Response to "CYP-Mediated Drug-Drug Interaction Is Not a Major Determinant of Attenuation of Antiplatelet Function of Clopidogrel by Vonoprazan"

Cytochrome P450-Based Drug-Drug Interactions of Vonoprazan In Vitro and In Vivo

Background

Vonoprazan fumarate is a potassium-competitive acid blocker that was developed as a novel acid-suppressing drug for multiple indications. As a potential alternative to proton-pump inhibitors, the determination of the drug-drug interactions is vital for further applications. Probe drug cocktails are a type of rapid, economical, and efficient approach for evaluating cytochrome P450 enzyme activities. Since vonoprazan is metabolized partly by cytochrome P450, cocktails were used to study CYP-based drug-drug interactions.

Methods

This study was conducted both in vitro and in vivo. In the in vitro study of rat liver microsomes, ultra-performance liquid chromatography coupled to tandem mass spectrometry was utilized to assess the reversible inhibition of cytochrome P450 by vonoprazan by determining the concentration of probe drugs (phenacetin, bupropion, tolbutamide, dextromethorphan, midazolam, chlorzoxazone). The differences in the levels of probe drugs between the rat groups with or without vonoprazan administration were also tested in the rats.

Results

In vitro analysis revealed that the IC₅₀ values of midazolam, tolbutamide, dextromethorphan, and bupropion in rat microsomes were 22.48, 18.34, 3.62, and 3.68 μM, respectively, while chlorzoxazone and phenacetin displayed no inhibition. In vivo analysis revealed that midazolam, bupropion, dextromethorphan, and tolbutamide showed significant (P < 0.05) differences in distinct pharmacokinetic parameters after vonoprazan administration, while those of chlorzoxazone and phenacetin were not significantly different.

Conclusion

The in vitro and in vivo results indicated that vonoprazan can inhibit CYP3A4, CYP2C9, CYP2D6, and CYP2B6, suggesting that the coadministration of vonoprazan with cytochrome P450 substrates should be performed cautiously in clinical settings.

Inhibitory Effect of Vonoprazan on the Metabolism of [14C]Prasugrel in Human Liver Microsomes

BACKGROUND AND OBJECTIVES

A recent report indicated that the pharmacodynamic interaction between clopidogrel and vonoprazan leading to attenuation of the anti-platelet effect of clopidogrel was unlikely to be caused by the inhibition of cytochrome P450 (CYP) 2B6, CYP2C19, or CYP3A4/5 by vonoprazan, based on in vitro CYP inhibition data. The current report investigates another important antiplatelet inhibitor, prasugrel, that is also activated through metabolism by CYP2B6, CYP2C19 and CYP3A4/5, for its CYP-based DDI potential with vonoprazan. The report describes in vitro metabolic inhibition assessments using radiolabeled prasugrel and human liver microsomes (HLMs).

METHODS

Reversible and time-dependent inhibition studies of vonoprazan as well as esomeprazole on the formation of the active metabolite R-138727 of prasugrel were conducted using HLMs.

RESULTS

Vonoprazan up to 10 μM, a concentration over 100-fold higher than the clinical maximum plasma concentration (C_max) of 75.9 nM after 20 mg once daily for 7 days, did not significantly affect the formation of R-138727 from [¹⁴C]prasugrel via reversible or time-dependent inhibition.

CONCLUSIONS

The in vitro data show that the pharmacodynamic interaction reported in the literature between vonoprazan and prasugrel is unlikely to be caused by CYP inhibition by vonoprazan. The results were similar to those obtained from the study with clopidogrel.

Effects of proton pump inhibitors, esomeprazole and vonoprazan, on the disposition of proguanil, a CYP2C19 substrate, in healthy volunteers

AIMS

Vonoprazan, a new class of potassium-competitive proton pump inhibitors has been found to attenuate the antiplatelet function of clopidogrel in a recent clinical study, despite weak in vitro activity against CYP2C19. To elucidate the mechanism of this interaction, the present study investigated the effects of esomeprazole and vonoprazan on the pharmacokinetics of proguanil, a CYP2C19 substrate.

METHODS

Seven healthy male volunteers (CYP2C19 extensive metabolizers) received a single oral administration of 100 mg proguanil/250 mg atovaquone (control phase), oral esomeprazole (20 mg) for 5 days followed by proguanil/atovaquone (esomeprazole phase) and oral vonoprazan (20 mg) for 5 days followed by proguanil/atovaquone (vonoprazan phase). Concentrations of proguanil and its metabolite, cycloguanil, in plasma and urine in each phase were determined using liquid chromatography-tandem mass spectrometry.

RESULTS

Coadministration with proton pump inhibitors resulted in increase and decrease in the area under the plasma concentration-time curve (AUC) of proguanil and cycloguanil, respectively, significantly reducing their AUC ratio (cycloguanil/proguanil) to 0.317-fold (95% confidence interval [CI] 0.256-0.379) and 0.507-fold (95% CI 0.409-0.605) in esomeprazole phase and vonoprazan phase, respectively. Esomeprazole and vonoprazan also significantly reduced the apparent formation clearance (cumulative amount of cycloguanil in urine divided by AUC of proguanil) to 0.324-fold (95% CI 0.212-0.436) and 0.433-fold (95% CI 0.355-0.511), respectively, without significant changes in renal clearance of proguanil and cycloguanil.

CONCLUSIONS

Although further studies are needed, both esomeprazole and vonoprazan potentially inhibit CYP2C19 at clinical doses, suggesting caution in the coadministration of these drugs with CYP2C19 substrates.