Design, Synthesis, and Preclinical Characterization of Selective Factor D Inhibitors Targeting the Alternative Complement Pathway

J Med Chem. 2019 May 9;62(9):4656-4668. doi: 10.1021/acs.jmedchem.9b00271. Epub 2019 Apr 30.

Abstract

Complement factor D (FD), a highly specific S1 serine protease, plays a central role in the amplification of the alternative complement pathway (AP) of the innate immune system. Dysregulation of AP activity predisposes individuals to diverse disorders such as age-related macular degeneration, atypical hemolytic uremic syndrome, membranoproliferative glomerulonephritis type II, and paroxysmal nocturnal hemoglobinuria. Previously, we have reported the screening efforts and identification of reversible benzylamine-based FD inhibitors (1 and 2) binding to the open active conformation of FD. In continuation of our drug discovery program, we designed compounds applying structure-based approaches to improve interactions with FD and gain selectivity against S1 serine proteases. We report herein the design, synthesis, and medicinal chemistry optimization of the benzylamine series culminating in the discovery of 12, an orally bioavailable and selective FD inhibitor. 12 demonstrated systemic suppression of AP activation in a lipopolysaccharide-induced AP activation model as well as local ocular suppression in intravitreal injection-induced AP activation model in mice expressing human FD.

MeSH terms

  • Animals
  • Benzylamines / chemical synthesis
  • Benzylamines / metabolism
  • Benzylamines / pharmacology*
  • Binding Sites
  • Complement Factor D / antagonists & inhibitors
  • Complement Factor D / chemistry
  • Complement Factor D / metabolism
  • Complement Pathway, Alternative / drug effects*
  • Dogs
  • Drug Design
  • Humans
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Molecular Docking Simulation
  • Protein Conformation
  • Rats
  • Serine Proteinase Inhibitors / chemical synthesis
  • Serine Proteinase Inhibitors / metabolism
  • Serine Proteinase Inhibitors / pharmacology*

Substances

  • Benzylamines
  • Serine Proteinase Inhibitors
  • CFD protein, human
  • Complement Factor D