Ebola drug against Covid-19? Initial clinical trials with a potential antidote to the new coronavirus are ongoing in both China and the United States. It is the antiviral agent Remdesivir, which was originally developed against Ebola. This has already proven effective in animal experiments against SARS and Mers-CoV. In addition, there are first positive experiences in the treatment of Covid patients with the agent.
So far, there is no antidote that can prevent or stop infection with the SARS-CoV-2 coronavirus. So far, no active ingredient against this or other coronaviruses such as SARS or Mers-CoV has been approved as a drug. People who suffer from severe courses of Covid-19 can therefore only be given supportive treatment.
An Ebola drug against Covid-19?
But there is hope that this may change soon. Because some antiviral agents that were originally developed against other pathogens could also work against the new corona virus. The first tests are running with some active substances against HIV, the flu agent Tamiflu, but also with active substances that were effective in animal experiments and the first tests against the related viruses SARS and Mers-CoV.
The most promising candidate so far is the antiviral remdesivir from the US pharmaceutical company Gilead. This drug was originally developed against the Ebola virus, but proved to be ineffective in clinical studies in 2014. However, remdesivir has shown good effects in animal experiments against other RNA viruses, including the coronaviruses SARS and Mers-CoV. Remdesivir has also already undergone initial tests on healthy volunteers and Ebola patients and has proven to be tolerable in them.
How does Remdesivir work?
Remdesivir is a so-called nucleotide analog. In parts of its structure, the active substance is similar to the RNA building blocks that RNA viruses need to replicate their genetic material. In doing so, he deceives the viral enzymes that assemble the genome strands for virus replication and sabotages their work to a certain extent: Remdesivir is inserted into the viral RNA instead of the nucleotide building blocks by the enzymes.
“Once the active ingredient is incorporated into the growing RNA, the virus can no longer replicate,” explains Matthias Götte from the University of Alberta. He and his team have just investigated in a study how this principle works when using remdesivir against coronaviruses like SARS and Mers-CoV. It turned out that there are slight differences compared to the mechanism of action against Ebola – but “sabotage” works in both cases.
“Once remdesivir has been added to the growing RNA chain, this does not cause an immediate stop,” report Götte and his team. Instead, the virus enzyme can add three more building blocks before RNA synthesis stops. However, this delayed stop appears to be preventing the drug from being cut out of the RNA chain prematurely by a viral enzyme, the researchers found.
“I am cautiously optimistic that the results that our team found for remdesivir against Mers-CoV also apply to Covid-19,” said Götte.
First indications of effectiveness against Covid-19
In fact, there is already encouraging experience with remdesivir from China and the United States, where the drug has been used against the new coronavirus in some patients. In the United States, a Covid patient received the drug on the seventh day of his illness and the next day his symptoms had decreased significantly, according to doctors in the New England Journal of Medicine. Studies with over 700 Covid patients have also been running in Wuhan and Beijing for a few weeks.
However, there are only first impressions of the effectiveness of the drug, no hard data: “Although remdesivir has already been administered to some patients with Covid-19, we have not yet had enough reliable data to know whether it really affects the course,” emphasized Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID).
New studies in Asia and the USA
Therefore, further clinical studies with Remdesivir are now underway. At the University of Nebraska Medical Center in Omaha, Covid patients with pneumonia are currently being treated with the drug in a randomized clinical trial. You will receive 200 milligrams of remdesivir intravenously on the first day of treatment, and 100 milligrams each on the following days, as the NIAID announced. “A randomized placebo-controlled trial is the gold standard to find out if experimental therapy helps patients,” says Fauci.
In Asia, two further studies are starting with a total of 1,000 Covid patients, in whom the agent is administered in a similar dose. The aim of these tests is to determine whether the active ingredient works in both severe and moderate courses of the disease and whether the treatment must last for five or ten days. “These complementary studies help us get a broader, global database of the drug’s effect profile in a short period of time,” says Merdad Parsey, Gilead Medical Research Director.
What can you expect?
The results of the clinical studies are expected in early April. Should Remdesivir prove itself against SARS-CoV-2, this would not stop the spread of the coronavirus. But it helps prevent deaths from Covid-19. However, Götte also admits that remdesivir alone is probably not sufficient as an antidote to the pandemic.
“We will likely need more than one drug to fight emerging diseases like Covid-19,” said the researcher. “Ideally, we have several active ingredients up our sleeve because some strains of the virus may prove to be resistant to certain treatments.” (Journal of Biological Chemistry, 2020; doi: 10.1074 / jbc.AC120.013056)
Source: University of Alberta, Gilead, Clinicaltrials.com