New drugs give more hope against Covid

 The effort to vaccinate billions of people in a single year has overshadowed the slow-moving search for treatments against Covid-19, but many new treatments are a source of hope.

Medicines that have been proven to work

Corticosteroids: The first treatment officially recommended by the World Health Organization in September 2020, only for patients with the most severe symptoms.

Based on all available clinical trial data, the World Health Organization recommends "routine administration of corticosteroids" to patients with "acute or critical" form of COVID-19.

This treatment reduces mortality among these patients and may also reduce the risk of them being placed on ventilators, according to the World Health Organization. It makes it possible to fight the infections that accompany acute forms of the disease.

sarilumab and tocilizumab: These medicines are synthetic, called "monoclonal" antibodies and belong to a family called "interleukin-6 antagonists" (or IL-6 antagonists). It has been recommended by the World Health Organization since July 2021 for more severe cases as well.

The organization recommends that these patients receive "both corticosteroids and interleukin-6 antagonists."

Tocilizumab (sold as Roche's Actra and Ro-Actra) and sarilumab (sold as Sanofi's Kefzara), originally developed for rheumatoid arthritis, suppress immunity. And they fight, like corticosteroids, a wild immune system that appears to be the source of severe forms of Covid.

- Ronabrev: The World Health Organization on Friday recommended the use of this combination of two monoclonal antibodies (cacerevimab and imdivimab), but only for two categories of patients: "those with mild forms of Covid and at high risk of hospitalization", such as the elderly or those with From a weakened immune system (due to cancer or after a transplant, for example), then patients with a "severe or critical form who do not have antibodies", ie who did not develop antibodies after infection or vaccination.

This injectable drug is mainly useful for patients with weakened immune systems for whom vaccination is not effective. Prepared by the biotechnology company Regeneron with Roche Laboratories.

The main obstacle to its use is the high cost of a single dose, which amounts to $2,000, according to NGOs. Which is what the World Health Organization hopes to reduce.

Medicines under test

Oral antivirals: Many laboratories are working to produce antivirals that can be swallowed in tablet form.

Among the most advanced is molonoperavir (produced in partnership between biotech company Ridgeback Biotherapeutics and MSD Lab).

The drug is still undergoing trials on patients (whether they are in hospital or not) as well as for prophylaxis in people who have been in contact with infected people. The results of the trials are expected to be known by the end of the year.

Biotech company Atia Pharmaceuticals and the Roche Laboratory are evaluating the effectiveness of a similar treatment called AT-527. Pfizer is also developing a drug that combines two molecules, one of which is ritonavir, which is widely used against HIV (the virus that causes AIDS).

Infectious disease specialist Karen Lacombe stressed during a recent press conference held by the French Research Agency for Emerging Infectious Diseases that the market for such "effective and easy-to-treat treatments for early forms of Covid is likely to be enormous."

But she cautioned that it is necessary to "take caution" in the face of sometimes resounding statements issued by pharmaceutical companies, and wait for the results of clinical trials on patients.

This is particularly due to the fact that antivirals in general have not yet been very convincing in the treatment of Covid.

New antibodies: Some drug labs are developing long-acting monoclonal antibodies.

GlaxoSmithKline is developing one of them, sutrofimab, which at the end of June was classified by the European Commission as one of the five most promising treatments.

The other, called AZD7442, is a cocktail of antibodies made by AstraZeneca, which revealed preliminary results of its trials at the end of August. The drug company says it could be effective in preventing Covid in patients whose health is already fragile.

The French company Xenoterra is also working on another type of synthetic antibody called a "polyclonal antibody". Its XAV-19 product is based on pig antibodies that have been modified for the human body. This drug is in the final phase of clinical trials.

Ineffective medicines

Since the onset of the epidemic, many treatments have dashed hope. This is what happened with hydroxychloroquine (promoted by French researcher Didier Raul), remdesivir (initially considered very promising), ivermectin and the lopinavir-ritonavir combination (brand name Caltera) used against HIV.

Over time, the World Health Organization recommended that it not be used to treat Covid. These drugs have in common that they were initially designed for another use but have been tested against this new disease in what is called "repotting," or the use of a drug to treat a disease other than the one it was originally intended to fight.

"Repositioning a drug is what we are doing very urgently at the beginning of the epidemic," Karen Lacombe explained. But with the exception of interleukin-6, all of these drugs disappointed the scientists, which indicates the "limitation" of repositioning or reusing a drug in her opinion.

"This is what makes us enter a different therapeutic era by developing drugs to combat SARS-CoV-2," the virus that causes Covid.