Efficacy of ilaprazole in the treatment of duodenal ulcers: A meta-analysis

The role of the methoxy group in approved drugs

The methoxy substituent is prevalent in natural products and, consequently, is present in many natural product-derived drugs. It has also been installed in modern drug molecules with no remnant of natural product features because medicinal chemists have been taking advantage of the benefits that this small functional group can bestow on ligand-target binding, physicochemical properties, and ADME parameters. Herein, over 230 methoxy-containing small-molecule drugs, as well as several fluoromethoxy-containing drugs, are presented from the vantage point of the methoxy group. Biochemical mechanisms of action, medicinal chemistry SAR studies, and numerous X-ray cocrystal structures are analyzed to identify the precise role of the methoxy group for many of the drugs and drug classes. Although the methoxy substituent can be considered as the hybridization of a hydroxy and a methyl group, the combination of these functionalities often results in unique effects that can amount to more than the sum of the individual parts.

Efficacy of Aceclofenac and Ilaprazole Combination Therapy versus Celecoxib Monotherapy for Treating NSAID-Induced Dyspepsia in Lumbar Spinal Stenosis Patients

Background and Objectives: Dyspepsia is a common adverse event associated with the use of nonsteroidal anti-inflammatory drugs (NSAIDs) in patients with lumbar spinal stenosis. Although proton pump and cyclooxygenase-2 inhibitors are potential treatment options, the optimal strategy remains unclear. This study aimed to compare the efficacy and safety of combination therapy with aceclofenac and ilaprazole versus celecoxib monotherapy for the treatment of dyspepsia caused by NSAID use in patients with lumbar spinal stenosis. Materials and Methods: This prospective, double-blind, randomized, actively controlled study was conducted at Seoul National University Bundang Hospital in South Korea from July 2020 to September 2021. The participants were randomized into one of two treatment groups: celecoxib monotherapy (control group) and combination therapy with aceclofenac and ilaprazole (test group). The primary efficacy endpoint was the mean change in the Short-Form Leeds Dyspepsia Questionnaire (SF-LDQ) scores from baseline to treatment week 8. The secondary efficacy endpoint was the mean change in Short-Form-12 (SF-12) scores from baseline (week 0) to treatment week 8. Results: The study enrolled 140 patients who were randomly assigned to receive combination therapy with aceclofenac and, ilaprazole or celecoxib. In the per protocol set, the mean change in SF-LDQ scores from week 0 to week 8 was -0.51 ± 4.78 and 1.85 ± 6.70 in the combination therapy and celecoxib group, respectively (p = 0.054). SF-12 scores did not differ significantly between the two groups. Adverse events were reported in both groups, but there was no significant difference in incidence. Conclusions: Combination therapy with aceclofenac and ilaprazole can be a treatment option for NSAID-induced dyspepsia in some situations.

Efficacy and safety of proton pump inhibitors and H2 receptor antagonists in the initial non‑eradication treatment of duodenal ulcer: A network meta‑analysis

The present network meta-analysis aimed to enhance the corresponding evidence with respect to the efficacy and safety of pharmaceuticals treatments. Frequentist network meta-analysis was used. Medical literature up to November 2022 was searched for randomized clinical trials assessing the efficacy and safety of these pharmaceuticals, either compared with each other or compared with placebo. With the exception of ranitidine (300 mg four times daily) and vonoprazan (20 mg once daily) having lower safety than placebo, the efficacy and safety of the remaining treatments were superior to placebo. Cimetidine (400 mg four times daily) and pantoprazole (40 mg once daily) were ranked first in terms of efficacy. The frequentist network meta-analysis shows that for cimetidine (except 400 mg once daily), famotidine, rabeprazole, ilaprazole, lansoprazole (except 7.5 mg once daily) and omeprazole (except 10 mg once daily or 30 mg once daily), the efficacy comparison between the different doses of each of the aforementioned pharmaceuticals did not indicate statistically significant differences. In conclusion, pantoprazole (40 mg once daily) was the best choice for the initial non-eradication treatment of patients with duodenal ulcer, and cimetidine (400 mg twice daily), omeprazole (20 mg once daily), lansoprazole (15 mg once daily), ilaprazole (5 mg once daily) and rabeprazole (10 mg once daily) could be used as the first choice. If the aforementioned pharmaceuticals cannot be prescribed, famotidine (40 mg twice daily) is recommended.

