Evidence-based clinical guidelines for chronic constipation 2023.

In July 2023 the Japan Gastroenterological Association published the first version of its clinical guidelines for chronic constipation 2023. Based on the latest evidence, these guidelines describe the definition, classification, diagnostic criteria, diagnostic testing methods, epidemiology, pathophysiology, and treatment of chronic constipation. They include flowcharts for both diagnosis and treatment of chronic constipation. In the treatment of chronic constipation, the first step involves differentiating between secondary forms, such as organic disease-associated constipation, systemic disease-associated constipation, and drug-induced constipation. The next step is to determine whether the chronic constipation stems from a motility disorder, a form of primary chronic constipation. For functional constipation and constipation-predominant irritable bowel syndrome, treatment should be initiated after evaluating symptoms like reduced frequency of bowel movement frequency type or defecation difficulty type. The first line of treatment includes improvement of lifestyle habits and diet therapy. The first drugs to consider for oral treatment are osmotic laxatives. If these are ineffective, secretagogues and ileal bile acid transporter inhibitors are candidates. However, stimulant laxatives are exclusively designated for as-needed use. Probiotics, bulk-forming laxatives, prokinetics, and Kampo medicine, for which there is insufficient evidence, are considered alternative or complementary therapy. Providing the best clinical strategies for chronic constipation therapy in Japan, these clinical guidelines for chronic constipation 2023 should prove useful for its treatment worldwide.

BRAF K601E-mutated metastatic colorectal cancer in response to combination therapy with encorafenib, binimetinib, and cetuximab: A case report.

BACKGROUND: BRAF mutation has been recognized as a negative prognostic marker for metastatic colorectal cancer (mCRC), but these data are from common BRAF V600E-mutated mCRC. Combination therapy of BRAF inhibitor and anti-epidermal growth factor receptor (EGFR) antibody has been approved for BRAF V600E-mutated mCRC. However, BRAF non-V600 mutations are rare mutations, and their clinical behavior is not understood. Moreover, the BRAF K601E mutation is extremely rare in mCRC, and there have been no reports on its specific treatment. CASE SUMMARY: Herein, we report the case of a 59-year-old female with super aggressive mCRC with multiple metastases, which extended to whole body including mediastinal to abdominal lymph nodes, bones, pleura, and peritoneum. The companion diagnostics of tumor tissues showed RAS/BRAF wild-type without microsatellite instability. She received chemotherapy with mFOLFOX6 (oxaliplatin plus infusional 5-fluorouracil [5-FU] and leucovorin) plus panitumumab, following FOLFIRI (irinotecan plus infusional 5-FU and leucovorin) plus ramucirumab. For the next regimen selection, a comprehensive genomic profiling panel was performed and revealed a BRAF K601E mutation, which was not covered in the initial companion diagnostics. After disease progression, a combination of encorafenib, binimetinib, and cetuximab was selected as third-line chemotherapy. The serum levels of tumor markers were immediately decreased accompanied by improvements in pleural effusion and ascites. However, the disease progressed again, and best supportive care was done instead. CONCLUSION: This case offers novel insights into the clinical behaviors of BRAF non-V600E-mCRC, potentially advancing personalized therapy for rare and aggressive cases.

Potential of Anti-Leukotriene Drugs as New Therapeutic Agents for Inhibiting Cholangiocarcinoma Progression.

Cholangiocarcinoma (CCA) is a cancer with a poor prognosis due to difficulties in diagnosis and limited treatment options, highlighting the urgent need for new targeted therapies. In a clinical setting, we found that leukotriene levels in bile were higher than in serum. Immunohistochemical analysis of surgically resected samples also revealed that CysLT receptor 1 (CysLTR1) was more highly expressed in CCA than in normal bile duct tissue, prompting us to investigate leukotriene as a potential therapeutic target in CCA. In vitro studies using CCA cell lines expressing CysLTR1 showed that leukotriene D4, a major ligand of CysLTR1, promoted cell proliferation, with increased phosphorylation of AKT and extracellular signal-regulated kinase 1/2 (ERK1/2). Additionally, treatment with two clinically available anti-allergic drugs-zileuton, an inhibitor of CysLT formation, and montelukast, a CysLTR1 inhibitor-had inhibitory effects on cell proliferation and migratory capacity, accompanied by the reduced phosphorylation of AKT and ERK1/2. Furthermore, the simultaneous administration of both drugs synergistically enhanced the inhibitory effect on cell proliferation. Our study suggests that use of these drugs may represent a novel approach to treat CCA through drug repositioning.

