Randomised clinical trials: linaclotide phase 3 studies in IBS-C - a prespecified further analysis based on European Medicines Agency-specified endpoints

Treatment of non-constipated irritable bowel syndrome with the histamine 1 receptor antagonist ebastine: a randomised, double-blind, placebo-controlled trial

OBJECTIVE

We evaluated the histamine 1 receptor antagonist ebastine as a potential treatment for patients with non-constipated irritable bowel syndrome (IBS) in a randomised, placebo-controlled phase 2 study.

METHODS

Non-constipated patients with IBS fulfilling the Rome III criteria were randomly assigned to 20 mg ebastine or placebo for 12 weeks. Subjects scored global relief of symptoms (GRS) and abdominal pain intensity (API). A subject was considered a weekly responder for GRS if total or obvious relief was reported and a responder for API if the weekly average pain score was reduced by at least 30% vs baseline. The primary endpoints were the proportion of subjects who were weekly responders for at least 6 out of the 12 treatment weeks for both GRS and API ('GRS+API', composite endpoint) and for GRS and API separately.

RESULTS

202 participants (32±11 years, 68% female) were randomly allocated to receive ebastine (n=101) or placebo (n=101). Treatment with ebastine resulted in significantly more responders (12%, 12/92) for GRS+API compared with placebo (4%, 4/87, p=0.047) while the proportion of responders for GRS and API separately was higher for ebastine compared with placebo, although not statistically significant (placebo vs ebastine, GRS: 7% (6/87) vs 15% (14/91), p=0.072; API: 25% (20/85) vs 37% (34/92), p=0.081).

CONCLUSIONS

Our study shows that ebastine is superior to placebo and should be further evaluated as novel treatment for patients with non-constipated IBS.

TRIAL REGISTRATION NUMBER

The study protocol was approved by the local ethics committee of each study site (EudraCT number: 2013-001199-39; ClinicalTrials.gov identifier: NCT01908465).

[Frequent Gastro-Intestinal Disorders: Management of Functional Dyspepsia and Irritable Bowel Syndrome in Clinical Practice]

Frequent Gastro-Intestinal Disorders: Management of Functional Dyspepsia and Irritable Bowel Syndrome in Clinical Practice Abstract: Functional dyspepsia (FD) and irritable bowel syndrome (IBS), two common gastrointestinal entities with overlapping symptoms, should be diagnosed according to Rome IV criteria. This includes one or more of the following symptoms: in FD, postprandial fullness, early satiation, epigastric pain or burning; in IBS, recurrent abdominal pain associated with defecation, change in frequency of stool or form of stool. To exclude structural diseases, attention should be paid to alarm symptoms. As far as treatment is concerned, a stepwise scheme proves to be effective for both diseases. Step 1: doctor-patient discussion with explanation of diagnosis and prognosis as well as clarification of therapy goals; lifestyle adaptations; use of phytotherapeutics; step 2: symptom-oriented medication: for FD, PPIs or prokinetics; for IBS, antispasmodics, secretagogues, laxatives, bile acid sequestrants, antidiarrheals, antibiotics, probiotics; step 3: visceral analgesics (antidepressants).

Italian guidelines for the management of irritable bowel syndrome: Joint Consensus from the Italian Societies of: Gastroenterology and Endoscopy (SIGE), Neurogastroenterology and Motility (SINGEM), Hospital Gastroenterologists and Endoscopists (AIGO), Digestive Endoscopy (SIED), General Medicine (SIMG), Gastroenterology, Hepatology and Pediatric Nutrition (SIGENP) and Pediatrics (SIP)

The irritable bowel syndrome (IBS) is a chronic disorder of gut-brain interaction. IBS is still associated with areas of uncertainties, especially regarding the optimal diagnostic work-up and the more appropriate management. Experts from 7 Italian Societies conducted a Delphi consensus with literature summary and voting process on 27 statements. Recommendations and quality of evidence were evaluated using the grading of recommendations, assessment, development, and evaluation (GRADE) criteria. Consensus was defined as >80% agreement and reached for all statements. In terms of diagnosis, the consensus supports a positive diagnostic strategy with a symptom-based approach, including the psychological comorbidities assessment and the exclusion of alarm symptoms, together with the digital rectal examination, full blood count, C-reactive protein, serology for coeliac disease, and fecal calprotectin assessment. Colonoscopy should be recommended in patients with alarm features. Regarding treatment, the consensus strongly supports a dietary approach for patients with IBS, the use of soluble fiber, secretagogues, tricyclic antidepressants, psychologically directed therapies and, only in specific IBS subtypes, rifaximin. A conditional recommendation was achieved for probiotics, polyethylene glycol, antispasmodics, selective serotonin reuptake inhibitors and, only in specific IBS subtypes, 5-HT3 antagonists, 5-HT4 agonists, bile acid sequestrants.

Belgian consensus on irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is characterised by recurrent abdominal pain related to defaecation or associated with altered stool frequency or consistency. Despite its prevalence, major uncertainties in the diagnostic and therapeutic management persist in clinical practice.

METHODS

A Delphi consensus was conducted by 20 experts from Belgium, and consisted of literature review and voting process on 78 statements. Grading of recommendations, assessment, development and evaluation criteria were applied to evaluate the quality of evidence. Consensus was defined as > 80 % agreement.

RESULTS

Consensus was reached for 50 statements. The Belgian consensus agreed as to the multifactorial aetiology of IBS. According to the consensus abdominal discomfort also represents a cardinal symptom, while bloating and abdominal distension often coexist. IBS needs subtyping based on stool pattern. The importance of a positive diagnosis, relying on history and clinical examination is underlined, while additional testing should remain limited, except when alarm features are present. Explanation of IBS represents a crucial part of patient management. Lifestyle modification, spasmolytics and water-solube fibres are considered first-line agents. The low FODMAP diet, selected probiotics, cognitive behavioural therapy and specific treatments targeting diarrhoea and constipation are considered appropriate. There is a consensus to restrict faecal microbiota transplantation and gluten-free diet, while other treatments are strongly discouraged.

CONCLUSIONS

A panel of Belgian gastroenterologists summarised the current evidence on the aetiology, symptoms, diagnosis and treatment of IBS with attention for the specificities of the Belgian healthcare system.

Management of bloating

Abdominal bloating is a subjective sensation of trapped abdominal gas, producing abdominal pressure, fullness sensation, and, in some patients, associated objective abdominal distension. In this month's edition of the journal, a new validated questionnaire to assess the prevalence and impact of gas-related symptoms is presented by Duracinsky et al., showing that gas-related abdominal symptoms are prevalent in patients with irritable bowel syndrome and have a measurable impact on patients daily life. A parallel study by Gardiner et al. assessing the severity of bloating in functional gastrointestinal disorders shows that severe bloating is associated with the severity of abdominal pain, constipation, and somatization, advancing our understanding of the clinical characteristics and relevance of gas-related symptoms in the broad spectrum of functional gastrointestinal disorders. Management of bloating includes non-pharmacological and pharmacological strategies. Dietary interventions to reduce intestinal fermentation and ingestion of food supplements like prebiotics or probiotics can reduce bloating by reducing gas production. The main targets of pharmacological treatments are to improve transit and evacuation with prokinetics, to improve intestinal gas tolerance with antispasmodics and/or neuromodulators, and to modify intestinal microbiota with antibiotics. Secretagogues act by increasing intestinal secretion and decreasing visceral sensitivity and have been reported to be an effective treatment alternative for patients with bloating associated with constipation. Biofeedback therapy addressed to correct abdomino-phrenic dysynergia may be useful for patients with objective abdominal distension, and patients with bloating associated with outlet obstructed defecation may benefit from anorectal biofeedback.

