A randomised controlled trial assessing the efficacy and safety of repeated tegaserod therapy in women with irritable bowel syndrome with constipation

Questioning the bacterial overgrowth hypothesis of irritable bowel syndrome: an epidemiologic and evolutionary perspective

Although studies indicate that small intestinal bacterial overgrowth (SIBO) is prevalent in irritable bowel syndrome (IBS), it remains unclear whether SIBO causes IBS. This review presents an epidemiologic and evolutionary inquiry that questions the bacterial overgrowth hypothesis of IBS, as follows. (1) Although the hypothesis may be biologically plausible, there is also a strong rationale for competing hypotheses; it is unlikely that SIBO is the predominant cause of IBS in all comers, because competing explanations are sensible and defensible. Moreover, data indicate that the test used to promulgate the SIBO hypothesis - the lactulose hydrogen breath test - may not have measured SIBO in the first place. (2) We do not have evidence of SIBO being absent before IBS symptoms, and present after IBS emerges. (3) There is not a dose-response relationship between small intestinal microbiota and IBS symptoms. (4) The relationship between SIBO and IBS is highly inconsistent among studies. (5) Many effective IBS therapies do not address SIBO at all, yet have a more favorable "number needed to treat" than antibiotics. (6) IBS does not behave like a traditional infectious disease, suggesting that microbes may not principally cause the syndrome. (7) Other factors may confound the relationship between SIBO and IBS, including proton pump inhibitors. (8) Whereas the brain-gut hypothesis is evolutionary sensible, the bacterial hypothesis is harder to defend from an evolutionary perspective. The article concludes that bacteria may contribute to some IBS symptoms, but that bacteria cannot be the only explanation, and a causal link between SIBO and IBS is not secure.

Review article: the treatment of functional abdominal bloating and distension

BACKGROUND

Abdominal bloating and distension are common symptoms in patients with functional gastrointestinal disorders (FGIDs), however, relatively little is known about their treatment.

AIM

To review the treatment trials for abdominal bloating and distension.

METHODS

A literature review in Medline for English-language publications through February 2010 of randomised, controlled treatment trials in adults. Study quality was assessed according to Jadad's score.

RESULTS

Of the 89 studies reviewed, 18% evaluated patients with functional dyspepsia, 61% with irritable bowel syndrome (IBS), 10% with chronic constipation and 10% with other FGIDs. No studies were conducted in patients diagnosed with functional abdominal bloating. The majority of trials investigated the efficacy of prokinetics or probiotics, although studies are heterogeneous with respect to diagnostic criteria and outcome measures. In general, bloating and/or distension were evaluated as secondary endpoints or as individual symptoms as part of a composite score rather than as primary endpoints. A greater proportion of IBS patients with constipation reported improvement in bloating with tegaserod vs. placebo (51% vs. 40%, P<0.0001) and lubiprostone (P<0.001). A greater proportion of nonconstipating IBS patients reported adequate relief of bloating with rifaximin vs. placebo (40% vs. 30%, P<0.001). Bloating was significantly reduced with the probiotics, Bifidobacterium infantis 35624 (1×10(8) dose vs. placebo: -0.71 vs. -0.44, P<0.05) and B. animalis (live vs. heat-killed: -0.56±1.01 vs. -0.31±0.87, P=0.03).

CONCLUSIONS

Prokinetics, lubiprostone, antibiotics and probiotics demonstrate efficacy for the treatment of bloating and/or distension in certain FGIDs, but other agents have either not been studied adequately or have shown conflicting results.

The role of genetics in IBS

Irritable bowel syndrome (IBS) is a common disorder that has been shown to aggregate in families and to affect multiple generations, but not in a manner consistent with a major Mendelian effect. Relatives of an individual with IBS are 2 to 3 times as likely to have IBS, with both genders being affected. To date, more than 100 genetic variants in more than 60 genes from various pathways have been studied in a number of candidate gene studies, with several positive associations reported. These findings suggest that there may be distinct, as well as shared, molecular underpinnings for IBS and its subtypes.

Review article: endpoints used in functional dyspepsia drug therapy trials

BACKGROUND

The measurement of patient-reported outcomes (PRO) in treatment trials for functional gastrointestinal disorders is a matter of controversy.

AIM

To focus on instruments and endpoints that have been used to evaluate the efficacy of therapeutic agents in functional dyspepsia (FD) trials, also considering the newly defined Rome III FD criteria.

METHODS

A Medline search was conducted to identify relevant studies pertaining to FD treatment, with particular emphasis on the studies to date which have used validated outcome measures.

RESULTS

Currently available outcome measures are heterogeneous across studies. They include global binary endpoints, analogue or categorical scoring scales, uni- or multi-dimensional disease specific questionnaires, global outcome evaluations and quality of life questionnaires. Across the available outcome measures, substantial heterogeneity is found, not only in the type of endpoint measure, but also in the number and types of symptoms that are considered to be part of the FD symptom complex. Especially based on content validity, none of the existing questionnaires or endpoints can be considered sufficiently validated to be recommended unequivocally as the primary outcome measure for FD trials according to the Rome III criteria. On the other hand, existing well-validated multi-dimensional questionnaires that include many non-FD symptoms can be narrowed down to evaluate only the cardinal symptoms according to Rome III.

CONCLUSIONS

There is an urgent need to develop Rome III-based patient-reported outcomes for functional dyspepsia. Well-validated multi-dimensional questionnaires may serve as a guidance for this purpose, and could also be considered for use in ongoing clinical trials.

Clinical trial: the efficacy and tolerability of velusetrag, a selective 5-HT4 agonist with high intrinsic activity, in chronic idiopathic constipation - a 4-week, randomized, double-blind, placebo-controlled, dose-response study

BACKGROUND

Velusetrag is an orally active 5-HT(4) receptor agonist of potential benefit in treating chronic idiopathic constipation.

