FDA and EMA end points: which outcome end points should we use in clinical trials in patients with irritable bowel syndrome?

Therapeutic Potential of Palmitoylethanolamide in Gastrointestinal Disorders

Palmitoylethanolamide (PEA) is an endocannabinoid-like bioactive lipid mediator belonging to the family of N-acylethanolamines, most abundantly found in peanuts and egg yolk. When the gastrointestinal (GI) effects of PEA are discussed, it must be pointed out that it affects intestinal motility but also modulates gut microbiota. This is due to anti-inflammatory, antioxidant, analgesic, antimicrobial, and immunomodulatory features. Additionally, PEA has shown beneficial effects in several GI diseases, particularly irritable bowel syndrome and inflammatory bowel diseases, as various studies have shown, and it is important to emphasize its relative lack of toxicity, even at high dosages. Unfortunately, there is not enough endogenous PEA to treat disturbed gut homeostasis, even though it is produced in the GI tract in response to inflammatory stimuli, so exogenous intake is mandatory to achieve homeostasis. Intake of PEA could be through animal and/or vegetable food, but bearing in mind that a high dosage is needed to achieve a therapeutic effect, it must be compensated through dietary supplements. There are still open questions pending to be answered, so further studies investigating PEA's effects and mechanisms of action, especially in humans, are crucial to implementing PEA in everyday clinical practice.

Is a Simplified, Less Restrictive Low FODMAP Diet Possible? Results from a Double-Blind, Pilot Randomized Controlled Trial

A low fermentable oligo-, mono-, di-saccharides, and polyols (FODMAPs) diet (LFD) is the most evidence-based dietary therapy for patients with irritable bowel syndrome (IBS).1 However, the current step-down approach to the LFD has significant limitations including being costly, complex, time-consuming, and associated with reduced dietary intake of some micronutrients.2-4 Recently, a step-up approach has been proposed that restricts only a limited number of FODMAPs initially, evaluating symptom response and restricting additional FODMAPs only if necessary.2,5,6 In a double-blind trial, fructans and galacto-oligosaccharides were found to be the most likely FODMAP subgroups to trigger IBS symptoms.7 To date, no study has compared the efficacy of a traditional LFD restriction phase with a more targeted or simplified restriction phase. In a double-blind, pilot-feasibility randomized controlled trial, we compared the efficacy of a 4-week FODMAP-simple restriction phase (eliminating solely fructans and galactooligosaccharides) and a traditional LFD restriction phase in patients with IBS with diarrhea (IBS-D) (ClinicalTrials.gov registration number NCT05831306).

Assessing 'response' to the low-FODMAP diet in irritable bowel syndrome: Should we be reporting harder primary endpoints?

BACKGROUND & AIMS

The low-FODMAP diet (LFD) has become almost synonymous with IBS care, yet the challenges associated with this rigorous therapeutic approach are often underacknowledged. Despite positive outcomes in RCTs, comparator groups frequently exhibit substantial response rates, raising questions about the definition of 'response'. Whilst the assessment of response in drug trials has evolved to utilize the more stringent FDA/EMA primary clinical endpoints, trials of the LFD have not yet followed. The aim of this article is to opine whether the current approach to the measurement of clinical response to the LFD in clinical trials should be reconsidered.

METHODS

A comprehensive literature review of LFD clinical trials from the past decade was conducted, focusing on recorded response metrics for primary clinical endpoints.

RESULTS

While response definitions vary, the 50-point IBS-SSS delta emerged as the predominant metric. Notably, no trials to date have adopted the more stringent primary clinical endpoints used in drug trials. Other response measures included binary response metrics (such as 'adequate clinical response'), changes in visual analogue scales or stool form/output, reductions in abdominal pain, as well as changes the magnitude of the IBS-SSS delta. Whether these metrics correspond to a clinically meaningful improvement for the patient is less clear, and as such aligning patient-clinician expectations can be challenging.

CONCLUSIONS

A paradigm shift in the conceptualization of 'response' coupled with an emphasis on harder clinical endpoints in the context of clinical trials may serve to better justify the trade-off between symptom-improvement and the inherent challenges associated with this burdensome therapeutic approach.

Patient-Reported Outcomes in Disorders of Gut-Brain Interaction

Disorders of gut-brain interaction are characterized by chronic gastrointestinal symptoms in the absence of abnormal endoscopic or radiologic findings or objective biomarkers that can be identified during routine clinical evaluation. The assessment of the symptom pattern and severity, therefore, is the key modality to evaluate the presence, impact, and evolution of these conditions, for both clinical and regulatory purposes. Patient-reported outcomes are structured symptom assessment questionnaires designed to evaluate symptom patterns, quantify severity of symptoms, and evaluate response to treatment at follow-up. This review provides an overview of currently available patient-reported outcomes for evaluating the main disorders of gut-brain interaction, specifically, functional dyspepsia; irritable bowel syndrome; and chronic constipation. It summarizes their content, level of validation for clinical practice and for research, and the regulatory approach to these conditions. Expected future developments and need for further research on patient-reported outcomes for these and other disorders of gut-brain interaction are highlighted.

Adult-onset megacolon with focal hypoganglionosis: A detailed phenotyping and prospective cohort study

BACKGROUND

In this prospective cohort study, we evaluated features of "adult-onset megacolon with focal hypoganglionosis."

METHODS

We assessed the radiologic, endoscopic, and histopathologic phenotyping and treatment outcomes of 29 patients between 2017 and 2020. Data from community controls, consisting of 19,948 adults undergoing health screenings, were analyzed to identify risk factors. Experts reviewed clinical features and pathological specimens according to the London Classification for gastrointestinal neuromuscular pathology.

KEY RESULTS

The median age of the patients with adult-onset megacolon with focal hypoganglionosis at symptom onset was 59 years (range, 32.0-74.9 years), with mean symptom onset only 1 year before diagnosis. All patients had focal stenotic regions with proximal bowel dilatation (mean diameter, 78.8 mm; 95% confidence interval [CI], 72-86). The comparison with community controls showed no obvious risk factors. Ten patients underwent surgery, and all exhibited significant hypoganglionosis: 5.4 myenteric ganglion cells/cm (interquartile range [IQR], 3.7-16.4) in the stenotic regions compared to 278 cells/cm (IQR, 190-338) in the proximal and 95 cells/cm (IQR, 45-213) in the distal colon. Hypoganglionosis was associated with CD3+ T cells along the myenteric plexus. Colectomy was associated with significant symptom improvement compared to medical treatment [change in the Global Bowel Satisfaction score, -5.4 points (surgery) vs. -0.3 points (medical treatment); p < 0.001].

CONCLUSIONS AND INFERENCES

Adult-onset megacolon with focal hypoganglionosis has distinct features characterized by hypoganglionosis due to inflammation. Bowel resection appears to benefit these patients.

Effect of Bifidobacterium bifidum G9-1 on the Intestinal Environment and Diarrhea-Predominant Irritable Bowel Syndrome (IBS-D)-like Symptoms in Patients with Quiescent Crohn's Disease: A Prospective Pilot Study

Diarrhea-predominant irritable bowel syndrome (IBS-D)-like symptoms are distressing for patients with quiescent Crohn's disease (qCD) and worsen their quality of life. In the present study, we assessed the effect of the probiotic Bifidobacterium bifidum G9-1 (BBG9-1) on the intestinal environment and clinical features in patients with qCD. Eleven patients with qCD, who met the Rome III diagnostic criteria for IBS-D, received BBG9-1 (24 mg) orally three times daily for 4 weeks. Indices of the intestinal environment (fecal calprotectin level and gut microbiome) and clinical features (CD/IBS-related symptoms, quality of life and stool irregularities) were evaluated before and after treatment. Treatment with BBG9-1 tended to reduce the IBS severity index in the studied patients (p = 0.07). Among gastrointestinal symptoms, abdominal pain and dyspepsia tended to be improved by the BBG9-1 treatment (p = 0.07 and p = 0.07, respectively), and IBD-related QOL showed a significant improvement (p = 0.007). With regard to mental status, the patient anxiety score was significantly lower at the endpoint of BBG9-1 treatment than at the baseline (p = 0.03). Although BBG9-1 treatment did not affect the fecal calprotectin level, it suppressed the serum MCP-1 level significantly and increased the abundance of intestinal Bacteroides in the study patients. The probiotic BBG9-1 is able to improve IBD-related QOL with a reduction of anxiety score in patients with quiescent CD and IBS-D-like symptoms.