Efficacy and safety of linaclotide in patients with irritable bowel syndrome with constipation: Chinese sub-cohort analysis of a phase III, randomized, double-blind, placebo-controlled trial

OBJECTIVE

To conduct a sub-cohort analysis to evaluate the efficacy and safety of linaclotide in Chinese patients with constipation-predominant irritable bowel syndrome (IBS-C) using data from a completed trial (NCT01880424).

METHODS

In this phase III, double-blind, placebo-controlled trial, IBS-C patients were randomized to receive linaclotide (290 μg/d) or placebo for 12 weeks. Efficacy was assessed with two co-primary responder end-points (12-wk abdominal pain/discomfort: ≥30% reduction in either score with neither deteriorating from baseline for ≥6 wks; 12-wk IBS degree of relief: score ≤2 for ≥ 6 wks), seven secondary endpoints and several additional end-points.

RESULTS

In total, 659 Chinese IBS-C patients received linaclotide (n = 327) or placebo (n = 332). The 12-week abdominal pain/discomfort end-point was met in 62.1% and 53.3% of the linaclotide-treated and placebo-treated patients, respectively (odds ratio [OR] 1.43, 95% confidence interval [CI] 1.05-1.96, P = 0.023); the 12-week IBS degree of relief end-point was achieved in 32.7% and 16.9% of the patients treated with linaclotide and placebo, respectively (OR 2.40, 95% CI 1.66-3.47, P < 0.001). The linaclotide-treated patients had a shorter time to the first spontaneous bowel movement than the placebo-treated patients (23.6 h vs 43.7 h, P < 0.001). Linaclotide produced significantly greater improvement than placebo in all secondary end-points from the first 2 weeks (all P < 0.001). Diarrhea was reported in 8.3% of linaclotide-treated patients and 1.2% of placebo-treated patients.

CONCLUSION

Linaclotide (290 μg/d) was efficacious and well-tolerated in Chinese IBS-C patients with a rapid onset of effect.

Diabetic Gastroenteropathy: Soothe the Symptoms or Unravel a Cure?

Autonomic neuropathy in patients with diabetes mellitus, and especially complications related to gastrointestinal neuropathy, are often overlooked in the clinic. Diabetic gastroenteropathy affects every segment of the gastrointestinal tract and generates symptoms that may include nausea, early satiety, vomiting, abdominal pain, constipation, and diarrhea. Severe cases can be complicated by weight loss, dehydration, and electrolyte disturbances. The pathophysiology is complex, the diagnostics and treatment options are multidisciplinary, and there is generally a lack of evidence for the treatment options. The aims for this review are first to summarize the pathophysiology and describe possible and expected symptoms and complications.Further, we will try to supply the clinician with a straightforward tool for diagnostics, and then, we shall summarize established treatment options, including diet recommendations, pharmacological and non-pharmacological options. Finally, we will explore the multiple possibilities of novel treatment, looking at medications related to the pathophysiology of neuropathy, other manifestations of autonomic neuropathies, and symptomatic treatment for other gastrointestinal disorders, also including new knowledge of endosurgical and neuromodulatory treatment. The overall goal is to increase awareness and knowledge on this frequent diabetic complication and to provide better tools for diagnosis and treatment. Ultimately, we hope to encourage further research in this field, as there are clear shortcomings in terms of biomarkers, pathophysiology, as well as treatment possibilities. In conclusion, diagnosis and management of diabetic gastroenteropathy are challenging and often require multidisciplinary teams and multimodal therapies. Treatment options are sparse, but new pharmacological, endoscopic, and neuromodulatory techniques have shown promising results in initial studies.

Review article: current and future treatment approaches for IBS with constipation

BACKGROUND

Multiple efficacious therapies are currently available for treating irritable bowel syndrome with constipation (IBS-C). IBS-C specific survey tools that assess symptom relief, treatment satisfaction, and quality of life are important for gauging real-world effectiveness.

AIMS/METHODS

This article reviews clinical trial efficacy data as well as survey data on adequate relief and quality of life from pivotal trials for lubiprostone, linaclotide, plecanatide, tenapanor, and tegaserod. A brief discussion of agents in development with novel mechanisms of action is also provided.

RESULTS/CONCLUSIONS

Quality of life and symptom metrics should be standardized and continue to be represented in future IBS-C trials. The choice of agent should be tailored to probability of improving symptoms, safety, tolerability, and cost.

Comparison of the Efficacy and Safety of Different Doses of Linaclotide for Patients with Chronic Constipation: A Meta-Analysis and Bayesian Analysis

BACKGROUND

It is ambiguous whether a higher dose of linaclotide provides higher efficacy for chronic constipation (CC) patients. The meta-analysis aimed to assess the efficacy and safety of linaclotide doses ranging from 62.5 μg to 600 μg for CC patients.

METHODS

A comprehensive search was conducted, and STATA16 software was used for data analysis.

RESULTS

Seven studies with 4,107 patients were eligible. A significantly enhanced number of completely spontaneous bowel movement (CSBM) responders were found in the extremely low-dose group (OR: 2.94; 95% CI: 1.98-4.34; p < 0.001), the low-dose group (OR: 3.24; 95% CI: 2.44-4.31; p < 0.001), the medium-dose group (OR: 3.08; 95% CI: 1.46-6.50; p=0.003), and high-dose group (OR: 4.79; 95% CI: 3.04-7.54; p < 0.001). Bayesian analysis showed the high-dose group obtained the maximum CSBM responder rate (OR: 4.94; 95% credible interval (CrI): 3.22-7.79; probability rank = 0.87) indirectly compared with extremely low-dose, low-dose, and medium-dose groups. However, no significant difference presented in the CSBM responder rate by pairwise comparisons of the different dose groups. Additionally, no more any adverse events occurred in the higher linaclotide dose group (RR: 0.91; 95% CrI: 0.60-1.38) indirectly compared with other dose groups.

CONCLUSIONS

High dose of linaclotide could be more effective and safer for CC patients, which need more trials to confirm in the future.

Biopsychosocial Model and Perceived Constipation Severity According to the Constipation Phenotype

PURPOSE

Constipation is a frequent complaint of patients with functional bowel disorders. The present study aimed to evaluate the relationship between the perceived constipation severity with demographics, clinical, physiological, and psychological parameters in constipated patients.

PATIENTS AND METHODS

Four hundred seven constipated patients were included and had clinical, physiological, and psychological evaluation. The self-reported severity of constipation was analyzed using stepwise linear regression in the total population and within each clinical group.