AIM

To evaluate the efficacy, safety and tolerability of velusetrag in chronic idiopathic constipation.

METHODS

After a 2-week baseline period, patients [<3 spontaneous bowel movements (SBM)/week] received placebo or velusetrag (15, 30 or 50 mg) daily for 4 weeks in a randomized, double-blind design, followed by a 1-week follow-up period. The primary endpoint was the change from baseline in weekly SBM frequency averaged over the 4-week treatment period.

RESULTS

Patients receiving velusetrag (15, 30 and 50 mg) achieved statistically and clinically significant increases in weekly SBM frequency relative to those receiving placebo. Mean increases were 3.6, 3.3 and 3.5 SBM/week respectively, compared with 1.4 SBM/week for placebo (P < 0.0001). Statistically significant increases in the weekly frequency of complete SBM (CSBM) were also reported (mean increases of 2.3, 1.8 and 2.3 for 15, 30 and 50 mg velusetrag respectively, compared with 0.6 for placebo). Common adverse events associated with velusetrag were diarrhoea, headache, nausea and vomiting, generally occurring during the initial days of dosing.

CONCLUSION

Velusetrag was efficacious and well tolerated in patients with chronic idiopathic constipation (ClinicalTrials.gov identifier NCT00391820).

Effect of autogenic training on general improvement in patients with irritable bowel syndrome: a randomized controlled trial

Autogenic training (AT) is a useful and comprehensive relaxation technique. However, no studies have investigated the effects of AT on irritable bowel syndrome (IBS). In this study we tested the hypothesis that AT improves symptoms of IBS. Twenty-one patients with IBS were randomly assigned to AT (n = 11, 5 male, 6 female) or control therapy (n = 10, 5 male, 5 female). AT patients were trained intensively, while the control therapy consisted of discussions about patients' meal habits and life styles. All patients answered a question related to adequate relief (AR) of IBS symptoms and four questionnaires: Self-induced IBS Questionnaire (SIBSQ), Self-reported Depression Scale (SDS), State-Trait Anxiety Inventory (STAI), and Medical Outcome Short Form 36 Health Survey (SF-36). The proportion of AR in the last AT session in the AT group (9/11, 81.8%) was significantly higher than that in the controls (3/10, 30.0%, Chi-square test, p = 0.048). Two subscales of the SF-36, i.e., social functioning and bodily pain, were significantly improved in the AT group (p < 0.05) as compared to the control group. Role emotional (p = 0.051) and general health (p = 0.068) showed a tendency for improvement in the AT group. AT may be useful in the treatment of IBS by enhancing self-control.

Meta-analysis: factors affecting placebo response rate in the irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a functional disorder of the gastrointestinal tract with a significant placebo response.

AIM

To conduct a systematic review and meta-analysis examining the magnitude of placebo response rate in treatment trials for IBS.

METHODS

MEDLINE, EMBASE and the Cochrane central register of controlled trials were searched to identify randomized controlled trials (RCTs) comparing pharmacological therapies with placebo in adult IBS patients. Studies reported either global assessment of IBS symptom cure or improvement or abdominal pain cure or improvement. Data were extracted as intention-to-treat analyses with drop-outs assumed to be treatment failures and pooled using a random-effects model. Proportion of placebo patients experiencing symptom improvement or resolution was reported with a 95% confidence interval (CI). Effect of trial characteristics on magnitude of placebo response was examined.

RESULTS

In all, 73 RCTs were eligible, including 8364 patients with IBS allocated to placebo. Pooled placebo response rate across all RCTs was 37.5% (95% CI 34.4-40.6%). Rates were higher in European RCTs, RCTs that used physician-reported outcomes and RCTs using shorter duration of therapy.

CONCLUSIONS

Placebo response rates across RCTs of pharmacological therapies in IBS were high. Future research should identify patient characteristics predicting placebo response.

Role of prucalopride, a serotonin (5-HT(4)) receptor agonist, for the treatment of chronic constipation

Constipation affects up to a quarter of the population in developed countries and is associated with poor quality of life and significant economic burden. Many patients with chronic constipation are dissatisfied with current therapy due to lack of long-term efficacy or side effects. Previous nonselective 5-hydroxytryptamine receptor 4 (5-HT₄) agonists have been associated with significant interactions with other receptors (5-HT_1B, 5-HT_1D, and 5-HT_2B for tegaserod; hERG for cisapride), leading to adverse cardiovascular events resulting in withdrawal of these drugs from the market. Prucalopride is a novel gastrointestinal prokinetic agent. It acts as a high affinity, highly-selective 5-HT₄ agonist. Its efficacy in patients with chronic constipation has been demonstrated in several phase II and phase III clinical trials showing significant improvements in bowel transit, bowel function, gastrointestinal symptoms, and quality of life, with benefit maintained for up to 24 months in open label, multicenter, follow-up studies. Prucalopride’s high selectivity for the 5-HT₄ receptor may explain its favorable safety and tolerability profiles, even in elderly subjects with stable cardiovascular disease. Prucalopride is a well tolerated and efficacious prokinetic medication that should enhance the treatment of chronic constipation unresponsive to first-line treatments.

Functional dyspepsia

Dyspepsia is a common term used for a heterogeneous group of abdominal symptoms. Functional dyspepsia (FD) is the focus of this review. The 2006 Rome III criteria defined FD and its subgroups, postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS). FD is a very common condition with a high prevalence throughout the world, adversely affecting the quality of life of patients. The pathophysiology of FD has been under investigation during the past two decades. Multiple mechanisms such as abnormal gastric emptying, visceral hypersensitivity, impaired gastric accommodation, and central nervous system factors are likely involved. Several tests are available for the assessment of various physiologic functions possibly involved in the pathogenesis of FD, and some of these could be used in clinical practice, helping to understand the abnormalities underlining patients' complaints. Currently, the possibilities of pharmacological therapy for FD are still limited, however, experience of using prokinetics, tricyclic antidepressants, selective serotonin-reuptake inhibitors (SSRIs), proton-pump inhibitors (PPIs), and several alternative techniques has been accumulated. The different combinations of alterations in physiologic gastrointestinal and central nervous system functions result in the very heterogeneous nature of FD so combined approaches to these patients could be beneficial in challenging cases.

