A recombinant fusion protein composed of the full-length extracellular domain (soluble) of human receptor tyrosine kinase ephrin type-B receptor 4 (sEphB4) and fused, at its C-terminus, to full-length human serum albumin (HSA), with potential antineoplastic and anti-angiogenic activities. sEphB4-HSA functions as a decoy receptor for the membrane-bound ligand Ephrin-B2 (Efnb2) and interferes with the binding of Efnb2 to its native receptors, including EphB4 and EphA3. This may result in a reduction of angiogenesis and a reduction in cell growth of Efnb2 and/or EphB4 over-expressing tumor cells. In addition, this agent also prevents the angiogenic effects of numerous growth factors due to interactions between Efnb2 and EphB4. Efnb2 and EphB4 are overexpressed in a variety of tumor cell types; the bi-directional signaling of Efnb2-EphB4 plays an important role in angiogenesis and tumor cell migration, invasion, and proliferation. Albumin reduces this agent’s degradation, improves circulation time and may thus improve efficacy. Check foractive clinical trials using this agent.