Treatment of COVID-19: A review of emerging treatment

COVID-19 has caused a devastating pandemic, infecting 3,090,445 people and causing 217,769 deaths, as of 30 April, 2020. The current evidence base for selected drugs repositioned to treat COVID- 19 are summarized here. Chloroquine (CQ) and hydroxychloroquine (HCQ) block the entry of the SARS-CoV-2 virus into cells and have immunomodulatory effects. Early, poor quality studies pointed to benefit with CQ and HCQ treatment in COVID-19 infection, but no further evidence supporting their use is available to date, and the drugs cannot be recommended for treatment or prophylaxis. However, several countries use CQ or HCQ for compassionate treatment. Lopinavir-ritonavir, which is effective against HIV, was evaluated in one clinical trial which showed no benefit. Remdesivir, a drug developed for EBOLA, has been shown to have in-vitro efficacy against SARS-CoV-2, and the treatment has been used on compassionate grounds in severe cases. Limited studies have shown clinical improvement with remdesivir which is approved for emergency use in severe COVID-19. The RNA polymerase inhibitor favipiravir has been shown to improve clinical features, hasten viral clearance, and improve HRCT findings. Corticosteroids have shown no benefit. Trials are underway with the IL-6 receptor blocking monoclonal antibody tocilizumab, with retrospective data showing reduction in inflammatory markers and clinical improvement. Convalescent plasma has been shown to be of some benefit in severe cases of SARS, MERS and H1N1 influenza, and is recommended by the FDA for those with serious or immediately life-threatening infection with COVID-19. Several large randomized controlled trials are underway, evaluating these repositioned therapies as well as many other treatments. No effective specific treatments are available for COVID- 19 infection as yet.