Evolution of clinical trials for irritable bowel syndrome: issues in end points and study design

Irritable bowel syndrome (IBS) involves a broad range of physiological and psychological alterations that may affect brain-gut dysregulation, gut function, visceral perception, and mucosal integrity and function. Despite advances in our understanding of basic neuroenteric mechanisms and the role of effectors and transmitters in the brain-gut axis, a reliable biologic marker of IBS has yet to be identified. IBS diagnosis and status depend entirely on an assessment of IBS signs and symptoms. This has made development of optimal end points and study design for evaluation of efficacy of IBS drugs a challenge. This article addresses three main topics: the evolution of primary end points for IBS clinical trials; a potential path forward for IBS end points in new clinical trials; and recommendations for the future development of patient-reported outcome (PRO) instruments for use in IBS clinical trials.

The effect of tegaserod on symptoms and quality of life in korean women with irritable bowel syndrome with constipation

INTRODUCTION

Tegaserod has been used for treatment of irritable bowel syndrome (IBS) but there is no data regarding its effect on Korean patients. The aim of this study was to evaluate the effect of tegaserod on symptoms and quality of life (QOL) in Korean female IBS patients with constipation and to evaluate the usefulness of the IBS-QOL in clinical study.

METHODS

A prospective, open labeled, multicenter study was performed. Female patients fulfilling Rome II criteria for IBS received 6 mg of tegaserod twice a day for 4 weeks. The efficacy on IBS symptoms and QOL was assessed using 7-point scaled symptom questionnaire and IBS-QOL questionnaire, respectively.

RESULTS

A total of 81 female patients (range 18-73 years of age) were enrolled in this study. Tegaserod therapy significantly reduced the overall symptom scores after 4 weeks (p <0.01). The improved symptoms included abdominal discomfort or pain, hard or lumpy stool, straining during a bowel movement, feeling of incomplete bowel movement, and abdominal fullness or bloating. The IBS-QOL of responders to tegaserod treatment was also significantly improved after 4 weeks (p <0.01). Furthermore, improvement of symptom scores significantly correlated with improvement of the IBS-QOL scores (r = -0.60, p <0.001).

CONCLUSIONS

Tegaserod 6 mg given twice daily improved the QOL as well as the bowel symptoms in Korean female IBS patients with constipation. The IBS-QOL can be used as a reliable end-point in clinical study.

[How can an effective drug to treat irritable bowel syndrome be successfully developed?]

BACKGROUND

Irritable bowel syndrome (IBS) is a prevalent disorder, and although the pharmaceutical industry knows the potential fallout of a successful drug launch in this area, effective drug treatments are rare.

AIM

To give an overview of the main factors interfering with the development of IBS drugs and to provide pertinent methodological indications to improve their investigation in clinical trials.

RESULTS

Developing IBS drugs remains a major challenge, as numerous factors, related or unrelated to the nature of the disease itself, interfere with the demonstration of efficacy : the multiplicity of physiopathological mechanisms, wide variation in symptoms across patients and over time, associated psychological traits and environmental aspects, and a very significant placebo effect. There can be no question of developing drugs to target a single receptor in the hope of thereby impacting the whole range of factors involved in the genesis of IBS symptoms. Drug safety is, moreover, a prime consideration, given that this pathology, while certainly disabling, is not life-threatening. If a significant difference between a new treatment and placebo is to be demonstrated on a clinical trial, inclusion and efficacy criteria and study treatment duration must be predefined very precisely. The primary endpoint is abdominal pain, but the assessment of relief of the patient's symptoms has been also recommended, even if there is as yet no consensus as to its definition. The impact of a new IBS drug on patient's quality of life is an important secondary endpoint.

CONCLUSION

In IBS more, perhaps, than in other pathologies, study design needs very careful consideration if new IBS drug trials are to be conclusive. However, some critical methodological issues (e.g., definite primary endpoint, interpretation of results, and definition of responders) are still unresolved.

A randomized, double-blind, placebo-controlled trial of St John's wort for treating irritable bowel syndrome

OBJECTIVES

St John's wort (SJW) is known to effectively treat patients with mild-to-moderate depression. Antidepressants are frequently used to treat irritable bowel syndrome (IBS). To date, no study that examines the efficacy of SJW in IBS has been carried out. The aim of this study was to evaluate the efficacy of SJW in IBS after 12 weeks.

METHODS

In this randomized, double-blind, placebo-controlled trial, 70 participants with an established diagnosis of IBS were randomized and assigned by concealed allocation to either SJW or placebo. Both treatment arms were balanced on symptom subtype. The primary end point was self-reported overall bowel symptom score (BSS) at 12 weeks. Secondary end points were individual BSS for diarrhea (D-BSS), constipation (C-BSS), pain or discomfort, and bloating; adequate relief (AR) of IBS on at least 50% of the last 4 weeks of therapy; and IBS quality-of-life score at 12 weeks.

RESULTS

In all, 86% of the participants were women, and the median age was 42 years. Overall, 29% had C-IBS, 37% D-IBS, and 31% had mixed IBS. Both groups reported decreases in overall BSS from baseline, with the placebo arm having significantly lower scores at 12 weeks (P=0.03) compared with SJW. These patterns of improvement were mirrored in the secondary end points with the placebo group faring better than the SJW-treated group, with significant differences observed at week 12 for D-BSS (P=0.03) and percent with AR (P=0.02). A similar proportion of subjects in each treatment group (SJW: 51% vs. placebo: 54%) believed that the study drug they received decreased IBS life interferences (P=0.79).

