Gastroesophageal reflux disease (GERD) is a condition caused by the reflux of stomach contents into the esophagus, presenting with typical symptoms such as heartburn and acid regurgitation.

GERD is a chronic condition that affects quality of life, and patients with this condition are known to have a lower quality of life compared to healthy individuals. In particular, nocturnal heartburn can lead to sleep deprivation and affect daily life, as well as overall quality of life.

This study aims to evaluate the efficacy of alleviating nocturnal heartburn symptoms in patients with erosive reflux disease (ERD).

This multicenter, double-blind, randomized, active-controlled Phase 4 study aims to exploratorily evaluate the comparative effects and safety of zastaprazan 20 mg and esomeprazole 40 mg in subjects with gastroesophageal reflux disease.

Inclusion Criteria:

1. Korean adults aged 19 years or older as of the date of written consent
2. Those diagnosed with erosive gastroesophageal reflux disease based on upper gastrointestinal endoscopy (EGD)
3. Those who reported nighttime heartburn for more than 3 months at the time of screening (Visit 1)
4. Those who voluntarily decided to participate and provide written informed consent

Exclusion Criteria:

1. Those who cannot undergo upper gastrointestinal endoscopy (EGD)
2. Individuals with a history of drug or alcohol abuse (within the past year)
3. Individuals who have received other investigational products within one month prior to the screening visit (Visit 1)
4. In addition to the above, individuals with clinically significant findings that the investigator deems medically inappropriate for the present study