Rationale for the use of sphingosine analogues in COVID-19 patients.

Despite the recent announcement of promising drug candidates to treat COVID-19, there is currently no effective antiviral drug or vaccine. There is strong evidence that acute lung injury/acute respiratory distress syndrome (ALI/ARDS), likely triggered by a cytokine storm, is responsible for the severity of disease seen in COVID-19 patients. In support of this hypothesis, pilot studies using IL-6 receptor inhibitors such as tocilizumab have shown promising results. Therefore, the use of drugs or cocktails of drugs with broader ability to inhibit these cytokine receptors is likely to be effective. In this article, we propose the use of sphingosine analogues, which have been shown to mitigate acute lung damage in animal models of ALI/ARDS, as early adjuvant therapies to prevent and/or mitigate the cytokine response in COVID-19 patients. This proposal is based on the ability of these drugs to decrease the production of IL-6 and other cytokines. The potential application of fingolimod (FTY720), the oldest sphingosine analogue approved for the treatment of multiple sclerosis, in the early stages of COVID-19 is discussed in more detail as a prototype drug.