Clinical performance of Circulating HBV RNA and iTACT-HBcrAg Assays in HBeAg-negative and HBsAg-cleared Chronic Hepatitis B Patients.

Hepatitis B virus (HBV) RNA and hepatitis B core-related antigen (HBcrAg) have been reported to reflect the transcriptional activity of covalently closed circular HBV DNA. We retrospectively investigated the proportions of quantifiable serum HBV RNA and immunoassay for total antigen including complex via pretreatment-hepatitis B core-related antigen (iTACT-HBcrAg) in chronic hepatitis B patients negative for hepatitis B e antigen (HBeAg) and/or with hepatitis B surface antigen (HBsAg) seroclearance. This study included 246 HBeAg-negative HBV-infected patients, who comprised 13 with liver cirrhosis (LC, the LC group), 118 chronic hepatitis (CH, the CH group), and 115 inactive carriers (IC, the IC group), and 44 patients with HBsAg seroclearance. iTACT-HBcrAg and HBV RNA levels were determined using stored serum samples. Higher proportions of the patients had quantifiable iTACT-HBcrAg than HBV RNA in all groups of HBeAg-negative patients (iTACT-HBcrAg: 84.6%, 90.7%, 35.7%, HBV RNA: 23.1%, 26.3%, 14.8%, for the LC, CH, IC groups). With HBsAg seroclearance (HBsAg <0.05 IU/mL), the proportions of quantifiable samples for HBV RNA were also lower than iTACT-HBcrAg (0% for HBV RNA). Thus, iTACT-HBcrAg was more often detectable than circulating HBV RNA in this study population. Further long-term prospective evaluation of iTACT-HBcrAg is desirable for its utilization in clinical practice.

Urinary dipeptidase 1 and trefoil factor 1 are promising biomarkers for early diagnosis of colorectal cancer.

BACKGROUND: Currently utilized serum tumor markers and fecal immunochemical tests do not have sufficient diagnostic power for colorectal cancer (CRC) due to their low sensitivities. To establish non-invasive urinary protein biomarkers for early CRC diagnosis, we performed stepwise analyses employing urine samples from CRCs and healthy controls (HCs). METHODS: Among 474 urine samples, 363 age- and sex-matched participants (188 HCs, 175 stage 0-III CRCs) were randomly divided into discovery (16 HCs, 16 CRCs), training (110 HCs, 110 CRCs), and validation (62 HCs, 49 CRCs) cohorts. RESULTS: Of the 23 urinary protein candidates comprehensively identified from mass spectrometry in the discovery cohort, urinary levels of dipeptidase 1 (uDPEP1) and Trefoil factor1 (uTFF1) were the two most significant diagnostic biomarkers for CRC in both training and validation cohorts using enzyme-linked immunosorbent assays. A urinary biomarker panel comprising uDPEP1 and uTFF1 significantly distinguished CRCs from HCs, showing area under the curves of 0.825-0.956 for stage 0-III CRC and 0.792-0.852 for stage 0/I CRC. uDPEP1 and uTFF1 also significantly distinguished colorectal adenoma (CRA) patients from HCs, with uDPEP1 and uTFF1 increasing significantly in the order of HCs, CRA patients, and CRC patients. Moreover, expression levels of DPEP1 and TFF1 were also significantly higher in the serum and tumor tissues of CRC, compared to HCs and normal tissues, respectively. CONCLUSIONS: This study established a promising and non-invasive urinary protein biomarker panel, which enables the early detection of CRC with high sensitivity.

Serum interleukin-6 levels at the start of the second course of atezolizumab plus bevacizumab therapy predict therapeutic efficacy in patients with advanced hepatocellular carcinoma: a multicenter analysis.

