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.