OBJECTIVES: Dexlansoprazole, a once-daily proton pump inhibitor (PPI) in a Dual Delayed Release formulation has demonstrated efficacy in a phase 3b study in maintaining symptom control among gastroesophageal reflux disease (GERD) patients previously controlled on twice daily (BID) PPIs. A pharmacy budget impact model (BIM) from a US payer perspective was developed to assess the impact of switching GERD patients from BID PPIs to QD dexlansoprazole over a three-year period. METHODS: An excel-based BIM on a hypothetical plan of 1 million members was developed. Based on published literature, 28% of members had GERD, among which 57% were prescribed PPI therapy. Among these, 74%, 23% and 3% of patients were on QD, BID and as needed PPI therapy, respectively. The proportion of patients switching from BID PPI to QD dexlansoprazole and efficacy of dexlansoprazole in achieving symptom control among those patients was assumed to range from 84%-88% based on the results of the phase 3b trial. Market share of PPIs and drug costs were derived using internally available data.  The market share of dexlansoprazole in year 1 was 4.23% and 8.44% pre- and post-switching, respectively. Model outcomes for years 1, 2 and 3 included: net total and per member per month (PMPM) pharmacy savings. RESULTS: The net pharmacy saving from switching to QD dexlansoprazole was estimated to be $7.9, $6.4 & $5.9 million for years 1, 2, & 3, respectively. PMPM pharmacy cost savings ranged from $0.66 in year 1 to $0.50 in year 3. The model results were most sensitive to cost of esomeprazole, proportion of GERD patients on PPI, prevalence of the disease, and proportion of patients switching from BID esomeprazole to QD dexlansoprazole. CONCLUSIONS: Based on the economic model, switching GERD patients from twice daily PPIs to QD dexlansoprazole may generate cost savings for US health plans.