Emerging therapies in the management of Irritable Bowel Syndrome (IBS)

INTRODUCTION

Irritable bowel syndrome (IBS) is a common, symptom-based disorder of chronic abdominal pain and altered bowel habits. The pathogenesis of IBS is multifactorial, leading to the potential for the development of multiple, diverse treatment strategies. This mechanistic heterogeneity also leads to the realization that available therapies are only effective in a subset of IBS suffers. Current US Food and Drug Administration (FDA) approved therapies for IBS with diarrhea (IBS-D) and IBS with constipation (IBS-C) are reviewed. Limited symptom responses and side effect experiences lead to considerable patient dissatisfaction with currently available IBS treatments. Only a small percentage of IBS patients are on prescription therapies underscoring the potential market and need for additional therapeutic options.

AREAS COVERED

: Expanding on currently available therapies, the serotonergic and endogenous opioid receptor systems continue to be a focus of future IBS treatment development. Additional novel emerging therapies include the endogenous cannabinoid system, bile acid secretion and sequestration, and exploit our enhanced understanding of visceral sensory signaling and intestinal secretomotor function.

EXPERT OPINION

While challenges remain for the future development of IBS therapies, the diverse etiologies underlying the disorder present an opportunity for novel therapies. Hence, great potential is anticipated for future IBS treatment options.

Developing a Scale for the Evaluation of People With Post-prandial Distress Syndrome

Background: Functional dyspepsia (FD) is one of the most critical health problems worldwide. Although there has been an increased intervention to improve FD symptoms, it is difficult to compare the effect of intervention measures with the existing methods of reporting the outcome, and it is a lack of clinical evaluation tools that can be used to evaluate patients' symptoms and treatment. One way of potentially addressing this way is to offer a patient-reported symptom scoring scales, which can be self-reported by patients to highlight interventions' authenticity and reliability. Nevertheless, there is still a lack of validated patient-reported outcome instruments for post-prandial distress syndrome (PDS). This study aims to establish a symptom scoring scale to evaluate the effectiveness of interventions for PDS.

Methods: The study consists of two steps. The first step was to formulate the scale. Through a systematic literature review and group discussion, an item pool and scale framework were formed. Then, through the expert consultation and pre-investigation, the formal version of the scale was formed. The second step is to test the reliability and validity of the scale. The scale is tested in the target population to determine whether the reliability and validity of the scale.

Discussion: The improvement in patients' self-reported symptoms had a significant impact on the researchers' evaluation of the intervention's authenticity. Therefore, we develop a symptom scoring scale for reporting studies evaluating the effectiveness of PDS interventions. The scale will be used for a more significant comparison to evaluate PDS interventions' effectiveness. The scale also improves trial reporting, reducing research waste by prioritizing the collection and reporting of critical results for all relevant stakeholders.

Clinical Trial Registration: ChiCTR, ChiCTR2100044489. Registered on March 22, 2021.

The placebo response rate in pharmacological trials in patients with irritable bowel syndrome: a systematic review and meta-analysis

BACKGROUND

Clinical trials in irritable bowel syndrome are associated with high placebo response rates. We aimed to identify the magnitude of the placebo response and the contributing factors to this occurrence.

METHODS

We did a systematic review and meta-analysis with a search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials between April 1, 1959, and April 30, 2020. We included all randomised controlled trials that compared an active pharmacotherapeutic agent with placebo and had a dichotomous outcome of response to therapy (in terms of global improvement or improvement in abdominal pain) in adults (aged ≥18 years) with irritable bowel syndrome. Exclusion criteria were trials reporting on treatment satisfaction as a dichotomous outcome of response to therapy or clinician-reported outcomes and a treatment duration of less than 4 weeks. Our main outcome was identification of the magnitude of the pooled placebo response rate for the following endpoints: global improvement, abdominal pain, and US Food and Drug Administration (FDA) endpoints. We extracted information from published reports and pooled proportions through meta-analysis with random effects. The study was registered with PROSPERO, CRD42020170908.

FINDINGS

Of the 6863 publications identified, 70 articles describing 73 randomised controlled trials were included in our analysis. The pooled placebo response rate was 27·3% (95% CI 24·3-30·9) using the global improvement endpoint, 34·4% (31·2-37·8) using the abdominal pain endpoint, and 17·9% (15·2-21·0) using the composite FDA endpoint responder definition, all with substantial heterogeneity between the trials. Studies published before 2006, and those done in Europe, with a parallel design, a run-in period of 2 weeks or less, a dose schedule of three times a day or more, or a smaller sample size of the control group were significantly associated with an increased pooled placebo response rate.

INTERPRETATION

More than a quarter of patients with irritable bowel syndrome had a placebo response in terms of global improvement, with multiple associated moderators. We recommend future trials apply a run-in period of at least 2 weeks and dose once or twice a day to minimise the placebo response rate.

FUNDING

None.

Efficacy of the Combination of Pinaverium Bromide 100 mg Plus Simethicone 300 mg in Abdominal Pain and Bloating in Irritable Bowel Syndrome: A Randomized, Placebo-controlled Trial

GOALS

We aimed to evaluate the efficacy and safety of PB+S (pinaverium bromide 100 mg plus simethicone 300 mg) in patients with irritable bowel syndrome (IBS).

BACKGROUND

IBS is a multifactorial disorder; thus, combination therapy with different mechanisms of action is expected to be useful. PB+S has shown effectiveness in an open-label clinical study in IBS. However, there are no placebo-controlled trials.

MATERIALS AND METHODS

IBS-Rome III patients with abdominal pain/discomfort for at least 2 days within the week prior to baseline assessment were included in this 12-week, randomized, double-blind, placebo-controlled study of PB+S versus placebo, bid. The primary endpoint was overall symptom improvement, evaluated weekly by the patient (Likert Scale). Secondary endpoints included the weekly improvement in the severity of abdominal pain and bloating assessed both by patients (10-cm Visual Analogue Scale) and investigators (Likert Scale); frequency of Bristol Scale stool types (consistency) evaluated by patients and the IBS Quality of Life scores.

RESULTS

A total of 285 patients (female: 83%; 36.5±8.9 y old) received at least 1 dose of PB+S (n=140) or placebo (n=145). No difference was observed in overall symptom improvement between the groups (P=0.13). However, PB+S was superior in abdominal pain (effect size: 31%, P=0.038) and bloating (33%, P=0.019). Patients with IBS-C and IBS-M showed the best improvement in the frequency of stool types with PB+S. No differences were observed in IBS Quality of Life scores and adverse events.

CONCLUSIONS

PB+S was superior to placebo in improving abdominal pain and bloating in patients with active IBS. The effect on the frequency of stool consistency was particularly significant in IBS-C and IBS-M.

Presentation and Characteristics of Abdominal Pain Vary by Irritable Bowel Syndrome Subtype: Results of a Nationwide Population-Based Study

INTRODUCTION

Abdominal pain is a cardinal feature of irritable bowel syndrome (IBS); however, differences in abdominal pain among IBS subtypes remain unknown. We aimed to characterize abdominal pain symptoms among established IBS subtypes using data from the National Gastrointestinal (GI) Survey.

METHODS

Individuals participating in the National GI Survey completed National Institutes of Health GI Patient-Reported Outcomes Measurement Information System (GI-PROMIS) questionnaires. Adults meeting modified Rome III IBS criteria and reporting abdominal pain in the previous 7 days were eligible. Outcomes included abdominal pain severity, bothersomeness, interference with daily activities, frequency, and location. Results were stratified by subtype (diarrhea [IBS-D], constipation [IBS-C], and mixed [IBS-M]). Regression models adjusted for demographics and comorbidities.

RESULTS

One thousand one hundred fifty-eight individuals (245 IBS-D, 232 IBS-C, and 681 IBS-M) with active IBS symptoms (defined as abdominal pain in the past 7 days) were included. Demographics were similar among the subtypes except for age, race/ethnicity, education, and marital status. The GI-PROMIS score was lower for IBS-D (percentile score of 68.6, SD = 25.1; P = 0.001) and IBS-M (69.1, SD = 25.1; P < 0.001) compared with IBS-C (75.5, SD = 20.7). Abdominal pain was more bothersome (P = 0.001), caused more interference with daily activities (P = 0.03), and was more frequent (P = 0.047) for individuals with IBS-C compared with individuals with IBS-D. No differences in these domains were seen between individuals with IBS-D and IBS-M. Individuals with IBS-C and IBS-M had more widespread pain compared with those with IBS-D.