BACKGROUND AND AIM: Serum interleukin-6 (IL-6) before the administration of atezolizumab plus bevacizumab (Atez + Bev) is a prognostic biomarker in patients with hepatocellular carcinoma (HCC) treated with Atez + Bev. We previously revealed that the neutrophil-to-lymphocyte ratio and serum chemokine levels during treatment with Atez + Bev were more useful as prognostic biomarkers. Therefore, we examined the predictive ability of serum IL-6 for the efficacy of Atez + Bev in patients with HCC. METHODS: We enrolled 94 patients with HCC who received treatment with Atez + Bev. Initial responses were assessed through dynamic computed tomography or magnetic resonance imaging. The levels of IL-6 in serum were measured before and at the initiation of the second course of Atez + Bev. Subsequently, the relationship of IL-6 levels with treatment efficacy was evaluated. RESULTS: IL-6 levels at the initiation of the second course tended to be higher in patients with progressive disease versus those with non-progressive disease in the initial evaluation (P = 0.054). Moreover, the cutoff value (7.4 pg/mL) was useful in stratifying patients by overall survival (i.e. low vs high: not reached vs 21.4 months, respectively, P = 0.001) and progression-free survival (low vs high: 11.9 vs 5.2 months, respectively, P = 0.004). This result was reproduced in patients with HCC who received Atez + Bev as first-line therapy. In the multivariate analyses, IL-6 levels at the initiation of the second course were independent predictive factors for progression-free and overall survival. CONCLUSIONS: Serum levels of IL-6 at the initiation of the second course of treatment may predict Atez + Bev efficacy and prognosis in HCC.

MicroRNA-223-3p levels in serum-derived extracellular vesicles predict regression of M2BPGi-based liver fibrosis after hepatitis C virus eradication by direct-acting antiviral agents.

BACKGROUND: We retrospectively investigated microRNA (miRNA) levels in serum-derived extracellular vesicles (EVs) as predictive indicators for regression of liver fibrosis, after achievement of a sustained virological response (SVR) by direct-acting antiviral (DAA) therapy for chronic hepatitis C (CHC). METHODS: The study subjects were recruited from a historical cohort of 108 CHC patients whose pretreatment serum Mac-2-binding protein glycosylation isomer (M2BPGi) levels were ≥ 2.0 cut-off index (COI). We classified patients with M2BPGi levels < 1.76 and ≥ 1.76 COI at 2 years after the end of treatment (EOT) into the regression and non-regression groups, respectively. Eleven of the patients were assigned to the discovery set, and we comprehensively investigated the miRNAs contained in serum-derived EVs at 24 weeks after the EOT (EOT24W), using RNA sequencing. The remaining 97 patients were assigned to the validation set, and reproducibility was verified by quantitative real-time PCR. RESULTS: Through analysis of the discovery and validation sets, we identified miR-223-3p and miR-1290 as candidate predictors. Subsequently, we analyzed various clinical data, including these candidate miRNAs. Multivariate analyses revealed that the levels of miR-223-3p at EOT24W were significantly associated with regression of M2BPGi-based liver fibrosis (Odds ratio: 1.380; P = 0.024). Consistent results were obtained, even when the serum M2BPGi levels were aligned by propensity score matching and in patients with advanced M2BPGi-based liver fibrosis (pretreatment M2BPGi levels ≥ 3.3 COI). CONCLUSIONS: The miR-223-3p level in serum-derived EVs at EOT24W is a feasible predictor of regression of M2BPGi-based liver fibrosis after achievement of an SVR by DAA therapy.

Krüppel-like Factor-4-Mediated Macrophage Polarization and Phenotypic Transitions Drive Intestinal Fibrosis in THP-1 Monocyte Models In Vitro.

Background and Objectives: Despite the fact that biologic drugs have transformed inflammatory bowel disease (IBD) treatment, addressing fibrosis-related strictures remains a research gap. This study explored the roles of cytokines, macrophages, and Krüppel-like factors (KLFs), specifically KLF4, in intestinal fibrosis, as well as the interplay of KLF4 with various gut components. Materials and Methods: This study examined macrophage subtypes, their KLF4 expression, and the effects of KLF4 knockdown on macrophage polarization and cytokine expression using THP-1 monocyte models. Co-culture experiments with stromal myofibroblasts and a conditioned medium from macrophage subtype cultures were conducted to study the role of these cells in intestinal fibrosis. Human-induced pluripotent stem cell-derived small intestinal organoids were used to confirm inflammatory and fibrotic responses in the human small intestinal epithelium. Results: Each macrophage subtype exhibited distinct phenotypes and KLF4 expression. Knockdown of KLF4 induced inflammatory cytokine expression in M0, M2a, and M2c cells. M2b exerted anti-fibrotic effects via interleukin (IL)-10. M0 and M2b cells showed a high migratory capacity toward activated stromal myofibroblasts. M0 cells interacting with activated stromal myofibroblasts transformed into inflammatory macrophages, thereby increasing pro-inflammatory cytokine expression. The expression of IL-36α, linked to fibrosis, was upregulated. Conclusions: This study elucidated the role of KLF4 in macrophage polarization and the intricate interactions between macrophages, stromal myofibroblasts, and cytokines in experimental in vitro models of intestinal fibrosis. The obtained results may suggest the mechanism of fibrosis formation in clinical IBD.

