Exploration of the clinical characteristics and potential mechanisms of liver injury induced by proton pump inhibitors

BACKGROUND AND AIMS

Data related to clinical characteristics and potential mechanisms of proton pump inhibitors (PPIs)-related liver injury are sparse, thus the purpose of this study is to summarize the clinical features and molecular mechanisms of PPIs-induced liver injury.

METHODS

We collected case report on liver injury induced by PPIs in English and Chinese for retrospective analysis. Clinical and pathological data and outcomes were obtained and analyzed. Network pharmacology and molecular docking techniques were employed to examine the mechanism.

RESULT

Twenty-three patients with PPIs-induced liver injury were enrolled. PPIs-induced liver injury is a rare adverse reaction, ranging from asymptomatic elevated transaminases to fulminant liver failure. Omeprazole was the drug with the highest number of associated reports. The most common symptom was fatigue. The most common liver injury pattern was hepatocellular injury. A total of 13 intersection targets of PPIs and liver injury were screened, and the top 10 targets were included, and the PI3K-Akt signaling pathway was significantly enriched. The results of molecular docking implied that the PPIs could combine well with key targets.

CONCLUSION

Patients receiving long-term treatment with PPIs should consider monitoring liver function. PPIs exhibit considerable capacity in liver injury via especially the PI3K-Akt signaling pathway.

The Effect of Food on the Pharmacokinetics of the Potassium-Competitive Acid Blocker Vonoprazan

Herein, we report a food‐effect study of vonoprazan, an oral potassium‐competitive acid blocker. In a phase 1, randomized, open‐label, crossover study, healthy subjects received a single 20‐mg dose of vonoprazan either following an overnight fast or 30 minutes after a high‐fat breakfast. Plasma vonoprazan levels were determined at 0 hour and at 17 subsequent assessment points up to 48 hours after dosing. After a 5‐day washout, subjects received a second 20‐mg vonoprazan dose in the alternative fed/fasted state (identical process repeated). Twenty‐four subjects completed the study. Vonoprazan exposure was not meaningfully affected by food. Geometric mean ratios for maximum concentration, area under the concentration‐time curve from time 0 to 24 hours, and area under the plasma concentration–time curve extrapolated to infinity obtained under fed and fasting conditions were 1.05 (90% confidence interval, 0.98‐1.12), 1.13 (1.09‐1.18), and 1.15 (1.11‐1.19), respectively. Four subjects experienced 6 adverse events that were all mild and considered unrelated to the study drug. Vonoprazan can be administered without regard to food intake.

Safety, Tolerability and Pharmacokinetics of Single Ascending and Multiple Oral Doses of Tegoprazan in Healthy Chinese Subjects

BACKGROUND AND OBJECTIVES

Tegoprazan is one of the potassium-competitive acid blockers (P-CABs). It exhibits its anti-secretory effects by competitively and reversibly blocking the availability of K⁺ of the H⁺, K⁺-ATPase. This study was designed to investigate the safety and pharmacokinetics of tegoprazan in healthy Chinese subjects.

METHODS

Thirty-eight healthy Chinese subjects were recruited in this randomized, single-center, double-blind, placebo-controlled study, with a single ascending dose of 50, 100, 200 mg and a multiple dose of 100 mg for 10 days. The plasma concentration of tegoprazan was determined by a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method. Pharmacokinetics were evaluated via non-compartmental and compartmental model analysis. Safety was assessed by physical examinations, vital signs, clinical laboratory tests, and electrocardiograms.

RESULTS

No serious adverse event was observed in this study. After single-dose administration (50, 100 and 200 mg), tegoprazan was rapidly absorbed with a median maximum measure plasma concentration (T_max) at 0.5 h and declined with a terminal (elimination) half-life (t_1/2) of 3.87-4.57 h. The maximum measured plasma concentration (C_max) for tegoprazan was 813.80, 1494.60 and 2829.00 ng/mL. Meanwhile, the corresponding area under the concentration-time curve (AUC) from time zero to infinity (AUC_0-inf) was 2761.00, 5980.05 and 11,044.72 ng∙h/mL in 50, 100, 200 mg group, respectively. Dose-dependent increase was observed in the value of C_max and AUC after administration of tegoprazan 50 to 200 mg. The two-compartment model well described the pharmacokinetic profile of tegoprazan. In the steady state, no accumulation was found after repeated administration at the 100-mg dose level. No experimental differences were found based on gender.

