Marseille-based researchers are developing a treatment for Covid-19 and presenting encouraging translational results to treat patients with severe forms of the disease. In France, the circulation of the virus continues to intensify and the number of patients in intensive care is up very slightly for the first time since April 9.
- Researchers have highlighted the role of complement molecules in our immune response, in particular C5a.
- The avdoralimab antibody limits the infiltration of cells by the virus and prevents lung inflammation associated with acute respiratory distress syndrome.
In parallel with the frantic race for the vaccine against Covid-19, the search for a treatment to treat infected patients is also in full emulation. After the hopes produced by the combination of molecules remdesivir / diltiazem and by the anticoagulant heparin, scientists based in Marseille presented this Wednesday, July 29, in the journal Nature, the very encouraging results of their search for treatment for patients who have developed severe forms of the disease to recover from their infection. The team, named Explore Covid-19, brings together researchers from Innate Pharma, Marseille Immunopole, the Marseille-Luminy Immunology Center and several hospitals and university centers in the region.
Complement molecules, then unknown, identified
The researchers dissected the organization of the immune response of infected patients to understand how it works and target the molecules that can effectively fight against the invasion of Covid-19. “From the start, we know that the aggravation of the disease is linked to an overreaction of the immune system, and in particular to the action of cytokines, which are molecules which circulate in the body and which have inflammatory properties.”, explains Éric Vivier, immunologist and scientific director of Innate Pharma, at France info. Among the cytokine molecules involved, the Marseille team focused on that “called complement molecules”, says Éric Vivier. This is'”a set of 35 molecules which are secreted by the body and which activate each other, in cascade.”
One of these complement molecules, whose role in the immune response was previously unknown, particularly attracted researchers. This is the C5 molecule which is split into two proteins: C5a and C5b. “As much as C5b is very important for immunity, as much C5a does not seem really required, but seems to play a very important role in triggering the immune reaction”, notes Éric Vivier. The first results of their analyzes revealed that this protein is present disproportionately in the bodies of people with lung damage linked to Covid-19 infection. “As soon as we enter forms of Covid-19 pneumonia, we observe a very significant increase in the quantity of C5a“which is modeled on”the clinical course of the disease”, confirms the immunologist. This accumulation of C5a has the particularity of attracting immune cells, called myeloid cells, which contributes to the runaway of the immune system, which will lead to tissue deterioration.
Expected human results
After identifying the immune mechanisms during Covid-19 infection, researchers focused their attention on finding an effective treatment. To do this, they looked for known immune mechanisms to “reposition medication“existing for”to be able to take care of patients as quickly as possible”. The avdoralimab antibody, developed by the Innate Pharma laboratory for the management of several pathologies such as cancers, emerged from their observations. It allows to block the way highlighted by the team and “limit myeloid cell infiltration at inflammatory sites and prevent lung inflammation associated with acute respiratory distress syndrome”, notes the biotechnology company in a communicated.
The first clinical tests, carried out on mice, presented encouraging results. Since May, the team has started the process of human clinical trials and continues to recruit patients to test their drug. From now on, we have to wait for the results on the effectiveness of the antibody avdoralimab on humans in order to see if it effectively makes it possible to block the runaway of the immune system and to avoid the development of the most serious forms of the disease. .
An increase in the number of patients in intensive care
For the first time since April 9, the number of patients in intensive care is no longer falling, with one additional person, said the Directorate General of Health (DGS). This indicator is very closely monitored since it helps to understand the state of virus circulation. A total of 5,375 people are hospitalized for a coronavirus infection, including 381 severe cases in intensive care. The circulation of the virus remains “sustained with an increasing number of daily cases and more than 1,000”, insists the DGS. The number of new cases is also increasing and is 54% higher than the previous week,”especially among 20-30 year olds”, reveals the public health agency France in its weekly epidemiological update.
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