While the hiccups accumulate on the side of vaccinations, the encouraging results of antibody-based treatments are raising hopes for a new method to fight the Covid-19 epidemic.
This Sunday, government spokesman Gabriel Attal also said that these treatments were being studied in France.
But how do they work?
What are their results?
We detail everything we know about them.
What do these treatments consist of?
These treatments are composed of antibodies, called “neutralizing monoclonal antibodies”.
They are “synthetic antibodies specific for the Spike protein, a viral protein involved in infectivity by SARS-CoV-2.
They block the entry of the virus into cells, ”summarizes Professor Renato Monteiro, president of the French Society of Immunology and head of the immunology department at Bichat hospital.
These treatments therefore make it possible to avoid developing serious forms of Covid-19 after infection with the new coronavirus.
These treatments are administered intravenously, "with an infusion over an hour on an outpatient basis," explains the doctor, who is based on tests already published on the subject.
“This treatment was very well tolerated.
The two companies (Regeneron and Eli Lilly) are now working on antibodies to be administered subcutaneously or intramuscularly ”, he adds.
Are these treatments effective?
Yes, in very specific cases, such as in older patients, explains Professor Monteiro.
“They have been shown to be effective when patients did not have circulating anti-SARS-Cov-2 antibodies (infected but asymptomatic subjects have effective antibodies).
Since the elderly are exposed to an aging immune system, their antibody response against the virus may be weakened.
In this case, the neutralizing monoclonal antibodies have a better chance of being effective in these elderly subjects, ”explains the specialist.
On the other hand, for this treatment to be effective, it is necessary to react quickly after detection of the infection.
"The treatment must be administered within three days after the positive PCR test (in the initial phase where the patient carries a strong presence of the virus in the blood) and before the onset of respiratory symptoms (inflammatory phase)", specifies Renato Monteiro .
The American pharmaceutical group Eli Lilly, which has developed a treatment of this type (combining the antibodies called "bamlanivimab" and "etesevimab"), announced on January 26 that its treatment made it possible to reduce hospitalizations and deaths in patients by 70%. high-risk patients recently tested positive for Covid-19.
Its phase 3 trial involved 1,035 patients.
At the same time, biotech company Regeneron announced positive interim results for its phase 3 trial of REGEN-COV, a combination of two antibodies, for preventive use, i.e. even before there is infection with the virus.
The data analyzed relate to approximately 400 patients.
Morning essentials newsletter
A tour of the news to start the day
Subscribe to the newsletterAll newsletters
"These data on the use of REGEN-COV as a passive vaccine suggest that it may both reduce the transmission of the virus and reduce the viral load and the disease burden in those who are still infected," said George. Yancopoulos, the president of Regeneron.
The company recently announced that its treatment remains equally effective against the British and South African variants, although its potency is "reduced" against the latter.
Are they already used elsewhere?
In November, US health authorities urgently authorized the treatment designed by the biotechnology company Regeneron.
It is this treatment that was administered to Donald Trump when he was infected with the new coronavirus.
At the end of January, Germany was the first paid by the European Union to test this treatment, announcing the purchase of 200,000 doses, without specifying which laboratory they came from.
They will be used in teaching hospitals from this week.
What side effects?
For the moment, the essays published on the subject do not relay "no serious effects", notes Professor Monteiro.
In the United States, the Food and Drug Administration (FDA), the authority which authorizes the placing on the market of drugs, underlines a risk of anaphylactic shock, as well as classic reactions after injections, such as fever, tremors. , headaches or even nausea.
Are these treatments easy to produce and administer?
In terms of production and delivery, these treatments do not seem to pose a problem.
“The advantage of a monoclonal antibody is that it is produced by a single cell clone, always secreting the same antibody identically, and in an unlimited way, facilitating industrial production.
They can be stored at 2 to 8 ° C, which facilitates transport, ”explains Renato Monteiro.
But in the United States, these treatments have been difficult to administer, due to a lack of staff and the logistical capacity of hospitals to administer them.
"Lilly has had feedback from nurses and doctors [...] concerning the complexity and the time required for the preparation and administration" of the treatment, affirmed the laboratory Lilly, specifying to work with the American health authorities to potentially reduce intravenous administration time from 60 to 16 minutes.
Another difficulty: the cost of the doses.
Germany, which ordered 200,000 doses of such treatment in January, had to settle a bill of 400 million euros.
Or 2,000 euros per dose.
"There is no question of giving it to everyone because we would not have the means and we do not yet know when to administer it to patients", explained to us, there is little, the epidemiologist Yves Buisson, president of the Covid-19 group at the National Academy of Medicine.
Will they be used in France?
For the moment, the government assures us that this is a working path.
"There was a meeting around the President of the Republic on this subject and I can confirm that we will develop clinical protocols to work on this track", declared Gabriel Attal, the spokesperson of the government, Sunday, on BFM TV.
READ ALSO>
Covid-19: the “Zero Covid” strategy, good idea or fad?
“Whenever there are treatments that seem promising, we invest to see if these treatments are actually confirmed.
Monoclonal antibodies are one of them, ”he said.
In France, since April, the Pasteur Institute has also been working on research into an antibody-based treatment, but they are still at the preclinical stage.