Safety, tolerability, pharmacodynamics and pharmacokinetics of DWP14012, a novel potassium-competitive acid blocker, in healthy male subjects

Efficacy of Potassium-Competitive Acid Blockers Versus Proton Pump Inhibitors for Gastric Ulcers: Bayesian and Frequentist Network Meta-Analysis With Cross-Inference Through a Quality management System

Purpose

Proton pump inhibitors (PPIs) have been the mainstay treatment for gastric ulcer (GU) for over 30 years. However, since the discovery of a new class of acid suppressants, potassium-competitive acid blockers (P-CABs), the desire for a therapeutic agent has continued and the clinical trials on P-CABs have been conducted. In this regard, we aimed to assess whether P-CABs are noninferior to PPIs in patients with GU in terms of efficacy.

Methods

We performed a systematic review and network meta-analysis (NMA) based on randomized controlled trials (RCTs). Additionally, we used a new methodology of inference concept with the purpose of grouping between P-CABs and PPIs. Moreover, our quality management system was integrated throughout the research to ensure data accuracy.

Findings

We initially screened 438 studies and extracted 10 homogeneous GU RCTs with 6315 participants. The odds ratios (ORs) for the 4-week cure rate in Bayesian + frequentist NMA, tegoprazan 100 mg (OR = 4.14, 95% credible interval [CI] 0.56-26.3) and pantoprazole 40 mg (OR = 4.12, 95% CI 1.90-8.88) were the largest, respectively. The ORs for the 8-week cure rate in Bayesian + frequentist NMA, lansoprazole 30 mg (OR = 8.77, 95% credible interval [CI] 0.95-78.9) and lansoprazole 30 mg (OR = 7.91, 95% CI 2.60-24.03) was the largest, respectively.

Conclusions

The results of the NMA reveal that the cure rates of P-CABs in cases of GU were not inferior to those of PPIs. As the inference by grouping PPIs and P-CABs, the results showed similar trends in terms of effectiveness between the two therapeutic classes.

Randomized, Double-Blind, Active-Controlled Phase 3 Study to Evaluate Efficacy and Safety of Zastaprazan Compared With Esomeprazole in Erosive Esophagitis

INTRODUCTION

Zastaprazan is a potent potassium-competitive acid blocker developed to treat gastroesophageal reflux disease. The aim of this study was to evaluate the efficacy and safety of zastaprazan compared with esomeprazole in patient with erosive esophagitis (EE).

METHODS

A phase III, multicenter, randomized, double-blind, noninferiority clinical study was conducted with 300 subjects with confirmed EE. Subjects were randomized to receive zastaprazan 20 mg or esomeprazole 40 mg once daily up to 8 weeks. The primary end point was the cumulative proportion of subject with healed EE confirmed by endoscopy at week 8. The secondary end points included the healing rate at week 4, symptom response, and quality of life assessment. Safety profiles and serum gastrin levels were also assessed.

RESULTS

In the full analysis set, the cumulative healing rate at week 8 were 97.92% (141/144) for zastaprazan and 94.93% (131/138) ( P = 0.178) for esomeprazole. The healing rate at week 4 in the zastaprazan group was higher than the esomeprazole group (95.14% [137/144] vs 87.68% [121/138]; P = 0.026). There was no significant difference between groups in healing rates (the per-protocol set) at week 8 and week 4, symptom responses, quality of life assessments, and safety profiles. In addition, serum gastrin levels increased during treatment in both groups, with a significant difference between the 2 groups ( P = 0.047), but both decreased after treatment.

DISCUSSION

An 8-week therapy of zastaprazan 20 mg is noninferior to esomeprazole 40 mg in subjects with predominantly low-grade EE. The healing rate at week 4 appears to be higher for zastaprazan than esomeprazole.

Randomized Multicenter Study to Evaluate the Efficacy and Safety of Fexuprazan According to the Timing of Dosing in Patients With Erosive Esophagitis

Background/Aims

Fexuprazan, a novel potassium-competitive acid blocker, was developed for treating acid-related disorders. Pharmacokinetic and pharmacodynamic properties of fexuprazan, unlike those of proton pump inhibitors, are independent of food effect. This study aims to evaluate differences in efficacy and safety of fexuprazan in patients with erosive esophagitis (EE) according to the timing of dosing.

Methods

In this multicenter, open-label noninferiority study, patients who had typical reflux symptoms with endoscopically confirmed EE were randomized 1:1 to receive fexuprazan 40 mg daily 30 minutes before or after meal. Treatment was completed after 2 weeks or 4 weeks when healing was endoscopically confirmed. The primary endpoint was the proportion of patients with healed EE confirmed by endoscopy up to week 4. Safety endpoints included treatment-emergent adverse events (TEAEs).

Results

In the prior-to-meal group (n = 89) and after-meal group (n = 86), 4-week EE healing rates were 98.77% and 100.00% (difference, 0.01%; 95% CI, -0.01% to 0.04%) and 2-week EE healing rates were 95.77% and 97.14% (difference, 0.01%; 95% CI, -0.05% to 0.07%), respectively. TEAEs were 9.78% and 8.70% in the prior-to-meal group and the after-meal group, respectively.

Conclusions

Non-inferiority analysis revealed that taking fexuprazan after meal was non-inferior to taking fexuprazan before meals in patients with EE. The frequency of adverse events was similar between the 2 study groups. The drug is safe and effective for healing EE regardless of the timing of dosing.

Assessment of the efficacy of on-demand tegoprazan therapy in gastroesophageal reflux disease through a randomized controlled trial

In patients with gastroesophageal reflux disease (GERD) whose symptoms improve with acid-suppression therapy, on-demand treatment could constitute maintenance therapy. This study investigated the comparative efficacy and safety of on-demand tegoprazan and proton-pump inhibitor (PPI) therapy in GERD. From six university hospitals in the Daejeon-Chungcheong region, we enrolled patients with GERD who had experienced symptomatic improvement with acid-suppressive therapy and, using a randomization table, randomly allocated these participants to two groups: to receive either tegoprazan 50 mg + esomeprazole placebo or tegoprazan placebo + esomeprazole 20 mg, respectively. The primary endpoint of this study was the intergroup difference in patient satisfaction with on-demand therapy. Among the 69 participants who completed 8 weeks of on-demand therapy and rated patient satisfaction on a 5-point Likert scale, the tegoprazan and esomeprazole groups scored an average of 4.31 and 4.15 points, respectively, without any significant intergroup difference. In the tegoprazan group, 26.2% (182/694) of those with episodes experienced symptom improvement within 30 min, which is a significantly higher proportion compared to 16.1% (104/646) in the esomeprazole group. Compared to the esomeprazole group, the tegoprazan group had a significantly shorter time to symptom improvement overall and a significantly higher proportion of patients who improved within 30 min. No serious treatment-emergent adverse events were reported. Tegoprazan is effective as on-demand therapy for GERD and offers the expectation of faster symptom improvement than with PPIs. Clinical trial KCT0009296, registered at cris.nih.go.kr.

Safety of potassium-competitive acid blockers in the treatment of gastroesophageal reflux disease

INTRODUCTION

Proton pump inhibitors (PPIs) are the first-line treatment for gastroesophageal reflux disease (GERD). However, due to their intrinsic limitations, there are still unmet clinical needs that have fostered the development of potassium-competitive acid blockers (P-CABs). Currently, four different drugs (vonoprazan, tegoprazan, fexuprazan, and keverprazan) are marketed in some Asian countries, whereas only vonoprazan and tegoprazan are available in Western countries (USA and Brazil or Mexico, respectively).

AREAS COVERED

This review summarizes the current knowledge on P-CABs acute and long-term safety in GERD treatment compared to that of PPIs. Full-text articles and abstracts were searched in PubMed.

