The purpose of this study is to evaluate the BE of single oral dose of TAK-438 OD 20 milligram (mg) tablet without water and TAK-438 20 mg tablet with water (Study 1), and TAK-438 OD 20 mg tablet with water and TAK-438 20 mg tablet with water (Study 2) in Japanese healthy adult male participants.

The drug being tested in this study is called TAK-438 OD tablet. TAK-438 OD tablet is being tested in Japanese healthy adult men. This study will evaluate bioequivalence of single oral dose of TAK-438 OD 20 mg tablet without water and TAK-438 20 mg tablet with water (Study 1), and TAK-438 OD 20 mg tablet with water and TAK-438 20 mg tablet with water (Study 2).

The study will enroll up to 144 participants in total (Study 1 + 2). In Study 1 and 2, participants will be randomly assigned (by chance, like flipping a coin) to one of the two treatment groups;

Study 1:

• TAK-438 OD 20 mg tablet without water (Period 1) + TAK-438 20 mg tablet with water (Period 2)
• TAK-438 20 mg tablet with water (Period 1) + TAK-438 OD 20 mg tablet without water (Period 2)

Study 2:

• TAK-438 OD 20 mg tablet with water (Period 1) + TAK-438 20 mg tablet with water (Period 2)
• TAK-438 20 mg tablet with water (Period 1) + TAK-438 OD 20 mg tablet with water (Period 2)

This single-center trial will be conducted in Japan. The overall time to participate in this study is approximately 11 days. Participants will make two visits to the clinic and be hospitalized for four days each in Periods 1 and 2.

Inclusion Criteria:

1. In the opinion of the investigator or sub-investigator, the participant is capable of understanding and complying with protocol requirements.
2. The participant signs and dates a written, informed consent form prior to the initiation of any study procedures.
3. The participant is a healthy Japanese adult male, aged 20 to 60 years, inclusive, at the time of informed consent.
4. The participant weighs at least 50 kilogram (kg) and has a body mass index (BMI) from 18.5 to 25.0 kilogram per square meter (kg/m^2), inclusive at Screening.
5. The participant must be a current nonsmoker who has not used tobacco- or nicotine-containing products (example, nicotine patch) for at least 6 months prior to the start of study drug administration in Period 1.
6. The participant must be judged to be in good health by the investigator, based on clinical evaluations including laboratory safety tests, medical history, physical examination, 12-lead electrocardiogram (ECG), and vital sign measurements performed at the Screening Visit and prior to the start of study drug administration in Period 1.

Exclusion Criteria:

1. The participant has received any investigational compound within 16 weeks (112 days) prior to the start of study drug administration in Period 1.
2. The participant has received TAK-438 in a previous clinical study or as a therapeutic agent.
3. The participant is an immediate family member of or a study site employee, or is in a dependent relationship with a study site employee who is involved in the conduct of this study (example, spouse, parent, child, sibling) or may consent under duress.
4. The participant has uncontrolled, clinically significant neurologic, cardiovascular, pulmonary, hepatic, renal, metabolic, gastrointestinal, urologic, or endocrine disease or other abnormality (other than the disease being studied), which may impact the ability of the participant to participate in the study or potentially confound its results.
5. The participant has hypersensitivity to any component of TAK-438 OD tablet or TAK-438 tablet.
6. The participant has a positive urine drug result for drugs of abuse at Screening.
7. The participant has a history of drug or alcohol abuse within 2 years prior to the Screening visit or is unwilling to agree to abstain from alcohol and drugs throughout the study.
8. The participant has taken any excluded medication, supplements, or food products during the specified time periods.
9. The participant has current or recent (within 6 months) gastrointestinal disease that would be expected to influence the absorption of drugs (ie, a history of malabsorption, esophageal reflux, peptic ulcer disease, erosive esophagitis), frequent (more than once per week) occurrence of heartburn, or any surgical intervention.
10. The participant has a history of cancer, except basal cell carcinoma which has been in remission for at least 5 years prior to Day 1.
11. The participant has a positive test result for hepatitis B virus surface antigen (HBsAg), hepatitis C virus (HCV) antibody, human immunodeficiency virus (HIV) antibody/antigen, or serological reactions for syphilis at Screening.
12. The participant has poor peripheral venous access.
13. The participant has undergone whole blood collection of at least 200 milliliter (mL) within 4 weeks (28 days) or at least 400 mL within 12 weeks (84 days) prior to the start of study drug administration in Period 1.
14. The participant has undergone whole blood collection of at least 800 mL in total within 52 weeks (364 days) prior to the start of study drug administration in Period 1.
15. The participant has undergone blood component collection within 2 weeks (14 days) prior to the start of study drug administration in Period 1.
16. The participant has a Screening or Check-in (Day -1) ECG that was abnormal (clinically significant).
17. The participant has abnormal Screening laboratory values that suggest a clinically significant underlying disease or participant with the following laboratory abnormalities: alanine aminotransferase (ALT) or aspartate aminotransferase (AST) above the upper limits of normal (ULN).
18. The participant who, in the opinion of the investigator or sub-investigator, is unlikely to comply with the protocol or is unsuitable for any other reason.

Takeda makes patient-level, de-identified data sets and associated documents available for all interventional studies after applicable marketing approvals and commercial availability have been received (or program is completely terminated), an opportunity for the primary publication of the research and final report development has been allowed, and other criteria have been met as set forth in Takeda's Data Sharing Policy (see www.TakedaClinicalTrials.com for details). To obtain access, researchers must submit a legitimate academic research proposal for adjudication by an independent review panel, who will review the scientific merit of the research and the requestor's qualifications and conflict of interest that can result in potential bias. Once approved, qualified researchers who sign a data sharing agreement are provided access to these data in a secure research environment.

The safety analysis set was defined as all participants who received at least one dose of study drug.

Treatment-emergent adverse events (TEAEs) are adverse events (AE) that started after the first dose of study drug until Day 3 in Period 2 (up to Day 13)

At each visit the investigator had to document any occurrence of adverse events and abnormal laboratory findings. Any event spontaneously reported by the participant or observed by the investigator was recorded, irrespective of the relation to study treatment.