Factors affecting the sodium-glucose cotransporter 2 inhibitors-related initial decline in glomerular filtration rate and its possible effect on kidney outcome in chronic kidney disease with type 2 diabetes: The Japan Chronic Kidney Disease Database.

AIM: Sodium-glucose cotransporter 2 (SGLT2) inhibitors often cause a transient decrease in glomerular filtration rate (GFR) shortly after the initiation, referred to as the 'initial drop'. However, the clinical significance of this initial drop in real-world practice remains unclear. MATERIALS AND METHODS: Using the nationwide Japan Chronic Kidney Disease Database, we examined factors that affected the initial drop, in patients with chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). We also evaluated the effects of the initial drop on a composite kidney outcome (a decline in GFR of ≥50% or progression to end-stage kidney disease). RESULTS: Data from 2053 patients with CKD and T2DM newly prescribed an SGLT2 inhibitor were analysed. The follow-up period after SGLT2 inhibitor administration was 1015 days (interquartile range: 532, 1678). Multivariate linear regression models revealed that the concomitant use of the renin-angiotensin system inhibitors and diuretics, urinary protein levels ≥2+, and changes in GFR before the initiation of the SGLT2 inhibitor were associated with a larger initial GFR decline (ß = -0.609, p = .039; ß = -2.298, p < .001; ß = -0.936, p = .048; ß = -0.079, p < .001, respectively). Patients in the quartile with the largest initial GFR decline experienced a higher incidence of the subsequent composite kidney outcome than those in the other quartiles (p < .001). CONCLUSIONS: The concomitant use of renin-angiotensin system inhibitors and diuretics, higher urine protein levels and pre-treatment GFR changes were associated with a larger initial GFR decline. Of these factors, the use of a diuretic had the largest effect. Furthermore, patients with CKD and T2DM experiencing an excessive initial GFR drop might be at a higher risk of adverse kidney outcomes.

Real-world data on efficacy/safety and economic impact of nivolumab administered every 2 and 4 weeks among Japanese patients.

AIM: A new treatment interval for nivolumab administration at 480 mg every 4 weeks, in addition to 240 mg every 2 weeks, was approved in Japan in 2020. Using model-based evaluation, it was speculated that the effects or safety of nivolumab do not differ between the two treatment intervals; however, real-world data on nivolumab efficacy, safety, and economic impact are lacking. Accordingly, we aimed to examine the effects of nivolumab treatment intervals (2 weeks vs. 4 weeks) in terms of efficacy, safety, and economic impact in Japanese patients with cancer. METHODS: We retrospectively analyzed 126 patients treated with nivolumab. The patients were divided into two groups depending on whether they received nivolumab at 240 mg every 2 weeks (2-week group) or 480 mg every 4 weeks (4-week group). RESULTS: Efficacy results found no significant difference between the 4- and 2-week groups considering median overall survival (p = 0.70) and median progression-free survival (p = 0.57). The incidence of any grade and ≥  grade 3 immune-related adverse events did not differ between the 4-week and 2-week groups (any grade, p = 0.13; ≥  grade 3, p = 0.36). Excluding drug costs, the 4-week group had significantly lower medical costs than the 2-week group (2-week vs. 4-week: mean, 94,659 JPY [679.0 USD] vs. 58,737 JPY [421.3 USD]; p < 0.05). CONCLUSION: Collectively, our findings suggest that nivolumab 480 mg every 4 weeks may be more effective than nivolumab 240 mg every 2 weeks in terms of economic impact.

Efficacy of antiviral therapy for the prevention of mother-to-child transmission of hepatitis B virus and the risk of postpartum hepatitis flare after discontinuation of antiviral therapy.

The use of nucleos(t)ide analogs (NAs) is recommended for mothers with a high viral load of hepatitis B virus (HBV) during the second or third trimester of pregnancy. However, postpartum hepatitis flares can occur in some cases. We examined the efficacy of NA administration for the prevention of mother-to-child transmission of hepatitis B virus, and evaluated the risk of postpartum hepatitis flares in mothers after NA discontinuation. Nine pregnant women with a high viral load (HBV DNA ≥5.3 log IU/mL) received tenofovir disoproxil fumarate (TDF) at approximately 28 weeks of gestation, and TDF was discontinued at 4-10 weeks after delivery. We evaluated the virological and biochemical parameters in mothers after TDF discontinuation. Hepatitis flares in mothers were defined as alanine transaminase level ≥60 U/L. None of the infants developed any congenital anomaly or acquired HBV infection during infancy. Hepatitis flares occurred within 6 months after TDF discontinuation in five of seven cases, whereas two cases were lost to follow-up. Furthermore, three cases required the resumption of NA use. NA administration was highly effective against mother-to-child-transmission of HBV in pregnant women with high HBV DNA levels. However, hepatitis flares were commonly observed after NA discontinuation in the postpartum period. Patients should be followed up carefully after NA discontinuation, and NA resumption should be considered based on a comprehensive assessment of virological and biochemical parameters.