EXPERT OPINION

P-CABs proved to address some of the unmet clinical needs in GERD, with a favorable risk-benefit ratio compared to conventional PPIs. Preclinical and clinical findings have highlighted P-CAB safety to be superimposable, to that of PPIs, in short-term treatments, although further studies are warranted to monitor their effects in long-term therapy. From an epidemiological point of view, the paucity of rigorous data for many variables (e.g. age, ethnicity, drug interactions, comorbidities, genetic polymorphisms, interindividual susceptibility, and gut dysbiosis) deserves a worldwide framework of continuous pre/post-marketing pharmacovigilance programs to reduce potential confounding factors and accurately link acute and chronic P-CAB therapy to adverse outcomes.

Population pharmacokinetic analysis of zastaprazan (JP-1366), a novel potassium-competitive acid blocker, in patients and healthy volunteers

Zastaprazan (JP-1366) is a novel potassium-competitive acid blocker for the treatment of acid-related disorders. We aimed to establish a population pharmacokinetic (PK) model of zastaprazan, thereby characterizing the PK of zastaprazan in patients with gastroesophageal reflux disease (GERD) as well as evaluating the impact of various covariates, including CYP2C19 phenotypes, on zastaprazan PK. This population PK analysis included zastaprazan plasma concentration-time data from 92 patients with erosive GERD and 68 healthy volunteers without any gastrointestinal disorders and was performed using nonlinear mixed-effect modeling. Simulations were conducted to predict zastaprazan PK under various dosing regimens in patients with GERD. The plasma PK of zastaprazan was adequately described by a two-compartment model with Erlang-type absorption (six sequential compartments) and first-order elimination. CYP2C19 phenotypes had no significant effect on zastaprazan PK. The disease status was identified as a significant covariate on apparent clearance of zastaprazan, showing lower values in patients with GERD compared to healthy volunteers. However, the model-based simulation indicated that the impact of disease status on zastaprazan exposure was not clinically meaningful. Overall, the current population PK model successfully characterized the observed zastaprazan PK in both patients with GERD and healthy volunteers.

Efficacy and safety of fexuprazan in patients with symptoms and signs of laryngopharyngeal reflux disease: a randomized clinical trial

PURPOSE

Laryngopharyngeal reflux disease (LPRD) is mainly treated with proton pump inhibitors (PPI) such as esomeprazole, which have shortcomings like delayed absorption and increased osteoporosis. Fexuprazan is a novel potent potassium-competitive acid blocker that inhibits gastric acid secretion with rapid onset and long duration of action. To assess the efficacy and safety of fexuprazan compared to esomeprazole in patients with LPRD.

METHODS

This prospective, randomized, double-blinded, multicenter, active-controlled trial was conducted in nine otolaryngologic clinics. Patients with reflux symptom index (RSI) ≥ 13 and reflux finding score (RFS) ≥ 7 were randomly assigned to the fexuprazan or esomeprazole groups, and received fexuprazan 40-mg or esomeprazole 40-mg once daily for 8 weeks. The outcomes were (1) mean change, change rate, and valid rate in RSI, RFS, and LPR-related questionnaires; and (2) adverse events.

RESULTS

A total of 136 patients (fexuprazan n = 68, esomeprazole n = 68) were followed up for ≥ 1 month. Each parameter significantly improved after 4 and 8 weeks in each group, with no significant differences between the two groups. For those with severe symptoms (RSI ≥ 18), the fexuprazan group (n = 32) showed more improvement in the mean change and change rate in the RSI than esomeprazole group (n = 31) after 4 weeks (p = .036 and .045, respectively). This phenomenon was especially observed in hoarseness and troublesome cough.

CONCLUSION

Fexuprazan improved symptoms and signs without no serious adverse events in patients with LPRD. In patients with severe symptoms, fexuprazan resulted in a faster symptom improvement than PPI.

TRIAL REGISTRATION

KCT0007251, https://cris.nih.go.kr/cris/search/detailSearch.do?seq=22100 .

AGA Clinical Practice Update on Integrating Potassium-Competitive Acid Blockers Into Clinical Practice: Expert Review

DESCRIPTION

The purpose of this American Gastroenterological Association (AGA) Institute Clinical Practice Update (CPU) is to summarize the available evidence and offer expert Best Practice Advice on the integration of potassium-competitive acid blockers (P-CABs) in the clinical management of foregut disorders, specifically including gastroesophageal reflux disease, Helicobacter pylori infection, and peptic ulcer disease.

METHODS

This expert review was commissioned and approved by the AGA Institute Governing Board and CPU Committee to provide timely guidance on a topic of high clinical importance to the AGA membership. This CPU expert review underwent internal peer review by the CPU Committee and external peer review through the standard procedures of Gastroenterology. These Best Practice Advice statements were developed based on review of the published literature and expert consensus opinion. Because formal systematic reviews were not performed, these Best Practice Advice statements do not carry formal ratings of the quality of evidence or strength of the presented considerations. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Based on nonclinical factors (including cost, greater obstacles to obtaining medication, and fewer long-term safety data), clinicians should generally not use P-CABs as initial therapy for acid-related conditions in which clinical superiority has not been shown. BEST PRACTICE ADVICE 2: Based on current costs in the United States, even modest clinical superiority of P-CABs over double-dose proton pump inhibitors (PPIs) may not make P-CABs cost-effective as first-line therapy. BEST PRACTICE ADVICE 3: Clinicians should generally not use P-CABs as first-line therapy for patients with uninvestigated heartburn symptoms or nonerosive reflux disease. Clinicians may use P-CABs in selected patients with documented acid-related reflux who fail therapy with twice-daily PPIs. BEST PRACTICE ADVICE 4: Although there is currently insufficient evidence for clinicians to use P-CABs as first-line on-demand therapy for patients with heartburn symptoms who have previously responded to antisecretory therapy, their rapid onset of acid inhibition raises the possibility of their utility in this population. BEST PRACTICE ADVICE 5: Clinicians should generally not use P-CABs as first-line therapy in patients with milder erosive esophagitis (EE) (Los Angeles classification of erosive esophagitis grade A/B EE). Clinicians may use P-CABs in selected patients with documented acid-related reflux who fail therapy with twice-daily PPIs. BEST PRACTICE ADVICE 6: Clinicians may use P-CABs as a therapeutic option for the healing and maintenance of healing in patients with more severe EE (Los Angeles classification of erosive esophagitis grade C/D EE). However, given the markedly higher costs of the P-CAB presently available in the United States and the lack of randomized comparisons with double-dose PPIs, it is not clear that the benefits in endoscopic outcomes over standard-dose PPIs justify the routine use of P-CABs as first-line therapy. BEST PRACTICE ADVICE 7: Clinicians should use P-CABs in place of PPIs in eradication regimens for most patients with H pylori infection. BEST PRACTICE ADVICE 8: Clinicians should generally not use P-CABs as first-line therapy in the treatment or prophylaxis of peptic ulcer disease. BEST PRACTICE ADVICE 9: Although there is currently insufficient evidence for clinicians to use P-CABs as first-line therapy in patients with bleeding gastroduodenal ulcers and high-risk stigmata, their rapid and potent acid inhibition raises the possibility of their utility in this population.

Potassium-competitive Acid Blockers: Current Clinical Use and Future Developments

PURPOSE OF THE REVIEW

Acid suppression with proton pump inhibitors (PPIs) represents the standard of care in the treatment of acid-related diseases. However, despite their effectiveness, PPIs display some intrinsic limitations, which underlie the unmet clinical needs that have been identified over the past decades. The aims of this review are to summarize the current status and future development of the new class of antisecretory drugs (potassium-competitive acid blockers, P-CABs) that have recently been introduced into medical practice.

RECENT FINDINGS

Over the past decades, clinical needs unmet by the current acid suppressants have been recognized, especially in the management of patients with GERD, Helicobacter pylori infection and NSAID-related peptic ulcer. The failure to address these needs is mainly due to their inability to achieve a consistent acid suppression in all patients and, particularly, to control nighttime acidity. It was then realized that an extended duration of acid suppression would exert additional benefits. The available data with P-CABs show that they are able to address these unmet clinical needs. Four different P-CABs (vonoprazan, tegoprazan, fexuprazan and keverprazan) are currently available. However, only two of them are approved outside Asia. Vonoprazan is available in North, Central and South America while tegoprazan is marketed only in Latin American countries. Two other compounds (namely linazapran glurate and zestaprazan) are presently under clinical development. While clinical trials on GERD have been performed with all P-CABs, only vonoprazan and tegoprazan have been investigated as components of Helicobacter pylori eradication regimens. The available data show that-in the above two clinical indications-P-CABs provide similar or better efficacy in comparison with PPIs. Their safety in the short-term overlaps that of PPIs, but data from long-term treatment are needed.