CONCLUSIONS

Tegoprazan was well tolerated in the dose range of 50-200 mg in single- and 100 mg in multiple-dose studies. Tegoprazan shows dose linearity with oral administration after a single dose of 50 to 200 mg and less drug accumulation after 10 days of continuous administration in 100 mg.

Randomised clinical trial: safety, tolerability, pharmacokinetics, and pharmacodynamics of single and multiple oral doses of tegoprazan (CJ-12420), a novel potassium-competitive acid blocker, in healthy male subjects

BACKGROUND

Tegoprazan (CJ-12420) is a potassium-competitive acid blocker (P-CAB) with therapeutic potential for gastro-oesophageal reflux disease (GERD) by reversibly suppressing gastric H⁺ /K⁺ -ATPase.

AIMS

To investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of tegoprazan METHODS: A phase I, randomised, double-blind and placebo-controlled clinical trial was conducted in 56 healthy male subjects without Helicobacter pylori infection. In the single ascending dose study, 50, 100, 200 and 400 mg tegoprazan were administered to 32 subjects. In the multiple ascending dose study, 100 and 200 mg tegoprazan were administered every 24 hours to each of the eight subjects for 7 days. In the comparative pharmacodynamics study, 40 mg esomeprazole was administered to eight subjects every 24 hours for 7 days. The assessment included safety, tolerability, pharmacodynamics through monitoring of 24-hour gastric pH and pharmacokinetics of tegoprazan in plasma and urine.

RESULTS

Tegoprazan was generally well tolerated. Most adverse events reported in the study were mild in intensity and resolved without any sequelae. Exposure to tegoprazan increased in a dose-proportional manner. Multiple dosing with tegoprazan showed no accumulation in plasma on day 7. The pharmacodynamic analysis revealed that tegoprazan showed rapid, dose-dependent gastric acid suppression.

CONCLUSIONS

Tegoprazan was well tolerated and showed rapid and potent gastric acid suppression. This supports the further development of tegoprazan as a treatment for acid-related disorders.

The use of defibrotide in blood and marrow transplantation

Hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a potentially life-threatening complication of conditioning during hematopoietic stem cell transplantation (HSCT) or chemotherapy without HSCT, with a historically reported mean incidence of 13.7% post-HSCT. Typical symptoms of VOD/SOS may include hyperbilirubinemia, painful hepatomegaly, weight gain, and ascites. Defibrotide, a polydisperse mixture of predominantly single-stranded polydeoxyribonucleotides, is currently the only therapy approved to treat hepatic VOD/SOS with pulmonary/renal dysfunction (ie, multiorgan dysfunction/multiorgan failure [MOD/MOF]) following HSCT in the United States and to treat severe hepatic VOD/SOS post-HSCT in the European Union. In preclinical and human studies, defibrotide has demonstrated profibrinolytic, antithrombotic, anti-inflammatory, and angio-protective actions, thus promoting an anticoagulant phenotype of the endothelium that protects and stabilizes the function of endothelial cells. In a phase 3, historically controlled, multicenter trial in adults and children with VOD/SOS and MOD/MOF (defibrotide: n = 102; controls treated before defibrotide availability: n = 32), defibrotide resulted in significantly greater day +100 survival following HSCT (38.2%) vs controls (25.0%; propensity analysis-estimated between-group difference: 23%; P = .0109). The most common adverse events (AEs) were hypotension and diarrhea; rates of common hemorrhagic AEs were similar in the defibrotide and historical control group (64% and 75%, respectively). In a phase 3 prophylaxis trial, defibrotide was found to lower incidence of VOD/SOS in children (not an approved indication) and reduce the incidence of graft-versus-host disease. This review describes the development and clinical applications of defibrotide, focusing on its on-label use in patients with VOD/SOS and MOD/MOF after HSCT.

[Gastroesophageal Reflux Disease]

Gastroesophageal reflux disease (GERD) is a condition that develops when reflux of stomach contents causes troublesome symptoms and/or complications. The prevalence of GERD is increasing worldwide and in Asia-Pacific. The latest Korean guidelines for GERD were published in 2012, and several international guidelines and consensus statements for the management of GERD have also been recently published. Here, we review these guidelines and consensus statements in order to provide a better understanding of the diagnosis and treatment of GERD.