The pharmacotherapeutic management of duodenal and gastric ulcers

INTRODUCTION

Although the incidence and prevalence of duodenal and gastric ulcers have been declining, it remains challenging for health care systems. Based on the underlying cause, history, and characteristics of ulcers, management is generally provided by administering proton pump inhibitors (PPIs) or antibiotics.

AREAS COVERED

This article is based on global guidelines and English language literature from the past decade obtained through searches using PubMed, Clinicaltrials.gov, the US FDA, and the Cochrane library. Using a stepwise approach, dose and duration of treatment, drug interactions, warnings and contraindications, adverse effects, and administration points were specified. New drug candidates that may get American and European approvals were also introduced.

EXPERT OPINION

Despite the wide use of PPIs, their development lags behind the clinical need. There is an absolute requirement to develop third-generation PPIs with higher potency and improved pharmacokinetic and safety profiles. Regarding the antibiotic resistance crisis, including those used against H. pylori, conducting more clinical trials and investigating regional antibiotic resistance are warranted. Potassium competitive acid blockers, ilaprazole, and an H. pylori vaccine all show promise for the future.

Accelerating Development of Benziamidazole-Class Proton Pump Inhibitors: A Mechanism-Based PK/PD Model to Optimize Study Design with Ilaprazole as a Case Drug

Proton pump inhibitors (PPIs) are the mainstay for treatment of acid-related diseases. This study developed a mechanism-based pharmacokinetic (PK) and pharmacodynamics (PD) model with ilaprazole as case drug, so as to support and accelerate the development of novel PPIs. The model was established and verified using the PK and PD data from 26 subjects receiving 5 to 30 mg of ilaprazole and 22 subjects receiving the loading dose of ilaprazole 20 mg followed by 10 mg once daily for 2 days. The nonlinear mixed-effects modeling approach was performed for the PK/PD model. A two-compartment model with linear elimination and covariates (body weight and gender) described the observed data well. The relationship between plasma concentrations of ilaprazole and gastric acid pH was well quantified with individual variability, in which the synthesis and degradation of H⁺/K⁺-ATPase, the food effect, the circular rhythms of gastric acid secretion, and the irreversible inhibition of H⁺/K⁺-ATPase by ilaprazole were integrated. This PK/PD model well predicted the PK and PD profile of ilaprazole in healthy subjects and patients with duodenal ulcers receiving wide range dose regimens. The mechanism-based PK/PD model provided a potential strategy to accelerate the development of novel PPIs by waiving the unnecessary clinical trials.

Identification of the New In Vivo Metabolites of Ilaprazole in Rat Plasma after Oral Administration by LC-MS: In Silico Prediction of the H+/K+-ATPase Inhibitor

Ilaprazole is a proton pump inhibitor used to treat digestive diseases. In this study, blood samples were collected after oral administration of ilaprazole and prepared by liquid–liquid extraction. The metabolites of ilaprazole were detected by liquid chromatography–high-resolution mass spectrometry (LC-HRMS) and LC-MSⁿ. A total of twelve in vivo metabolites were detected in rat plasma and six new metabolites of ilaprazole, including one reductive metabolite with sulfide (M3), two hydroxylated metabolites with sulfoxide (M7 and M8), and three oxidative metabolites with sulfone (M9, M11, and M12), were identified. The possible metabolic pathways of ilaprazole and the fragmentation behaviors of its metabolites were elucidated. The result of the in silico prediction indicates that all the new metabolites showed the potential ability to inhibit H⁺/K⁺-ATPase activity.

Efficacy, safety and pharmacokinetics of ilaprazole infusion in healthy subjects and patients with esomeprazole as positive control

AIMS

The objectives were to investigate the pharmacokinetics, pharmacodynamics and safety of ilaprazole infusion in healthy subjects and patients with esomeprazole as positive control, and then recommend the dosage regimen for Phase 2b/3 studies.

METHODS

Three clinical studies were performed. First, 16 healthy subjects received infusion of ilaprazole 30 mg or esomeprazole 80 mg. Second, 12 healthy subjects received ilaprazole 20 mg followed by 10 mg once daily for 2 days. Finally, 20 patients with duodenal ulcers received ilaprazole 20 mg followed by 10 mg for 2 days or esomeprazole 40 mg twice daily for 3 days. Serial blood samples were collected and intragastric pH was recorded.