DISCUSSION

In this population-based study, we found that abdominal pain characteristics differ between the IBS subtypes. Namely, individuals with IBS-C experience more bothersome, frequent, and diffuse abdominal pain compared with those with IBS-D.

Efficacy and Safety of Peppermint Oil in a Randomized, Double-Blind Trial of Patients With Irritable Bowel Syndrome

BACKGROUND & AIMS

Peppermint oil is frequently used to treat irritable bowel syndrome (IBS), despite a lack of evidence for efficacy from high-quality controlled trials. We studied the efficacy and safety of small-intestinal-release peppermint oil in patients with IBS and explored the effects of targeted ileocolonic-release peppermint oil.

METHODS

We performed a double-blind trial of 190 patients with IBS (according to Rome IV criteria) at 4 hospitals in The Netherlands from August 2016 through March 2018; 189 patients were included in the intent-to-treat analysis (mean age, 34.0 years; 77.8% female; 57.7% in primary care), and 178 completed the study. Patients were randomly assigned to groups given 182 mg small-intestinal-release peppermint oil, 182 mg ileocolonic-release peppermint oil, or placebo for 8 weeks. The primary endpoint was abdominal pain response, as defined by the US Food and Drug Administration: at least a 30% decrease in the weekly average of worst daily abdominal pain compared with baseline in at least 4 weeks. The co-primary endpoint was overall relief of IBS symptoms, as defined by the European Medicines Agency. Secondary endpoints included abdominal pain, discomfort, symptom severity, and adverse events.

RESULTS

Abdominal pain response did not differ significantly between the peppermint oil and placebo groups: 29 of 62 patients in the small-intestinal-release peppermint oil group had a response (46.8%, P = .170 vs placebo), 26 of 63 patients in the ileocolonic-release peppermint oil group had a response (41.3%, P = .385 vs placebo), and 22 of 64 patients in the placebo group had a response (34.4%). We did not find differences among the groups in overall relief (9.7%, P = .317 and 1.6%, P = .351 vs 4.7% for placebo). The small intestinal peppermint oil did, however, produce greater improvements than placebo in secondary outcomes of abdominal pain (P = .016), discomfort (P = .020), and IBS severity (P = .020). Adverse events, although mild, were more common in both peppermint oil groups (P < .005).

CONCLUSIONS

In a randomized trial of patients with IBS, we found that neither small-intestinal-release nor ileocolonic-release peppermint oil (8 weeks) produced statistically significant reductions in abdominal pain response or overall symptom relief, when using US Food and Drug Administration/European Medicines Agency recommended endpoints. The small-intestinal-release peppermint oil did, however, significantly reduce abdominal pain, discomfort, and IBS severity. These findings do not support further development of ileocolonic-release peppermint oil for treatment of IBS. Clinicaltrials.gov, Number: NCT02716285.

Pharmacological treatments for patients with irritable bowel syndrome: An umbrella review of systematic reviews and meta-analyses

INTRODUCTION

Several pharmacological treatments are beneficial for patients with irritable bowel syndrome (IBS), and there are numbers of systematic reviews evaluating the effectiveness of these treatments. However, the overall quality of the evidence has not been quantitatively assessed. The aim of this study is to evaluate the possible biases in the published systematic reviews and determine the treatments with reliable evidence.

METHODS AND ANALYSIS

We will perform an umbrella review to identify eligible systematic reviews. A comprehensive literature search will be conducted in MEDLINE, EMBASE, and the Cochrane library for systematic reviews. We will describe the general information such as participants, interventions, outcome measurements, and conclusion. Additionally, the heterogeneity and inconsistency between trials will be assessed by the I statistical test and Cochrane Q test. We will assess risk of bias, and summarize the strength evidence.

CONCLUSION

The umbrella reviews will assess the reliability of the evidence so that doctors and patients can make better medical choices.

PROSPERO REGISTRATION NUMBER

CRD42018109597.

[Guideline Recommendation for Endpoints Used in Clinical Trials for Functional Dyspepsia]

Functional dyspepsia is a disease, in which there is no organic lesion but chronic and repetitive postprandial fullness, early satiation, epigastric pain, and epigastric burning. Functional dyspepsia is not life-threatening but its symptoms are relapsing and remitting and persist over a lifetime, limiting the social life and reducing the quality of life. Therefore, the treatment for acute relapsing period may help improve the short-term symptoms. Continuous medication may be needed to improve the long-term symptoms. Research designs to demonstrate the short-term efficacy of therapeutic agents may differ from clinical trials to demonstrate long-term efficacy. There are many difficulties in clinical trial design, implementation, and screening because there are no international standards of clinical trials for functional dyspepsia. The purpose of this guideline recommendation is to develop a standard for clinical trials, such as clinical trial subjects and evaluation methods, in the development of therapeutic agents for functional dyspepsia. The ultimate aim is to enhance the safety and efficacy of therapeutic agents for functional dyspepsia and promote the development of new therapeutic agents.

Disease activity, steroid use and extraintestinal manifestation are associated with increased disability in patients with inflammatory bowel disease using the inflammatory bowel disease disability index: a cross-sectional multicentre cohort study

BACKGROUND

The inflammatory bowel disease disability index (IBD-DI) was developed recently. The aim was to translate the IBD-DI into Danish and validate it for future clinical studies and practice, and to assess the level of disability among IBD patients.

PATIENTS AND METHODS

The IBD-DI was translated using a transcultural adaptation method. Between January and December 2017, patients from three outpatient clinics in three different regions in Denmark were given the final version of the IBD-DI for self-completion. Validation was carried out according to guidelines. Disability level was assessed among the entire cohort and in various subgroups.

RESULTS

A total of 200 patients were included in the study, including 112 Crohn's disease (CD) and 88 ulcerative colitis (UC) patients. The response rate was 90%. The IBD-DI showed excellent reliability and validity. CD patients showed worse disability levels than UC patients [mean (SD): CD: 37.3 (20.2) vs. UC: 21.7 (16.4); P=0.04]. In both CD and UC, significantly increased disability levels were found between patients with active disease, use of steroid and extraintestinal manifestation (P<0.05).

CONCLUSION

A valid and reliable version of the IBD-DI is now available in Danish for future studies. Several clinical factors are shown to affect the levels of disability among patients with CD and UC. The disability levels are significantly increased in patients with active disease, treated with systemic steroids, and extraintestinal manifestations are present in both CD and UC. Further testing of the Danish IBD-DI is needed to assess its responsiveness and interpretability.

Focus on the use of antidepressants to treat pediatric functional abdominal pain: current perspectives

Chronic abdominal pain is frequently encountered in pediatric practice. A large proportion of cases meet Rome criteria for abdominal pain-functional gastrointestinal disorders (AP-FGIDs). These disorders are costly and, in some cases, lead to impairment of daily functioning and overall quality of life. Pathophysiologic mechanisms include early stressful events, visceral hypersensitivity, dysmotility, changes in intestinal microbiota, and altered central nervous system processing. They are considered disorders of the brain-gut interaction. The diagnosis is made on clinical grounds using symptom-based criteria (Rome criteria). Anxiety and depressive symptoms are more prevalent in patients with AP-FGIDs. Therefore, attention has been directed to the use of neuromodulators as potential interventions for AP-FGIDs. Antidepressants are one type of neuromodulators, and one of the most studied drugs for the management of AP-FGIDs in adult and pediatric population. Data available in pediatric population have significant limitations including nonuniform methodology with different study designs and primary endpoints. Evidence of the efficacy of antidepressants in the management of pediatric AP-FGIDs is not consistent. There is an urgent need for well-designed randomized clinical trials using age-appropriate validated outcome measures. Careful consideration must be given to adverse effects, particularly increased suicidal ideation.

