Discovery of 3-(Arylamido)pyrazolopyridine HIF-2α Agonists and a Codrug Strategy with Prolyl Hydroxylase Inhibition for Synergistic Treatment of Renal Anemia

Activation of the hypoxia-inducible factor-2 (HIF-2) pathway represents a promising strategy for the treatment of renal anemia. Here, we identify compound 48 (ZG-2686), a 3-(benzamido)pyrazolopyridine derivative, as a novel and potent HIF-2α agonist (Emax = 375.7 ± 9.7%, EC₅₀ = 0.25 ± 0.05 μM). Molecular dynamics (MD) simulations provided detailed insights into the binding mode of 48 with the HIF-2α/β complex. In cellular assays, 48 synergistically enhanced HIF-2α-dependent EPO gene expression when combined with the clinically approved prolyl hydroxylase domain (PHD) inhibitor Vadadustat. To further exploit this synergy, we designed and synthesized the bifunctional codrug 50 (ZG-2688), linking 48 with Vadadustat. Notably, codrug 50 induced superior upregulation of EPO levels in vivo compared to coadministration of the two individual agents. Together, these findings demonstrate the first rationally designed codrug integrating an HIF-2α agonist and a PHD inhibitor, highlighting a new direction for the development of renal anemia therapies.