Pharmacological management of gastro-esophageal reflux disease: state of the art in 2024

INTRODUCTION

Gastroesophageal reflux disease (GERD) is a chronic disease of the esophagus characterized by the regurgitation of stomach contents into the esophagus, causing troublesome symptoms and/or complications. Among patients with GERD, around 30% of patients have visible mucosal damage, while 70% have normal esophageal mucosa. Accordingly, the optimal pharmacological treatment of GERD should address different disease manifestations, including symptoms, the mucosal damage when present, and possible chronic complications, including strictures, Barrett's esophagus, and esophageal adenocarcinoma.

AREAS COVERED

Available medical treatments for GERD include proton pump inhibitors (PPIs), potassium-competitive acid blockers (PCABs), histamine receptor antagonists (H2-RAs), prokinetics, and mucosal protectants, such as alginates, hyaluronic acid/chondroitin-sulfate, and poliprotect. Each compound has its own advantages and disadvantages, and knowledge of expected benefits and tips for their use is paramount for the success of treatment. In addition, the appropriateness of indications for initiating treatment is also crucial to achieve positive results when managing GERD patients.

EXPERT OPINION

PPIs, PCABs, H2-RAs, prokinetics, and mucosal protectants can all be used in patients with GERD, but careful assessment of patients' characteristics as well as advantages and disadvantages of each therapeutic compound is essential to ensure successful treatment of GERD.

Scalable Synthesis of the Key Fexuprazan Intermediate and Investigation of a Reaction Mechanism

A three-step method for the synthesis of methyl 5-(2,4-difluorophenyl)-4-methoxy-1H-pyrrole-3-carboxylate 1, a key intermediate of fexuprazan, is reported in this paper. Using low-priced sodium p-tolylsulfinate as the starting material, compound 28 was obtained with a 96.8% yield in the first step by optimizing the experimental parameters with a Box-Behnken experimental design. Subsequently, isonitrile compound 29 was obtained by dehydration. Finally, impurities 31 and 32 in the last step of the reaction were identified and converted into target product 1 by a one-pot method, which significantly improves the utilization of atoms. Key intermediate 1 was obtained via a three-step process with a yield of 68-70% and purity that exceeded 99%. In addition, the mechanism of the cyclization reaction was proposed. This method has potential for industrial production because the raw materials are inexpensive, the procedure is simple, and a high yield is obtained.

Pharmacodynamics Between a Dual Delayed-Release Formulation of Low-Dose Esomeprazole and Famotidine in Healthy Korean Subjects

PURPOSE

Gastritis, one of the most common clinically diagnosed conditions, is defined as the infiltration of inflammatory cells into the gastric mucosa. Drugs for gastritis include histamine-2 receptor antagonists and proton pump inhibitors (PPIs), which reduce acidity in the stomach, and antacids, which neutralize acid. Esomeprazole is a PPI for gastroesophageal reflux disease and gastric and duodenal ulcers that has been shown to be safe and effective at a 10 mg dose. Dual-release drugs have not yet been approved for the treatment of gastritis domestically or internationally. In this study, a dual delayed-release (DR) esomeprazole (10 mg), was compared to famotidine (20 mg) to determine its effectiveness in the treatment of gastritis.

METHODS

This study was a randomized, open-label, multiple-dose, 2-treatment, 2-period, 2-sequence crossover study with a 7-day washout between periods. In each period, the subjects were administered one dose of esomeprazole (10 mg) or famotidine (20 mg) for 7 days at each period. The 24-hour gastric pH was recorded after single and multiple doses. The percentage of time (duration%) that the pH was maintained above 4 in the 24 hours after 7 days of repeated dosing was evaluated.

FINDINGS

The mean percentages of time that the gastric pH was above 4 after multiple doses over 7 days of a dual DR esomeprazole (10 mg) and famotidine (20 mg) was 47.31% ± 14.85% and 23.88% ± 10.73%.

IMPLICATIONS

Multiple doses of a dual DR esomeprazole (10 mg) showed effective gastric acid secretion suppression compared to famotidine with comparable safety and tolerability. These results provide evidence supporting the clinical use of a dual DR esomeprazole (10 mg) to treat gastritis.

CLINICALTRIALS

gov identifier: NCT04967014.

Efficacy of fexuprazan compared with rebamipide in Korean patients with gastritis: A matching-adjusted indirect comparison

BACKGROUND

Gastritis is one of the most frequently diagnosed diseases requiring medical treatment in South Korea. Fexuprazan, a novel potassium-competitive acid blocker, has been approved for treating gastritis and erosive esophagitis. Meanwhile, rebamipide is the most commonly used mucoprotective agent for acute and chronic gastritis in real-world settings in South Korea. However, there have been no studies comparing the efficacy of these two drugs yet.

AIM

To compare the efficacy of fexuprazan with that of rebamipide for acute and chronic gastritis.

METHODS

This was a matching-adjusted indirect comparison. Individual patient data from a phase III study of fexuprazan (10 mg BID) were compared with cumulative data from two matching studies of rebamipide (100 mg TID). Erosion improvement and healing rates were compared between two weeks of fexurapan, two weeks of rebamipide, and four weeks of rebamipide. The two main outcome variables were presented as percentages, and the risk differences (RD) and 95% confidence intervals (CI) were calculated for the relative treatment effects.

RESULTS

In the primary analysis, the erosion improvement and healing rates after a two-week treatment with fexuprazan were 64.5% and 53.2%, respectively, while a two-week treatment with rebamipide resulted in erosion improvement and healing rates of 43.6% (RD: 21.0%; 95%CI: 9.6-32.3; P < 0.01) and 35.6% (RD: 17.6%; 95%CI: 6.1-29.2; P = 0.003), respectively. In the additional analysis, the erosion improvement and healing rates for the two-week fexuprazan treatment (64.2% and 51.2%, respectively) were similar to those obtained during a four-week treatment with rebamipide (60.6%; RD: 3.6%; 95%CI: -9.8, 17.0; P = 0.600 and 53.5%; RD: -2.3%; 95%CI: -16.1, 11.5; P = 0.744, respectively).

CONCLUSION

The two-week fexuprazan treatment was superior to the two-week rebamipide treatment and similar to the four-week rebamipide treatment for patients with gastritis.

Potassium-competitive acid blockers and proton-pump inhibitors for healing of erosive esophagitis: a systematic review and network meta-analysis

Background

Proton-pump inhibitors (PPIs) and potassium-competitive acid blockers (P-CABs) are recommended for erosive esophagitis (EE), with good safety and tolerance. However, it is unclear which is the best treatment option for EE.

Objectives

This study aimed to evaluate the comparative efficacy of P-CABs and PPIs for healing EE patients, seeking an appropriate treatment choice in the 4- or 8-week treatment and standard or double dose.

Design

A systematic review and network meta-analysis.

Data sources and methods

Relevant databases were searched to collect randomized controlled trials of PPIs and P-CABs in the treatment of EE up to 31 May 2023. Studies on standard or double-dose PPIs or P-CABs which were published in English and assessed 4- or 8-week healing effects in EE were included. A network meta-analysis was performed to evaluate the efficacy of the treatments under the frequentist framework. Sensitivity and subgroup analyses of patients with different baseline EE were also conducted.

