While waiting to reach global immunisation against COVID-19 – via the approval of COVID-19 vaccine(s) – it is essential to develop effective treatments to cure people affected by the disease.
In mild cases, COVID-19 can cause fever, fatigue and dry cough. Patients with mild illness should be eligible for isolation and, sometimes, simply symptomatic treatments. However, COVID-19 may be complicated with high levels of pro-inflammatory cytokines, such as interleukin-6 (IL-6), a protein produced by a variety of cell types. Elevations in IL-6 levels and others pro-inflammatory markers may be an important mediator when severe inflammatory responses occur. This condition leads to the so-called cytokine storm, which, in turn, can induce acute respiratory distress syndrome (ARDS), organ failure and sepsis, potentially progressing to patient’s death. Subjects presenting severe pneumonia require hospitalisations and frequently access to intensive care unit, where mechanical ventilation and pharmacological treatments can be provided.
Scientists around the world are striving to identify effective treatments for people affected by COVID-19. The World Health Organization (WHO) is running the Solidarity trial to assess a number of anti- COVID-19 treatments. Worldwide hundreds of trials are ongoing and a multitude of drugs are being investigated.
Three different therapeutic approaches to fighting COVID-19 can be identified. They appear to work better at different times: for example, antiviral at the onset of the disease and immunomodulatory drugs in late-stage phases. Combinations of therapies are also under examination.
Antiviral drugs act by reducing the growth of viruses. There have been efforts to repurpose other clinical available drugs based on antiviral activities within other diseases (human immunodeficiency virus (HIV), hepatitis, severe influenza). Novel drugs with potential antiviral properties are also being considered. So far, Remdesivir is the first and only antiviral authorised at EU level for treatment of COVID-19. It has been shown to cut the duration of symptoms from 15 days to 11. It has not been shown to save lives (although new studies are ongoing).
Following the publication of the interim results of the WHO solidarity trial, indeed, the European Medicines Agency (EMA) is currently doing a regulatory assessment to draw further conclusions on the effectiveness of the drug and an update is expected in the coming weeks.
Immunomodulatory and anti-inflammatory drugs
As mentioned, inflammatory organ injury may occur in severe cases of COVID-19, with a subset of patients having well-elevated inflammatory markers. Immunomodulatory and anti-inflammatory drugs can decrease the activation of the immune system. Several therapeutic interventions to mitigate inflammatory organ injury have been proposed, such as corticosteroids and IL-6 inhibitors, e.g. sarilumab, siltuximab and tocilizumab.
Antibodies target the virus
Antibodies target the virus (convalescent plasma and synthetic antibodies) are other potential treatments tools. Neutralising antibodies can alter the course of infection in the infected host supporting virus clearance or protect an uninfected host that is exposed to the virus. These antibodies offers the potential to prevent and/or treat COVID-19.
Convalescent plasma (also called hyper-immune plasma) is collected from recovered COVID-19 patients; it may contain neutralising antibodies against the virus, and could be an effective therapeutic weapon. Human monoclonal antibodies that neutralises SARS-CoV-2 can also be produced synthetically.
In this thematic section, we summarize some of the current therapeutic approaches for COVID-19. We will continue to closely follow developments in the area as several clinical trials are ongoing, the scientific evidence is constantly evolving and there is a shared consensus in the research community on the need for more studies.