Guanylate cyclase-C as a therapeutic target in gastrointestinal disorders

Functional gastrointestinal disorders (FGIDs) and IBDs are two of the most prevalent disorders of the GI tract and consume a significant proportion of healthcare resources. Recent studies have shown that membrane-bound guanylate cyclase-C (GC-C) receptors lining the GI tract may serve as novel therapeutic targets in the treatment of FGIDs and IBDs. GC-C receptor activation by its endogenous paracrine hormones uroguanylin and guanylin, and the resulting intracellular production of its downstream effector cyclic GMP, occurs in a pH-dependent manner and modulates key physiological functions. These include fluid and electrolyte homeostasis, maintenance of the intestinal barrier, anti-inflammatory activity and regulation of epithelial regeneration. Studies of the GC-C paracrine signalling axis have revealed the therapeutic potential of these receptors in treating GI disorders, including chronic idiopathic constipation and irritable bowel syndrome-constipation. This review focuses on the evolving understanding of GC-C function in health and disease, and strategies for translating these principles into new treatments for FGIDs and IBDs.

Systematic Review: Disease Activity Indices in Eosinophilic Esophagitis

OBJECTIVES

There is no clear consensus regarding the most appropriate measure(s) of eosinophilic esophagitis (EoE) disease activity. We aimed to identify all scoring indices used for the measurement of disease activity in EoE, appraise their operating properties, and discuss their value as outcome measures.

METHODS

MEDLINE, EMBASE, and CENTRAL (The Cochrane library) were searched from inception to 11 May 2016. Randomized controlled trials (RCTs), cohort, case-control, and cross-sectional studies that reported outcomes to measure EoE disease activity or response to treatment were eligible. Operating properties of histologic, endoscopic, and patient reported/symptomatic and health-related quality of life measures were critically appraised according to guidelines proposed by the United States Food and Drug Administration.

RESULTS

Of 4,373 citations, 130 studies were eligible, of which 20 were RCTs. Although no index met all evaluative criteria, we found that: (1) the EoE histologic scoring system (EoEHSS) is the most valid histologic measure; (2) the Endoscopic Reference Score (EREFS) is the most reliable and responsive endoscopy measure; and (3) the Eosinophilic Esophagitis Activity Index (EEsAI) or the Dysphagia Symptoms Questionnaire (DSQ) had superior construct validity and responsiveness in adults. The Pediatric Quality of Life Inventory EoE was the most valid pediatric symptomatic measure.

CONCLUSIONS

Current evidence supports the use of the EoEHSS and EREFS as measures of histologic and endoscopic EoE disease activity, respectively, and the EEsAI, DSQ, or Pediatric Quality of Life Inventory EoE as measures of adult and pediatric symptoms. Additional research is needed to optimize endpoint configuration to facilitate development of new therapies.

The neurokinin-2 receptor antagonist ibodutant improves overall symptoms, abdominal pain and stool pattern in female patients in a phase II study of diarrhoea-predominant IBS

BACKGROUND

Tachykinins have been implicated in the pathophysiology of IBS with diarrhoea (IBS-D). Our aim was to study the efficacy and safety of ibodutant, a selective neurokinin-2 (NK2) receptor antagonist, in patients with IBS-D.

METHODS

This multinational double-blind, placebo-controlled study recruited 559 patients with IBS-D according to Rome III criteria. After a 2-week treatment-free run-in, patients were randomised to ibodutant 1 mg, 3 mg, 10 mg or placebo once daily for eight consecutive weeks. Responders were those with a combined response of satisfactory relief (weekly binary question yes/no) of overall IBS symptoms and abdominal pain/discomfort on ≥75% weeks (primary end point). Secondary end points included abdominal pain and stool pattern. Data were also analysed according to US Food and Drug Administration (FDA)-approved interim end points (improvement of pain and stool consistency). Safety was assessed by monitoring adverse events and laboratory tests. Prespecified statistical analysis involved the whole group as well as gender subgroups.

RESULTS

Demographics and baseline characteristics were comparable for all treatment arms. In the overall population, responsiveness tended to increase with escalating ibodutant doses. In the prespecified analysis by gender, ibodutant 10 mg demonstrated significant superiority over placebo in females (p=0.003), while no significant effect occurred in males. This was confirmed for secondary end points and for the responder analysis according to FDA-approved end points. The tolerability and safety of ibodutant was excellent at all doses.

CONCLUSIONS

Ibodutant showed dose-dependent efficacy response in IBS-D, reaching statistical significance at the 10 mg dose in female patients. The safety and tolerability profile of ibodutant was similar to placebo.

TRIAL REGISTRATION NUMBER

NCT01303224.

Development and validation of a simple and multifaceted instrument, GERD-TEST, for the clinical evaluation of gastroesophageal reflux and dyspeptic symptoms

AIM

To evaluate the psychometric properties of a newly developed questionnaire, known as the gastroesophageal reflux and dyspepsia therapeutic efficacy and satisfaction test (GERD-TEST), in patients with GERD.

METHODS

Japanese patients with predominant GERD symptoms recruited according to the Montreal definition were treated for 4 wk using a standard dose of proton pump inhibitor (PPI). The GERD-TEST and the Medical Outcome Study Short Form-8 Health Survey (SF-8) were administered at baseline and after 4 wk of treatment. The GERD-TEST contains three domains: the severity of GERD and functional dyspepsia (FD) symptoms (5 items), the level of dissatisfaction with daily life (DS) (4 items), and the therapeutic efficacy as assessed by the patients and medication compliance (4 items).

RESULTS

A total of 290 patients were eligible at baseline; 198 of these patients completed 4 wk of PPI therapy. The internal consistency reliability as evaluated using the Cronbach's α values for the GERD, FD and DS subscales ranged from 0.75 to 0.82. The scores for the GERD, FD and DS items/subscales were significantly correlated with the physical and mental component summary scores of the SF-8. After 4 wk of PPI treatment, the scores for the GERD items/subscales were greatly reduced, ranging in value from 1.51 to 1.87 and with a large effect size (P < 0.0001, Cohen's d; 1.29-1.63). Statistically significant differences in the changes in the scores for the GERD items/subscales were observed between treatment responders and non-responders (P < 0.0001).

CONCLUSION

The GERD-TEST has a good reliability, a good convergent and concurrent validity, and is responsive to the effects of treatment. The GERD-TEST is a simple, easy to understand, and multifaceted PRO instrument applicable to both clinical trials and the primary care of GERD patients.

Randomised clinical trial: the analgesic properties of dietary supplementation with palmitoylethanolamide and polydatin in irritable bowel syndrome

BACKGROUND

Intestinal immune activation is involved in irritable bowel syndrome (IBS) pathophysiology. While most dietary approaches in IBS involve food avoidance, there are fewer indications on food supplementation. Palmithoylethanolamide, structurally related to the endocannabinoid anandamide, and polydatin are dietary compounds which act synergistically to reduce mast cell activation.

AIM

To assess the effect on mast cell count and the efficacy of palmithoylethanolamide/polydatin in patients with IBS.

METHODS

We conducted a pilot, 12-week, randomised, double-blind, placebo-controlled, multicentre study assessing the effect of palmithoylethanolamide/polydatin 200 mg/20 mg or placebo b.d. on low-grade immune activation, endocannabinoid system and symptoms in IBS patients. Biopsy samples, obtained at screening visit and at the end of the study, were analysed by immunohistochemistry, enzyme-linked immunoassay, liquid chromatography and Western blot.

RESULTS

A total of 54 patients with IBS and 12 healthy controls were enrolled from five European centres. Compared with controls, IBS patients showed higher mucosal mast cell counts (3.2 ± 1.3 vs. 5.3 ± 2.7%, P = 0.013), reduced fatty acid amide oleoylethanolamide (12.7 ± 9.8 vs. 45.8 ± 55.6 pmol/mg, P = 0.002) and increased expression of cannabinoid receptor 2 (0.7 ± 0.1 vs. 1.0 ± 0.8, P = 0.012). The treatment did not significantly modify IBS biological profile, including mast cell count. Compared with placebo, palmithoylethanolamide/polydatin markedly improved abdominal pain severity (P < 0.05).

CONCLUSIONS

The marked effect of the dietary supplement palmithoylethanolamide/polydatin on abdominal pain in patients with IBS suggests that this is a promising natural approach for pain management in this condition. Further studies are now required to elucidate the mechanism of action of palmithoylethanolamide/polydatin in IBS. ClinicalTrials.gov number, NCT01370720.

