SLM 6031434 Hydrochloride is a Sphk2 inhibitor (Ki = 0.4 μM for mouse Sphk2). Exhibts some selectivity for Sphk2 over Sphk1 (Ki > 20 μM). Decreases levels of sphingosine-1-phosphate (S1P) in U937 cells in vitro and increases blood levels of S1P in wild-type mice.