Berlin, Oct. 27 (BUS): A great deal of work may have already been done to prevent cases of severe coronavirus infection with vaccines, but much more needs to be done to develop drugs to treat those infected. But the arsenal of frontline health care workers is about to grow.
To complement the proven highly effective Covid-19 vaccines, pharmaceutical companies around the world are working on drugs to treat the viral disease. It could be an additional tool in efforts to stop the epidemic, and help protect people who haven’t been vaccinated — perhaps because they can’t.
No drug has yet been developed specifically for the novel coronavirus and approved for all patients. So doctors are reusing existing treatments to treat some complications of Covid-19 in some cases. Many patients in hospital are given blood thinners, for example, because Covid-19 increases the risk of blood clots, heart attack and stroke. Antibiotics are often given to protect against potential bacterial infections.
The difficulty of treating Covid-19 lies in the biology of the virus, Swiss molecular biologist Emmanuel Wheeler wrote recently in the Berliner Zeitung newspaper. If you are infected with SARS-CoV-2, there are no symptoms at first, he says, German news agency DPA reported.
“When you get a cough or a sore throat, in most cases, your immune system has already started to fight the virus,” wrote Wheeler, who is conducting research at the Berlin-based Max Delbrück Center for Molecular Medicine. “As with influenza, drugs that directly target the virus often come too late.”
The only such drug to have received conditional marketing approval in the European Union (EU) so far (in July 2020) is remdesivir, developed by US biopharmaceutical company Gilead Sciences and sold under the brand name Veklury. Its use is only indicated for the treatment of Covid-19 in adults and adolescents (aged 12 years and over and weighing at least 40 kg) with pneumonia requiring supplemental oxygen but without gas ventilation.
Originally developed to treat the Ebola virus, remdesivir has been found to prevent replication of a wide range of human and animal coronaviruses. However, in November 2020, the World Health Organization (WHO) issued a conditional recommendation against the use of remdesivir in hospitalized patients, regardless of disease severity, saying that there is currently no evidence that it improves survival and other outcomes in these patients.
And in mid-September, Germany’s Federal Joint Commission (G-BA), the country’s highest decision-making body of doctors, dentists, hospitals and health insurance funds, evaluated the effect of remdesivir on people with moderate cases of Covid-19. And absolutely nothing in severe cases.
Although the anti-inflammatory drug dexamethasone has not received official approval from the European Union for use against the novel coronavirus, doctors in Germany are giving it to some hospitalized patients. Weiler calls it a “central drug for COVID-19.” It is given to suppress an overactive immune reaction known as a cytokine storm, a severe inflammatory phase that often occurs in COVID-19 patients who develop pneumonia.
According to the Robert Koch Institute (RKI), which is responsible for disease control and prevention in Germany, dexamethasone has been shown to be most effective in Covid-19 patients who require invasive ventilation. But he warns that using it for less serious disease could “be harmful.”
Eight drugs to treat Covid-19 are currently in various stages of the approval process by the European Medicines Agency (EMA). They include antibody drugs that are already used in mild cases of illness.
It is used in special cases, for example, a “cocktail” of the monoclonal antibodies casirivimab and imdevimab, developed by the US biotech company Regeneron Pharmaceuticals and the Swiss healthcare company Roche, sold under the trade name Regn-CoV2. It is the first drug recommended by the World Health Organization for patients at high risk of severe Covid-19 infection, and for patients who are very ill and do not have normal antibodies.
Monoclonal antibodies are proteins made in a laboratory that mimic the natural antibodies your body produces to fight infection – “monoclonal” because they are made by cloning a unique white blood cell. They are engineered to attach to the barbed protein of SARS-CoV-2 at different sites. When they do this, the virus is unable to enter the body’s cells. The EMA is reviewing the available data on the use of four monoclonal antibodies in total, which are time-consuming and expensive to produce.
Dr Christian Drosten, head of the Institute of Virology at Charité University Hospital Berlin, said in his regular Covid-19 podcast that the administration of monoclonal antibodies to treat the disease “was always too late”, that is, when the virus had already multiplied on a large scale. inside the body. He noted that this is true for the average patient at the time when symptoms appear.
A recent clinical trial of the long-acting antibody combination (LAAB) AZD7442, produced by British-Swedish biopharmaceutical company AstraZeneca and also known as Evusheld, showed it reduced the risk of developing Covid-19 symptoms by 77 percent. In mid-October, an exponential moving average (EMA) began with a rolling review (eg, accelerated) of Evoshield. The EMA is also evaluating two additional treatments for Covid-19, both of which have already been approved for other diseases, such as rheumatoid arthritis.
Molnupiravir, an antiviral pill from US pharmaceutical giant Merck, recently made headlines when the company announced it had halved hospital admissions and deaths among people with Covid-19 in a clinical trial. Similar to remdesivir, the drug blocks the replication of SARS-CoV-2 within a person’s cells. Merck says it plans to obtain an emergency use authorization in the United States as soon as possible, and to submit marketing requests to regulators around the world.
Ivermectin, an antiparasitic (like intestinal worms in horses and cattle) with approved uses in both animals and humans, has been touted in some circles as an antidote to Covid-19. However, a comprehensive analysis of several studies found no evidence of efficacy. The antimalarials hydroxychloroquine and chloroquine have not been shown to be effective in preventing or treating the disease.
HF