Results

In all, 34 studies involving 25,054 patients and 9 PPIs, 6 P-CABs, or placebo treatment interventions were included. The pooled 4-week healing rate was significantly statistically lower than the pooled 8-week healing rate for most treatments. Besides, the higher healing rate of double-dose treatment than standard-dose treatment was not observed in the initial treatment of most drugs. The main analysis only included studies conducted for both patients with and without severe EE at baseline, and the proportion of severe EE included in the study was >10%, Keverprazan 20 mg qd ranked best with a surface under the cumulative ranking curve (SUCRA) value of 84.7, followed by Ilaprazole 10 mg qd with a SUCRA value of 82.0, for the healing rate at 8 weeks. Sensitivity analysis showed that the results were robust. Subgroup analysis showed that most P-CABs had higher healing rates than PPIs, particularly for patients with severe EE. And the healing rate of Keverprazan 20 mg qd at 8 weeks ranked best in the subgroup without or with severe EE at baseline.

Conclusion

This study showed that an 8-week treatment seemed more effective than the 4-week treatment for healing EE patients. The healing effect of Keverprazan (20 mg qd) ranked best in 8-week treatment, for both severe and non-severe EE patients.

Trial registration

The study protocol was registered with INPLASY (registration number INPLASY2023120053).

In Vitro Metabolism and Transport Characteristics of Zastaprazan

Zastaprazan (JP-1366), a novel potassium-competitive acid blocker, is a new drug for the treatment of erosive esophagitis. JP-1366 is highly metabolized in human, mouse, and dog hepatocytes but moderately metabolized in rat and monkey hepatocytes when estimated from the metabolic stability of this compound in hepatocyte suspension and when 18 phase I metabolites and 5 phase II metabolites [i.e., N-dearylation (M6), hydroxylation (M1, M19, M21), dihydroxylation (M7, M8, M14, M22), trihydroxylation (M13, M18), hydroxylation and reduction (M20), dihydroxylation and reduction (M9, M16), hydrolysis (M23), hydroxylation and glucuronidation (M11, M15), hydroxylation and sulfation (M17), dihydroxylation and sulfation (M10, M12), N-dearylation and hydroxylation (M3, M4), N-dearylation and dihydroxylation (M5), and N-dearylation and trihydroxylation (M2)] were identified from JP-1366 incubation with the hepatocytes from humans, mice, rats, dogs, and monkeys. Based on the cytochrome P450 (CYP) screening test and immune-inhibition analysis with CYP antibodies, CYP3A4 and CYP3A5 played major roles in the metabolism of JP-1366 to M1, M3, M4, M6, M8, M9, M13, M14, M16, M18, M19, M21, and M22. CYP1A2, 2C8, 2C9, 2C19, and 2D6 played minor roles in the metabolism of JP-1366. UDP-glucuronosyltransferase (UGT) 2B7 and UGT2B17 were responsible for the glucuronidation of M1 to M15. However, JP-1366 and active metabolite M1 were not substrates for drug transporters such as organic cation transporter (OCT) 1/2, organic anion transporter (OAT) 1/3, organic anion transporting polypeptide (OATP)1B1/1B3, multidrug and toxic compound extrusion (MATE)1/2K, P-glycoprotein (P-gp), and breast cancer-resistant protein (BCRP). Only M1 showed substrate specificity for P-gp. The findings indicated that drug-metabolizing enzymes, particularly CYP3A4/3A5, may have a significant role in determining the pharmacokinetics of zastaprazan while drug transporters may only have a small impact on the absorption, distribution, and excretion of this compound.

RETRACTED: A Phase III Head-to-Head Study to Compare the Efficacy and Safety of Fexuprazan and Esomeprazole in Treating Patients with Erosive Esophagitis

Background: Fexuprazan (Fexuclue®; Daewoong Pharmaceutical Co., Ltd., Seoul, Korea) is a novel potassium-competitive acid blocker (P-CAB). This multi-center, randomized, double-blind, active-controlled, parallel-group, therapeutic confirmatory, phase III study was conducted to assess its efficacy and safety compared with esomeprazole (Nexium®; AstraZeneca, Gothenburg, Mölndal, Sweden) in Korean patients with erosive esophagitis (EE). Methods: This study evaluated patients diagnosed with EE at a total of 25 institutions in Korea between 13 December 2018 and 7 August 2019. After voluntarily submitting a written informed consent form, the patients were evaluated using a screening test and then randomized to either of the two treatment arms. The proportion of the patients who achieved the complete recovery of mucosal breaks at 4 and 8 weeks, the proportion of those who achieved the complete recovery of heartburn at 3 and 7 days and 8 weeks, and changes in the GERD-Health-Related Quality of Life Questionnaire (GERD-HRQL) scores at 4 and 8 weeks from baseline served as efficacy outcome measures. The incidence of treatment-emergent adverse events (TEAEs) and adverse drug reactions (ADRs) and the serum gastrin levels served as safety outcome measures. Results: The study population comprised a total of 231 patients (n = 231) with EE, including 152 men (65.80%) and 79 women (34.20%); their mean age was 54.37 ± 12.66 years old. There were no significant differences in the efficacy and safety outcome measures between the two treatment arms (p > 0.05). Conclusions: It can be concluded that the efficacy and safety of Fexuclue® are not inferior to those of esomeprazole in Korean patients with EE.

Pharmacokinetic interactions between fexuprazan, a potassium-competitive acid blocker, and nonsteroidal anti-inflammatory drugs in healthy males

Fexuprazan, a novel potassium-competitive acid blocker, is expected to be used for the prevention of nonsteroidal anti-inflammatory drugs (NSAIDs) induced ulcer. This study aimed to evaluate pharmacokinetic (PK) interactions between fexuprazan and NSAIDs in healthy subjects. A randomized, open-label, multicenter, six-sequence, one-way crossover study was conducted in healthy male subjects. Subjects randomly received one of the study drugs (fexuprazan 40 mg BID, celecoxib 200 mg BID, naproxen 500 mg BID, or meloxicam 15 mg QD) for 5 or 7 days in the first period followed by the combination of fexuprazan and one of NSAIDs for the same days and the perpetrator additionally administered for 1-2 days in the second period. Serial blood samples for PK analysis were collected until 48- or 72-h post-dose at steady state. PK parameters including maximum plasma concentration at steady state (Cmax,ss) and area under plasma concentration-time curve over dosing interval at steady state (AUCτ,ss) were compared between monotherapy and combination therapy. The PKs of NSAIDs were not significantly altered by fexuprazan. For fexuprazan, differences in PK parameters (22% in Cmax, 19% in AUCτ,ss) were observed when co-administered with naproxen, but not clinically significant. The geometric mean ratio (90% confidence interval) of combination therapy to monotherapy for Cmax,ss and AUCτ,ss was 1.22 (1.02-1.46) and 1.19 (1.00-1.43), respectively. There were no significant changes in the systemic exposure of fexuprazan by celecoxib and meloxicam. Fexuprazan and NSAIDs did not show clinically meaningful PK interactions.

The efficacy and safety of fexuprazan in treating erosive esophagitis: a phase III, randomized, double-blind, multicenter study

BACKGROUND AND AIM

Fexuprazan is a novel potassium-competitive acid blocker (P-CAB). This study aimed to explore the noninferior efficacy and safety of fexuprazan to esomeprazole in treating erosive esophagitis (EE).

METHODS

This was a phase III, randomized, double-blind multicenter study. Patients with endoscopically confirmed EE were randomized to receive fexuprazan 40 mg or esomeprazole 40 mg once a daily for 4-8 weeks. The healing rates of EE, symptom response, GERD-health-related quality life (GERD-HRQL), and treatment-emergent adverse events (TEAEs) were compared between fexuprazan group and esomeprazole group.

RESULTS

A total of 332 subjects were included in full analysis set (FAS) and 311 in per-protocol set (PPS). The healing rates of fexuprazan and esomeprazole groups at 8 weeks were 88.5% (146/165) and 89.0% (145/163), respectively, in FAS and 97.3% (145/149) and 97.9% (143/146), respectively, in PPS. Noninferiority of fexuprazan compared with esomeprazole according to EE healing rates at 8 weeks was demonstrated in both FAS and PPS analysis. No significant difference was found between groups in EE healing rates at 4 weeks, symptom responses, and changes of GERD-HRQL. The incidence of drug-related AEs was 19.4% (32/165) in fexuprazan arm and 19.6% (32/163) in esomeprazole arm.

