P-Glycoprotein-Mediated Efflux Reduces the In Vivo Efficacy of a Therapeutic Targeting the Gastrointestinal Parasite Cryptosporidium

J Infect Dis. 2019 Aug 30;220(7):1188-1198. doi: 10.1093/infdis/jiz269.


Recent studies have illustrated the burden Cryptosporidium infection places on the lives of malnourished children and immunocompromised individuals. Treatment options remain limited, and efforts to develop a new therapeutic are currently underway. However, there are unresolved questions about the ideal pharmacokinetic characteristics of new anti-Cryptosporidium therapeutics. Specifically, should drug developers optimize therapeutics and formulations to increase drug exposure in the gastrointestinal lumen, enterocytes, or systemic circulation? Furthermore, how should researchers interpret data suggesting their therapeutic is a drug efflux transporter substrate? In vivo drug transporter-mediated alterations in efficacy are well recognized in multiple disease areas, but the impact of intestinal transporters on therapeutic efficacy against enteric diseases has not been established. Using multiple in vitro models and a mouse model of Cryptosporidium infection, we characterized the effect of P-glycoprotein efflux on bumped kinase inhibitor pharmacokinetics and efficacy. Our results demonstrated P-glycoprotein decreases bumped kinase inhibitor enterocyte exposure, resulting in reduced in vivo efficacy against Cryptosporidium. Furthermore, a hollow fiber model of Cryptosporidium infection replicated the in vivo impact of P-glycoprotein on anti-Cryptosporidium efficacy. In conclusion, when optimizing drug candidates targeting the gastrointestinal epithelium or gastrointestinal epithelial infections, drug developers should consider the adverse impact of active efflux transporters on efficacy.

Keywords: Cryptosporidium; P-gp; drug development; drug efflux; enteric; gastrointestinal.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / metabolism*
  • Animals
  • Biological Transport, Active
  • Caco-2 Cells
  • Cell Membrane Permeability / drug effects
  • Cryptosporidiosis / drug therapy*
  • Cryptosporidiosis / parasitology
  • Cryptosporidium / drug effects*
  • Disease Models, Animal
  • Drug Discovery / methods
  • Enterocytes / drug effects
  • Enterocytes / metabolism
  • Enterocytes / parasitology
  • Female
  • Gastrointestinal Absorption / drug effects
  • Humans
  • Interferon-gamma / genetics
  • Intestinal Diseases, Parasitic / drug therapy*
  • Mice
  • Mice, Knockout
  • Naphthalenes / chemistry
  • Naphthalenes / metabolism*
  • Naphthalenes / therapeutic use*
  • Piperidines / chemistry
  • Piperidines / metabolism*
  • Piperidines / therapeutic use*
  • Pyrazoles / chemistry
  • Pyrazoles / metabolism*
  • Pyrazoles / therapeutic use*
  • Pyrimidines / chemistry
  • Pyrimidines / metabolism*
  • Pyrimidines / therapeutic use*
  • Quinolines / chemistry
  • Quinolines / metabolism*
  • Quinolines / therapeutic use*
  • Treatment Outcome


  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • BKI 1369
  • IFNG protein, mouse
  • Naphthalenes
  • Piperidines
  • Pyrazoles
  • Pyrimidines
  • Quinolines
  • bumped kinase inhibitor 1294
  • Interferon-gamma