Current Status of Celiac Disease Drug Development

Celiac disease (CeD) is one of the most common immune-mediated diseases. Symptoms and disease activity are incompletely controlled by the gluten-free diet, which is currently the only available therapy. Although no therapies are yet approved, there is a growing field of candidates and an improving understanding of the regulatory pathway. In this review, we briefly discuss the epidemiology, pathophysiology, and current treatment paradigm for CeD. We also review the major classes of therapies being considered for CeD and discuss extensively what is known and can be surmised regarding the regulatory pathway for approval of a CeD therapeutic. The coming years will see an increasing number and diversity of potential therapies entering clinical trials and hopefully the first approved agents targeting this significant unmet medical need. Although biomarkers including histology and serology will always be important in therapeutic clinical trials, they currently lack the necessary evidence linking them to improved patient outcomes required for use as primary outcomes for drug approval. For this reason, patient-reported outcomes will likely be primary end points in Phase III CeD trials for the foreseeable future.

Design of Treatment Trials for Functional Gastrointestinal Disorders

This article summarizes recent progress and regulatory guidance on design of trials to assess the efficacy of new therapies for functional gastrointestinal disorders (FGIDs). The double-masked, placebo-controlled, parallel-group design remains the accepted standard for evaluating treatment efficacy. A control group is essential, and a detailed description of the randomization process and concealed allocation method must be included in the study report. The control will most often be placebo, but for therapeutic procedures and for behavioral treatment trials, respectively, a sham procedure and control intervention with similar expectation of benefit, but lacking the treatment principle, are recommended. Investigators should be aware of, and attempt to minimize, expectancy effects (placebo, nocebo, precebo). The primary analysis should be based on the proportion of patients in each treatment arm who satisfy a treatment responder definition or a prespecified clinically meaningful change in a patient-reported outcome measure. Data analysis should use the intention-to-treat principle. Reporting of results should follow the Consolidated Standards for Reporting Trials guidelines and include secondary outcome measures to support or explain the primary outcome and an analysis of harms data. Trials should be registered in a public location before initiation and results should be published regardless of outcome.

Efficacy of Mirtazapine in Patients With Functional Dyspepsia and Weight Loss

BACKGROUND & AIMS

A subset of patients with functional dyspepsia (FD) present with early satiation and weight loss, for which there are no established therapeutic options. We investigated the efficacy of mirtazapine (an antidepressant and antagonist of the histamine receptor H1, the α2 adrenergic receptor, and the serotonin receptors 5-HT2C and 5-HT-3) in patients with FD and weight loss.

METHODS

We conducted a randomized, placebo-controlled pilot trial that studied 34 patients with FD (29 women; mean age, 35.9 ± 2.3 years) with weight loss >10% of original body weight (mean loss, 12.4 ± 2.3 kg) without depression or anxiety. After a run-in period, patients were randomly assigned to groups given placebo (n = 17) or mirtazapine 15 mg each day for 8 weeks (n = 17) in a double-blind manner. Subjects were evaluated during a 2-week baseline and 8-week treatment for dyspepsia symptom severity, quality of life (on the basis of the Nepean Dyspepsia Index), and gastrointestinal-specific anxiety; they were given a nutrient challenge test and weighed. Data were analyzed by using linear mixed models, followed by planned contrasts with adaptive step-down Bonferroni multiple testing correction.

RESULTS

Two patients in each group dropped out. At weeks 4 and 8, mirtazapine significantly reduced mean dyspepsia symptom severity scores compared with week 0 (P = .003 and P = .017, respectively); there was no significant reduction in the placebo group (P > .37 for weeks 4 and 8). The difference in change from week 0 between mirtazapine and placebo showed a trend with a large effect size at week 4 (P = .059) that was not significant at week 8 (P = .55). However, improvements from week 0 to weeks 4 and 8 were significantly larger in the mirtazapine group than placebo group for early satiation, quality of life, gastrointestinal-specific anxiety, weight, and nutrient tolerance (mostly with large effect sizes).

CONCLUSIONS

In a randomized, placebo-controlled trial, mirtazapine significantly improved early satiation, quality of life, gastrointestinal-specific anxiety, nutrient tolerance, and weight loss in patients with FD. ClinicalTrials.gov number: NCT01240096.

Probiotics in functional bowel disorders

Functional bowel disorders (FBDs) are the most common gastrointestinal (GI) disorders seen by gastroenterologists and primary care physicians. The disorders affect patients functioning and quality of life (QOL) and are associated with significant healthcare burden. The current theory regarding the development of FBDs suggests brain-gut axis dysfunctions associated abnormal GI motility and sensation. Recent data suggest that alterations in the intestinal microbiota may have a role in the pathogenesis of FBDs; or at least have the potential to affect intestinal functions that are thought to be relevant to the development of functional GI symptoms. This has led to growing interest of healthcare providers and patients in targeting the intestinal microbiota for the treatment of FBDs. In this article we discuss the potential role probiotic interventions in the treatment of FBDs. We review the evidence from pre-clinical and clinical studies and discuss the current recommendations for the use of probiotics for FBDs in clinical practice.

Randomised controlled trial of mesalazine in IBS

OBJECTIVE

Low-grade intestinal inflammation plays a role in the pathophysiology of IBS. In this trial, we aimed at evaluating the efficacy and safety of mesalazine in patients with IBS.

DESIGN

We conducted a phase 3, multicentre, tertiary setting, randomised, double-blind, placebo-controlled trial in patients with Rome III confirmed IBS. Patients were randomly assigned to either mesalazine, 800 mg, or placebo, three times daily for 12 weeks, and were followed for additional 12 weeks. The primary efficacy endpoint was satisfactory relief of abdominal pain/discomfort for at least half of the weeks of the treatment period. The key secondary endpoint was satisfactory relief of overall IBS symptoms. Supportive analyses were also performed classifying as responders patients with a percentage of affirmative answers of at least 75% or >75% of time.

RESULTS

A total of 185 patients with IBS were enrolled from 21 centres. For the primary endpoint, the responder patients were 68.6% in the mesalazine group versus 67.4% in the placebo group (p=0.870; 95% CI -12.8 to 15.1). In explorative analyses, with the 75% rule or >75% rule, the percentage of responders was greater in the mesalazine group with a difference over placebo of 11.6% (p=0.115; 95% CI -2.7% to 26.0%) and 5.9% (p=0.404; 95% CI -7.8% to 19.4%), respectively, although these differences were not significant. For the key secondary endpoint, overall symptoms improved in the mesalazine group and reached a significant difference of 15.1% versus placebo (p=0.032; 95% CI 1.5% to 28.7%) with the >75% rule.

CONCLUSIONS

Mesalazine treatment was not superior than placebo on the study primary endpoint. However, a subgroup of patients with IBS showed a sustained therapy response and benefits from a mesalazine therapy.

TRIAL REGISTRATION NUMBER

ClincialTrials.gov number, NCT00626288.

The Stressometer: A Simple, Valid, and Responsive Measure of Psychological Stress in Inflammatory Bowel Disease Patients

BACKGROUND AND AIMS

Psychological stress is associated with inflammatory bowel disease [IBD], but the nature of this relationship is complex. At present, there is no simple tool to screen for stress in IBD clinical practice or assess stress repeatedly in longitudinal studies. Our aim was to design a single-question 'stressometer' to rapidly measure stress and validate this in IBD patients.

METHODS

In all, 304 IBD patients completed a single-question 'stressometer'. This was correlated with stress as measured by the Depression Anxiety Stress Scales [DASS-21], quality of life, and disease activity. Test-retest reliability was assessed in 31 patients who completed the stressometer and the DASS-21 on two occasions 4 weeks apart.

RESULTS

Stressometer levels correlated with the DASS-21 stress dimension in both Crohn's disease [CD] (Spearman's rank correlation coefficient [rs] 0.54; p < 0.001) and ulcerative colitis [UC] [rs 0.59; p < 0.001]. Stressometer levels were less closely associated with depression and anxiety [rs range 0.36 to 0.49; all p-values < 0.001]. Stressometer scores correlated with all four Short Health Scale quality of life dimensions in both CD and UC [rs range 0.35 to 0.48; all p-values < 0.001] and with disease activity in Crohn's disease [rs 0.46; p < 0.001] and ulcerative colitis [rs 0.20; p = 0.02]. Responsiveness was confirmed with a test-retest correlation of 0.43 [p = 0.02].

CONCLUSIONS

The stressometer is a simple, valid, and responsive measure of psychological stress in IBD patients and may be a useful patient-reported outcome measure in future IBD clinical and research assessments.

Targeting tachykinin receptors for the treatment of functional gastrointestinal disorders with a focus on irritable bowel syndrome

BACKGROUND

Tachykinins (TKs) are a family of endogenous peptides widely expressed in the central and in the peripheral nervous systems as well as in the gastrointestinal (GI) tract. They act as full agonists at three different membrane receptors neurokinin (NK) 1, NK2, and NK3, which are G protein-coupled receptors and in the GI tract are expressed both on neurons and effector cells.

