A humanized monoclonal antibody directed against sphingosine 1-phosphate (S1P) with potential antiangiogenic and antineoplastic activities. Upon administration, sonepcizumab binds S1P, which may result in the inhibition of tumor angiogenesis. S1P is the extracellular ligand for the G protein-coupled lysophospholipid receptor EDG-1 (endothelial differentiation gene-1).