RESULTS

The mean percentages time of intragastric pH >6 was 63.6 and 51.7% for healthy subjects after receiving ilaprazole 30 mg and esomeprazole 80 mg. Linear pharmacokinetics was observed when the dose was increased to 30 mg but the effect was saturated. Ilaprazole 20 mg followed by 10 mg for 2 days provided higher plasma exposure in healthy subjects than patients, but the effect was comparable. After multiple administrations, ilaprazole provided similar effect to esomeprazole. Ilaprazole infusion was safe and well tolerated without serious adverse events.

CONCLUSIONS

Ilaprazole provided comparable effect of pH control to esomeprazole, with lower dose and fewer times of administration. There was no significant difference of ilaprazole between healthy subjects and patients regarding intragastric acid inhibition. A loading dose of ilaprazole 20 mg followed by 10 mg once daily for 2 days was recommended for Phase 2b/3 studies.

Development of a UHPLC-MS/MS method for the quantification of ilaprazole enantiomers in rat plasma and its pharmacokinetic application

In Korea and China, ilaprazole is a widely used proton pump inhibitor in the treatment of gastric ulcers. In this study, a specific and sensitive LC-MS/MS method has been developed and validated for the quantification of ilaprazole enantiomers in the rat plasma, using R-lansoprazole as the internal standard. The enantioseparation was achieved on a CHIRALPAK AS-RH column (4.6 mm × 150 mm, i.d. 5 μm), with a mobile phase composed of 10 mM ammonium acetate aqueous solution and acetonitrile (60:40, V/V), at a flow-rate of 0.5 mL/min. The method was validated over the concentration range of 0.5-300 ng/mL for both, R- and S -ilaprazole. The lower limit of quantification was 0.5 ng/mL for both enantiomers. The relative standard deviation (RSD) of intra- and inter-day precision of R-ilaprazole and S-ilaprazole was less than 10.9%, and the relative error accuracy (RE) ranged from -0.5%-2.0%. Finally, the method was successfully evaluated in rats in a stereoselective pharmacokinetic study of the ilaprazole racemate.

Eradication Efficacy of Modified Dual Therapy Compared with Bismuth-Containing Quadruple Therapy as a First-Line Treatment of Helicobacter pylori

OBJECTIVES

This study assessed the effectiveness, adverse events, patient adherence, and costs of modified dual therapy compared with bismuth-containing quadruple therapy for treating Helicobacter pylori infection in Chinese patients. We also sought to determine whether modified dual therapy could be used as an alternative first-line treatment for H. pylori infection.

METHODS

A total of 232 H. pylori-infected, treatment-naive patients were enrolled in this open-label, randomized controlled clinical trial. Patients were randomly allocated into 2 groups: the 14-day modified dual therapy group and the bismuth-containing quadruple therapy group. Eradication rates, drug-related adverse events, patient compliance, and drug costs were compared between the 2 groups.

RESULTS

The modified dual therapy group achieved eradication rates of 87.9%, 91.1%, and 91.1% as determined by the intention-to-treat, per-protocol, and modified intention-to-treat analyses, respectively. The eradication rates were similar compared with the bismuth-containing quadruple therapy group: 89.7%, 91.2%, and 90.4%. In addition, modified dual therapy ameliorated variations in the CYP2C19, IL-1B-511, and H. pylori VacA genotypes. There were no significant differences in the compliance rates between the 2 groups. The modified dual therapy group exhibited significantly less overall side effects compared with the bismuth-containing quadruple therapy group (P < 0.001). Furthermore, the cost of medications in the modified dual therapy was lower compared with that in the bismuth-containing quadruple therapy.

CONCLUSIONS

Modified dual therapy at high dose and administration frequency is equally effective and safer and less costly compared with bismuth-containing quadruple therapy.

