Effect of netazepide, a gastrin/CCK2 receptor antagonist, on gastric acid secretion and rabeprazole-induced hypergastrinaemia in healthy subjects

Aims: To compare gastric acid suppression by netazepide, a Gastrin/CCK2 receptor antagonist, with that by a Proton Pump Inhibitor (PPI), and to determine if netazepide can prevent the trophic effects of PPI-induced hypergastrinaemia.

Methods: Thirty healthy subjects completed a double-blind, randomized, parallel group trial of oral netazepide and rabeprazole, alone and combined, once daily for 6 weeks. Primary end points were: basal and pentagastrin-stimulated gastric acid and 24 h circulating Gastrin and chromogranin A (CgA) at baseline, start and end of treatment, gastric biopsies at baseline and end of treatment and basal and pentagastrin-stimulated gastric acid and dyspepsia questionnaire after treatment withdrawal.

Results: All treatments similarly inhibited pentagastrin-stimulated gastric acid secretion. All treatments increased serum Gastrin, but the combination and rabeprazole did so more than netazepide alone. The combination also reduced basal acid secretion. Rabeprazole increased plasma CgA, whereas netazepide and the combination reduced it. None of the biopsies showed enterochromaffin-like (ECL) cell hyperplasia. Withdrawal of treatments led neither to rebound hyperacidity nor dyspepsia.

Conclusions: Netazepide suppressed pentagastrin-stimulated gastric acid secretion as effectively as did rabeprazole. The reduction in basal acid secretion and greater increase in serum Gastrin by the combination is consistent with more effective acid suppression. Despite our failure to show rabeprazole-induced ECL cell hyperplasia and rebound hyperacidity, the increase in plasma CgA after rabeprazole is consistent with a trophic effect on ECL cells, which netazepide prevented. Thus, netazepide is a potential treatment for the trophic effects of hypergastrinaemia and, with or without a PPI, is a potential treatment for acid-related conditions.