Clinical Impact of Proton Pump Inhibitor and Potassium-Competitive Acid Blocker for Predicting the Curability of Endoscopic Resection in Ulcerative Early Gastric Cancer.

INTRODUCTION: Endoscopic diagnosis is essential for predicting the curability of early gastric cancer (EGC; R0 resection) before treatment, but the relationship between ulcerative lesions and clinical outcomes remains unclear. We aimed to investigate the effect of proton pump inhibitor (PPI) or potassium-competitive acid blocker (P-CAB) on the morphological changes of ulcerative EGCs and its relevance to the clinical outcomes. METHODS: Altogether, 143 patients with differentiated ulcerative EGC that were resected by endoscopic submucosal dissection were retrospectively identified and divided into the following two cohorts depending on their PPI/P-CAB administration status: PPI/P-CAB (n = 76) and non-PPI/P-CAB (n = 67) cohorts. Furthermore, in each cohort, the patients were further divided into the improved and unimproved subgroups based on the ulcerative changes. RESULTS: In the PPI/P-CAB cohort, the deep submucosal invasion and lymphovascular invasion rates were significantly higher in the unimproved subgroup than in the improved subgroup, resulting in a significantly lower R0 resection rate. Contrarily, no significant differences were found between the two subgroups in the non-PPI/P-CAB cohort. The significance of PPI/P-CAB administration was observed only in the ulcerative EGCs with open-type atrophy (R0 resection rate; improved vs. unimproved, 90.9% vs. 48.0%, p = 0.001). When the finding of improved ulcer with PPI/P-CAB administration was used as the indication of endoscopic resection in ulcerative EGCs with open-type atrophy, high sensitivity (78.9%) and accuracy (76.3%) rates for the curability were observed, which were higher than those of conventional endoscopic diagnosis alone (p = 0.021). CONCLUSION: PPI or P-CAB administration might contribute to the potential selection of ulcerative EGCs, enabling endoscopic curative resection.

Metal-conjugated Maltotriose Chlorins as Novel Photosensitizers for Photodynamic Therapy.

BACKGROUND/AIM: Photodynamic therapy (PDT) is a relatively non-invasive anti-cancer therapy that employs a photosensitizer with a specific wavelength of light, causing a photochemical reaction that releases free radicals, thereby inducing tumor cell necrosis via oxidative stress. The oxygen molecule reaches the singlet excited state through efficient energy transfer from an excited triplet state of the photosensitizer. Heavy atoms are frequently introduced in photosensitizers for efficiently generating reactive oxygen species (ROS) in PDT, known as the heavy atom effect. However, metal-complexed photosensitizers often show low water-solubility. To overcome this limitation and produce ROS effectively, we focused on the better solubility of photosensitizers with heavy metals bound within the chlorin skeleton and conjugated with glucose in this study. MATERIALS AND METHODS: We established maltotriose (Mal3)-conjugation with heavy metallochlorins [M (Mal3-chlorin), M=Pt or Pd)] and evaluated its anti-tumor effect. RESULTS: M (Mal3-chlorin) showed effective ROS production and singlet oxygen induction. Consequently, these cytotoxic factors caused effective anti-tumor effects and induced morphological changes, followed by cell death in vitro. In a xenograft tumor mouse model, PDT with M (Mal3-chlorin) showed tumor growth suppression. CONCLUSION: M (Mal3-Chlorin) might be an excellent glucose-conjugated chlorin because of its strong anti-tumor PDT effect.

Prognostic Nutritional Index after Introduction of Atezolizumab with Bevacizumab Predicts Prognosis in Advanced Hepatocellular Carcinoma: A Multicenter Study.

