Progresses in clinical studies on antiviral therapies for COVID-19-Experience and lessons in design of clinical trials.

Antiviral therapy with antiviral agents is a very important component of treatment for the 2019 novel coronavirus disease (COVID-19) caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). It is important to clarify how to evaluate efficacy and safety of antiviral agents in treatment of COVID-19 during the pandemic of this disease. We need to answer the following questions: do we still need to use rigorously designed randomized controlled clinical trials (RCTs)? Or, will it be enough if we use loosened criteria, observational studies or even retrospective case series and case reports? The answer is "No, we still need to use the strictly designed preferably blinded multicenter RCTs to evaluate the antiviral agents." In this article, we reviewed almost all the RCT reports on monotherapies and combined therapies with antiviral agents for COVID-19, and found that among the reports on monotherapies, only remdesivir, and among combined antiviral agents, only the combined regimen with interferon-β1b, lopinavir-ritonavir and ribavirin were effective and safe based on evidences from RCTs. The results of five RCTs for chloroquine or hydroxychloroquine consistently showed that they were ineffective and unsafe in the treatment of COVID-19, especially at larger doses. Many aspects in the design of the clinical trials may be related to success or failure of a trial and the relevant factors need to be analyzed, discussed and emphasized from the specific requirements and considerations of antiviral therapies. We hope such discussions be of certain use in designing clinical trials for pediatric antiviral therapies.