RESULTS

The patients were mainly of female gender (81%) and were 47.4 ± 16.5 years old. They complained of IBS (65%), and 62% had defecation disorders. The depression scale was abnormal in 200 patients (49%). The relationships of the constipation severity varied according to the Rome IV phenotype. In all phenotypes, it was positively associated with bloating severity, and negatively with Bristol stool form. In IBS patients, perceived constipation severity was also associated with abdominal pain severity.

CONCLUSION

Our data support the hypothesis that perceived constipation severity is associated with clinical and physiological factors but not demographics and psychological factors. Besides, the relationships of perceived constipation severity with these factors vary according to clinical phenotypes.

Review article: diagnosis, management and patient perspectives of the spectrum of constipation disorders

BACKGROUND

Chronic constipation is a common, heterogeneous disorder with multiple symptoms and pathophysiological mechanisms. Patients are often referred to a gastroenterology provider after laxatives fail. However, there is limited knowledge of the spectrum and management of constipation disorders.

AIM

To discuss the latest understanding of the spectrum of constipation disorders, tools for identifying a pathophysiologic-based diagnosis in the specialist setting, treatment options and the patient's perspective of constipation.

METHODS

Literature searches were conducted using PubMed for constipation diagnostic criteria, diagnostic tools and approved treatments. The authors provided insight from their own practices.

RESULTS

Clinical assessment, stool diaries and Rome IV diagnostic criteria can facilitate diagnosis, evaluate severity and distinguish between IBS with constipation, chronic idiopathic constipation and dyssynergic defecation. Novel smartphone applications can help track constipation symptoms. Rectal examinations, anorectal manometry and balloon expulsion, assessments of neuromuscular function with colonic transit time and colonic manometry can provide mechanistic understanding of underlying pathophysiology. Treatments include lifestyle and diet changes, biofeedback therapy and pharmacological agents. Several classes of laxatives, as well as prokinetic and prosecretory agents, are available; here we describe their mechanisms of action, efficacy and side effects.

CONCLUSIONS

Constipation includes multiple overlapping subtypes identifiable using detailed history, current diagnostic tools and smartphone applications. Recognition of individual subtype(s) could pave the way for optimal, evidence-based treatments by a gastroenterology provider.

Medications for constipation in 2020

PURPOSE OF REVIEW

Chronic constipation is a common problem that substantially impacts the quality of life of patients and families, healthcare professionals, and resources. The purpose of this review is to discuss the medications that are available for management of chronic constipation, including medications that have been approved by the FDA for adults, other been studied in pediatrics now, and might become available within the upcoming years.

RECENT FINDINGS

Recent developments in the evaluation of childhood constipation are providing a better understanding into defecation disorders in children and not only new therapies are becoming available, including medications, but also other therapies, such as biofeedback for treatment of functional defecation disorders, electrical stimulation, and surgeries. The aim of this article is to provide an update on the medications that are available for management of chronic constipation, especially with the development and study of newer medications, such as Linaclotide and Lubiprostone with promising results in both adult and pediatric patients.

SUMMARY

This review will help us identify and have a better understanding regarding what medications are available for use and the indications, so that we can better manage patients with chronic constipation. VIDEO ABSTRACT.

Chronic constipation and abdominal pain: Independent or closely interrelated symptoms?

Constipation is both a symptom and a disorder, seen in both functional constipation and irritable bowel syndrome with constipation predominance (IBS-C). Despite the Rome IV criteria distinguishing between these conditions, they share many therapeutic approaches. This review aims to explore the relationship between constipation and abdominal pain and assess the evidence surrounding whether laxation improves abdominal pain and whether such a response to laxation differs between IBS-C and functional constipation. In patients with functional constipation, increasing frequency of bowel motions by laxatives regardless of mechanism of action is associated with reductions in the severity of abdominal pain, supporting the role of constipation as a contributor to abdominal discomfort. In patients with IBS-C, evidence from systematic reviews indicates that abdominal pain is driven by factors additional to constipation alone and that visceral analgesic modulation is also needed to optimize pain. Changing definitions of IBS-C and heterogeneity in clinical trial design including endpoints have raised uncertainty about the comparative ability of older laxatives without known neuromodulatory effects to improve chronic abdominal pain compared with new secretagogues and prokinetics for the management of IBS-C. While it is known that abdominal pain is associated with constipation and laxation contributes to relief of that pain, it remains unproven whether proposed visceral analgesic properties of new laxatives provide greater pain relief than laxation alone. However, it is likely that the response to laxation in IBS-C is only part of the puzzle.

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.

Effects of treatment with eluxadoline on abdominal pain in patients with IBS-D: Additional post hoc analyses of Phase 3 trials

BACKGROUND

Recurring abdominal pain is a characteristic and often unpredictable and debilitating symptom of irritable bowel syndrome with diarrhea (IBS-D). Measuring the effects of IBS-D treatments on abdominal pain remains a significant challenge in clinical trials. Here, we aimed to examine the effect of eluxadoline through various post hoc analyses.

METHODS

Data from two eluxadoline Phase 3 trials were pooled over 26 weeks, comparing eluxadoline 100 mg twice daily to placebo. Worst abdominal pain (WAP) was measured daily on a 0-10 scale. WAP responder criteria were prospectively defined as a ≥30% improvement in daily WAP score on ≥50% of days. Pairwise, two-sided Cochran-Mantel-Haenszel tests assessed treatment effects. Cumulative distribution functions were used to plot WAP response rates using variations on the response criteria.

KEY RESULTS

Of 1615 patients with IBS-D (66% female, mean age 46 years), 806 received eluxadoline and 809 received placebo; 48.3% and 44.0% were WAP responders (≥30% improvement), respectively (P value not significant). When the response threshold was increased to 50% daily WAP improvement from baseline, a significantly greater percentage of eluxadoline-treated patients versus placebo-treated patients were WAP responders (38.7% vs 32.5%, respectively; P = .009). At Week 26, average WAP changes from baseline were -3.4 and -3.0 points, respectively (P = .002).

CONCLUSIONS AND INFERENCES

Despite small effect sizes, eluxadoline demonstrated consistent and sustained improvement in WAP compared to placebo across a range of prospective and post hoc analyses. Assessing WAP response across a range of measures is important for fully understanding a treatment's efficacy.

An approach to the diagnosis and management of Rome IV functional disorders of chronic constipation

Introduction: Chronic constipation is highly prevalent, affecting between 10% and 15% of the population. The Rome IV criteria categorizes disorders of chronic constipation into four subtypes: (a) functional constipation, (b) irritable bowel syndrome with constipation, (c) opioid-induced constipation, and (d) functional defecation disorders, including inadequate defecatory propulsion and dyssynergic defecation. The initial management approach for these disorders is similar, focusing on diet, lifestyle and the use of standard over-the-counter laxatives. If unsuccessful, further therapy is tailored according to subtype.Areas covered: This review covers the definition, epidemiology, diagnostic criteria, investigations and management of the Rome IV disorders of chronic constipation.Expert opinion: By adopting a logical step-wise approach toward the diagnosis of chronic constipation and its individual subtypes, clinicians have the opportunity to tailor therapy accordingly and improve symptoms, quality of life, and patient satisfaction.

