These are three families of treatments against Covid-19, but they all share the same goal: to reduce the patient’s viral load at the start of the infection to prevent him from developing a severe form of the disease. While international trials have been carried out for several months, recent results give cause for hope. First option, that of conventional antivirals. At this stage, the existing molecules tested as part of an indication repositioning have not passed the ramp.
But eventually, doctors would like to be able to administer this type of drug as soon as possible after a positive test. The most promising at this stage is molnupiravir, an orally administered treatment with efficacy against the Sars-Cov-1 and Mers coronaviruses. “Preliminary data in animals show that it works against Sars-Cov-2”, summarizes Yazdan Yazdanpanah, director of the ANRS infectious and emerging diseases.
The track of monoclonal antibodies
On March 6, the American giant Merck, which is developing this molecule with Ridgeback Bio, announced the encouraging results of a phase 2 trial carried out on 202 symptomatic and non-hospitalized patients, including French people. According to the lab, his product significantly reduced viral load after five days and there were no safety alerts.
Additional studies – in particular the expected conclusions of an international trial in which the CHU Bichat in Paris took part – should confirm these results. In addition, the administration window is narrow, judges epidemiologist Dominique Costagliola in an article published on the site The Conversation, which points to the risk of emergence of resistance to the virus if one only had an antiviral. “We should be able to use cocktails of several molecules, like what is being done in the fight against HIV,” said this specialist.
The other path is that of monoclonal antibodies, a replica of our immune defenses made in the laboratory. At the beginning of February, the American laboratories Regeneron and Eli Lilly obtained an emergency authorization for the use of their respective cocktails combining two synthetic antibodies, both of which show positive clinical results. According to the results of a new trial revealed Wednesday by Eli Lilly, the combination (bamlanivimab and etesevimab) would reduce the rate of hospitalization and death by 87%.
Interferon treatments
One of the products making up this dual therapy, bamlanivimab, has received temporary authorization for use in France from the National Agency for the Safety of Medicines and Health Products, although it has not made the clinical evidence of its effectiveness when used alone. Monotherapy administration which may also increase the risk of emergence of resistance, notes Professor Yazdanpanah. Nevertheless, this antibody will be evaluated on certain patients at the start of infection (over 80 years of age at high risk of death, immunocompromised, 70-80 years with comorbidities, etc.) via the Cocoprev cohort. “We are waiting for the arrival of dual therapy and new data, continues the infectious disease specialist. But this treatment requiring an infusion for one hour will not be intended for all patients.”
Last track, that of the treatments by interferon administered by nasal route or by inhalation, “an antiviral substance which plays an important role in the control of respiratory diseases”, summarized the immunologist Alain Fischer, the “Mr. Vaccin” of the government, in front of the senators, Wednesday. Research has found a link between lack of interferon and progression to a severe form of Covid-19. “A small British study seems to show an effect on the viral load, but this must be confirmed”, summarizes Yazdan Yazdanpanah. Clinical trials on city patients are underway in France.
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