title: Potency, selectivity and prolonged binding of saxagliptin to DPP4: maintenance of DPP4 inhibition by saxagliptin in vitro and ex vivo when compared to a rapidly-dissociating DPP4 inhibitor.
abstract: BACKGROUND
  Dipeptidylpeptidase 4 (DPP4) inhibitors have clinical benefit in patients with type 2 diabetes mellitus by increasing levels of glucose-lowering incretin hormones, such as glucagon-like peptide -1 (GLP-1), a peptide with a short half life that is secreted for approximately 1 hour following a meal. Since drugs with prolonged binding to their target have been shown to maximize pharmacodynamic effects while minimizing drug levels, we developed a time-dependent inhibitor that has a half-life for dissociation from DPP4 close to the duration of the first phase of GLP-1 release.
  
  
  RESULTS
  Saxagliptin and its active metabolite (5-hydroxysaxagliptin) are potent inhibitors of human DPP4 with prolonged dissociation from its active site (Ki = 1.3 nM and 2.6 nM, t1/2 = 50 and 23 minutes respectively at 37°C). In comparison, both vildagliptin (3.5 minutes) and sitagliptin ( < 2 minutes) rapidly dissociated from DPP4 at 37°C. Saxagliptin and 5-hydroxysaxagliptin are selective for inhibition of DPP4 versus other DPP family members and a large panel of other proteases, and have similar potency and efficacy across multiple species.Inhibition of plasma DPP activity is used as a biomarker in animal models and clinical trials. However, most DPP4 inhibitors are competitive with substrate and rapidly dissociate from DPP4; therefore, the type of substrate, volume of addition and final concentration of substrate in these assays can change measured inhibition. We show that unlike a rapidly dissociating DPP4 inhibitor, inhibition of plasma DPP activity by saxagliptin and 5-hydroxysaxagliptin in an ex vivo assay was not dependent on substrate concentration when substrate was added rapidly because saxagliptin and 5-hydroxysaxagliptin dissociate slowly from DPP4, once bound. We also show that substrate concentration was important for rapidly dissociating DPP4 inhibitors.
  
  
  CONCLUSIONS
  Saxagliptin and its active metabolite are potent, selective inhibitors of DPP4, with prolonged dissociation from its active site. They also demonstrate prolonged inhibition of plasma DPP4 ex vivo in animal models, which implies that saxagliptin and 5-hydroxysaxagliptin would continue to inhibit DPP4 during rapid increases in substrates in vivo.
authors.affiliation: Departments of Metabolic Diseases - Diabetes, Pennington NJ 08534, USA.
authors.forename: Aiying
authors.initials: A
authors.lastname: Wang
authors.forename: Charles
authors.initials: C
authors.lastname: Dorso
authors.forename: Lisa
authors.initials: L
authors.lastname: Kopcho
authors.forename: Gregory
authors.initials: G
authors.lastname: Locke
authors.forename: Robert
authors.initials: R
authors.lastname: Langish
authors.forename: Eric
authors.initials: E
authors.lastname: Harstad
authors.forename: Petia
authors.initials: P
authors.lastname: Shipkova
authors.forename: Jovita
authors.initials: J
authors.lastname: Marcinkeviciene
authors.forename: Lawrence
authors.initials: L
authors.lastname: Hamann
authors.forename: Mark S
authors.initials: MS
authors.lastname: Kirby
mesh_terms: D000218:Adamantane / Q000031:analogs & derivatives* / Q000378:metabolism; D000465:Algorithms; D000818:Animals; D016477:Artifacts; D003001:Cloning, Molecular; D004150:Dipeptidases / Q000378:metabolism; D004151:Dipeptides / Q000378:metabolism*; D018819:Dipeptidyl Peptidase 4 / Q000097:blood / Q000378:metabolism*; D054873:Dipeptidyl-Peptidase IV Inhibitors / Q000378:metabolism*; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000378:metabolism; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism; D006801:Humans; D007004:Hypoglycemic Agents / Q000378:metabolism*; D007202:Indicators and Reagents; D007700:Kinetics; D008252:Macaca fascicularis; D009570:Nitriles / Q000378:metabolism; D011485:Protein Binding; D011719:Pyrazines / Q000378:metabolism; D011759:Pyrrolidines / Q000378:metabolism; D000068900:Sitagliptin Phosphate; D013045:Species Specificity; D014230:Triazoles / Q000378:metabolism; D000077597:Vildagliptin
chemical_list: C558749:5-hydroxysaxagliptin; D004151:Dipeptides; D054873:Dipeptidyl-Peptidase IV Inhibitors; D007004:Hypoglycemic Agents; D007202:Indicators and Reagents; D009570:Nitriles; D011719:Pyrazines; D011759:Pyrrolidines; D014230:Triazoles; D052216:Glucagon-Like Peptide 1; C502994:saxagliptin; D004150:Dipeptidases; C471241:DPP9 protein, human; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C487997:DPP8 protein, human; D018819:Dipeptidyl Peptidase 4; D000077597:Vildagliptin; D000218:Adamantane; D000068900:Sitagliptin Phosphate