Second Asian Consensus on Irritable Bowel Syndrome

BACKGROUND/AIMS

There has been major progress in our understanding of the irritable bowel syndrome (IBS), and novel treatment classes have emerged. The Rome IV guidelines were published in 2016 and together with the growing body of Asian data on IBS, we felt it is timely to update the Asian IBS Consensus.

METHODS

Key opinion leaders from Asian countries were organized into 4 teams to review 4 themes: symptoms and epidemiology, pathophysiology, diagnosis and investigations, and lifestyle modifications and treatments. The consensus development process was carried out by using a modified Delphi method.

RESULTS

Thirty-seven statements were developed. Asian data substantiate the current global viewpoint that IBS is a disorder of gut-brain interaction. Socio-cultural and environmental factors in Asia appear to influence the greater overlap between IBS and upper gastrointestinal symptoms. New classes of treatments comprising low fermentable oligo-, di-, monosacharides, and polyols diet, probiotics, non-absorbable antibiotics, and secretagogues have good evidence base for their efficacy.

CONCLUSIONS

Our consensus is that all patients with functional gastrointestinal disorders should be evaluated comprehensively with a view to holistic management. Physicians should be encouraged to take a positive attitude to the treatment outcomes for IBS patients.

Pathophysiology and management of diabetic gastroenteropathy

Polyneuropathy is a common complication to diabetes. Neuropathies within the enteric nervous system are associated with gastroenteropathy and marked symptoms that severely reduce quality of life. Symptoms are pleomorphic but include nausea, vomiting, dysphagia, dyspepsia, pain, bloating, diarrhoea, constipation and faecal incontinence. The aims of this review are fourfold. First, to provide a summary of the pathophysiology underlying diabetic gastroenteropathy. Secondly to give an overview of the diagnostic methods. Thirdly, to provide clinicians with a focussed overview of current and future methods for pharmacological and nonpharmacological treatment modalities. Pharmacological management is categorised according to symptoms arising from the upper or lower gut as well as sensory dysfunctions. Dietary management is central to improvement of symptoms and is discussed in detail, and neuromodulatory treatment modalities and other emerging management strategies for diabetic gastroenteropathy are discussed. Finally, we propose a diagnostic/investigation algorithm that can be used to support multidisciplinary management.

Bloating and Abdominal Distension: Clinical Approach and Management

Functional abdominal bloating and distension (FABD) are common gastrointestinal complaints, encountered on a daily basis by gastroenterologists and healthcare providers. Functional abdominal bloating is a subjective sensation that is commonly associated with an objective abdominal distension. FABD may be diagnosed as a single entity (the sole or cardinal complaint) or may overlap with other functional gastrointestinal disorders such as functional constipation, irritable bowel syndrome, and functional dyspepsia. The pathophysiology of FABD is not completely understood. Proposed underlying mechanisms include visceral hypersensitivity, behavioral induced abnormal abdominal wall-phrenic reflexes, the effect of poorly absorbed fermentable carbohydrates, and microbiome alterations. Management includes behavioral therapy, dietary interventions, microbiome modulation, and medical therapy. This review presents the current knowledge on the pathophysiology, evaluation, and management of FABD.

Chronic continuous abdominal pain: evaluation of diagnostic features, iatrogenesis and drug treatments in a cohort of 103 patients

BACKGROUND

Chronic continuous abdominal pain (CCAP) is characteristic of centrally mediated gastrointestinal pain disorders. It consumes significant healthcare resources yet is poorly understood, with minimal cohort-specific data in the literature.

AIMS

To examine in a large cohort of CCAP patients, (a) diagnostic features, (b) iatrogenic impact of opioids and surgery, (c) drug treatment effects and tolerance.

METHODS

Consecutive tertiary CCAP referrals to a neurogastroenterology clinic (2009-2016) were reviewed for Rome IV and neuropathic pain criteria. Medical, surgical and drug histories, interventions and outcomes were correlated with clinical diagnosis and associated opioid use.

RESULTS

Of 103 CCAP patients (mean age 40 ± 14, 85% female), 50% had physiological exacerbations precluding full Rome IV Centrally Mediated Abdominal Pain Syndrome criteria. However, there were no significant differences between patients who satisfied Rome IV criteria and those who did not. Overall, 81% had allodynia (a nonpainful stimulus evoking pain sensation). Opioid use was associated with allodynia (P = 0.003). Prior surgery was associated with further operations post CCAP onset (P < 0.001). Although 68% had undergone surgical interventions, surgery did not resolve pain in any patient and worsened pain in 35%. Whilst duloxetine was the most effective neuromodulator (P = 0.003), combination therapy was superior to monotherapy (P = 0.007).

CONCLUSIONS

This is currently the largest cohort CCAP dataset that supports eliciting neuropathic features, including allodynia, for a positive clinical diagnosis, to guide treatment. Physiological exacerbation of CCAP may represent visceral allodynia, and need not preclude central origin. Use of centrally acting neuromodulators, and avoidance of detrimental opioids and surgical interventions appear to predict favourable outcomes.

Effectiveness and tolerability of linaclotide in the treatment of IBS-C in a "real-life" setting: Results from a Portuguese single-center study

BACKGROUND

Although linaclotide has been approved to treat moderate to severe IBS-C, no data are available on its effectiveness and tolerability in patients in a real-life setting.

METHODS

A prospective single-center study of the effectiveness and tolerability of linaclotide was carried out on patients (n = 40) with moderate to severe IBS-C, all fulfilling the Rome IV criteria. Clinical information was recorded using a dietary questionnaire at baseline, and 3 and 6 months after initiating treatment. The end-points to measure effectiveness included abdominal pain and bloating (11-NRS), the number of bowel movements and patient satisfaction. Tolerability was assessed through the frequency of adverse events.

KEY RESULTS

In terms of efficacy, an improvement in abdominal pain and in the intensity of bloating was evident in the cohort after 6 months of linaclotide therapy. The proportion of patients with moderate or severe symptoms of bloating fell from 93.3% to 33.3% and those with pain from 93.4% to 20%. Weekly bowel movements also improved and accordingly, 97% of the patients were moderately or very satisfied with the treatment. At the end of the study, diarrhea was the most frequent adverse event (10%), although it was considered mild in 66.7% of these subjects and moderate in 33.3%. A lack of efficacy (n = 3) and excessive diarrhea (n = 7) were motives for discontinuing the treatment.

CONCLUSIONS AND INFERENCES

Linaclotide proved to be a safe and effective drug to reduce the main symptoms of IBS-C in everyday clinical practice, with an improvement comparable to that seen in clinical trials.

A randomized controlled and long-term linaclotide study of irritable bowel syndrome with constipation patients in Japan

BACKGROUND

Clinical testing was required to verify the effect of linaclotide 0.5 mg/d in patients with irritable bowel syndrome with constipation (IBS-C) in Japan.

