ASP3325

ASP3325 is an investigational **oral small-molecule inhibitor of sodium-dependent phosphate transport protein 2B**, developed by **Astellas** for the treatment of **hyperphosphatemia in patients with chronic kidney disease, including those undergoing hemodialysis**. Public clinical-trial records and a peer-reviewed publication describe it as a selective **NaPi-IIb inhibitor** intended to reduce intestinal phosphate absorption. ASP3325 entered **Phase 1** testing in healthy volunteers and in hemodialysis patients with hyperphosphatemia, but published clinical results reported that inhibition of NaPi-IIb with ASP3325 did **not** meaningfully improve hyperphosphatemia or reduce intestinal phosphate absorption in end-stage renal disease, suggesting the program was not advanced further.