INTRODUCTION: Atezolizumab plus bevacizumab (Atez/Bev) is the preferred treatment for advanced hepatocellular carcinoma (HCC). However, biomarkers of therapeutic efficacy have remained unclear. We took a retrospective approach to explore the role of prognostic nutritional index (PNI) for predicting the outcomes of Atez/Bev treatment. METHODS: One hundred 25 HCC patients were enlisted; these patients received Atez/Bev treatment and underwent dynamic computerized tomography/magnetic resonance imaging to determine the treatment response on at least one occasion between October 2020 and January 2023, and their PNI before treatment and at the beginning of the second cycle (PNI-2c) was evaluated. RESULTS: During the initial evaluation, 2 (2%), 28 (22%), 70 (56%), and 25 (20%) patients exhibited a complete response, partial response, stable disease, and progressive disease (PD), respectively. Patients with non-PD tended to have higher PNI at baseline and PNI-2c than those with PD (p = 0.245 and 0.122, respectively), with optimal baseline PNI and PNI-2c cut-off values of 42.6 and 40.4, respectively. PNI at baseline could not be used to predict overall survival (OS) or progression-free survival (PFS). However, PNI-2c predicted OS and PFS (PNI-2c ≥ 40.4 vs. < 40.4: 25.3 vs. 16.2 months, p = 0.008 for OS; 12.7 vs. 8.4 months, p = 0.036 for PFS). A multivariate analysis showed a significant association between PNI-2c and OS. CONCLUSIONS: PNI-2c is a predictor of prognosis in HCC patients treated with Atez/Bev therapy.

Serum Angiopoietin-2 Levels Predict the Development of Hepatocellular Carcinoma following Hepatitis C Virus Eradication Using Direct-Acting Antiviral Agents.

INTRODUCTION: Our previous studies showed that serum angiopoietin-2 (Ang-2) and C-X-C motif chemokine ligand 10 (CXCL10) levels predicted improvement in liver fibrosis following sustained virological response (SVR) of hepatitis C virus (HCV) obtained with administration of with direct-acting antiviral agents (DAAs). These levels were evaluated retrospectively as predictive indicators of hepatocellular carcinoma (HCC) development following SVR. METHODS: We enrolled individuals from a historical cohort of 89 chronic HCV patients without history of HCC at baseline and with SVR following DAA therapy and had baseline serum levels of Mac-2 binding protein glycosylation isomer ≥2.0 cut-off index (C.O.I.). RESULTS: Multivariate analyses revealed that only the Ang-2 level at 24 weeks following the end of treatment (EOT24W) was significantly related to HCC development (hazard ratio 2.27; p = 0.003). This result was reproduced in individuals without history of HCC and with advanced liver fibrosis (M2BPGi level ≥3.3 C.O.I. at baseline). Time-dependent receiver operating characteristic curve analyses for the future risk of developing HCC within 5 years of follow-up (5y-HCC) showed the best cut-off Ang-2 level at the EOT24W was 2,780 pg/mL, and significantly stratified the cumulative incidence of HCC (≥2,780 vs. < 2,780 pg/mL, 5y-HCC: 45.5 vs. 8.2%, p < 0.001). CONCLUSIONS: At the EOT24W, serum Ang-2 level predicts the likelihood of developing HCC following SVR to DAA therapy.

Background factors of idiopathic peptic ulcers and optimal treatment methods: a multicenter retrospective Japanese study.

This study investigated the trends in idiopathic peptic ulcers, examined the characteristics of refractory idiopathic peptic ulcer, and identified the optimal treatment. The characteristics of 309 patients with idiopathic peptic ulcer were examined. We allocated idiopathic peptic ulcers that did not heal after 8 weeks' treatment (6 weeks for duodenal ulcers) to the refractory group and those that healed within this period to the healed group. The typical risk factors for idiopathic peptic ulcer (atherosclerosis-related underlying disease or liver cirrhosis complications) were absent in 46.6% of patients. Absence of gastric mucosal atrophy (refractory group: 51.4%, healed group: 28.4%; p = 0.016), and gastric fundic gland polyps (refractory group: 17.6%, healed group: 5.9%; p = 0.045) were significantly more common in the refractory group compared to the healed group. A history of H. pylori eradication (refractory group: 85.3%, healed group: 66.0%; p = 0.016), previous H. pylori infection (i.e., gastric mucosal atrophy or history of H. pylori eradication) (refractory group: 48.5%, healed group: 80.0%; p = 0.001), and potassium-competitive acid blocker treatment (refractory group: 28.6%, healed group, 64.1%; p = 0.001) were significantly more frequent in the healed group compared to the refractory group. Thus, acid hypersecretion may be a major factor underlying the refractoriness of idiopathic peptic ulcer.