CONCLUSION

This study demonstrated noninferior efficacy of fexuprazan to esomeprazole in treating EE. The incidence of TEAEs was similar between fexuprazan and esomeprazole. Trial registration number NCT05813561.

Efficacy and Safety of Fexuprazan in Patients with Acute or Chronic Gastritis

BACKGROUND/AIMS

Fexuprazan is a novel potassium-competitive acid blocker that could be of benefit to patients with gastric mucosal injury. The aim of this study was to assess the 2-week efficacy and safety of fexuprazan in patients with acute or chronic gastritis.

METHODS

In this study, 327 patients with acute or chronic gastritis who had one or more gastric erosions on endoscopy and subjective symptoms were randomized into three groups receiving fexuprazan 20 mg once a day (q.d.), fexuprazan 10 mg twice a day (b.i.d.), or placebo for 2 weeks. The posttreatment assessments were the primary endpoint (erosion improvement rate), secondary endpoints (cure rates of erosion and edema and improvement rates of redness, hemorrhage, and subjective symptoms), and drug-related adverse events.

RESULTS

Among the patients, 57.8% (59/102), 65.7% (67/102), and 40.6% (39/96) showed erosion improvement 2 weeks after receiving fexuprazan 20 mg q.d., fexuprazan 10 mg b.i.d., and placebo, respectively. Both fexuprazan 20 mg q.d. and 10 mg b.i.d. showed superior efficacy to the placebo (p=0.017 and p<0.001, respectively). Likewise, both fexuprazan 20 mg q.d. and 10 mg b.i.d. also showed higher erosion healing rates than the placebo (p=0.033 and p=0.010, respectively). No difference was noted in the edema healing rate and the improvement rates for redness, hemorrhage, and subjective symptoms between the fexuprazan and placebo groups. No significant difference was noted in the incidence of adverse drug reactions.

CONCLUSIONS

Fexuprazan 20 mg q.d. and 10 mg b.i.d. for 2 weeks showed therapeutic efficacy superior to that of placebo in patients with acute or chronic gastritis (ClinicalTrials.gov identifier NCT04341454).

Neuroendocrine mechanism of gastric acid secretion: Historical perspectives and recent developments in physiology and pharmacology

The physiology of gastric acid secretion is one of the earliest subjects in medical literature and has been continuously studied since 1833. Starting with the notion that neural stimulation alone drives acid secretion, progress in understanding the physiology and pathophysiology of this process has led to the development of therapeutic strategies for patients with acid-related diseases. For instance, understanding the physiology of parietal cells led to the developments of histamine 2 receptor blockers, proton pump inhibitors (PPIs), and recently, potassium-competitive acid blockers. Furthermore, understanding the physiology and pathophysiology of gastrin has led to the development of gastrin/CCK2 receptor (CCK2 R) antagonists. The need for refinement of existing drugs in patients have led to second and third generation drugs with better efficacy at blocking acid secretion. Further understanding of the mechanism of acid secretion by gene targeting in mice has enabled us to dissect the unique role for each regulator to leverage and justify the development of new targeted therapeutics for acid-related disorders. Further research on the mechanism of stimulation of gastric acid secretion and the physiological significances of gastric acidity in gut microbiome is needed in the future.

Keverprazan, a novel potassium-competitive acid blocker: Single ascending dose safety, tolerability, pharmacokinetics, pharmacodynamics and food effect in healthy subjects

BACKGROUND

Keverprazan is a novel potassium-competitive acid blocker for the treatment of acid-related diseases.

AIMS

To evaluate the safety, pharmacokinetics, pharmacodynamics, and food effect of single oral doses of keverprazan in healthy Chinese subjects.

METHODS

In the dose-escalated phase Ia trial, the first 8 subjects received keverprazan 5 mg, the others successively entered 10 mg, 20 mg, 40 mg, 60 mg groups and were randomized to receive keverprazan (n = 8), lansoprazole (LSZ) 30 mg (n = 2) or placebo (n = 2) in each dose group. The phase Ib study randomly enrolled subjects to the fasting-fed (n = 7) or fed-fasting (n = 7) groups for evaluating the food effect of keverprazan.

RESULTS

Twenty (35.71%) adverse events (AEs) occurred in phase Ia, including 13 (32.50%), 3 (37.50%), and 4 (50.00%) AEs in the keverprazan, placebo, and LSZ groups, respectively. Four (28.57%) AEs occurred in Phase Ib. The Tmax of keverprazan was 1.25-1.75 h. Cmax and AUC increased with the dose, and the t1/2, CL/F were 6.00-7.17 h, 88.8-198 L/h, respectively. The intragastric pH >5 holding-time ratio (HTR) increased with the dose but reached a ceiling at 20 mg. In the 30 mg LSZ and 5-60 mg keverprazan groups, the intragastric pH >5 HTRs during 24 h were 57.1%±26.4%, 7.9%±8.1%, 26.2%±22.8%, 80.2%±8.8%, 88.1%±8.6%, and 93.0%±1.7%, respectively. The geometric mean ratios (90% CI) of Cmax and AUC0-∞ of keverprazan in plasma under the fed vs. fasting state were 126.8% (109.0%-147.5%) and 134.9% (123.8%-146.9%).

CONCLUSION

Keverprazan is tolerable, and provides significant stable and lasting inhibition efficacy of intragastric acidity at 20 mg.

Keverprazan, a novel potassium-competitive acid blocker: Multiple oral doses safety, tolerability, pharmacokinetics, and pharmacodynamics in healthy subjects

Keverprazan, a novel potassium-competitive acid blocker, was approved for treating acid-related diseases. This study aimed to analyze the safety, pharmacokinetics (PKs) and pharmacodynamics (PDs) of multiple doses of keverprazan. This was a randomized, positive-/placebo-controlled, phase Ic trial. Twenty-six healthy adults were randomized to receive 20 mg/day keverprazan (n = 8), 40 mg/day keverprazan (n = 8), placebo (n = 6), or 20 mg/day vonoprazan (n = 4) for 7 days. Safety, PK and PD assessments were conducted. In the keverprazan, vonoprazan, and placebo groups, adverse events (AEs) were reported in nine (56.25%), two (50.00%), and three (50.00%) subjects, respectively. AEs were mild except a moderate abdominal pain leading to withdraw. No serious AEs occurred. The plasma concentration-time profiles of keverprazan showed rapid absorption (median time to maximum plasma concentration of 1.25-3.0 h). The terminal half-life was 6.23 and 7.01 h for keverprazan 20 and 40 mg groups on day 7. The maximum plasma concentration was 43.1 and 93.2 ng/mL, respectively. There was no apparent accumulation of keverprazan and the major metabolite after 7-day administration. The intragastric pH greater than 5 holding time ratios (HTRs) over 24 h postdose increased from 79.1%, 84.4%, and 84.5% on day 1 to 99.0%, 97.4%, and 100.0% on day 7 in the vonoprazan 20 mg and keverprazan 20 and 40 mg groups, respectively. The intragastric pH greater than 5 HTR of keverprazan reached a plateau at 20 mg. Keverprazan is well-tolerable. A steady-state in exposure was generally reached after 7 days of treatment. A dose of 20 mg/day keverprazan can elicit a significant, stable, and long-lasting gastric acid inhibition effect.

Pharmacokinetic and pharmacodynamic exploration of various combinations of tegoprazan immediate and delayed-release formulations

AIMS

The new modified-release formulation of tegoprazan, a novel potassium-competitive acid blocker, is expected to improve the management of acid-related disease, including nocturnal acid breakthrough, by prolonging the duration of acid suppression. This study aimed to explore the pharmacokinetics (PK) and pharmacodynamics (PD) of various combinations of tegoprazan with immediate-release (IR) and delayed-release (DR) formulations.

METHODS

A three-cohort, open-label, randomized, single-dose, three-treatment, six-sequence, three-period crossover study was conducted. Various combinations of tegoprazan IR and DR formulations (50, 75 or 100 mg) were administered orally once per period. The 24-h intragastric pH was monitored before and after each administration. PK blood samples were collected for up to 48 h. PK and PD were compared among treatments.