Standard-Dose Proton Pump Inhibitors in the Initial Non-eradication Treatment of Duodenal Ulcer: Systematic Review, Network Meta-Analysis, and Cost-Effectiveness Analysis

Background: Short-term use of standard-dose proton pump inhibitors (PPIs) is the first-line initial non-eradication treatment for duodenal ulcer (DU), but the choice on individual PPI drug is still controversial. The purpose of this study is to compare the efficacy, safety, and cost-effectiveness of standard-dose PPI medications in the initial non-eradication treatment of DU. Methods: We searched PubMed, Embase, Cochrane Library, Clinicaltrials.gov, China National Knowledge Infrastructure, VIP database, and the Wanfang database from their earliest records to September 2017. Randomized controlled trials (RCTs) evaluating omeprazole (20 mg/day), pantoprazole (40 mg/day), lansoprazole (30 mg/day), rabeprazole (20 mg/day), ilaprazole (10 mg/day), ranitidine (300 mg/day), famotidine (40 mg/day), or placebo for DU were included. The outcomes were 4-week ulcer healing rate (4-UHR) and the incidence of adverse events (AEs). A network meta-analysis (NMA) using a Bayesian random effects model was conducted, and a cost-effectiveness analysis using a decision tree was performed from the payer's perspective over 1 year. Results: A total of 62 RCTs involving 10,339 participants (eight interventions) were included. The NMA showed that all the PPIs significantly increased the 4-UHR compared to H2 receptor antagonists (H2RA) and placebo, while there was no significant difference for 4-UHR among PPIs. As to the incidence of AEs, no significant difference was observed among PPIs, H2RA, and placebo during 4-week follow-up. Based on the costs of both PPIs and management of AEs in China, the incremental cost-effectiveness ratio per quality-adjusted life year (in US dollars) for pantoprazole, lansoprazole, rabeprazole, and ilaprazole compared to omeprazole corresponded to $5134.67, $17801.67, $25488.31, and $44572.22, respectively. Conclusion: Although the efficacy and tolerance of different PPIs are similar in the initial non-eradication treatment of DU, pantoprazole (40 mg/day) seems to be the most cost-effective option in China.

Prospective Single Arm Study on the Effect of Ilaprazole in Patients with Heartburn but No Reflux Esophagitis

PURPOSE

Patients with gastroesophageal reflux disease without esophagitis show varying responses to proton pump inhibitors (PPIs). The aim of this study was to objectively evaluate the effect of a new PPI, ilaprazole, on patients with heartburn but without reflux esophagitis.

MATERIALS AND METHODS

This prospective study was performed on 20 patients with heartburn but without reflux esophagitis. All patients underwent upper endoscopy and 24-hr combined multichannel intraluminal impedance and pH esophageal monitoring (MII-pH). They were then treated with ilaprazole (20 mg) once daily for 4 weeks. The GerdQ questionnaire, histologic findings, and inflammatory biomarkers were used for assessment before and after ilaprazole.

RESULTS

Among the 20 patients, 13 (65%) showed GerdQ score ≥8. Based on MII-pH results, patients were classified as true nonerosive reflux disease (n=2), hypersensitive esophagus (n=10), and functional heartburn (n=8). After treatment, patients showed a statistically significant improvement in GerdQ score (p<0.001). Among histopathologic findings, basal cell hyperplasia, papillary elongation, and infiltration of intraepithelial T lymphocytes improved significantly (p=0.008, p=0.021, and p=0.008; respectively). Expression of TNF-α, IL-8, TRPV1, and MCP-1 decreased marginally after treatment (p=0.049, p=0.046, p=0.045, and p=0.042; respectively).

CONCLUSION

Daily ilaprazole (20 mg) is efficacious in improving symptom scores, histopathologic findings, and inflammatory biomarkers in patients with heartburn but no reflux esophagitis.

Effect of ilaprazole on the healing of endoscopic submucosal dissection-induced gastric ulcer: randomized-controlled, multicenter study

BACKGROUND

The optimal treatment regimen or the duration of treatment for an endoscopic submucosal dissection (ESD)-induced gastric ulcer has not been established. The aim of this study was to assess the efficacy of novel proton-pump inhibitor, ilaprazole, for the treatment of ESD-induced gastric ulcer.

METHODS

This was a prospective, open-label, randomized multicenter study. Between June 2015 and March 2018, a total of 176 patients (178 lesions) who underwent ESD for a gastric neoplasm were randomly allocated to receive the oral proton-pump inhibitor ilaprazole 20 mg or rabeprazole 20 mg daily for 8 weeks. The primary outcome was the ulcer healing rate at 4 and 8 weeks.

