title: Netazepide, a gastrin/CCK2 receptor antagonist, causes dose-dependent, persistent inhibition of the responses to pentagastrin in healthy subjects.
abstract: OBJECTIVE
  To confirm by means of pentagastrin, a synthetic gastrin agonist, that netazepide is a gastrin/CCK2 receptor antagonist in healthy subjects, and that antagonism persists during repeated dosing.
  
  
  METHODS
  We did two studies in which we infused pentagastrin (0.6 μg kg(-1)  h(-1) intravenously), aspirated gastric secretion and measured the volume, pH and H(+) secretion rate of the gastric aspirate. First, we did a double-blind, five-way crossover study (n = 10) to assess the effect of single oral doses of netazepide (1, 5, 25 and 100 mg) and placebo on the response to pentagastrin. Then, we did a single-blind, placebo-controlled study (n = 8) to assess the effect of the first and last oral doses of netazepide (100 mg) twice daily for 13 doses on the response to pentagastrin.
  
  
  RESULTS
  Netazepide was well tolerated. After placebo, pentagastrin increased the volume and H(+) secretion rate and reduced the pH of gastric aspirate. Compared with placebo, single doses of netazepide caused dose-dependent inhibition of the pentagastrin response (P < 0.02); netazepide (100 mg) abolished the response. After 13 doses, the reduction in volume and H(+) secretion rate persisted (P < 0.001), but the pH effect was mostly lost.
  
  
  CONCLUSIONS
  Netazepide is an orally active, potent, competitive antagonist of human gastrin/CCK2 receptors. Antagonism is dose dependent and persists during repeated dosing, despite tolerance to the effect on pH. Further studies are required to explain that tolerance. Netazepide is a tool to study the physiology and pharmacology of gastrin, and merits studies in patients to assess its potential to treat gastric acid-related conditions and the trophic effects of hypergastrinaemia.
authors: Hammersmith Medicines Research, Central Middlesex Hospital, London, NW10 7NS, UK.
authors: Malcolm
authors: M
authors: Boyce
authors: Steve
authors: S
authors: Warrington
authors: James
authors: J
authors: Black
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001570:Benzodiazepinones / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004361:Drug Tolerance; D005260:Female; D005755:Gastrins / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D010418:Pentagastrin / Q000494:pharmacology*; D010671:Phenylurea Compounds / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D043887:Receptor, Cholecystokinin B / Q000037:antagonists & inhibitors*; D016037:Single-Blind Method; D055815:Young Adult
chemical_list: D001570:Benzodiazepinones; D005755:Gastrins; D010671:Phenylurea Compounds; D043887:Receptor, Cholecystokinin B; D010418:Pentagastrin; C104428:YF 476
keywords: YF476; gastrin receptor antagonist; netazepide; pentagastrin