RESULTS

Eighteen healthy Korean subjects completed the study. All treatment groups showed intragastric pH above 4 approximately 1 h following tegoprazan administration. Among the various combinations, the IR and DR combination at a 1:1 ratio induced greater gastric acid suppression (%Time pH ≥ 4) than IR alone in each dose group, both for 24 h (50 mg; 59% vs. 52%, P = .2188, 95% confidence interval [CI] -6.92-22.27, 100 mg; 85% vs. 70%, P < .05, 95% CI 8.92-22.19) and at night (50 mg; 27% vs. 16%, P = .1563, 95% CI -11.79-37.71, 100 mg; 77% vs. 49%, P < .05, 95% CI 16.14-42.98), with similar systemic exposure.

CONCLUSIONS

The combinatorial tegoprazan in the IR and DR 1:1 ratio formulation was found to induce stronger gastric acid suppression throughout the day and at night, compared to the conventional IR formulation.

A Comparative Pharmacokinetic Study of Fexuprazan 10 mg: Demonstrating Bioequivalence with the Reference Formulation and Evaluating Steady State

Fexuprazan is a potassium-competitive acid blocker approved for treating gastric-acid-related diseases. Although the effectiveness of the recent formulation fexuprazan 10 mg has been demonstrated in Phase 3 clinical trials, data on the pharmacokinetics (PKs) of administering fexuprazan 10 mg twice daily at a 12 h interval are lacking. Moreover, it is imperative to ensure the bioequivalence of the new formulation with the previously approved 40 mg formulation. This study evaluated the pharmacokinetics (PKs) of the single- and multiple-dose oral administration of fexuprazan 10 mg tablets in healthy participants (Part 1) and investigated their bioequivalence with 40 mg tablets (Part 2). Part 1 comprised a single- and multiple-dose, one-sequence, two-period design and eight participants, while Part 2 comprised a single-dose, 2 × 2 crossover design and 24 participants. In Part 1, in Periods 1 and 2, participants received single and multiple doses (twice daily) of fexuprazan 10 mg, respectively. The maximum plasma concentration (Cmax) area under the concentration-time curve from 0 to 12 h (AUC0-12h) of the multiple-dose participants was approximately double that of the single-dose participants. In Part 2, the geometric mean ratios (90% confidence intervals) for Cmax and AUC from zero to the time of the last quantifiable concentration (AUClast) of the use of four fexuprazan 10 mg tablets to those of one fexuprazan 40 mg tablet were 1.0290 (0.9352-1.1321) and 1.0290 (0.9476-1.1174), respectively, meeting the bioequivalence criteria. Favorable PKs were observed after single and multiple administrations of one fexuprazan 10 mg tablet, and four fexuprazan 10 mg tablets were pharmacokinetically equivalent to one fexuprazan 40 mg tablet.

Review of the clinical development of fexuprazan for gastroesophageal reflux-related disease

Proton pump inhibitors (PPIs) are a mainstay treatment for acid peptic disorders such as gastroesophageal reflux disease (GERD). Although PPIs are considered first-line medications for acid suppression, they have notable limitations such as requiring acid-mediated activation, short half-life and duration of action, and metabolic variability. Fexuprazan is a newly developed potassium-competitive acid blocker (P-CAB), which inhibits acid generation and secretion in a competitive and reversible manner. Fexuprazan, like other P-CABs, has significantly different pharmacodynamic and pharmacokinetic properties than PPIs with potential advantages including rapid, robust, and durable acid suppression, lack of CYP2C19 metabolism, independence from food intake, and no requirement for activation into an active form. Completed clinical trials of fexuprazan have demonstrated comparable efficacy to PPIs for the healing of erosive esophagitis and relief of GERD-related esophageal symptoms without concerning safety signals. Ongoing clinical trials are evaluating fexuprazan for the prevention of NSAID-induced peptic ulcer disease, non-erosive GERD, and acute and chronic gastritis, as well as healing efficacy and maintenance of erosive esophagitis (EE). Fexuprazan is approved in South Korea for the treatment of EE and at the time of this writing is being considered for regulatory approval in several other countries. In this article, we summarize and discuss the pharmacology, efficacy, and safety of fexuprazan.

Prediction of the Drug–Drug Interaction Potential between Tegoprazan and Amoxicillin/Clarithromycin Using the Physiologically Based Pharmacokinetic and Pharmacodynamic Model

Tegoprazan is a novel potassium-competitive acid blocker. This study investigated the effect of drug–drug interaction on the pharmacokinetics and pharmacodynamics of tegoprazan co-administered with amoxicillin and clarithromycin, the first-line therapy for the eradication of Helicobacter pylori, using physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) modeling. The previously reported tegoprazan PBPK/PD model was modified and applied. The clarithromycin PBPK model was developed based on the model provided by the SimCYP® compound library. The amoxicillin model was constructed using the middle-out approach. All of the observed concentration–time profiles were covered well by the predicted profiles with the 5th and 95th percentiles. The mean ratios of predicted to observed PK parameters, including the area under the curve (AUC), maximum plasma drug concentration (Cmax), and clearance, were within the 30% intervals for the developed models. Two-fold ratios of predicted fold-changes of Cmax and AUC from time 0 to 24 h to observed data were satisfied. The predicted PD endpoints, including median intragastric pH and percentage holding rate at pH above 4 or 6 on day 1 and day 7, were close to the corresponding observed data. This investigation allows evaluation of the effects of CYP3A4 perpetrators on tegoprazan PK and PD changes, thus providing clinicians with the rationale for co-administration dosing adjustment.

Pharmacodynamic and Pharmacokinetic Drug Interactions between Fexuprazan, a Novel Potassium-Competitive Inhibitor, and Aspirin, in Healthy Subjects

Acid-reducing agents are commonly used for the prevention of aspirin-induced gastrointestinal complications such as peptic ulcers. As a novel potassium-competitive acid blocker, fexuprazan is expected to prevent aspirin-induced gastrointestinal complications. This randomized, open-label study aimed to evaluate the pharmacodynamic and pharmacokinetic interactions between aspirin and fexuprazan in healthy Koreans. Subjects randomized to the aspirin group received 500 mg aspirin in combination with 80 mg fexuprazan. For the fexuprazan group, fexuprazan 80 mg was administered alone and then in combination with aspirin 500 mg. Platelet aggregation inhibited by aspirin and the pharmacokinetic parameters of aspirin and fexuprazan were compared between monotherapy and combination therapy. A total of 22 subjects completed the study. The platelet aggregation-inhibitory activity and systemic exposure to aspirin were not significantly affected by fexuprazan coadministration. The systemic exposure of fexuprazan was decreased up to 20% by aspirin coadministration, which was not regarded as clinically meaningful considering the previously reported exposure-response relationship. In conclusion, there were no clinically relevant pharmacodynamic or pharmacokinetic interactions between aspirin and fexuprazan. This finding suggests the potential of fexuprazan for the prevention of aspirin-induced gastrointestinal complications, serving as a baseline for optimizing its therapeutic application with aspirin.

Size-reduced fexuprazan 20 mg demonstrated the optimal bioavailability and bioequivalence with the reference formulation

Fexuprazan (DWP14012), a potassium-competitive acid blocker, is a medical formulation prescribed to inhibit the secretion of gastric acid. The present study encompasses a comparative evaluation of pharmacokinetic (PK) analysis between the previous (reference) and size-reduced (test) formulation of fexuprazan 20 mg in healthy subjects. The study employed a randomized, open-label, single-dose, 2-sequence, 2-period, crossover design with a 7-day wash-out between periods. A total of 24 subjects were enrolled in this randomized study. During each period, the 21 subjects received either the test or reference formulation. Blood samples were collected at multiple time point ranging from 0 (pre-dose) to 48 hours post-dosing for PK analysis. The calculated PK parameters were considered bioequivalent when the 90% confidence intervals (CIs) of the geometric mean ratios (GMRs) were within the bioequivalence limit of 0.8-1.25. Safety and tolerability were included in the evaluation. A total of 20 subjects completed the study. Point estimates (90% CIs) of the GMRs were 1.1014 (0.9892-1.2265) for the maximum plasma concentration and 1.0530 (0.9611-1.1536) for the area under the plasma concentration-time curve from zero to the time of the last quantifiable concentration, between the test and reference formulations. The reference and size-reduced test formulations of fexuprazan were well tolerated with no reports of serious adverse events. In conclusion, size-reduced and previous formulations of fexuprazan 20 mg were bioequivalent with regard to PKs, safety and tolerability.