CONCLUSIONS

SJW was a less effective treatment for IBS than placebo.

The effect of tegaserod on symptoms and quality of life in korean women with irritable bowel syndrome with constipation

INTRODUCTION

Tegaserod has been used for treatment of irritable bowel syndrome (IBS) but there is no data regarding its effect on Korean patients. The aim of this study was to evaluate the effect of tegaserod on symptoms and quality of life (QOL) in Korean female IBS patients with constipation and to evaluate the usefulness of the IBS-QOL in clinical study.

METHODS

A prospective, open labeled, multicenter study was performed. Female patients fulfilling Rome II criteria for IBS received 6 mg of tegaserod twice a day for 4 weeks. The efficacy on IBS symptoms and QOL was assessed using 7-point scaled symptom questionnaire and IBS-QOL questionnaire, respectively.

RESULTS

A total of 81 female patients (range 18-73 years of age) were enrolled in this study. Tegaserod therapy significantly reduced the overall symptom scores after 4 weeks (p <0.01). The improved symptoms included abdominal discomfort or pain, hard or lumpy stool, straining during a bowel movement, feeling of incomplete bowel movement, and abdominal fullness or bloating. The IBS-QOL of responders to tegaserod treatment was also significantly improved after 4 weeks (p <0.01). Furthermore, improvement of symptom scores significantly correlated with improvement of the IBS-QOL scores (r = -0.60, p <0.001).

CONCLUSIONS

Tegaserod 6 mg given twice daily improved the QOL as well as the bowel symptoms in Korean female IBS patients with constipation. The IBS-QOL can be used as a reliable end-point in clinical study.

Pharmacological management of constipation

The approach of this review is to give a pragmatic approach to using laxatives, based on a combination of what is known about mechanism of action and the available literature on evidence.

Estrogen rapidly modulates 5-hydroxytrytophan-induced visceral hypersensitivity via GPR30 in rats

BACKGROUND & AIMS

Sex hormones have been reported to modulate visceral hypersensitivity (VH). Estrogen regulates neurons not only by binding to estrogen receptors (ERalpha and ERbeta) to initiate transcription but also via the G-protein coupled receptor GPR30, which binds and rapidly mediates actions of estrogen. We examined the role of sex hormones in a VH model without colonic inflammation.

METHODS

5-Hydroxytryptophan (5HTP) was injected subcutaneously into awake female rats to induce VH; the 5HT3 antagonist (granisetron) or saline (control) were injected 30 minutes later. Immunohistochemistry was used to quantify calcitonin gene-related peptide-immunoreactive (CGRP-IR) neurons in the dorsal root ganglion (DRG). 5HTP-induced VH was evaluated in ovariectomized rats injected with 17beta-estradiol, progesterone, or both. ER alpha/beta agonist, GPR30 agonist, ER antagonist (ICI-182,780) or GPR30 antisense oligodeoxynucleotide were given to 5HTP-primed, estrogen-treated ovariectomized rats.

RESULTS

Rats given 5HTP had increased VH that was inhibited by granisetron, accompanied by a decrease in CGRP-IR in the DRG. Ovariectomy eliminated 5HTP-induced VH, whereas estrogen and the combination of estrogen and progesterone, but not progesterone alone, restored the VH. The GPR30 agonist, but not the ERbeta agonist, rapidly restored VH. VH was preserved by coadministration of ICI-182,780 and estrogen but was absent after administration of the GPR30 antisense oligodeoxynucleotide. GPR30 colocalized with 5HT3 in DRG neurons; no significant inflammation occurred in colonic mucosa.

CONCLUSIONS

In the absence of mucosal inflammation, estrogen can rapidly modulate 5HTP-induced VH. Loss of gonad hormones suppresses VH, whereas estrogen replacement restores it. Estrogen-mediated VH appears to act through GPR30.

Post-infectious irritable bowel syndrome

Post-infectious irritable bowel syndrome (PI-IBS) is a common disorder wherein symptoms of IBS begin after an episode of acute gastroenteritis. Published studies have reported incidence of PI-IBS to range between 5% and 32%. The mechanisms underlying the development of PI-IBS are not fully understood, but are believed to include persistent sub-clinical inflammation, changes in intestinal permeability and alteration of gut flora. Individual studies have suggested that risk factors for PI-IBS include patients’ demographics, psychological disorders and the severity of enteric illness. However, PI-IBS remains a diagnosis of exclusion with no specific disease markers and, to date, no definitive therapy exists. The prognosis of PI-IBS appears favorable with spontaneous and gradual resolution of symptoms in most patients.

Prucalopride: a new drug for the treatment of chronic constipation

Prucalopride belongs to a novel class of 5-hydroxytryptamine-4 receptor agonists, and has been evaluated extensively for the treatment of chronic constipation. Prucalopride has a stimulatory effect on gastrointestinal motility and transit, as established by in vivo and in vitro studies in animals and humans. Its therapeutic efficacy, tolerability and safety have been evaluated in Phase II and Phase III studies in chronic constipation. The cardiovascular safety profile of the drug was studied in vitro and in vivo in animal studies, in clinical studies in chronic constipation patients, as well as in specific additional clinical cardiovascular studies. Phase II studies identified a dose-dependent effect of prucalopride on bowel pattern and associated symptoms in chronic constipation. The Phase III studies mainly recruited patients with insufficient response to laxatives, and showed consistent efficacy and excellent tolerability for prucalopride.