PURPOSE

This article reviews the literature concerning the role of TKs in the GI tract function in physiological and pathological conditions and their potential relevance in the treatment of functional GI disorders with particular reference to irritable bowel syndrome (IBS). The efficacy of NK1 antagonists in chemotherapy-induced and postoperative nausea and vomiting is well established. While pharmacodynamic studies have reported conflicting and negative results concerning the effects of NK1 and of NK3 antagonists, respectively, on the GI tract function in humans, clinical studies applying the NK3 antagonist talnetant in IBS-D were negative. Pharmacodynamic studies applying NK2 antagonists have suggested a role for antagonism of NK2 receptors in modulation of GI chemical-induced altered motility and of stress-induced altered bowel habits. Clinical studies and in particular a recently completed Phase 2 study have reported that the NK2 antagonist ibodutant is effective and safe in treating symptoms of D-IBS, especially in females.

Priority review drugs approved by the FDA and the EMA: time for international regulatory harmonization of pharmaceuticals?

INTRODUCTION

The US Food and Drug Administration (FDA) priority review process applies to a drug that is considered a significant improvement over the available alternatives. The European Medicines Agency (EMA) accelerated approval applies to a product that is of major public health interest. This study assessed differences in the characteristics of priority review new molecular entities and new therapeutic biologic products approved by the FDA and the EMA.

METHODS

This study includes regulatory information on drug applications, approvals, indications, and orphan designations of all priority review drugs approved by the FDA and the EMA in the period 1999-2011. Descriptive statistics, t-tests, and chi-squared and Wilcoxon tests were performed.

RESULTS

Overall, 100 FDA priority review new molecular entities and new therapeutic biologics were approved by both agencies; 87.0% of the products were first approved by the FDA. The average FDA review time (9.2 ± 8.4 months) was significantly lower than the EMA average review time (14.6 ± 4.0 months) (p < 0.0001). The FDA and the EMA granted orphan designation to 43.0% and 33.0%, respectively, of the applications. There were differences in the administration route (1.0% of all products), dosage (8.0%), strength (23%), posology (51.0%), indications (30.0%), restrictions of use (52.0%), limitations of use (19.0%), and outcomes limitations (28.0%) approved by both regulatory agencies.

CONCLUSION

Significant differences exist in the characteristics of the priority review drugs approved by the FDA and the EMA. Harmonization of the US and European regulatory frameworks may facilitate timely approval of pharmaceutical products.

Pharmacologic treatment in pediatric functional abdominal pain disorders: a systematic review

OBJECTIVE

To systematically review literature assessing efficacy and safety of pharmacologic treatments in children with abdominal pain-related functional gastrointestinal disorders (AP-FGIDs).

STUDY DESIGN

MEDLINE and Cochrane Database were searched for systematic reviews and randomized controlled trials investigating efficacy and safety of pharmacologic agents in children aged 4-18 years with AP-FGIDs. Quality of evidence was assessed using Grades of Recommendation, Assessment, Development and Evaluation approach.

RESULTS

We included 6 studies with 275 children (aged 4.5-18 years) evaluating antispasmodic, antidepressant, antireflux, antihistaminic, and laxative agents. Overall quality of evidence was very low. Compared with placebo, some evidence was found for peppermint oil in improving symptoms (OR 3.3 (95% CI 0.9-12.0) and for cyproheptadine in reducing pain frequency (relative risk [RR] 2.43, 95% CI 1.17-5.04) and pain intensity (RR 3.03, 95% CI 1.29-7.11). Compared with placebo, amitriptyline showed 15% improvement in overall quality of life score (P = .007) and famotidine only provides benefit in global symptom improvement (OR 11.0; 95% CI 1.6-75.5; P = .02). Polyethylene glycol with tegaserod significantly decreased pain intensity compared with polyethylene glycol only (RR 3.60, 95% CI 1.54-8.40). No serious adverse effects were reported. No studies were found concerning antidiarrheal agents, antibiotics, pain medication, anti-emetics, or antimigraine agents.

CONCLUSIONS

Because of the lack of high-quality, placebo-controlled trials of pharmacologic treatment for pediatric AP-FGIDs, there is no evidence to support routine use of any pharmacologic therapy. Peppermint oil, cyproheptadine, and famotidine might be potential interventions, but well-designed randomized controlled trials are needed.

Linaclotide improves quality of life in patients with irritable bowel syndrome with constipation: A Meta-analysis

AIM: To perform a meta-analysis to determine the efficacy and the safety of linaclotide, compared with placebo, for patients with irritable bowel syndrome with constipation (IBS-C).

METHODS: CNKI, CBM, Wanfang, VIP, PubMed, EMBASE, clinical trials.gov and the Cochrane library were searched for randomized, placebo controlled trials examining the effect of linaclotide in adults with IBS-C. Dichotomous results were pooled by using the RevMan v.5.2 software to yield relative risks (RRs) and 95% confidence intervals (CIs).

RESULTS: The search identified three randomized controlled trials of linaclotide in patients with IBS-C published in four papers. Meta-analysis suggested that linaclotide significantly improved abdominal pain (RR = 1.58, 95%CI: 1.02-2.46), complete spontaneous bowel movements (CSBMs) (RR = 3.19, 95%CI: 2.40-4.25) and quality of life (RR = 1.38, 95%CI: 1.09-1.74). Linaclotide also improved stool form and reduced the severity of abdominal pain, bloating and overall symptoms in patients with IBS-C. Diarrhoea was the most frequent adverse event (AE) in the group of linaclotide.

CONCLUSION: Our study suggests that linaclotide significantly improves bowel function, reduces abdominal pain and improves quality of life in patients with IBS-C.

Optimal management of constipation associated with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common chronic functional disorder of the gastrointestinal tract, meanly characterized by recurrent abdominal pain or discomfort and altered bowel habit. It is a complex disorder involving biological, environmental, and psychosocial factors. The diagnosis is achieved according to the Rome III criteria provided that organic causes have been excluded. Although IBS does not constitute a life-threatening condition, it has a remarkable prevalence and profoundly reduces the quality of life with burdening socioeconomic costs. One of the principal concerns about IBS is the lack of effective therapeutic options. Up to 40% of patients are not satisfied with any available medications, especially those suffering from chronic constipation. A correct management of IBS with constipation should evolve through a global approach focused on the patient, starting with careful history taking in order to assess the presence of organic diseases that might trigger the disorder. Therefore, the second step is to examine lifestyle, dietary habits, and psychological status. On these bases, a step-up management of disease is recommended: from fiber and bulking agents, to osmotic laxative drugs, to new molecules like lubiprostone and linaclotide. Although new promising tools for relief of bowel-movement-related symptoms are being discovered, a dedicated doctor-patient relationship still seems to be the key for success.

Citalopram for pediatric functional abdominal pain: a randomized, placebo-controlled trial

BACKGROUND

Antidepressants are effective in adults with pain-related functional gastrointestinal disorders. We investigated the effectiveness of citalopram in the treatment of childhood functional abdominal pain (FAP).

METHODS

Children with FAP, based on the Rome III criteria (n = 115, aged 6-18 years), were randomized to receive either citalopram 20 mg/day or placebo for 4 weeks. Treatment response was defined as ≥ 2 point reduction in the 6-point Faces pain rating scale or 'no pain'. Depression, anxiety, somatization, and physician-rated global severity and improvement were also evaluated. Patients were followed up for 8 weeks after medication period.

KEY RESULTS

Eighty-six patients completed the medication (43 in each group). Response rate in the citalopram and placebo groups based on per-protocol (intention-to-treat) analysis was 55.8% (40.6%) and 39.5% (30.3%) at week 4 (p = 0.097 [0.169]) and 72.0% (52.5%) and 53.4% (41.0%) at week 12 (p = 0.059 [0.148]), respectively. In per-protocol analysis, more reduction was observed in pain (F = 3.84, p = 0.024) and global severity scores (F = 4.12, p = 0.021) in the citalopram group compared with the placebo group over the study period. Such differences were not present in the intention-to-treat analysis. No difference was found between the two groups regarding change in depression, anxiety, or somatization score over the study.