Randomized controlled trial to evaluate the efficacy and safety of fexuprazan compared with esomeprazole in erosive esophagitis

BACKGROUND

Fexuprazan, a novel potassium-competitive acid blocker, reversibly suppresses the K+/H+-ATPase enzyme in proton pumps within gastric parietal cells. Fexuprazan's suppression of gastric acid was maintained in healthy individuals for 24 h in a dose-dependent manner.

AIM

To compare fexuprazan to esomeprazole and establish its efficacy and safety in patients with erosive esophagitis (EE).

METHODS

Korean adult patients with endoscopically confirmed EE were randomized 1:1 to receive fexuprazan 40 mg or esomeprazole 40 mg once daily for eight weeks. The primary endpoint was the proportion of patients with healed EE confirmed by endoscopy at week 8. The secondary endpoints included the healing rate of EE at week 4, symptom response, and quality of life assessment. Safety profiles and serum gastrin levels were compared between the groups.

RESULTS

Of the 263 randomized, 218 completed the study per protocol (fexuprazan 40 mg, n = 107; esomeprazole 40 mg, n = 111). Fexuprazan was non-inferior to esomeprazole regarding the healing rate at week 8 [99.1% (106/107) vs 99.1% (110/111)]. There were no between-group differences in the EE healing rate at week 4 [90.3% (93/103) vs 88.5% (92/104)], symptom responses, and quality of life assessments. Additionally, serum gastrin levels at weeks 4 and 8 and drug-related side effects did not significantly differ between the groups.

CONCLUSION

Fexuprazan 40 mg is non-inferior to esomeprazole 40 mg in EE healing at week 8. We suggest that fexuprazan is an alternative promising treatment option to PPIs for patients with EE.

Potassium-competitive acid blockers and gastroesophageal reflux disease

Proton pump inhibitors (PPIs), the most commonly used antisecretory medi-cations in the management of reflux illness, virtually eliminate elective surgery for ulcer disease, and relegate anti-reflux surgery to patients with gastroesophageal reflux disease (GERD) who are inadequately managed by medical therapy. However, PPI medications still leave some therapeutic demands of GERD unmet. Furthermore, up to 40%-55% of daily PPI users have chronic symptoms, due to PPI refractoriness. Potassium-competitive acid blockers (P-CABs) transcend many of the problems and limits of PPIs, delivering quick, powerful, and extended acid suppression and allowing for treatment of numerous unmet needs. Recently, it has become clear that compromised mucosal integrity plays a role in the etiology of GERD. As a result, esophageal mucosal protection has emerged as a novel and potential treatment approach. An increasing body of research demonstrates that when P-CABs are used as primary drugs or add-on drugs (to regular treatment), they provide a considerable extra benefit, particularly in alleviating symptoms that do not respond to PPI therapy.

Acid Suppressive Drugs

Histamine H₂ receptor antagonists (H₂RAs) suppress gastric acid production by blocking H₂ receptors in parietal cells. Studies have shown that proton pump inhibitors (PPIs) are superior to H₂RAs as a treatment for acid-related disorders, such as peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD). PPIs reduce gastric acid production by irreversibly inhibiting the H⁺/K⁺ ATPase pump, and they also increase gastric emptying. Although PPIs have differing pharmacokinetic properties, each PPI is effective in managing GERD and PUDs. However, PPIs have some limitations, including short plasma half-lives, breakthrough symptoms (especially at night), meal-associated dosing, and concerns associated with long-term PPI use. Potassium-competitive acid blockers (P-CABs) provide more rapid and profound suppression of intragastric acidity than PPIs. P-CABs are non-inferior to lansoprazole in healing erosive esophagitis and peptic ulcers, and may also be effective in improving symptoms in patients with non-erosive reflux disease. Acid suppressive drugs are the most commonly used drugs in clinical practice, and it is necessary to understand the pharmacological properties and adverse effects of each drug.

Model-Based Prediction of Acid Suppression and Proposal of a New Dosing Regimen of Fexuprazan in Humans

Fexuprazan is a potassium-competitive acid blocker (P-CAB). The compounds in this newly developed drug family suppress intragastric acidity. As there are already other acid-suppressing drugs on the market, such as H₂ antagonists and proton pump inhibitors (PPIs), it would be informative to compare the biological effects of fexuprazan against another approved drug with the same indication. The drug concentration predicted by the pharmacokinetic (PK) model could serve as an input function for a pharmacodynamic (PD) model. The apparent pharmacokinetics of fexuprazan could be described by a simpler model. However, a physiologically based pharmacokinetic (PBPK) model was developed in a previous study. A one-compartment model was also proposed in the present study. Both the newly suggested model and the previously validated PBPK model were used as input functions of the PD models. Our simulation revealed that the effects of fexuprazan could be effectively simulated by the proposed PK–PD models. A PK–PD model was also proposed for the oral administration of the PPI reference drug esomeprazole. A model-based analysis was then performed for intragastric pH using several dosing methods. The expected pH could be predicted for both drugs under several dosing regimens using the proposed PK–PD models.

Night-time gastric acid suppression by tegoprazan compared to vonoprazan or esomeprazole

AIM

Nocturnal acid breakthrough has been considered an unmet need of proton pump inhibitors. Tegoprazan, a novel potassium-competitive acid blocker, is expected to show improved properties for this unmet need. This study was aimed to compare night-time acid suppression by tegoprazan with that by vonoprazan or esomeprazole, and to explore the effect of CYP2C19 phenotypes on acid-suppressive effects.

METHODS

A randomized, open-label, three-period, six-sequence crossover study was conducted. A single oral dose of tegoprazan 50 mg, vonoprazan 20 mg or esomeprazole 40 mg was administered at night in each period. Continuous intragastric pH was monitored at baseline and after each dosing.

RESULTS

16 healthy subjects (6 CYP2C19 extensive metabolizers, 5 intermediate metabolizers, 5 poor metabolizers) completed the study. After a single dose of tegoprazan, intragastric pH increased more rapidly to over 4 at approximately 1 hour compared to the other treatments, and elevated intragastric pH was maintained stably at night. Tegoprazan exhibited night-time acid suppression for slightly but not significantly longer than vonoprazan, and greater than esomeprazole; % Time pH ≥4 at night-time was 66.0%, 60.5% and 36.1% for tegoprazan, vonoprazan and esomeprazole, respectively. Night-time acid suppression by tegoprazan and vonoprazan was not dependent on CYP2C19 phenotypes, while that by esomeprazole tended to be influenced by CYP2C19 phenotypes.

CONCLUSIONS

Tegoprazan produced more rapid, potent and well sustained night-time acid suppression versus vonoprazan or esomeprazole when administered at night. Furthermore, tegoprazan showed no CYP2C19 phenotype dependency in acid suppression. It suggests the potential of tegoprazan, especially in preventing nocturnal acid breakthrough.