METHODS

This was a randomized, double-blind, placebo-controlled (Part 1) and long-term, open-label extension (Part 2) study of linaclotide at 60 hospitals and clinics in Japan. Patients with IBS-C diagnosed using Rome III criteria (n = 500) were randomly assigned to linaclotide 0.5 mg (n = 249) or placebo (n = 251) for a 12-week treatment period followed by open-label treatment with linaclotide (n = 324) for an additional 40 weeks. The primary endpoints were the responder rate of global improvement of IBS symptoms and complete spontaneous bowel movement (CSBM) during 12 weeks. The secondary endpoints included responder rates of SBM and abdominal pain/discomfort relief.

KEY RESULTS

Part 1: The responder rates for global improvement and for CSBM frequency were significantly higher for linaclotide compared to placebo (P < 0.001). Secondary endpoints including responder rates for SBM and abdominal pain/discomfort relief in the linaclotide group were also significantly greater than those in the placebo group. Part 2: Patients switched from placebo to linaclotide showed similar responder rates for global improvement and CSBM frequency to those in patients who continued to receive linaclotide, supporting sustained efficacy. Diarrhea was seen in 14.5% of patients; all cases were mild or moderate.

CONCLUSIONS AND INFERENCES

This study suggests that a linaclotide dose of 0.5 mg is effective and safe for IBS-C patients in Japan.

Linaclotide improves gastrointestinal transit in cystic fibrosis mice by inhibiting sodium/hydrogen exchanger 3

Gastrointestinal dysfunction in cystic fibrosis (CF) is a prominent source of pain among patients with CF. Linaclotide, a guanylate cyclase C (GCC) receptor agonist, is a US Food and Drug Administration-approved drug prescribed for chronic constipation but has not been widely used in CF, as the cystic fibrosis transmembrane conductance regulator (CFTR) is the main mechanism of action. However, anecdotal clinical evidence suggests that linaclotide may be effective for treating some gastrointestinal symptoms in CF. The goal of this study was to determine the effectiveness and mechanism of linaclotide in treating CF gastrointestinal disorders using CF mouse models. Intestinal transit, chloride secretion, and intestinal lumen fluidity were assessed in wild-type and CF mouse models in response to linaclotide. CFTR and sodium/hydrogen exchanger 3 (NHE3) response to linaclotide was also evaluated. Linaclotide treatment improved intestinal transit in mice carrying either F508del or null Cftr mutations but did not induce detectable Cl^- secretion. Linaclotide increased fluid retention and fluidity of CF intestinal contents, suggesting inhibition of fluid absorption. Targeted inhibition of sodium absorption by the NHE3 inhibitor tenapanor produced improvements in gastrointestinal transit similar to those produced by linaclotide treatment, suggesting that inhibition of fluid absorption by linaclotide contributes to improved gastrointestinal transit in CF. Our results demonstrate that linaclotide improves gastrointestinal transit in CF mouse models by increasing luminal fluidity through inhibiting NHE3-mediated sodium absorption. Further studies are necessary to assess whether linaclotide could improve CF intestinal pathologies in patients. GCC signaling and NHE3 inhibition may be therapeutic targets for CF intestinal manifestations. NEW & NOTEWORTHY Linaclotide's primary mechanism of action in alleviating chronic constipation is through cystic fibrosis transmembrane conductance regulator (CFTR), negating its use in patients with cystic fibrosis (CF). For the first time, our findings suggest that in the absence of CFTR, linaclotide can improve fluidity of the intestinal lumen through the inhibition of sodium/hydrogen exchanger 3. These findings suggest that linaclotide could improve CF intestinal pathologies in patients.

UK clinical experience up to 52 weeks with linaclotide for irritable bowel syndrome with constipation

BACKGROUND

Linaclotide, a guanylate cyclase C agonist, has been shown in clinical trials to improve symptoms of irritable bowel syndrome with constipation (IBS-C). Here we report data from a real-world study of linaclotide in the UK.

METHODS

This 1-year, multicentre, prospective, observational study in the UK enrolled patients aged 18 years and over initiating linaclotide for IBS-C. The primary assessment was change from baseline in IBS Symptom Severity Scale (IBS-SSS) score at 12 weeks, assessed in patients with paired baseline and 12-week data. Change from baseline in IBS-SSS score at 52 weeks was a secondary assessment. Adverse events were recorded.

RESULTS

In total, 202 patients were enrolled: 185 (91.6%) were female, median age was 44.9 years (range 18.1-77.2) and 84 (41.6%) reported baseline laxative use. Mean (standard deviation) baseline IBS-SSS score was 339 (92), with most patients (n = 129; 66.8%) classified as having severe disease (score ⩾300). In patients with paired data, there was a significant mean (95% confidence interval) decrease in IBS-SSS score from baseline to 12 weeks [-77.0 (-96.3, -57.7); p < 0.001; n = 124] and baseline to 52 weeks [-70.7 (-95.0, -46.5); p < 0.001; n = 76]. Overall, 174 adverse events were reported in 77 (38.1%) patients, most commonly diarrhoea (n = 54; 26.7%), abdominal pain (n = 21; 10.4%) and abdominal distension (n = 13; 6.4%).

CONCLUSION

Linaclotide significantly improved IBS-SSS score at 12 and 52 weeks. These results provide insights into outcomes with linaclotide treatment over 1 year in patients with IBS-C in real-world clinical practice.

New treatments and therapeutic targets for IBS and other functional bowel disorders

Functional bowel disorders (FBDs) are a spectrum of disorders characterized by combinations of symptoms attributable to the lower gastrointestinal tract. Most current first-line therapies for IBS and other FBDs target the predominant symptom and mainly affect one symptom in the symptom complex. Additional broadly effective treatment alternatives targeting the entire symptom complex are needed. New drugs for FBDs (such as lubiprostone, linaclotide, plecanatide, prucalopride, eluxadoline and rifaximin) target key mechanisms in the pathophysiology of these disorders and improve both the abnormal bowel habit and other key symptoms, such as abdominal pain and bloating. The current development of new treatment alternatives is focusing on different aspects of the complex pathophysiology of IBS and other FBDs: gut microenvironment (via diet and modulation of gut microbiota), enterohepatic circulation of bile acids, gastrointestinal secretion, motility and sensation, gut-brain interactions, gut barrier function and the immune system within the gastrointestinal tract. Studies also suggest that personalized treatment of IBS and other FBDs is possible using various diagnostic markers.

Irritable bowel syndrome: How to improve decision making in clinical practice

Irritable bowel syndrome (IBS) is a highly prevalent functional disorder, characterised by the presence of recurrent abdominal pain associated with changes in bowel habits. Its physiopathology is complex, its clinical manifestations are diverse, and the therapeutic possibilities are multiple and not well known. In clinical practice, the diagnosis of IBS represents an important challenge; this means that in many cases the patients do not receive the proper diagnosis, which implies an absence of a targeted treatment, and therefore bad symptomatic control. In this article, the fundamental questions posed by the doctor when dealing with a patient with symptoms compatible with IBS are presented chronologically. The main objective is to provide clinical and eminently practical information that facilitates the management of patients with IBS, from both diagnostic and therapeutic points of view.