CONCLUSIONS & INFERENCES

Overall, we found a trend toward the effectiveness of citalopram in the treatment of children with FAP. Trials with longer treatment duration in larger samples of patients are required in this regard.

Advances in the management of constipation-predominant irritable bowel syndrome: the role of linaclotide

Constipation-predominant irritable bowel syndrome (IBS-C) is a commonly prevalent and clinically challenging disorder to treat. Until recently, most therapeutic agents had limited ability to address the complexity of symptoms inherent to the syndrome. The development of linaclotide provides a physiologically sound approach to treatment of the multiple symptoms of IBS-C. Clinical trials demonstrate the efficacy of linaclotide, and a platform to better understand the symptomatology of IBS-C. Based on recent clinical evidence, linaclotide should be considered for patients with IBS-C because it improves abdominal pain and bowel symptoms. In phase III trials, linaclotide met the US Food and Drug Administration responder endpoint with a number needed to treat (NNT) of 5.1-7.9, and European Medicines Agency coprimary endpoints at 12 weeks with a NNT of 4.39-7.69, and at 26 weeks with a NNT of 4.93-5.68. It is safe and effective, with diarrhea reported as the most common adverse effect, which leads to discontinuation of the medication in approximately 5% of patients.

The impact of psychiatric and extraintestinal comorbidity on quality of life and bowel symptom burden in functional GI disorders

BACKGROUND

Functional gastrointestinal disorders (FGID) patients report poor health-related quality of life (HRQOL) and experience high rates of psychiatric and extraintestinal functional disorder (EIFD) comorbidity. The independent influence of these comorbidities on HRQOL and symptom burden remains unknown. We sought to determine whether FGID with mood or EIFD comorbidity have poorer HRQOL and greater GI symptom burdens; to determine the influence of comorbidities on HRQOL in FGID independent of bowel symptoms.

METHODS

Subjects reported on comorbidities (anxiety, depression, somatization, EIFD), FGID criteria (irritable bowel syndrome, IBS; functional dyspepsia, FD) using ROME III Research questionnaire, GI symptom burden, and HRQOL. Differences in measures were assessed between subjects with and without ROME III criteria. Multiple regression determined the relative contribution of comorbidities to HRQOL, and mediation analysis explored whether comorbidity influences HRQOL.

KEY RESULTS

In a cohort of 912 GI outpatients (47.2 ± 1.5 years, 75.8% female), 606 (66.4%) met Rome III IBS and/or FD criteria. Comorbidities were common in FGID (≥1 in 77.4%), leading to lower HRQOL and greater GI symptom burden (each p < 0.05). Poorer HRQOL was predicted by both psychiatric and EIFD comorbidity (each p < 0.05) independent of GI symptoms (p < 0.001). Comorbidities together exerted a greater effect on predicted variation in HRQOL (70.9%) relative to GI symptoms (26.5%).

CONCLUSIONS & INFERENCES

Psychiatric and EIFD comorbidities are common in FGID, decrease HRQOL and are associated with greater GI symptom burdens; these factors were stronger predictors of HRQOL than GI symptoms in FGID patients.

Efficacy and safety of acotiamide for the treatment of functional dyspepsia: systematic review and meta-analysis

BACKGROUND

There are no treatments with established efficacy for this disorder so far.

AIM

To systematically review the efficacy of acotiamide in the treatment of patients with FD.

METHODS

We searched main electronic databases through November 2013. RCTs evaluating the efficacy of acotiamide versus placebo in FD patients were included. Pooled risk ratio (RR) with 95% confidential interval (CI) was calculated.

RESULTS

Six publications including seven RCTs were eligible for inclusion. The summary RR of overall improvement of FD symptoms in patients receiving acotiamide versus placebo was 1.29 (95% CI, 1.19-1.40, P < 0.00001; I(2) = 15%). Acotiamide improved the symptoms of patients with postprandial distress syndrome (PDS) (RR, 1.29; 95% CI, 1.09-1.53, P = 0.003; I(2) = 0%), and the summary RR for patients with epigastric pain syndrome (EPS) was 0.92 (95% CI, 0.76-1.11, P = 0.39; I(2) = 0%). Acotiamide showed a significantly beneficial effect on the elimination of some individual FD symptoms compared with placebo. Adverse events were not significantly different between acotiamide and placebo groups. Subgroup analyses suggested that acotiamide 100 mg three times daily (tid) showed consistent efficacy not only for the overall improvement but also for the elimination of some individual symptoms in FD patients.

CONCLUSIONS

Acotiamide has the potential to improve the symptoms of patients with FD, particularly of patients with PDS, without major adverse effects. The dosage of acotiamide 100 mg tid might be the appropriate dose in the treatment of FD.

Patient-reported outcomes as primary end points in clinical trials of inflammatory bowel disease

The Food and Drug Administration (FDA) is moving from the Crohn's Disease Activity Index to patient-reported outcomes (PROs) and objective measures of disease, such as findings from endoscopy. PROs will become an important aspect of assessing activity of inflammatory bowel disease (IBD) and for labeling specific drugs for this disease. PROs always have been considered in the management of patients with rheumatoid arthritis or multiple sclerosis, and have included measurements of quality of life, disability, or fatigue. Several disease-specific scales have been developed to assess these PROs and commonly are used in clinical trials. Outcomes reported by patients in clinical trials of IBD initially focused on quality of life, measured by the Short-Form 36 questionnaire or disease-specific scales such as the Inflammatory Bowel Disease Questionnaire or its shorter version. Recently considered factors include fatigue, depression and anxiety, and work productivity, as measured by the Functional Assessment Chronic Illness Therapy-Fatigue, the Hospital Anxiety Depression, and the Work Productivity Activity Impairment Questionnaire, respectively. However, few data are available on how treatment affects these factors in patients with IBD. Although disability generally is recognized in patients with IBD, it is not measured. The international IBD disability index currently is being validated. None of the PROs currently used in IBD were developed according to FDA guidance for PRO development. PROs will be a major primary end point of future trials. FDA guidance is needed to develop additional PROs for IBD that can be incorporated into trials, to better compare patients' experience with different therapies.

[Efficacy of fenoverine and trimebutine in the management of irritable bowel syndrome: multicenter randomized double-blind non-inferiority clinical study]

BACKGROUND/AIMS

Antispasmodic agents have been used in the management of irritable bowel syndrome. However, systematic reviews have come to different conclusions about the efficacy in irritable bowel syndrome. Fenoverine acts as a synchronizer of smooth muscle in modulating the intracellular influx of calcium. We compared fenoverine with trimebutine for the treatment of patients with IBS.

METHODS

A multicenter, randomized, double-blind, non-inferiority clinical study was conducted to compared fenoverine with trimebutine. Subjects were randomized to receive either fenoverine (100 mg three times a day) or trimebutine (150 mg three times a day) for 8 weeks. A total of 197 patients were analyzed by the intention-to-treat approach. The primary endpoint was the proportion of patients who had 30% reduction in abdominal pain or discomfort measured by bowel symptom scale (BSS) score at week 8 compared to the baseline. The secondary endpoints were changes of abdominal bloating, diarrhea, constipation, overall and total scores of BSS, and overall satisfaction.

RESULTS

At week 8, fenoverine was shown to be non-inferior to trimebutine (treatment difference, 1.76%; 90% CI, -10.30-13.82; p=0.81); 69.23% (54 of 78 patients) of patients taking fenoverine and 67.47% (56 of 83 patients) of patients taking trimebutine showed 30% reduction in abdominal pain or discomfort compared to the baseline. There results of the secondary endpoints were also comparable between the fenoverine group and the trimebutine group.

CONCLUSIONS

Fenoverine is non-inferior to trimebutine for treating IBS in terms of both efficacy and tolerability.

Placebo effect in clinical trial design for irritable bowel syndrome

Ongoing efforts to improve clinical trial design in irritable bowel syndrome have been hindered by high placebo response rates and ineffective outcome measures. We assessed established strategies to minimize placebo effect as well as the various approaches to placebo effect which can affect trial design. These include genetic markers such as catechol-O-methyltransferase, opioidergic and dopaminergic neurobiologic theory, pre-cebo effect centered on expectancy theory, and side effect unblinding grounded on conditioning theory. We reviewed endpoints used in the study of IBS over the past decade including adequate relief and subjective global relief, emphasizing their weaknesses in fully evaluating the IBS condition, specifically their motility effects based on functional net value and relative benefit-harm based on dropouts due to adverse events. The focus of this review is to highlight ongoing efforts to improve clinical trial design which can lead to better outcomes in a real-world setting.

