A hope for those who react badly to vaccines and an acceptable alternative for "antivax"?
The Anglo-Swedish laboratory AstraZeneca published on Friday August 20 very promising results concerning its preventive treatment of Covid-19, called AZD7442.
In the process, the group announced its intention to file, first in the United States, an application for authorization to market this remedy by the end of the year.
Preliminary results from a phase III trial - the last link in the drug development process - indicate that AZD7442 reduces the risk of developing a symptomatic form of Covid-19 by 77%.
In the same yard as vaccines
None of the 5,200 French, North American, British, Spanish and Belgian volunteers who received a dose of AstraZeneca treatment (one third obtained a placebo) in the study showed signs of the disease during the entire duration of the test.
This is a relief for the laboratory which, moreover, markets one of the main vaccines used to fight the Covid-19 pandemic.
Last June, their AZD7442 treatment failed to convince in a previous study aimed at evaluating, this time, its effectiveness in treating people already infected with the virus.
It is this disappointment that pushed AstraZeneca to focus on the path of preventive treatment for its drug.
In this sense, it plays in the same court as vaccines since "the two pursue the same goal: to protect against serious forms of the disease", underlines Penny Ward, visiting professor in pharmaceutical medicine at King's College London, interviewed by France 24.
It differs from most other similar remedies - developed by Regeneron, GlaxoSmithKline or Eli Lilly - which aim to cure rather than prevent.
Regeneron's drug, for example, had been used to treat former US President Donald Trump after his contamination with Covid-19.
All these treatments are based on monoclonal antibodies.
That is, it is a cocktail of synthetic antibodies - two in the case of AZD7442 - designed specifically to fight a specific disease.
"This is the big difference with vaccines which seek to stimulate the immune system so that it manufactures its own antibodies, while these treatments allow the direct injection of antibodies deemed effective in the laboratory", summarizes Penny. Ward.
A comparison which seems, a priori, flattering for treatments based on monoclonal antibodies since they are "ready to use", require only one injection and have an immediate effect - do not wait for the system The immune system begins to work to be protected, as in the case of vaccines.
For those who need more than a vaccine
AZD7442 even has two additional advantages since "it seems that the antibodies have been specially modified to protect for a very long time - up to a year according to AstraZeneca - and that they are effective against the Delta variant", specifies Penny Ward.
He would not be ashamed of certain vaccines against Covid-19, the protection of which would wear off well before a year, according to data collected in Israel, which is currently generating a lively debate.
However, "vaccination should always be preferred over treatment with monoclonal antibodies when possible," says Penny Ward.
This is due to the double effect of vaccines.
They push the immune system to make antibodies, but also to develop T cells, responsible for the immune memory that must allow the body to recognize the SARS-COV-2 virus to defend itself, even when there is no more. of antibodies.
A second benefit that treatments like AZD7442 do not provide.
This is why most of the laboratories that develop treatments based on synthetic antibodies seek as a priority to make remedies for patients who are already sick.
It's a niche in which they don't have to compete with vaccines.
However, AZD7442 could be a game-changer for millions of people.
Vaccines do not always produce the desired immune response.
This is particularly true in "people with certain comorbidities that affect their immune system, such as patients with cancer, the AIDS virus or who take drugs that weaken their immune system," says Penny Ward.
AstraZeneca is aware of the expectations of these millions of patients.
The laboratory said that 75% of the volunteers who participated in its study had chronic diseases that limited the immune response induced by the injection of a vaccine.
In these cases, the treatment could become "a therapeutic complement which would be administered after the normal course of vaccination", summarizes Penny Ward.
It could even be used to convince the vaccine-resistant of the "antivax" movement to undergo protective treatment, notes the Washington Post.
With this detail they risk to look gray when discovering the painful bill since treatments based on monoclonal antibodies are, in general, much more expensive than vaccines.
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