Efficacy of 5-HT3 antagonists and 5-HT4 agonists in irritable bowel syndrome: systematic review and meta-analysis

OBJECTIVES

Irritable bowel syndrome (IBS) is a chronic functional disorder. 5-Hydroxytryptamine (5-HT) is a key modulator of gastrointestinal sensorimotor function. Many patients have IBS that can be difficult to treat, which has led to the development of newer agents, such as 5-HT(3) antagonists and 5-HT(4) agonists. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to estimate the efficacy of all available 5-HT agents in IBS.

METHODS

MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched (up to June 2008). Trials recruiting adults with IBS in primary, secondary, or tertiary care comparing 5-HT(3) antagonists or 5-HT(4) agonists with placebo were eligible. Dichotomous symptom data were pooled to obtain a relative risk (RR) of remaining symptomatic after therapy, with a 95% confidence interval (CI). The number needed to treat (NNT) was calculated from the reciprocal of the risk difference.

RESULTS

The strategic search identified 1,593 citations. A total of 29 RCTs were eligible for inclusion; placebo was compared with 5-HT(3) antagonists in 11 RCTs, with tegaserod in 11, and with mixed 5-HT(3) antagonists/5-HT(4) agonists in 7. The study quality was generally high. The RR of IBS symptoms persisting with 5-HT(3) antagonists vs. placebo was 0.78 (95% CI: 0.71-0.86), with a similar benefit for both alosetron and cilansetron. Tegaserod was also superior to placebo (RR=0.85; 95% CI: 0.80-0.90). Renzapride and cisapride had no benefit in IBS.

CONCLUSIONS

Alosetron, cilansetron, and tegaserod are all effective in the treatment of IBS. Serious adverse events were rare in the eligible RCTs included in this systematic review.

The placebo response in functional dyspepsia--reanalysis of trial data

Clinical trial data rarely identify factors contributing to the placebo response. We reanalysed the data from the placebo arm (n = 157) of a functional dyspepsia (FD) trial to determine predictors of placebo response including total GIS score, change in GIS score during run-in, type of FD symptoms, duration of illness, age, gender, body mass index (BMI), family occurrence of FD-like symptoms, smoking and alcohol consumption. The same response criteria were applied to the drug arm (n = 158) of the study. Based on the initial 40% response criterion of the study, 35 (22.2%) were classified as placebo responders (PR), whilst 122 (78.8%) were placebo non-responders (PnR). Response rates for the drug arm were 41.1 and 56.9% respectively. PR had significantly lower GIS scores compared to PnR at visit 1 (10.6 +/- 0.6 and 12.3 +/- 0.4, respectively, P = 0.035), but not at visit 2 with study medication dispensing (10.9 +/- 0.5 and 11.3 +/- 0.4). Hence, PR symptoms increased during run-in by 4.2% whilst PnR symptoms decreased by 6.3% (P < 0.005). Gender, age and duration and type of FD symptoms were not different between PR and PnR. Smoking was less prevalent in PR (3%) compared to PnR (21%) (P < 0.025). Increasing the criteria for the placebo response resulted in higher BMI for PR than for PnR (P = 0.035). None of the predictors for placebo response were able to distinguish responders from non-responders to the drug. Variables predicting the PR point towards behavioural and biological mechanism of the PR, operating simultaneously and independently.

Editorial: is adequate relief fatally flawed or adequate as an end point in irritable bowel syndrome?

There is controversy on the validity of binary end points used in irritable bowel syndrome (IBS) clinical trials. In a usual-care observational study, baseline severity influenced the response measured as satisfactory relief. This editorial reviews the observations from a non-pharmacological study to assess the effect of baseline severity on the performance of binary end points in large drug trials. The pivotal finding is that once the patients who reported adequate relief at baseline were excluded from the analysis, baseline severity no longer affected the proportion of patients reporting adequate relief of IBS with treatment. As large drug trials enriched the study cohorts for at least moderate severity after a no-treatment, run-in period, it seems likely that the precaution of excluding mild disease de facto resolved the hypothetical weakness of the adequate relief end point. Given the high responsiveness and longitudinal construct validity demonstrated with adequate relief end point, it should be accepted as a trial end point.

Adequate relief in a treatment trial with IBS patients: a prospective assessment

OBJECTIVES

Adequate relief (AR) of irritable bowel syndrome (IBS) symptoms (IBS-AR) has been used as a primary end point in many randomized controlled trials of IBS and is considered by the Rome III committee to be an acceptable primary end point. However, controversy exists on whether baseline severity confounds the effect of the treatment outcome. The aim (1) is to compare a subjective report of IBS-AR with global assessment of improvement (IBS-GAI), change in IBS symptom severity scale (IBS-SSS), and IBS quality of life (IBS-QOL); (2) to explore whether initial IBS symptom severity influences the ability of these outcome measures to detect differences post treatment; and (3) to determine whether psychological symptoms influence the sensitivity of these measures, in a randomized controlled treatment trial.

METHODS

A total of 289 adult IBS patients were recruited to a treatment trial. Baseline IBS-SSS scores were used to classify IBS severity as mild (<175), moderate (175-300), or severe (>300). Questionnaires were completed at baseline and after 3 weeks of treatment with sham acupuncture or wait-list control.

RESULTS

IBS baseline severity (IBS-SSS) significantly affected the proportion of patients who reported IBS-AR at 3 weeks (mild, 70%; moderate, 49.7%; severe, 38.8%) (P<0.05). However, once the patients who reported IBS-AR at baseline (28.0%) were excluded from the analysis, baseline severity no longer affected the proportion of patients reporting IBS-AR. Baseline severity did not have a significant effect on patients reporting moderate or significant improvement on the IBS-GAI (mild, 30%; moderate, 25.3%; severe, 18.8%) (P=NS). Psychological symptoms had no significant correlations with responders after adjusting for baseline severity.

CONCLUSIONS

These data suggest that IBS-AR as an end point is inversely related to baseline symptom severity. However, if patients who report AR at screening were excluded from study participation, baseline symptom severity was no longer confounded with a report of AR at the study end point.

