S1PR1 and Crohn disease: Other selective S1P receptor modulators are in development or used in clinical trials like Etrasimod (selective modulator of S1PR1,4,5, phase III clinical trial in UC patients), Amiselimod (high affinity to S1PR1, clinical trials in Crohn’s disease (CD)), Ponesimod (selective modulator of S1PR1,4,5 tested in clinical trial phase II for psoriasis) (Pérez-Jeldres et al., 2021) (Table 2).