Potent Potassium-competitive Acid Blockers: A New Era for the Treatment of Acid-related Diseases

Conventional proton pump inhibitors (PPIs) are used as a first-line therapy to treat acid-related diseases worldwide. However, they have a number of limitations including slow onset of action, influence by cytochrome P450 polymorphisms, unsatisfactory effects at night, and instability in acidic conditions. Alternative formulations of conventional PPIs have been developed to overcome these problems; however, these drugs have only introduced small advantages for controlling acid secretion compared to conventional PPIs. Potassium-competitive acid blockers (P-CABs) were developed and have beneficial effects including rapid, long-lasting, and reversible inhibition of the gastric hydrogen potassium ATPase, the proton pump of the stomach. Vonoprazan was recently innovated as a novel, orally active P-CAB. It is currently indicated for the treatment of gastric and duodenal ulcers, reflux esophagitis, and prevention of low-dose aspirin- or nonsteroidal anti-inflammatory drug-related gastric and duodenal ulcer recurrence in Japan. Vonoprazan does not require enteric coating as it is acid-stable, and it can be taken without food because it is quickly absorbed. Vonoprazan accumulates in parietal cells under both acidic and neutral conditions. It does not require an acidic environment for activation, has long-term stability at the site of action, and has satisfactory safety and tolerability. Thus, vonoprazan may address the unmet medical need for the treatment of acid-related diseases.

Pharmacokinetic Drug-Drug Interactions Between Vonoprazan and Low-Dose Aspirin or Nonsteroidal Anti-inflammatory Drugs: A Phase 2, Open-Label, Study in Healthy Japanese Men

Background

Gastroprotective agents are recommended for patients receiving low-dose aspirin (LDA) or nonsteroidal anti-inflammatory drugs (NSAIDs). Vonoprazan is a potassium-competitive acid blocker recently approved for the prevention of peptic ulcer recurrence in patients receiving LDA or NSAIDs.

Methods

This phase 2, open-label, single-center study in healthy Japanese males evaluated drug–drug interactions between vonoprazan 40 mg and LDA (100 mg) or NSAIDs [loxoprofen sodium (60 mg), diclofenac sodium (25 mg), or meloxicam (10 mg)] and vice versa. Subjects were allocated to one of eight cohorts and received their orally administered treatment regimen (to assess the effect of vonoprazan vs. NSAID or LDA, or vice versa) once daily. Endpoints were the pharmacokinetics of plasma concentrations of the study drugs alone and in combination (primary), safety (secondary), and vonoprazan effects on aspirin-mediated inhibition of platelet-aggregation.

Results

Of 109 subjects screened, 64 were assigned to one of eight cohorts (n = 8 per cohort) and received treatment, one subject discontinued due to a treatment-emergent adverse event (TEAE), and 63 completed the study. There were few differences in the pharmacokinetics of vonoprazan when administered with LDA or NSAIDs, and few differences in the pharmacokinetics of LDA or NSAIDs when administered with vonoprazan. The differences were small and not clinically meaningful. Inhibition of arachidonic-induced platelet aggregation by LDA was not influenced by vonoprazan. Six patients experienced a TEAE, all were mild and were deemed unrelated to study drugs. One subject withdrew due to infection (tonsillitis).

Conclusions

No clinically meaningful drug–drug interactions were observed and vonoprazan was well tolerated when administered with LDA or NSAIDs.

Study registration

JapicCTI-153100

Electronic supplementary material

The online version of this article (doi:10.1007/s40261-016-0455-2) contains supplementary material, which is available to authorized users.

Vonoprazan-based therapy for Helicobacter pylori eradication: experience and clinical evidence

Stable suppression of gastric acid secretion is a crucial factor in Helicobacter pylori eradication. Vonoprazan is a potassium-competitive acid blocker recently approved for use in Japan. As vonoprazan has a long duration of action and causes rapid and strong inhibition of gastric acid secretion, it has gained clinical attention for treating erosive oesophagitis, peptic ulcers, and H. pylori infection. In this review, we discuss the recent knowledge regarding the safety and efficacy of vonoprazan, focusing on its use in H. pylori eradication. The latest literature and our clinical experience have shown that vonoprazan-based therapies have satisfactory eradication rates. Additionally, vonoprazan-based therapies are associated with similar rates of adverse events as standard triple therapies with conventional proton-pump inhibitors.