Clinical trial: the efficacy, impact on quality of life, and safety and tolerability of prucalopride in severe chronic constipation--a 12-week, randomized, double-blind, placebo-controlled study

BACKGROUND

Chronic constipation may result in disabling symptoms, is often unsatisfactorily treated by laxatives and negatively impacts quality of life (QoL).

AIM

A randomized, double-blind, placebo-controlled, phase III trial to evaluate the efficacy and safety of a selective, high-affinity 5-HT(4) receptor agonist, prucalopride, in patients with chronic constipation [<or=2 spontaneous complete bowel movements (SCBMs)/week].

METHODS

Placebo, 2 or 4 mg prucalopride was administered orally once daily, for 12 weeks. The primary efficacy endpoint was the proportion of patients with >or=3 SCBMs/week, averaged over 12 weeks. Other assessments included BM frequency, constipation-related QoL and symptoms and tolerability.

RESULTS

Among 641 patients, significantly more patients taking prucalopride 2 or 4 mg (24%) than placebo (12%), achieved the primary efficacy endpoint (>or=3 SCBMs/week) or an increase of >or=1 SCBMs/week; 43% and 47% vs. 28% respectively. Prucalopride-treated patients also achieved significantly greater satisfaction with treatment and bowel function, and improved perception of constipation severity and constipation-related QoL, compared with placebo. Most frequent treatment-related adverse events were headache, abdominal pain, nausea and diarrhoea (mainly during day 1). There were no differences in comparison to placebo in the incidence of serious adverse effects or cardiovascular events.

CONCLUSION

Over 12 weeks, prucalopride was effective and well tolerated in chronic constipation.

Challenges to the therapeutic pipeline for irritable bowel syndrome: end points and regulatory hurdles

Recent advances in our understanding of basic neuroenteric mechanisms and the role of effectors and transmitters in the brain-gut axis have provided opportunities to develop new therapeutic agents for irritable bowel syndrome (IBS). Furthermore, human pharmacodynamic studies utilizing transit, colonic, or rectal sensitivity and brain imaging have been useful in determining therapeutic efficacy (particularly for drugs that act on motor function). This review provides an overview of medications that have not yet been approved for treatment of patients with IBS yet have shown promise in phase IIB trials. These include drugs that act on the serotonin receptor and transporter system: antidepressants, norepinephrine reuptake inhibitors, opioids, cholecystokinin antagonists, neurokinin-antagonists, chloride channel activators, guanylate cyclase C agonists, atypical benzodiazepines, probiotics, and antibiotics. The changing landscape in the regulatory approval process has impacted the development of IBS drugs. Guidance documents from regulatory agencies in Europe and the United States have focused on patients' reported outcomes and associated quality of life. After a decade of experience with different end points that have generated some data on psychometric validation and unprecedented information about responsiveness of the binary or global end points to drug therapy, it is necessary to pursue further validation studies before or during pivotal phase IIB or III trials. The hope of providing relief to patients should galvanize all parties to achieve these goals.

Identification of patients with non-d, non-C irritable bowel syndrome and treatment with renzapride: an exploratory, multicenter, randomized, double-blind, placebo-controlled clinical trial

This was an exploratory study of renzapride in 168 male and female patients with non-D, non-C irritable bowel syndrome (IBS). Patients were randomized to placebo or renzapride (1, 2, or 4 mg/day) for 8 weeks. The primary efficacy variable was patient-reported satisfactory relief of IBS symptoms. Secondary variables included relief of abdominal pain/discomfort. The proportion of patients reporting satisfactory relief of their IBS symptoms for at least 50% of the time did not differ significantly from those on placebo. However, post hoc analysis in women showed differences in responder rate on renzapride versus placebo of 18.2% (95% CI -5% to 42%; P = 0.066) during weeks 1-4 and 6% (95% CI -21% to 33%; P = 0.339) during weeks 5-8. Renzapride was well tolerated and most adverse events were mild to moderate in intensity. Further studies are warranted to determine whether renzapride is beneficial in this patient population.

Randomized, double-blind, placebo-controlled trial of the 5-HT1A receptor antagonist AZD7371 tartrate monohydrate (robalzotan tartrate monohydrate) in patients with irritable bowel syndrome

OBJECTIVES

To investigate the efficacy and safety of the 5-hydroxytrypamine 1A (5-HT(1A)) receptor antagonist AZD7371 tartrate monohydrate (robalzotan tartrate monohydrate), termed AZD7371 here, in patients with irritable bowel syndrome (IBS).

METHODS

Patients meeting the Rome II criteria for IBS (N = 402) were randomized to treatment with AZD7371 20 mg or 5 mg or matching placebo tablets twice daily for 12 wk. The patients completed daily and weekly diary assessments, reporting abdominal discomfort or pain and description of bowel movements. They also completed validated symptom and quality-of-life questionnaires.

RESULTS

Neither AZD7371 regimen was significantly more effective than placebo in providing adequate relief from IBS symptoms in at least 2 out of 4 wk per month over the 12 wk of treatment. There was also no significant difference between the treatment groups and placebo in the change in score in the validated symptom and quality-of-life questionnaires. Overall, 22.1% of patients experienced adverse events (AEs) attributed to the study medication: 44 of 133 (33.1%) in the 20 mg AZD7371 group, 27 of 131 (20.6%) in the 5 mg AZD7371 group, and 17 of 134 (12.7%) in the placebo group. Also, 31 of 57 (54%) of AEs leading to discontinuation were central nervous system-related. Hallucinations or hallucination-like AEs were reported by eight patients taking AZD7371, and by none of the patients in the placebo group. After these events led to discontinuation in six patients, the study was prematurely terminated.

CONCLUSIONS

In view of the AE profile and lack of efficacy in IBS, the clinical development of AZD7371 has been stopped.