RESULTS

A total of 155 (157 lesions) and 154 patients (156 lesions) were included in the modified intention-to-treat (mITT) and per-protocol analyses, respectively. There was no significant difference in the ulcer healing rate (ilaprazole vs. rabeprazole, 97.4% vs. 97.0 p = 0.78 at 4 weeks, 100% vs. 100%, p = 0.95 at 8 weeks in the mITT analysis) or stage of ulcer (scar stage, 25.6% vs. 17.7%, p = 0.25 at 4 weeks, 92.3% vs. 88.6%, p = 0.59 at 8 weeks in the mITT analysis) between the treatment groups. The quality of ulcer healing was not significantly different between the two groups. No independent predictive factor for higher-quality ulcer healing was found in the multivariate analysis.

CONCLUSIONS

According to this trial, ilaprazole and rabeprazole showed no significant difference in the healing of artificial gastric ulcers. Most of the ulcers achieved complete healing within 4-8 weeks.

TRIAL REGISTRATION

ClinicalTrial.gov NCT02638584.

Laparoscopic omental filling with intraoperative endoscopy for a perforated duodenal ulcer

As a surgical treatment for a perforated duodenal ulcer, duodenal omental filling is effective. However, filling the perforation site with a sufficient amount of omentum is difficult in some situations. We herein report that we successfully filled a perforated duodenal ulcer with a sufficient amount of omentum using intraoperative endoscopy. The operation was performed with three ports, the operation time was 110 min, and the estimated blood loss was small. The postoperative course was good. No stenosis of deformity of the duodenum was observed on follow-up endoscopy. Laparoscopic surgery has a shorter operation time, shorter postoperative hospital stay, and less postoperative pain than open surgery. The combined use of intraoperative endoscopy with laparoscopic surgery is effective for a large perforation, and it can be expected to reduce the rate of conversion to open surgery. This combined procedure is considered useful as a laparoscopic omental filling operation.

Repositioning of proton pump inhibitors in cancer therapy

Drug repositioning, as a smart way to exploit new molecular targets of a known drug, has been gaining increasing attention in the discovery of anti-cancer drugs. Proton pump inhibitors (PPIs) as benzimidazole derivatives, which are essentially H⁺-K⁺-ATPases inhibitors, are commonly used in the treatment of acid-related diseases such as gastric ulcer. In recent years, exploring the new application of PPIs in anti-cancer field has become a hot research topic. Interestingly, cancer cells display an alkaline intracellular pH and an acidic extracellular pH. The extracellular acidity of tumors can be corrected by PPIs that are selectively activated in an acid milieu. It is generally believed that PPIs might provoke disruption of pH homeostasis by targeting V-ATPase on cancer cells, which is the theoretical basis for PPIs to play an anti-cancer role. Numerous studies have shown specialized effects of the PPIs on tumor cell growth, metastasis, chemoresistance, and autophagy. PPIs may really represent new anti-cancer drugs due to better safety and tolerance, the potential selectivity in targeting tumor acidity, and the ability to inhibit mechanism pivotal for cancer homeostasis. In this review, we focus on the new therapeutic applications of PPIs in multiple cancers, explaining the rationale behind this approach and providing practical evidence.

Efficacy of proton pump inhibitors for patients with duodenal ulcers: A pairwise and network meta-analysis of randomized controlled trials

BACKGROUND/AIM

To compare the efficacy and tolerance of different proton pump inhibitors (PPIs) in different doses for patients with duodenal ulcers.

MATERIALS AND METHODS

An electronic database was searched to collect all randomized clinical trials (RCTs), and a pairwise and network meta-analysis were performed.

RESULTS

A total of 24 RCTs involving 6188 patients were included. The network meta-analysis showed that there were no significant differences for the 4-week healing rate of duodenal ulcer treated with different PPI regimens except pantoprazle 40 mg/d versus lansoprazole 15 mg/d [Relative risk (RR) = 3.57; 95% confidence interval (CI) = 1.36-10.31)] and lansoprazole 30 mg/d versus lansoprazole 15 mg/d (RR = 2.45; 95% CI = 1.01-6.14). In comparison with H2receptor antagonists (H2RA), pantoprazole 40 mg/d and lansoprazole 30 mg/d significantly increase the healing rate (RR = 2.96; 95% CI = 1.78-5.14 and RR = 2.04; 95% CI = 1.13-3.53, respectively). There was no significant difference for the rate of adverse events between different regimens, including H2RA for a duration of 4-week of follow up.

CONCLUSION

There was no significant difference for the efficacy and tolerance between the ordinary doses of different PPIs with the exception of lansoprazle 15 mg/d.