Prediction of Drug-Drug Interaction Potential of Tegoprazan Using Physiologically Based Pharmacokinetic Modeling and Simulation

This study aimed to develop a physiologically based pharmacokinetic (PBPK) model of tegoprazan and to predict the drug-drug interaction (DDI) potential between tegoprazan and cytochrome P450 (CYP) 3A4 perpetrators. The PBPK model of tegoprazan was developed using SimCYP Simulator^® and verified by comparing the model-predicted pharmacokinetics (PKs) of tegoprazan with the observed data from phase 1 clinical studies, including DDI studies. DDIs between tegoprazan and three CYP3A4 perpetrators were predicted by simulating the difference in tegoprazan exposure with and without perpetrators, after multiple dosing for a clinically used dose range. The final PBPK model adequately predicted the biphasic distribution profiles of tegoprazan and DDI between tegoprazan and clarithromycin. All ratios of the predicted-to-observed PK parameters were between 0.5 and 2.0. In DDI simulation, systemic exposure to tegoprazan was expected to increase about threefold when co-administered with the maximum recommended dose of clarithromycin or ketoconazole. Meanwhile, tegoprazan exposure was expected to decrease to ~30% when rifampicin was co-administered. Based on the simulation by the PBPK model, it is suggested that the DDI potential be considered when tegoprazan is used with CYP3A4 perpetrator, as the acid suppression effect of tegoprazan is known to be associated with systemic exposure.

A pilot study to investigate the utility of NAT2 genotype-guided isoniazid monotherapy regimens in NAT2 slow acetylators

Isoniazid is a therapeutic agent for the treatment of latent tuberculosis infection. Genetic variants in the N-acetyltransferase 2 (NAT2) are associated with the safety and pharmacokinetics of isoniazid. The study aimed to evaluate the safety and pharmacokinetics of a NAT2 genotype-guided regimen of isoniazid monotherapy. A randomized, open-label, parallel-group and multiple-dosing study was performed in healthy subjects. The subjects received isoniazid for 29 days. The NAT2 slow acetylators (NAT2*5/*5, -*5/*6, -*5/*7, -*6/*6, -*6/*7, -*7/*7) randomly received standard dose (300 mg, standard-treatment group) or reduced dose (200 mg, PGx-treatment group) of isoniazid. Also, all the NAT2 rapid acetylators (NAT2*4/*4) received isoniazid 300 mg (reference group). The safety and pharmacokinetics were evaluated during the study. The PGx-treatment group showed a more stable serum liver enzyme profile and a lower incidence of adverse drug reactions (ADRs) than the standard-treatment group. The emergence rates of ADRs were 12.5, 60 and 33.3% in the reference, standard-treatment and PGx-treatment groups, respectively. The PGx-treatment group showed higher plasma isoniazid concentrations than the reference group, although the PGx-treatment group received a reduced dose of isoniazid. Our results showed that a NAT2 genotype-guided regimen may reduce ADRs during isoniazid monotherapy without concern over insufficient drug exposure.

Development of Physiologically Based Pharmacokinetic Model for Orally Administered Fexuprazan in Humans

Fexuprazan is a new drug candidate in the potassium-competitive acid blocker (P-CAB) family. As proton pump inhibitors (PPIs), P-CABs inhibit gastric acid secretion and can be used to treat gastric acid-related disorders such as gastroesophageal reflux disease (GERD). Physiologically based pharmacokinetic (PBPK) models predict drug interactions as pharmacokinetic profiles in biological matrices can be mechanistically simulated. Here, we propose an optimized and validated PBPK model for fexuprazan by integrating in vitro, in vivo, and in silico data. The extent of fexuprazan tissue distribution in humans was predicted using tissue-to-plasma partition coefficients in rats and the allometric relationships of fexuprazan distribution volumes (V_SS) among preclinical species. Urinary fexuprazan excretion was minimal (0.29-2.02%), and this drug was eliminated primarily by the liver and metabolite formation. The fraction absorbed (Fa) of 0.761, estimated from the PBPK modeling, was consistent with the physicochemical properties of fexuprazan, including its in vitro solubility and permeability. The predicted oral bioavailability of fexuprazan (38.4-38.6%) was within the range of the preclinical datasets. The C_max, AUC_last, and time-concentration profiles predicted by the PBPK model established by the learning set were accurately predicted for the validation sets.

Effect of meal timing on pharmacokinetics and pharmacodynamics of tegoprazan in healthy male volunteers

Abstract

Tegoprazan, a novel potassium‐competitive acid blocker, is used to treat acid‐related diseases. However, there is no information on the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of the marketed dosage of tegoprazan under various meal timings in a fed and fasted state. The study aimed to assess the effect of meal timing on PKs and PDs of tegoprazan 50 mg after a single administration in healthy male subjects. An open‐label, single‐dose, three‐treatment, three‐period crossover study was conducted. A total of 12 subjects were orally administered a single dose of tegoprazan 50 mg among various conditions: in a fasted state, at 30 min before or 30 min after a high‐fat meal. PK parameters were estimated by the noncompartmental method. Continuous 24‐h intragastric pH monitoring was done for PD analysis. The PKs and PDs of tegoprazan were compared among the various meal timings. Compared with the fasting condition, the PK profile of tegoprazan was similar when administered 30 min before a high‐fat meal; however, delayed absorption with similar systemic exposure was observed when administered 30 min after a high‐fat meal. The magnitude of acid suppression evaluated through the PD parameters increased when administered 30 min after a high‐fat meal compared with fasting the condition and when administered 30 min before a high‐fat meal. However, the increased difference in acid suppression was not clinically significant. Meal timing had no clinically significant effect on the PKs and PDs of tegoprazan 50 mg. Therefore, the marketed dosage of tegoprazan could be administered regardless of the meal timing.

Novel Therapies for Gastroesophageal Reflux Disease: Beyond Proton Pump Inhibitors

PURPOSE OF REVIEW

Despite the many areas of unmet needs in gastroesophageal reflux disease (GERD), proton pump inhibitors (PPIs) remain the cornerstone of medical therapy. However, since their introduction, the therapeutic limitations of PPIs in GERD management have been increasingly recognized.

RECENT FINDINGS

In this review we discuss the new medical, endoscopic, and surgical therapeutic modalities that have been developed over the last decade. They include the potassium-competitive acid blockers (P-CABs) which provide a rapid onset, prolonged, and profound acid suppression, mucosal protectants which promote the physiological protective barrier of the esophageal mucosa, new prokinetics and neuromodulators. There are growing numbers of novel therapeutic endoscopic techniques that are under investigation or were recently introduced into the market, further expanding our therapeutic armamentarium for GERD. The development of diverse therapeutic modalities for GERD, despite the availability of PPIs, suggests that there are many areas of unmet need in GERD that will continue and drive future exploration for novel therapies.

Review: Treatment of Helicobacter pylori Infection 2019

This review summarizes important studies regarding Helicobacter pylori therapy published from May 2018 to May 2019. The main themes that emerge involve studies assessing the efficacy of bismuth-based regimens. While in recent years the efficacy of bismuth-based quadruple therapy as a second-line therapy has been clearly established, there is now substantial evidence that it is the best performing first-line therapy. Antibiotic resistance was again intensely studied this year, and a clear and dramatic increase in resistance is noted for clarithromycin and levofloxacin; most notably, it may not be possible to support these therapies in most regions of the world much longer without testing. The utility of vonoprazan as an alternative to proton-pump inhibitor therapy, especially in resistant and difficult to treat groups, has also been considered in greater detail this year, as well as means of supporting and enhancing adherence to therapy. Several studies showed that the diversity of gut microbiota was significantly altered shortly after H pylori eradication. However, the diversity was restored to pre-treatment state after 2 months in patients treated with triple therapy. More studies are warranted to assess the long-term changes of gut microbiota after H pylori eradication.

Role of Acid Suppression in Acid-related Diseases: Proton Pump Inhibitor and Potassium-competitive Acid Blocker

Proton pump inhibitors are commonly utilized for the treatment of gastric acid-related diseases, such as gastroesophageal reflux disease, peptic ulcer disease, and Helicobacter pylori infection, and for the prevention of low-dose aspirin or nonsteroidal anti-inflammatory drug-induced peptic ulcers. Vonoprazan is a first-in-class potassium-competitive acid blocker, which has distinct advantages compared to other conventional proton pump inhibitors in terms of the efficacy for acid suppression. Due to its strong gastric acid suppression capabilities, vonoprazan serves as an effective drug for the treatment of gastroesophageal reflux disease and H. pylori infection.

Editorial: control of acid secretion

Linked Content

This article is linked to Sunwoo et al paper. To view this article visit https://doi.org/10.1111/apt.14818.