Harnessing the power of placebos in movement disorders: Insights from Parkinson's disease in clinical research and practice

The placebo effect alongside the detrimental nocebo and lessebo effects associated with the use of placebos are well-recognized phenomena. Research conducted in the last two decades has demonstrated that the placebo effect is a measurable health benefit with well-known neurobiological correlates. In this review, we describe the current knowledge about how to best make use of the placebo effect to improve clinical research and optimize clinical care. We will cover four key topics: (1) setting the stage: historical perspectives on the use of placebos; (2) optimizing the use of placebos in clinical trials; (3) use of placebos in clinical practice; and (4) how can we minimize the ethical risks of using placebos? The adoption of the placebo-controlled trial as a standard in the therapeutic development reduced the placebo effect to background noise in a therapeutic signal. Strategies to minimize the placebo effect in clinical trials have been used to obtain positive efficacy results. In more recent years, new study paradigms encouraged a change in the views on placebos and the placebo effect. Alternative study designs and the development of biomarkers for a placebo response permit a better understanding of the contribution of the placebo effect to the results of interventional studies, without minimizing it. In clinical practice, optimizing the placebo effect (and reducing nocebo effects) has the potential to improve care for our patients, but raises ethical challenges. An enhanced patient-physician relationship would be central to any evidence-based intervention used in clinical care to heighten the placebo effect. © 2018 International Parkinson and Movement Disorder Society.

Long-term results of linaclotide in the treatment of constipation-type irritable bowel syndrome

BACKGROUND

constipation-predominant irritable bowel syndrome (C-IBS) is a prevalent, complex and multifactorial disorder that represents a challenge in terms of diagnosis and therapeutic management.

OBJECTIVE

to evaluate the effectiveness, safety and treatment satisfaction of linaclotide in C-IBS patients.

METHODS

prospective, single-center and observational study conducted in patients diagnosed with C-IBS. The patients were treated with linaclotide (Constella®, Allergan Inc., Irvine, CA), once-daily via an oral capsule of 290-μg, 30 minutes before breakfast. The primary effectiveness endpoint was the number of bowel movements per week. The secondary endpoints included treatment satisfaction and changes from baseline in frequency and severity of symptoms (abdominal pain and bloating). This was assessed via an 11-point visual analog scale (VAS) reported by the patients in a daily register.

RESULTS

thirty female patients were consecutively included. The median follow-up time was 18 months. The mean (standard deviation [SD]) number of weekly bowel movements significantly increased from 0.9 (0.6) at baseline to 4.7 (3.9) at the end of follow-up, p < 0.0001. Abdominal pain significantly decreased from 5.7 (2.3) at baseline to 3.1 (2.8) at the end of the follow-up period, p < 0.0001. Similarly, bloating significantly decreased from 6.8 (1.6) to 2.9 (2.5) at the beginning and end of the treatment period, respectively, p < 0.0001. The mean (SD) degree of satisfaction at the end of the study was 6.7 (3.0).

CONCLUSIONS

long-term linaclotide treatment in patients with C-IBS is effective and safe in the clinical setting.

Determining an optimal dose of linaclotide for use in Japanese patients with irritable bowel syndrome with constipation: A phase II randomized, double-blind, placebo-controlled study

BACKGROUND

Clinical testing to determine a suitable dose of linaclotide for Japanese patients with irritable bowel syndrome with constipation (IBS-C) was needed.

METHODS

This was a randomized, double-blind, placebo-controlled, dose-finding trial. Japanese patients with IBS-C diagnosed using Rome III criteria (n = 559, men/women: 49/510) were randomly assigned to 1 of 4 linaclotide doses (0.0625, 0.125, 0.25, or 0.5 mg) or placebo for the 12-week treatment period. The primary endpoint was responder rate of global assessment of relief of IBS symptoms during 12 weeks. The secondary endpoints included responder rates of complete spontaneous bowel movement (CSBM), SBM and abdominal pain/discomfort relief and others.

KEY RESULTS

The primary endpoint was 23.2%, 36.2%, 38.7%, 34.8%, and 38.3% in placebo (n = 112), 0.0625 (n = 116), 0.125 (n = 111), 0.25 (n = 112), and 0.5 (n = 107) mg of linaclotide groups with the difference from the placebo group in each linaclotide group (13.0%, 15.5%, 11.6%, 15.1%, P > .05). Monthly responder rate of global assessment of relief of IBS symptoms at month 3 (48.6%), responder rate of CSBM during 12 weeks (45.8%), and responder rate of abdominal pain/discomfort relief during 12 weeks (32.7%) in the 0.5 mg were significantly higher than those in placebo group (29.5%, P < .01; 25.9%, P < .01; and 18.8%, P < .05 respectively). The most frequent adverse event in the linaclotide groups was diarrhea.

CONCLUSIONS & INFERENCES

This study suggests that a linaclotide dose of 0.5 mg may be appropriate in Japanese patients with IBS-C.

Linaclotide in irritable bowel syndrome with constipation: A Phase 3 randomized trial in China and other regions

BACKGROUND AND AIM

Linaclotide is a guanylate cyclase-C agonist approved in multiple countries to treat irritable bowel syndrome with constipation (IBS-C). China has unmet need for well-tolerated therapy that is effective in treating both bowel and abdominal symptoms of IBS-C. This trial evaluated linaclotide's efficacy and safety in IBS-C patients in China and other regions.

METHODS

This Phase 3, double-blind trial randomized IBS-C patients to once-daily oral 290-μg linaclotide or placebo at centers in China, North America, and Oceania. Patients reported bowel and abdominal symptoms daily; adverse events were monitored. Co-primary and secondary endpoints were tested using a predefined three-step serial gatekeeping multiple comparisons procedure.

RESULTS

The intent-to-treat population included 839 patients (mean age = 41 years; 82% female; 81% Asian). The trial met all co-primary and secondary endpoints. Co-primary responder criteria were met by 60.0% of linaclotide patients versus 48.8% of placebo patients for abdominal pain/discomfort (≥ 30% decrease for ≥ 6/12 weeks; P < 0.05), and 31.7% of linaclotide versus 15.4% of placebo patients for IBS degree of relief (score ≤ 2 for ≥ 6/12 weeks; P < 0.0001). Secondary 12-week change-from-baseline endpoints (spontaneous bowel movement/complete spontaneous bowel movement frequency, stool consistency, straining, abdominal pain, abdominal discomfort, and abdominal bloating) were significantly improved with linaclotide versus placebo (all P < 0.0001). Diarrhea was the most common adverse event (9.4% linaclotide, 1.2% placebo). Discontinuation rates due to diarrhea were low (0.7% linaclotide, 0.2% placebo).

CONCLUSIONS

Once-daily 290-μg linaclotide improved bowel habits, abdominal symptoms, and global measures in a predominantly Chinese IBS-C population.

