Potent acid inhibition by vonoprazan in comparison with esomeprazole with reference to genotype.T. Kagami, S. Sahara, H. Ichikawa, T. Uotani, M. Yamade, M. Sugimoto, Y. Hamaya, M. Iwaizumi, S. Osawa, K. Sugimoto, H. Miyajima andT. Furuta. Alimentary Pharmacology & Therapeutics.Article first published online: 18 MAR 2016
Background.Acid inhibitory effects of proton pump inhibitors (PPIs) are influenced by CYP2C19 genotype. In contrast, the potent acid inhibition of vonoprazan is not influenced by CYP2C19 genotype.
Aim.To compare the acid inhibitory effects of vonoprazan and esomeprazole in relation to CYP2C19 genotype.Methods. Twenty-eight healthy Japanese volunteers [7 CYP2C19 poor metabolisers (PMs), 11 intermediate metabolisers (IMs) and 10 rapid metabolisers (RMs)] received four different regimens in a randomised crossover manner: (i) vonoprazan 20 mg twice daily (b.d.), (ii) vonoprazan 20 mg daily, (iii) esomeprazole 20 mg b.d. and (iv) esomeprazole 20 mg daily. The timing of each dosing was 1 h before a meal. Twenty-four-hour intragastric pH monitoring was performed on day 7 on each regimen.Results.In the overall genotype group, pH ≥4 holding time ratios (pH 4 HTRs) with vonoprazan b.d., vonoprazan daily, esomeprazole b.d. and esomeprazole daily were 100%, 95%, 91%, and 68% respectively. pH 5 HTRs were 99%, 91%, 84% and 54% respectively. Vonoprazan b.d. potently suppressed acid for 24 h, and was significantly superior to other regimens irrespective of CYP2C19 genotype. Vonoprazan daily was equivalent to esomeprazole b.d. in IMs and PMs, but superior in RMs. CYP2C19 genotype-dependent differences were observed in esomeprazole daily but not in vonoprazan b.d. or daily.Conclusions.Vonoprazan 20 mg b.d. potently inhibited acid irrespective of CYP2C19 genotype, more potently than esomeprazole 20 mg b.d. pH 4 and 5 HTRs reached 100% and 99% respectively.