Efficacy of TAK-438 Compared to AG-1749 (Lansoprazole) in the Treatment of Erosive Esophagitis

• Endoscopic Healing Rate Over 2 Weeks of Erosive Esophagitis [ Time Frame: 2 Weeks ] [ Designated as safety issue: No ]
• Endoscopic Healing Rate Over 4 Weeks of Erosive Esophagitis [ Time Frame: 4 Weeks ] [ Designated as safety issue: No ]

The purpose of this study is to determine the efficacy of TAK-438, once daily (QD), compared to lansoprazole in patients with erosive esophagitis of Grade A to D as defined by the LA classification grading system.

• Drug: TAK-438
  TAK-438 20 mg, tablets, orally, once daily for up to 8 weeks.
• Drug: Placebo

  Lansoprazole placebo-matching capsules, orally, once daily for up to 8 weeks.

  For participants whose EE is not endoscopically healed at Week 8, the participants will receive additional treatment of TAK-438 40 mg, tablets, orally, once daily for up to an additional 8 weeks.

  Other Name: AG-1749
• Drug: Lansoprazole

  Lansoprazole 30 mg, capsules, orally, once daily for up to 8 weeks.

  For participants whose EE is not endoscopically healed at Week 8, the participants will receive additional treatment of TAK-438 40 mg, tablets, orally, once daily for up to an additional 8 weeks.

  Other Name: AG-1749
• Drug: Placebo
  TAK-438 placebo-matching tablets, orally, once daily for up to 8 weeks.

• Experimental: TAK-438 20 mg QD
  Interventions:

  • Drug: TAK-438
  • Drug: Placebo
• Active Comparator: AG-1749 30 mg QD
  Interventions:

  • Drug: Lansoprazole
  • Drug: Placebo

Inclusion Criteria:

1. At Visit 1 (start of the observation period), the participant must have endoscopically confirmed erosive esophagitis of Grade A to D, as defined by the LA classification grading system, and the target number of participants who are clearly Grade C or D is 30% (120 participants) or more of the total participants.
2. Outpatient (including inpatient for examination)

Exclusion Criteria:

1. Participants with an esophagus-related complication (eosinophilic esophagitis, esophageal varices, scleroderma, viral or fungal infection, esophageal stenosis, etc.), a history of radiotherapy or cryotherapy of the esophagus, a caustic or physiochemical trauma (esophageal sclerotherapy, etc.). However, participants with Schatzki's ring (mucosal tissue ring around inferior esophageal sphincter) or Barrett's esophagus are allowed to be included.
2. Participants who have received surgery or treatment affecting gastroesophageal reflux (cardioplasty, dilation of esophageal stenosis [excluding Schatzki's ring], etc.), or who have a history of surgery of stomach or duodenum (excluding removal of benign polyp under endoscopy)
3. Participants who have acute upper gastrointestinal bleeding, gastric or duodenal ulcer (mucosal defect with white coating) within 30 days prior to Visit 1 (start of the observation period). However, participants with gastric or duodenal erosions are allowed to be included.
4. Participants with a previous or current history of Zollinger-Ellison syndrome, or other gastric acid hypersecretion disorders