Medical Therapy of Constipation: Current Standards and Beyond

Chronic constipation is a very common medical problem with relevant impact on the patients' quality of life. Modern definitions recognize constipation as a polysymptomatic disorder, including various aspects of disturbed defecation. Current guidelines recommend a stepwise approach in the management of chronic constipation. Isolated or concomitant evacuation disorders should be identified and may need differential/additional treatment. Baseline measures include lifestyle components and bulking agents. The next step recommends treatment with conventional laxatives. In refractory patients, modern medical therapies, such as the prokinetic prucalopride or the secretagogues linalotide or lubiprostone, may be used effectively. For patients with opioid-induced constipation, the modern concept of peripherally acting µ-opioid antagonists has shown to successfully improve this increasing medical problem and even to potentially increase survival time in terminally ill patients on opioid therapy. Prolonged-released oral naloxone (in fixed combination with oxycodone), oral naloxegol or naldemedine, and subcutaneous methylnaltrexone have all demonstrated good efficacy and tolerability in the treatment of opioid-induced constipation. To adequately apply stepwise treatment algorithms, a simple tool to identify treatment failure may improve patient care.

Irritable bowel syndrome diagnosis and management: A simplified algorithm for clinical practice

BACKGROUND

Effective management of irritable bowel syndrome (IBS), a common functional gastrointestinal disorder, can be challenging for physicians because of the lack of simple diagnostic tests and the wide variety of treatment approaches available.

OBJECTIVE

The objective of this article is to outline a simple algorithm for day-to-day clinical practice to help physicians navigate key stages to reaching a positive IBS diagnosis and guidance on how to prioritise the use of specific management strategies.

METHODS

This algorithm was based on the opinion of an expert panel evaluating current evidence.

RESULTS

The key principles forming the foundation of this evidence-supported algorithm are: confidently naming and explaining an IBS diagnosis for the patient, followed by assessment of key patient characteristics likely to influence the choice of therapy, such as predominant symptoms, and exploring the patient agenda and preferences. Consultation should always include education and reassurance with an explanatory model of IBS tailored to the patient. Individualised lifestyle changes, dietary modifications, pharmacological therapies, psychological strategies or a combination of interventions may be used to optimise treatment for each patient.

CONCLUSION

The simple visual tools developed here navigate the key stages to reaching a positive diagnosis of IBS, and provide a stepwise approach to patient-centred management targeted towards the most bothersome symptoms. Establishing a strong patient-physician relationship is central to all stages of the patient journey from diagnosis to effective management.

New therapeutic perspectives in irritable bowel syndrome: Targeting low-grade inflammation, immuno-neuroendocrine axis, motility, secretion and beyond

Irritable bowel syndrome (IBS) is a chronic, recurring, and remitting functional disorder of the gastrointestinal tract characterized by abdominal pain, distention, and changes in bowel habits. Although there are several drugs for IBS, effective and approved treatments for one or more of the symptoms for various IBS subtypes are needed. Improved understanding of pathophysiological mechanisms such as the role of impaired bile acid metabolism, neurohormonal regulation, immune dysfunction, the epithelial barrier and the secretory properties of the gut has led to advancements in the treatment of IBS. With regards to therapies for restoring intestinal permeability, multiple studies with prebiotics and probiotics are ongoing, even if to date their efficacy has been limited. In parallel, much progress has been made in targeting low-grade inflammation, especially through the introduction of drugs such as mesalazine and rifaximin, even if a better knowledge of the mechanisms underlying the low-grade inflammation in IBS may allow the design of clinical trials that test the efficacy and safety of such drugs. This literature review aims to summarize the findings related to new and investigational therapeutic agents for IBS, most recently developed in preclinical as well as Phase 1 and Phase 2 clinical studies.

[Pharmacotherapy in Patients with Chronic Constipation]

Chronic constipation is one of the most common digestive diseases frequently observed in a clinical setting. It has been known to cause considerable damage to the quality of life of patients. Despite recent developments, there are considerable limitations in the use of constipation-modulating agents in Korea. Chloride channel inhibitors, such as lubiprostone and linaclotide, have not been introduced in Korea yet, and prucalopride and several kinds of polyethylene glycol are not covered under medical insurance. This article assesses medicines that are clinically available for the management of constipation in Korea, with a brief review of agents that have recently developed around the world.

Luminally Acting Agents for Constipation Treatment: A Review Based on Literatures and Patents

Constipation is one of the most frequently reported gastrointestinal (GI) disorders that negatively impacts quality of life and is associated with a significant economic burden to the patients and society. Traditional treatments including lifestyle modification and laxatives are often ineffective in the more severe forms of constipation and over the long term. New medications targeting at intestinal chloride channels and colonic serotonin receptors have been demonstrated effective in recent years. Emerging agents focusing on improving intestinal secretion and/or colonic motility have been shown effective in animal models and even in clinical trials. Recognization of the role of cystic fibrosis transmembrane regulator (CFTR) and calcium-activated chloride channels (CaCCs) in intestine fluid secretion and motility modulation makes CFTR and CaCCs promising molecule targets for anti-constipation therapy. Although there are multiple choices for constipation treatment, there is still a recognized need for new medications in anti-constipation therapy. The present review covers the discovery of luminally acting agents for constipation treatment described in both patents (2011–present) and scientific literatures.

Tenapanor Treatment of Patients With Constipation-Predominant Irritable Bowel Syndrome: A Phase 2, Randomized, Placebo-Controlled Efficacy and Safety Trial

OBJECTIVES

Tenapanor is a first-in-class, small-molecule inhibitor of the gastrointestinal sodium/hydrogen exchanger NHE3. This study assessed the efficacy and safety of tenapanor in patients with constipation-predominant irritable bowel syndrome (IBS-C).

METHODS

In this phase 2, double-blind study, patients with IBS-C (Rome III criteria) were randomized (1:1:1:1) to receive tenapanor 5 mg, 20 mg, or 50 mg b.i.d., or placebo b.i.d. for 12 weeks. The primary end point was the complete spontaneous bowel movement (CSBM) responder rate, defined as the proportion of patients reporting an increase from baseline of ≥1 CSBM/week for ≥6/12 treatment weeks. Secondary end points included abdominal symptom responder rates (≥30% score improvement from baseline for ≥6/12 weeks) and a composite responder rate (CSBM and abdominal pain response in the same week for ≥6/12 weeks).

RESULTS

Overall, 356 patients were randomized (mean age: 45.7 years; 86.8% women) and 304 completed the study. The CSBM responder rate was significantly higher in the tenapanor 50 mg b.i.d. group than in the placebo group (60.7 vs. 33.7%; P<0.001), as was the composite responder rate (50.0 vs. 23.6%; P<0.001). Responder rates for abdominal symptoms (pain, discomfort, bloating, cramping, and fullness) were significantly higher in the tenapanor 50 mg b.i.d. group than in the placebo group (all P<0.05). Diarrhea was the most frequent adverse event (tenapanor b.i.d.: 20 mg, 12.4%; 50 mg, 11.2%).

CONCLUSIONS

Tenapanor 50 mg b.i.d. significantly increased stool frequency and reduced abdominal symptoms in patients with IBS-C. Further research into tenapanor as a potential treatment for these patients is justified.