Potassium-competitive acid blockers: Advanced therapeutic option for acid-related diseases

Acid-related diseases (ARDs), such as peptic ulcers and gastroesophageal reflux disease, represent a major health-care concern. Some major milestones in our understanding of gastric acid secretion and ARD treatment reached during the last 50years include 1) discovery of histamine H₂-receptors and development of H₂-receptor antagonists, 2) identification of H⁺,K⁺-ATPase as the parietal cell proton pump and development of proton pump inhibitors (PPIs), and 3) identification of Helicobacter pylori (H. pylori) as the major cause of peptic ulcers and development of effective eradication regimens. Although PPI treatments have been effective and successful, there are limitations to their efficacy and usage, i.e. short half-life, insufficient acid suppression, slow onset of action, and large variation in efficacy among patients due to CYP2C19 metabolism. Potassium-competitive acid blockers (P-CABs) inhibit H⁺,K⁺-ATPase in a reversible and K⁺-competitive manner, and exhibit almost complete inhibition of gastric acid secretion from the first dose. Many pharmaceutical companies have tried to develop P-CABs, but most of their clinical development has been discontinued due to safety concerns or a similar efficacy to PPIs. Revaprazan was developed in Korea and was the first P-CAB approved for sale. Vonoprazan, approved in 2014 in Japan, has a completely different chemical structure and higher pKa value compared to other P-CABs, and exhibits rapid onset of action and prolonged control of intragastric acidity. Vonoprazan is an effective treatment for ARDs that is especially effective in healing reflux esophagitis and for H. pylori eradication. P-CABs, such as vonoprazan, promise to further improve the management of ARDs.

Synthetic studies of five-membered heteroaromatic derivatives as potassium-competitive acid blockers (P-CABs)

On the basis of a series of novel and potent potassium-competitive acid blockers represented by 1-sulfonylpyrrole derivative 7, we prepared several five-membered heterocyclic analogues (8) and evaluated their H(+),K(+)-ATPase activities in vitro. We also assessed the role of the methylaminomethyl side chain by comparison with methylamino and ethylamino derivatives. We observed that the five-membered core ring and its orientation affect inhibitory activity and that the methylaminomethyl moiety is the best side chain. On the basis of potency and ligand-lipophilicity efficiency, compound 7 remains the most drug-like of the compounds studied to date. This study revealed the factors necessary for potent H(+),K(+)-ATPase inhibition, such as differences in electron density, the properties of the lone pair at each apical position of the heteroaromatic ring, and the geometry of the substituents.

Characterization of a novel potassium-competitive acid blocker of the gastric H,K-ATPase, 1-[5-(2-fluorophenyl)-1-(pyridin-3-ylsulfonyl)-1H-pyrrol-3-yl]-N-methylmethanamine monofumarate (TAK-438)

Inhibition of the gastric H,K-ATPase by the potassium-competitive acid blocker (P-CAB) 1-[5-(2-fluorophenyl)-1-(pyridin-3-ylsulfonyl)-1H-pyrrol-3-yl]-N-methylmethanamine (TAK-438), is strictly K(+)-competitive with a K(i) of 10 nM at pH 7. In contrast to previous P-CABs, this structure has a point positive charge (pK(a) 9.06) allowing for greater accumulation in parietal cells compared with previous P-CABs [e.g., (8-benzyloxy-2-methyl-imidazo(1,2-a)pyridin-3-yl)acetonitrile (SCH28080), pK(a) 5.6]. The dissociation rate of the compound from the isolated ATPase is slower than other P-CABs, with the t(1/2) being 7.5 h in 20 mM KCl at pH 7. The stoichiometry of binding of TAK-438 to the H,K-ATPase is 2.2 nmol/mg in the presence of Mg-ATP, vanadate, or MgP(i). However, TAK-438 also binds enzyme at 1.3 nmol/mg in the absence of Mg(2+). Modeling of the H,K-ATPase to the homologous Na,K-ATPase predicts a close approach and hydrogen bonding between the positively charged N-methylamino group and the negatively charged Glu795 in the K(+)-binding site in contrast to the planar diffuse positive charge of previous P-CABs. This probably accounts for the slow dissociation and high affinity. The model also predicts hydrogen bonding between the hydroxyl of Tyr799 and the oxygens of the sulfonyl group of TAK-438. A Tyr799Phe mutation resulted in a 3-fold increase of the dissociation rate, showing that this hydrogen bonding also contributes to the slow dissociation rate. Hence, this K(+)-competitive inhibitor of the gastric H,K-ATPase should provide longer-lasting inhibition of gastric acid secretion compared with previous drugs of this class.

Update on the mechanisms of gastric acid secretion

Acid-related disorders represent a major healthcare concern. In recent years, our understanding of the physiologic processes underlying gastric acid secretion has improved notably. The identity of several apical ion transport proteins, which are necessary for acid secretion to take place, has been resolved. The recent developments have uncovered potential therapeutic targets for the treatment of acid-related disorders. This brief review provides an update on the mechanisms of gastric acid secretion, with a particular focus on apical ion transport.