Pharmacokinetics, Pharmacodynamics and Safety of Multiple-Infusion Ilaprazole in Healthy Chinese Subjects

BACKGROUND AND OBJECTIVES

Ilaprazole is a novel proton pump inhibitor that provides effective and long lasting inhibition of intragastric acid secretion. The objectives of this study were to investigate the pharmacokinetics, pharmacodynamics, and safety of intravenous ilaprazole after multiple administrations in healthy Chinese subjects.

METHODS

This was an open-label and multiple-dose clinical study. Ten healthy Chinese subjects received 10 mg ilaprazole infusion once daily for 5 days. Helicobacter pylori status was examined. Blood samples were collected and intragastric pH was recorded for 24 h. Safety was assessed throughout the study.

RESULTS

There was no accumulation after multiple administrations. The mean steady-state half-life and clearance were comparable to those following single administration. Ilaprazole provided sustainable and significant intragastric pH control in terms of percentage time at pH >4, pH >6 within 24 h and mean 24-h pH values. The pH value within 24 h was affected by Helicobacter pylori infection in subjects with continuous infusion. Intravenous ilaprazole was safe and there were no serious adverse events.

CONCLUSION

Intravenous ilaprazole provided stable pharmacokinetics and pharmacodynamics at a dose of 10 mg once daily for 5 days, and was well tolerated in healthy subjects.

Modeling the cost-effectiveness of ilaprazole versus omeprazole for the treatment of newly diagnosed duodenal ulcer patients in China

OBJECTIVES

To evaluate the cost-effectiveness of 10 mg ilaprazole once-daily vs 20 mg omeprazole once-daily to treat newly-diagnosed duodenal ulcer patients in China.

METHODS

A decision tree model was constructed and the treatment impact was projected up to 1 year. The CYP2C19 polymorphism distribution in the Chinese population, the respective cure rates in the CYP2C19 genotype sub-groups, the impact of Duodenal Ulcer (DU) on utility value and drug-related side-effect data were obtained from the literature. The total costs of medications were calculated to estimate the treatment costs based on current drug retail prices in China. Expert surveys were conducted when published data were not available. Probabilistic sensitivity analysis was performed to gauge the robustness of the results.

RESULTS

Ilaprazole, when compared with omeprazole, achieved a better overall clinical efficacy. For the overall population, ilaprazole achieved an incremental cost effectiveness ratio (ICER) of ¥132 056 per QALY gained. This is less than the WHO recommended threshold of 3-times the average GDP per capita in China (2014). Furthermore, sub-group analysis showed that ilaprazole is cost-effective in every province in CYP2C19 hetEM patients and in the most developed provinces in CYP2C19 homEM patients. Probabilistic sensitivity analysis suggests that the results are robust with 97% probability that ilaprozole is considered cost-effective when a threshold of 3-times China's average GDP per capita is considered.

LIMITATION

This study didn't have the data of ilaprazole combined with Hp eradication therapy. Caution should be taken when extrapolating these findings to DU patients with an Hp eradication therapy.

CONCLUSIONS

The cost-effectiveness analysis results demonstrated that ilaprazole would be considered a cost-effective therapy, compared with omeprazole, in Chinese DU patients based on the efficacy projections in various CYP2C19 polymorphism types.

High Dose Ilaprazole/Amoxicillin as First-Line Regimen for Helicobacter pylori Infection in Korea

Objective. The eradication rate of Helicobacter pylori (H. pylori) following standard triple therapy has declined over the past few decades. This study has determined whether high dose dual therapy (PPI and amoxicillin) is adequate for eradicating H. pylori in Korea. Methods. This was an open-labeled study of H. pylori infected treatment-naive patients. Subjects received dual therapy for 14 days: ilaprazole 40 mg tablets given twice a day and amoxicillin 750 mg tablets given 4 times a day. At the end of the therapy, the subjects visited the clinic to confirm compliance and monitor for any side effects. Subjects visited again after 4–6 weeks to confirm H. pylori status through a urea breath test. Results. The cure rate of H. pylori was 79.3% (23 of 29) (95% confidence interval: 61.6–90.2) in the intention-to-treat analysis and 82.1% (23 of 28) in the per-protocol analysis. Compliance rates were high (96.6%) and side effects were minimal and tolerable. Conclusion. A high dose of ilaprazole + amoxicillin was ineffective as the first-line therapy for eradicating H. pylori in Korea. Future studies should focus on intragastric pH measurements and assess amoxicillin resistance.