Fingolimod

Sphingosine‐1‐phosphate (S1P) is an important phospholipid that binds to various G‐protein‐coupled receptor subtypes, which can be identified as S1P1–5R. S1P and the receptors it binds to perform regular functions in the immune, cardiovascular, pulmonary, and nervous systems. S1P can be expressed ubiquitously, playing an important role in regulating inflammation. S1P1R, S1P2R, and S1P3R receptors can be found in the cardiovascular, immune, and central nervous systems. S1P4R is found on lymphocytic and hematopoietic cells, while S1P5R expression is found only on the spleen (on natural killer cells) or in the central nervous system.

The active form of the drug, fingolimod phosphate, is a sphingosine 1-phosphate receptor modulator that exerts its mechanism of action in MS by binding to various sphingosine 1-phosphate receptors (1, 3, 4, and 5). It suppresses the exit of lymphocytes from lymph nodes, leading to a lower level of lymphocytes circulating in the peripheral circulation. This reduces the inflammation that is associated with MS. The mechanism of action of fingolimod is not fully understood but may be related to reduced lymphocyte circulation into the central nervous system.

Immune modulating treatment such as fingolimod is not typically employed for SARS-CoV-2 pneumonia. Despite this, with the tissue findings of pulmonary edema and hyaline membrane formation, the timely use of immune modulators such as fingolimod can be considered to prevent acute respiratory distress syndrome (ARDS) associated with COVID-19.