies in newly diagnosed high-risk patients. In February 2021, the Committee for Medicinal Products for Human Use of the European Medicines Agency also supported the use of imdevimab and casirivimab as a treatment option in mildly ill high-risk patients, such as those over 65, the obese and diabetics. .

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