Mechanisms of visceral pain in health and functional gastrointestinal disorders

Background and aims Chronic visceral pain is common both in patients with identifiable organic disease and also in those without any structural, biochemical or immunological abnormality such as in the functional gastrointestinal disorders (FGIDs). We aim to provide a contemporaneous summary of pathways involved in visceral nociception and how a variety of mechanisms may influence an individual's experience of visceral pain. Methods In this narrative review, we have brought together evidence through a detailed search of Medline in addition to using our experience and exposure to recent research developments from ourselves and other research groups. Results FGIDs are a heterogeneous group of disorders whose aetiology largely remains an enigma. The germane hypothesis for the genesis and maintenance of chronic visceral pain in FGIDs is the concept of visceral hypersensitivity. A number of peripheral and central mechanisms have been proposed to account for this epiphenomenon. In the periphery, inflammatory mediators activate and sensitize nociceptive afferent nerves by reducing their transduction thresholds and by inducing the expression and recruitment of hitherto silent nociceptors culminating in an increase in pain sensitivity at the site of injury known as primary hyperalgesia. Centrally, secondary hyperalgesia, defined as an increase in pain sensitivity in anatomically distinct sites, occurs at the level of the spinal dorsal horn. Moreover, the stress responsive physiological systems, genetic and psychological factors may modulate the experience of visceral pain. We also address some novel aetiological concepts in FGIDs, namely the gastrointestinal microbiota, connective tissue abnormalities and the gastrointestinal neuromuscular disorders. Firstly, the gastrointestinal microbiota is a diverse and dynamic ecosystem, that safeguards the host from external pathogens, aids in the metabolism of polysaccharides and lipids, modulates intestinal motility, in addition to modulating visceral perception. Secondly, connective tissue disorders, which traditionally have been considered to be confined largely to the musculoskeletal system, have an increasing evidence base demonstrating the presence of visceral manifestations. Since the sensorimotor apparatus of the GI tract is embedded within connective tissue it should not be surprising that such disorder may result in visceral pain and abnormal gut motility. Thirdly, gastrointestinal neuromuscular diseases refer to a heterogeneous group of disorders in which symptoms arise from impaired GI motor activity often manifesting as abnormal transit with or without radiological evidence of transient or persistent dilation of the viscera. Although a number of these are readily recognizable, such as achalasia or Hirschsprung's disease, the cause in a number of patients is not. An international working group has recently addressed this "gap", providing a comprehensive morphologically based diagnostic criteria. Conclusions/implications Although marked advances have been made in understanding the mechanisms that contribute to the development and maintenance of visceral pain, many interventions have failed to produce tangible improvement in patient outcomes. In the last part of this review we highlight an emerging approach that has allowed the definition and delineation of temporally stable visceral pain clusters, which may improve participant homogeneity in future studies, potentially facilitate stratification of treatment in FGID and lead to improvements in diagnostic criteria and outcomes.

Effect of linaclotide in irritable bowel syndrome with constipation (IBS-C): a systematic review and meta-analysis

BACKGROUND

Treatment options for constipation-predominant irritable bowel syndrome (IBS-C) are limited. While linaclotide improved IBS-C symptoms in randomized controlled trials (RCTs), results vary among studies and the magnitude of benefit is unclear.

METHODS

Two investigators independently extracted data on study participants, methods and outcomes (i.e., symptoms, quality of life, and adverse events) from eligible articles i.e., RCTs comparing linaclotide with placebo in adult patients with IBS-C with a follow-up of 12 weeks or longer. The grading of recommendations assessment, development and evaluation (GRADE) methodology was used to rate the quality of evidence.

KEY RESULTS

Of 182 identified citations, three RCTs enrolling 1773 patients met the inclusion criteria. Compared with placebo, fewer patients on linaclotide failed to achieve responses i.e., FDA endpoint (1604 patients, risk ratio [RR] = 0.80; 95%CI 0.76-0.85), adequate IBS symptom relief (1773 patients, RR = 0.73; 95%CI 0.65-0.82), and clinically meaningful improvement in IBS-QOL (1659 patients, RR = 0.78; 95%CI 0.72-0.86). The incidence of diarrhea leading to discontinuation of treatment was higher for linaclotide (1773 patients, RR = 14.75; 95%CI 4.04-53.81). The quality of evidence was rated as moderate for FDA endpoint and adequate relief response, high for diarrhea, and low for IBS-QOL. Generalizability may be limited by the study population (i.e., predominantly white female patients), lack of data regarding prior therapy, and availability of few RCTs. The number of patients is insufficient to identify rare adverse events.

CONCLUSIONS & INFERENCES

Linaclotide is moderately effective in improving symptoms of IBS-C with diarrhea being the major side effect. Further studies are needed to evaluate the long-term efficacy and safety of linaclotide for IBS-C.

Adverse events appear to unblind clinical trials in irritable bowel syndrome

BACKGROUND

Clinical trial design is challenging in irritable bowel syndrome (IBS) due in part to a high placebo effect. We postulated that the mere presence of an adverse event (AE) may unmask patients in clinical trials who are assigned to the active agent, and this may lead to higher reported efficacy.

METHODS

We evaluated therapies receiving at least a Grade 1B from the American College of Gastroenterology Task Force for IBS or which passed recent phase III clinical trials. Therapies with AE data derived from less than 50 patients in each study arm were excluded. Statistically significant excess AE were identified, risk difference was calculated for each AE, and incidence of AE in the treatment arm was reported. We examined the relationship of attributable drug benefit, defined as the reciprocal of number-needed-to-treat found in literature, with various measures of AE incidence.

KEY RESULTS

Attributable drug benefit correlated significantly with average AE risk difference, calculated as treatment arm AE incidence minus placebo arm AE incidence (R(2) = 0.70, p = 0.039), and also with highest treatment arm AE incidence (R(2) = 0.70, p = 0.038) for each therapy. There were also trends toward correlation with average treatment arm AE incidence (R(2) = 0.54, p = 0.096) and highest AE risk difference (R(2) = 0.63, p = 0.059) for each therapy.

CONCLUSIONS & INFERENCES

Our study suggests that higher AE incidence on active therapy is associated with more beneficial patient-reported outcomes in IBS clinical trials. This raises the issue of spontaneous unblinding.

Lubiprostone: pharmacokinetic, pharmacodynamic, safety and regulatory aspects in the treatment of constipation-predominant irritable bowel syndrome

INTRODUCTION

Lubiprostone acts locally (apical membrane of human intestinal epithelial cells) as a highly selective type-2 chloride channel activator. It was approved in the USA for chronic idiopathic constipation (January 2006) and in women aged ≥ 18 years suffering from irritable bowel syndrome with constipation (IBS-C) (April 2008). So far, the only other pro-secretory medication approved in IBS-C and currently available in USA and Europe (since August and November 2012, respectively) is linaclotide.

AREAS COVERED

This review outlines the regulatory history, pharmacokinetic, pharmacodynamic and safety data in the treatment of IBS-C with a European perspective. It is based on publicly available data, namely, published literature, drug labels and the FDA's spontaneous reporting system.

EXPERT OPINION

Although interesting pharmacodynamic data suggest that lubiprostone may have additional mechanisms of action, its beneficial effects in IBS-C must be confirmed in the actual clinical scenario taking into account the new version of European Medicines Agency's guideline. This is especially important with regard to duration of studies (recommended to be at least 6 months) to adequately assess long-term sustained efficacy, withdrawal, rebound and safety. Further research is warranted in uncertain areas (i.e., males, pediatric and elderly patients). On the basis of current data, it is still too early to draw definite conclusions on the overall risk-benefit balance for IBS-C.

Pharmacological agents currently in clinical trials for disorders in neurogastroenterology

Esophageal, gastrointestinal, and colonic diseases resulting from disorders of the motor and sensory functions represent almost half the patients presenting to gastroenterologists. There have been significant advances in understanding the mechanisms of these disorders, through basic and translational research, and in targeting the receptors or mediators involved, through clinical trials involving biomarkers and patient responses. These advances have led to relief of patients' symptoms and improved quality of life, although there are still significant unmet needs. This article reviews the pipeline of medications in development for esophageal sensorimotor disorders, gastroparesis, chronic diarrhea, chronic constipation (including opioid-induced constipation), and visceral pain.