Optimizing the Use of Linaclotide in Patients with Constipation-Predominant Irritable Bowel Syndrome: An Expert Consensus Report

INTRODUCTION

Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by chronic or recurrent abdominal pain in association with defecation or a change in bowel habits. A predominant disorder of bowel habits, IBS is classified into three main subtypes: constipation-predominant IBS (IBS-C), diarrhea-predominant IBS (IBS-D) and IBS alternating between constipation and diarrhea (IBS-M). Linaclotide is a first-in-class, oral, once-daily guanylate cyclase-C receptor agonist (GC-CA) that is licensed for the symptomatic treatment of moderate-to-severe IBS-C in adults. This review aims to facilitate and optimize clinical practices, establishing common guidelines to monitor patients with IBS-C that are treated with linaclotide.

METHODS

A group of experts in functional digestive disorders was convened to review the efficacy and safety of linaclotide and to develop an updated consensus report for the treatment of patients with IBS-C. A search was performed for English, French and Spanish language articles in PubMed. On the basis of the articles identified, an initial document was drafted addressing different issues frequently raised by general practitioners and GI specialists that are related to the prescription, efficacy and safety of linaclotide. This document was then reviewed and modified by the expert panel until a final text was agreed upon and validated.

RESULTS

Based on the evidence, the panel addressed the following recommendations: (1) Linaclotide is indicated for the treatment of moderate to severe IBS-C in adults; (2) it is recommended that patients take linaclotide continuously and not sporadically; (3) patients should be warned about the risk of diarrhea and given choices concerning how to deal with this possible side effect; (4) the absence of tachyphylaxis or potential risks implies that linaclotide treatment can be maintained for long periods of time.

CONCLUSIONS

This document seeks to lay down a set of recommendations and to identify key issues that may be useful for the clinical management of IBS-C patients treated with linaclotide.

The Placebo and Nocebo Phenomena: Their Clinical Management and Impact on Treatment Outcomes

PURPOSE

This overview focuses on placebo and nocebo effects in clinical trials and routine care. Our goal was to propose strategies to improve outcomes in clinical practice, maximizing placebo effects and reducing nocebo effects, as well as managing these phenomena in clinical trials.

METHODS

A narrative literature search of PubMed was conducted (January 1980-September 2016). Systematic reviews, randomized controlled trials, observational studies, and case series that had an emphasis on placebo or nocebo effects in clinical practice were included in the qualitative synthesis. Search terms included: placebo, nocebo, clinical, clinical trial, clinical setting, placebo effect, nocebo effect, adverse effects, and treatment outcomes. This search was augmented by a manual search of the references of the key articles and the related literature.

FINDINGS

Placebo and nocebo effects are psychobiological events imputable to the therapeutic context. Placebo is defined as an inert substance that provokes perceived benefits, whereas the term nocebo is used when an inert substance causes perceived harm. Their major mechanisms are expectancy and classical conditioning. Placebo is used in several fields of medicine, as a diagnostic tool or to reduce drug dosage. Placebo/nocebo effects are difficult to disentangle from the natural course of illness or the actual effects of a new drug in a clinical trial. There are known strategies to enhance clinical results by manipulating expectations and conditioning.

IMPLICATIONS

Placebo and nocebo effects occur frequently and are clinically significant but are underrecognized in clinical practice. Physicians should be able to recognize these phenomena and master tactics on how to manage these effects to enhance the quality of clinical practice.

Rifaximin for the treatment of diarrhea-predominant irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic, functional bowel disorder characterized by abdominal pain or discomfort and altered bowel habit. The pathophysiology is unclear, but may include altered gut motility, visceral hypersensitivity, abnormal central pain processing, chronic low-grade intestinal inflammation, or disturbances in the gut microbiome. These etiological mechanisms, alongside environmental factors such as stress and anxiety, vary between individuals and represent potential targets for treatment. Rifaximin is a poorly absorbed oral antibiotic proposed to act on the gut microenvironment, used in the treatment of travelers' diarrhea and hepatic encephalopathy. Clinical trials suggest the drug can reduce global IBS symptoms and improve bloating, abdominal pain, and stool consistency in some patients with non-constipated IBS, leading to Food and Drug Administration approval in the United States. This article considers the pharmacology of rifaximin, the evidence for its use in IBS, and the safety and tolerability of the drug.

Childhood constipation: finally something is moving!

Recent developments in the evaluation and treatment of childhood constipation are likely to influence the way we deal with pediatric defecation disorders in the near future. Innovations in both colonic and anorectal manometry are leading to novel insights into functional defecation disorders in children. Promising results have been achieved with innovative therapies such as electrical stimulation and new drugs with targets that differ from conventional pharmacological treatments. Also, new surgical approaches, guided by manometric findings, have led to improvement in patient outcome. Finally, utilization of non-pharmacological interventions such as fiber and probiotics has been a field of particular interest in recent years. The aim of this article is to provide an update on these and other novel diagnostic and therapeutic tools related to childhood constipation.

Novel pharmacological therapies for irritable bowel syndrome

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder, which represents a major cost to healthcare services. Current pharmacological treatment includes fibre supplements, antispasmodics, laxatives, loperamide and antidepressants. This article reviews the novel pharmacological treatments already or recently approved for patients with IBS-C (lubiprostone, linaclotide) and IBS-D (alosetron, ramosetron, rifaximin, eluxadoline). Furthermore, results for drugs in development (plecanatide, ibudutant and ebastine) or used in chronic constipation or for other indications, with potential application in IBS (prucalopride, elobixibat, mesalazine, ondansetron and colesevelam) are also reviewed.

Modern Management of Irritable Bowel Syndrome: More Than Motility

In the treatment of irritable bowel syndrome (IBS), loperamide seems efficacious for diarrhea and ispaghula for constipation, while musculotropic spasmolytics may relieve abdominal pain. Antidepressants were found to be efficacious for abdominal pain, but their tolerance may be problematic and the therapeutic effect varied largely between trials. While meta-analyses suggest efficacy of probiotics as a group, the quality of the trials is often suboptimal and there is large variability. Lubiprostone, a chloride channel activator, and linaclotide, a guanylyl cyclase-C agonist, showed favorable effects on multiple symptoms in IBS with constipation. For IBS with diarrhea (IBS-D), the 5-HT3 receptor antagonist ramosetron showed efficacy in men and women, but is currently only approved in Japan. A multicenter study with the anti-emetic 5-HT3 receptor antagonist ondansetron showed efficacy on stool pattern in IBS-D. The poorly absorbable antibiotic rifaximin and eluxadoline, a mu opioid receptor agonist and delta antagonist, both showed efficacy in phase III trials in IBS-D and were approved by the FDA. Eluxadoline was associated with increased occurrence of sphincter of Oddi spasm and biliary pancreatitis. The non-pharmacological treatment of IBS, with dietary interventions (mainly gluten elimination and low FODMAP (fructose, oligo-, di-, monosaccharides and polyols)) has received a lot of attention lately. While responder rates vary across studies, perhaps based on regional variations in dietary intake of FODMAPs, the dietary approach seems to have acquired recognition as a valid therapeutic alternative. Long-term studies and comparative studies with pharmacotherapy, as well as elucidation of the underlying mechanisms of action, are needed.