Exploratory Study of Tegaserod for Dyspepsia in Women Receiving PPIs for Heartburn

Background and Aims

Tegaserod is a selective serotonin receptor (5-HT₄) agonist that relieves dysmotility symptoms associated with constipation. Here we explore its effects on functional dyspepsia symptoms and heartburn during continued proton pump inhibitor (PPI) treatment.

Methods

In this multicenter pilot study, following a 2-week screening/baseline period, women with functional dyspepsia and persisting heartburn treated with PPIs received add-on open-label tegaserod 6 mg twice daily (bid) for 4 weeks. Treatment responders were then randomized 1:1 to continue double-blind tegaserod or placebo therapy for 6 weeks. Efficacy variables included the proportion of days with satisfactory relief of dyspepsia symptoms (early satiety, postprandial fullness and bloating) as well as the change in individual symptom severity scores for these three cardinal dyspepsia symptoms. Health-related quality of life was evaluated using a validated questionnaire, the Nepean Dyspepsia Index. Adverse events (AEs) were monitored.

Results

Of 101 women enrolled, 71 completed open-label treatment, and 70 responders were randomized to double-blind treatment. The proportion of days with satisfactory relief of dyspepsia symptoms (least squares mean, LSM) increased with tegaserod and placebo, to 0.69 and 0.62, respectively at study end (P = 0.366). Similarly, both groups showed improvements in the composite daily symptom severity score (overall LSM change from baseline of 1.55 and 1.57, P = 0.934), and the Nepean Dyspepsia Index (overall LSM change of −39.0 and −37.8, P = 0.537). Tegaserod was well tolerated. Diarrhea was the most common AE (8.1% tegaserod, 0% placebo). There were no serious AEs or deaths.

Conclusions

A significant treatment effect was not demonstrated in this study using a treatment-withdrawal methodology. In future studies of functional dyspepsia patients with heartburn, a more rigorous parallel-group study design should be considered.

New insights into the placebo and nocebo responses

In modern medicine, the placebo response or placebo effect has often been regarded as a nuisance in basic research and particularly in clinical research. The latest scientific evidence has demonstrated, however, that the placebo effect and the nocebo effect, the negative effects of placebo, stem from highly active processes in the brain that are mediated by psychological mechanisms such as expectation and conditioning. These processes have been described in some detail for many diseases and treatments, and we now know that they can represent both strength and vulnerability in the course of a disease as well as in the response to a therapy. However, recent research and current knowledge raise several issues that we shall address in this review. We will discuss current neurobiological models like expectation-induced activation of the brain reward circuitry, Pavlovian conditioning, and anxiety mechanisms of the nocebo response. We will further explore the nature of the placebo responses in clinical trials and address major questions for future research such as the relationship between expectations and conditioning in placebo effects, the existence of a consistent brain network for all placebo effects, the role of gender in placebo effects, and the impact of getting drug-like effects without drugs.

Tegaserod treatment for dysmotility-like functional dyspepsia: results of two randomized, controlled trials

OBJECTIVES

Therapies for dysmotility-like functional dyspepsia (FD) are limited. We studied tegaserod, a selective serotonin type 4 receptor agonist, in patients with FD.

METHODS

Two identical multicenter, double-blind, randomized, placebo-controlled trials enrolled women >/=18 yr with recurring mid-upper abdominal discomfort characterized by postprandial fullness, early satiety, and/or bloating. Patients were randomized to tegaserod 6 mg b.i.d. or placebo. Two patient-reported primary variables were assessed: percentage of days with satisfactory symptom relief, and symptom severity using the composite average daily severity score (CADSS).

RESULTS

In total, 2,667 women were randomized with no differences between trials in terms of recruitment method, Helicobacter pylori status, heartburn, or medication use. Mean percentage of days with satisfactory symptom relief for tegaserod versus placebo in Trial 1: 32.2%versus 26.6% (95% CI of treatment difference 2.82, 9.27; P < 0.01), Trial 2: 31.9%versus 29.4% (95% CI of treatment difference -0.21, 6.53; P= 0.066). Mean CADSS in Trial 1: 3.14 versus 3.35 (95% CI of treatment difference -0.29, -0.10; P < 0.0001), Trial 2: 3.15 versus 3.23 (95% CI of treatment difference -0.18, 0.01; P= 0.094). Meta-analysis showed significant benefit for both end points: increase in days with satisfactory relief 4.6% (95% CI 2.29, 6.96); decrease in CADSS 0.14 (95% CI 0.21, 0.07). Treatment effect was greater in patients with severe baseline symptoms. Diarrhea requiring study discontinuation was more common with tegaserod than placebo (4.1%vs 0.3%).

CONCLUSIONS

Some improvement in dysmotility-like FD was observed with tegaserod treatment. The clinical implication of this improvement is uncertain.

Tegaserod in patients with mechanical sensitivity and overlapping symptoms of functional heartburn and functional dyspepsia

BACKGROUND

While functional heartburn (FH) and functional dyspepsia (FD) are recognized clinical entities, symptoms often overlap across both disorders. Despite their frequency, little is known of the underlying pathophysiology of overlapping symptoms. This study evaluated the effect of the 5-HT(4) agonist, tegaserod, on visceral sensitivity and symptom improvement in patients with overlapping symptoms of FH and FD.

RESEARCH DESIGN AND METHODS

Patients with overlapping symptoms of FH and FD (ROME II) and mechanical hypersensitivity (Barostat examination) were randomized to tegaserod 6 mg bid or placebo for 2 weeks with treatment crossover after a 2-week washout period. Esophageal and gastric Barostat sensory tests were performed and patients rated their overall symptoms at study end. When carry-over was detected, data were presented for period 1 only. Safety was also assessed.

