M1878 The Novel 5-HT4 Receptor Partial Agonist RQ-00000010 Enhances a Rate of Gastric Emptying in Dog Without QT Interval Prolongation

Abstract

Background: Proton pump inhibitors (PPI) are the drug of first choice for treating patients with gastroesophageal reflux disease (GERD). However, about 50% of non-erosive reflux disease (NERD) patients have a poor response to PPI treatment. It is reported that esophageal motility disorder involving a decline in esophageal clearance contributes to the poor PPI response. Accordingly, a drug capable of enhancing esophageal motility would be beneficial in the treatment of NERD patients. Rikkunshito, a gastrointestinal prokinetic agent, is known to improve esophageal clearance in GERD patients and gastric emptying in functional dyspepsia patients and to increase secretion of ghrelin in rats. Aim: To clarify the efficacy of rikkunshito in NERD patients, we evaluated the effects of rikkunshito on esophageal and lower esophageal sphincter (LES) motility and symptoms. Methods: Fifteen patients were enrolled in the study. They were diagnosed as having NERD according to endoscopic testing and the score (6 points or more) obtained on the questionnaire for the diagnosis of reflux disease (QUEST). All patients stopped taking all gastrointestinal-related drugs for over 1 week prior to rikkunshito treatment, and were administered rikkunshito (7.5 g per day, orally) for 8 weeks. Esophageal and LES functions during liquid or semisolid swallow were evaluated using MII-EM following gold standard methods before and after rikkunshitotreatment. Symptoms were assessed using the Gastrointestinal Symptom Rating Scale (GSRS) before, 4 weeks after, and 8 weeks after treatment. Results: Rikkunshito-treatment significantly improved the mean of complete bolus transit (CBT) during liquid or semisolid swallow from 60.7±7.7% to 90.0±5.8% (p 79%, semisolid: >69%) for CBT decreased from 53.3% to 16.7% and from 60.0% to 33.3% after treatment, respectively. In manometry evaluation, rikkunshito significantly improved the mean of LES residual pressure during liquid swallow from 6.0±1.3 mmHg to 3.8±1.4 mmHg (p<0.05). In addition, rikkunshito significantly ameliorated total GI symptom scores in GSRS (from 2.1±0.2 to 1.6±0.1: (p<0.05)) and showed a tendency toward improvement of subscales for reflux symptoms, abdominal pain and dyspeptic symptoms. Conclusion: We found that rikkunshito improved the esophageal clearance and symptoms in NERD patients through the amelioration of esophageal and LES motility disorder. Thus, rikkunshito may become a useful drug for treating NERD patients.