The effect of once daily omeprazole and succinic acid (VECAM) vs once daily omeprazole on 24-h intragastric pH Y. CHOWERS,* T. ATAROT,* V. S. PRATHA & R. FASSà *Vecta Ltd., Ra’annana, Israel  Clinical Applications Laboratory, San Diego, CA, USA àSouthern Arizona VA Health Care System and University of Arizona Health Sciences Center, Tucson, AZ, USA Abstract Background Parietal cell H + /K + ATPase activation is essential for optimal proton pump inhibitor (PPI) activity. Succinic acid (SA) was shown to induce gas- tric acid secretion. VECAM is a combination of omeprazole (OMP) and SA. To compare the effect of once daily bedtime dosing of VECAM 40 and VECAM 20 without food vs OMP 20 mg administered before breakfast on gastric acidity. Methods Open label, randomized, crossover study enrolling 36 healthy subjects comparing the study treatments at steady state for 24 h intragastric pH monitoring. Key Results The median percent time intragastric pH > 4 demonstrated that VECAM 40 was superior to VECAM 20 (65.7% vs 49.1% P < 0.0001) and OMP 20 mg (65.7% vs 47.6% P = 0.005) during 24 h. VE- CAM 40 was superior to VECAM 20 (52.8% vs 38.8% P = 0.0079) and OMP 20 mg (52.8% vs 27.2% P < 0.0001), and VECAM 20 was superior to OMP 20 mg (38.8 vs 27.2 P = 0.0069) during the nighttime. VECAM 20 and OMP 20 mg were comparable during 24 h. Conclusions & Inferences VECAM 40 and VECAM 20 were significantly better in maintaining intragastric pH > 4 during the nighttime than OMP 20 mg. Succinic acid eliminates the need for a sub- sequent meal for intragastric pH control by VECAM. Keywords gastroesophageal reflux disease, nighttime gastric acid reflux, nighttime heartburn, omeprazole, succinic acid. INTRODUCTION Gastroesophageal reflux disease (GERD) is a very common clinical disorder. In the general population, 20% of people experience heartburn or acid regurgita- tion at least once a week 1 and 40% at least once a month 2 GERD symptoms occur primarily during day- time, but up to 80% of the patients also suffer from symptoms during nighttime. 2,3 The majority of night- time symptoms occur during the first hours of sleep. 4 Effective control of nocturnal GERD is clinically important because symptoms affect patients’ sleep quality, daytime work productivity, and quality of life. In addition, esophageal inflammation, GERD compli- cations and extraesophageal manifestations are more common in patients with nocturnal GERD as com- pared with patients having daytime symptoms only. Proton pump inhibitors (PPIs) have become the mainstay of GERD treatment because of their high efficacy in inhibiting acid secretion. However, despite their superior efficacy, a few areas of unmet needs in GERD treatment remain. Proton pump inhibitors bind only to activated proton pumps. Hence, PPIs have to be taken 30–60 min prior to a meal for maximum efficacy. This practice has been associated with low compli- ance, resulting in only 6% of patients who dose their PPI correctly among once daily dosers. 5 Compliance is particularly problematic in GERD patients who suffer from nighttime symptoms. Furthermore, the patients who wish to prevent nighttime symptoms have to take their PPI before dinner rather than at bedtime. 5 Indeed, control of nighttime intragastric pH with PPI therapy has been only partially successful, resulting in noctur- nal acid breakthrough during twice-daily omeprazole (OMP) or lansoprazole therapy. 6 To overcome dependency on food consumption, a compound that maximally activates proton pumps Address for Correspondence Tal Atarot, 10 Zarhin street, PO B 4368, Ra’annana 43662, Israel. Tel: +972 52 895 8458; fax: +972 153 9 768 0304; e-mail: tal@vecta.co.il Received: 12 July 2011 Accepted for publication: 27 December 2011 Neurogastroenterol Motil (2012) 24, 426–e209 doi: 10.1111/j.1365-2982.2012.01884.x Ó 2012 Blackwell Publishing Ltd 426 Neurogastroenterology & Motility