Factors Associated with Potassium-Competitive Acid Blocker Non-Response in Patients with Proton Pump Inhibitor-Refractory Gastroesophageal Reflux Disease

Background/Aims: Approximately 20-40% of patients with gastroesophageal reflux disease (GERD) are refractory to proton pump inhibitor (PPI) treatment. The acid-inhibitory effect of vonoprazan, a novel potassium-competitive acid blocker (P-CAB), is significantly greater when compared to the effect of PPIs. We investigated the efficacy of vonoprazan treatment for PPI-refractory GERD and factors associated with P-CAB non-response. Methods: We enrolled 277 GERD patients receiving continuous PPI therapy. Subjects completed a self-report questionnaire including the frequency scale for the symptoms of GERD (FSSG). Patients with PPI-refractory GERD received 20 mg of vonoprazan once daily for 8 weeks. After that, subjects completed the same questionnaire, and the results were used to identify P-CAB responders and non-responders. Results: Twenty-eight patients were identified as P-CAB responders and 26 were non-responders. Vonoprazan treatment significantly decreased scores of FSSG, nighttime symptom, and Athens Insomnia Scale. Multivariate analysis demonstrated co-existing functional dyspepsia (FD; OR 4.94) and the presence of sleep disturbances (OR 4.34) was associated with P-CAB non-response, whereas alcohol consumption was inversely associated. Conclusions: Vonoprazan treatment might be appropriate as a promising new strategy for PPI-refractory GERD. Co-existing FD, sleep disturbances, and alcohol abstinence were significantly associated with P-CAB non-response. Other therapeutic options should be considered in patients with these factors.