This is a Phase 3 open-label crossover study to evaluate the acid-inhibitory effect following 7 days multiple doses of vonoprazan (20 mg per dose) and esomeprazole (20 mg per dose) (Cohort 1) or vonoprazan (20 mg per dose) and rabeprazole sodium (10 mg per dose) (Cohort 2) in healthy Japanese adult male participants (CYP2C19 genotype: EM). There will be a total of 20 participants, 5 per group for both Cohorts 1 and 2. At least 2 participants each with the homo EM (*1/*1) or hetero EM (*1/*2, *1/*3) CYP2C19 genotype will be enrolled among the 5 participants per group.~The drug being tested in this study is called vonoprazan. This study will look at the acid inhibitory effect following 7 days multiple doses of vonoprazan and esomeprazole (Cohort 1) or vonoprazan and rabeprazole sodium (Cohort 2) in healthy Japanese adult male participants with the CYP2C19 EM genotype.~The study will enroll a total of 20 participants, 5 per group for both Cohorts. At least 2 participants each with the homo EM (*1/*1) or hetero EM (*1/*2, *1/*3) CYP2C19 genotype will be enrolled among the 5 participants per group.~Group A, Cohort 1: vonoprazan (20 mg per dose for 7 days) followed by esomeprazole (20 mg per dose for 7 days)~Group B, Cohort 1: esomeprazole (20 mg per dose for 7 days) followed by TAK-438 (20 mg per dose for 7 days)~Group C, Cohort 2: vonoprazan (20 mg per dose for 7 days) followed by rabeprazole sodium (10 mg per dose for 7 days)~Group D, Cohort 2: rabeprazole sodium (10 mg per dose for 7 days) followed by vonoprazan (20 mg per dose for 7 days).~All participants will be asked to take Study Medication at the same time each day throughout the study. This single center trial will be conducted in Japan. The overall time to participate in this study is 31 days.
The purpose of this study is to investigate the acid-inhibitory effect of multiple oral doses of Vonoprazan (TAK-438) and the relative effect of vonoprazan versus two controls (esomeprazole and rabeprazole sodium) in healthy Japanese adult male participants with the CYP2C19 extensive metabolizer (EM) genotype.