The drug being tested in this study is called vonoprazan. Vonoprazan is being tested to treat people who have symptomatic gastroesophageal reflux disease (GERD) with a partial response to treatment with a high dose of esomeprazole. This study will look at improvement in heartburn symptoms in participants who take vonoprazan compared to esomeprazole.~The study will enroll approximately 213 patients. All participants will receive esomeprazole or esomeprazole placebo-matching capsules (this is a capsule that looks like esomeprazole but has no active ingredient) during a 7-week run-in period. Participants will then be randomly assigned (by chance, like flipping a coin) to one of the three treatment groups-which will remain undisclosed to the patient and study doctor during the study (unless there is an urgent medical need):~Esomeprazole 40 mg~Vonoprazan 20 mg~Vonoprazan 40 mg~All participants will be asked to take one capsule at the same time each day throughout the study. All participants will be asked to record heartburn symptoms in a diary every morning upon waking and every evening before going to sleep.~This multi-center trial will be conducted in Europe. The overall time to participate in this study is 12 weeks. Participants will make multiple visits to the clinic, and will be contacted by telephone 1 week after the last dose of study drug for a follow-up assessment.
The purpose of this study is to determine the effect of vonoprazan compared to esomeprazole for preventing heartburn symptoms over a 4-week treatment period in participants who have a partial response to treatment with esomeprazole.