RESULTS

Sixty patients were screened of whom 30 were randomized and 25 completed. Mechanical hypersensitivity was reported by 83% of 47 patients completing esophageal and gastric baseline Barostat examinations. Tegaserod did not significantly alter balloon volume to pain (primary variable); however, pressure to gastric pain increased (p = 0.044 vs. placebo). The severity of heartburn, regurgitation, early fullness, and bloating was significantly lower following tegaserod vs. placebo treatment (p = 0.026, p = 0.021, p = 0.016, and p = 0.030). Overall symptom improvement was reported by 52% tegaserod vs. 32% placebo patients (p = 0.275), and treatment was well tolerated.

CONCLUSIONS

Results suggest that tegaserod may increase the gastric pain threshold and decrease the severity of individual symptoms in patients with overlapping FH and FD. However, these findings must be considered within the context of the study limitations, including the small number of subjects, potential for and presence of a carry-over effect, along with the impact of Barostat balloon use on the assessment of gastric function.

Clinical trial: renzapride therapy for constipation-predominant irritable bowel syndrome--multicentre, randomized, placebo-controlled, double-blind study in primary healthcare setting

BACKGROUND

Relatively few pharmacological treatment options are available for treating patients with irritable bowel syndrome. New and effective medicines are urgently required.

AIM

To identify an appropriate dosage of renzapride (a 5-HT(4) receptor full agonist/5-HT(3) receptor antagonist) to treat abdominal pain/discomfort in patients with constipation-predominant irritable bowel syndrome.

METHODS

In this randomized, placebo-controlled, phase IIb study in the primary care setting, men and women were randomized to placebo or renzapride (1, 2 or 4 mg/day) for 12 weeks. The primary outcome measure was patient self-assessed relief of abdominal pain/discomfort during weeks 5-12. Secondary efficacy measures included patients' assessment of their bowel habits, stool consistency and quality of life.

RESULTS

Although there were no statistically significant differences between renzapride and placebo for relief from abdominal pain/discomfort, responder rates in the renzapride treatment groups increased dose dependently, with the 4 mg/day group being consistently numerically greater than placebo. Importantly, a larger numerical treatment difference vs. placebo was observed in women (8% and 12% respectively). Statistically significant improvements in bowel movement frequency and stool consistency were observed in the 4 mg/day group relative to placebo. Renzapride was well tolerated at all doses.

CONCLUSIONS

This study confirms the gastrointestinal prokinetic effects of renzparide. The data also suggested a potentially beneficial effect on abdominal pain/discomfort in women with constipation-predominant irritable bowel syndrome.

Tegaserod for female patients suffering from IBS with mixed bowel habits or constipation: a randomized controlled trial

OBJECTIVES

Though the greatest proportion of irritable bowel syndrome (IBS) patients report a mixed bowel pattern (IBS-Mixed), no available therapies have been rigorously evaluated in this subgroup. This study aimed to evaluate the efficacy and safety of the 5-HT(4) agonist tegaserod in women with IBS-Mixed and IBS with constipation (IBS-C).

METHODS

This prospective, double-blind, randomized, placebo-controlled, multicenter study was conducted in 100 centers in North America, South America, and Europe. Women with IBS-Mixed or IBS-C received tegaserod 6 mg or placebo twice daily. The primary efficacy variable was the patient's assessment of satisfactory relief over the 4-wk treatment period. The proportion of patients reporting satisfactory relief for >/=3 of 4 treatment weeks (75% rule) and individual IBS symptoms were assessed.

RESULTS

In total, 661 women were randomized (IBS-Mixed 324, IBS-C 337). Baseline symptom assessments identified clear differences between the two cohorts. Tegaserod provided significant improvement in satisfactory relief of IBS symptoms over 4 wk (OR 1.75, 95% CI 1.35-2.25, P < 0.001) in both IBS-Mixed and IBS-C patients. Using the 75% rule, 52.3% of tegaserod-receiving IBS-M patients and 43.3% of IBS-C patients were responders (vs 36.3, OR 1.88, 95% CI 1.16-3.04, P < 0.010; and 28.9, OR 1.90, 95% CI 1.19-3.05, P < 0.008 for placebo, respectively). The most frequent adverse events leading to study discontinuation in tegaserod-treated patients were diarrhea (1.5%) and abdominal pain (0.9%). Overall 7% of IBS-C patients reported diarrhea compared to 12% of IBS-Mixed (placebo 2.4%, 1.8%, respectively).

CONCLUSIONS

Tegaserod is effective in treating overall IBS symptoms in patients with IBS-Mixed and IBS-C.

Sensory signalling effects of tegaserod in patients with irritable bowel syndrome with constipation

Tegaserod relieves overall and multiple individual constipation-predominant irritable bowel syndrome (IBS-C) symptoms. However, mechanisms for the relief of abdominal pain/discomfort are not well understood. The effects of tegaserod on rectal sensitivity to distension were measured by the nociceptive flexion RIII reflex, as evidenced by spinal hyperexcitability (i.e. increase or facilitation of the RIII reflex), in IBS-C patients. A randomized, double-blind, placebo-controlled, parallel study was performed in 30 women with IBS-C. The effects of slow ramp rectal distension on the RIII reflex, recorded from the lower limb, were measured before [first experimental day (D1)] and after 7 days [day 8 (D8)] of placebo (n=15) or 6 mg tegaserod bid (n=15). Pressure-volume and sensation-volume relationships were measured during distension, and patients reported their IBS symptoms daily. On D1, rectal distension facilitated the RIII reflex in both treatment groups. On D8 vs D1 these facilitatory effects were significantly lower (P<0.001, analysis of variance) after tegaserod (mean reduction: -30.3+/-11.9%) than placebo (mean reduction: -10.1+/-12.9%). No significant changes in the volume-sensation relationship or differences in compliance were observed with tegaserod or placebo. In conclusion, tegaserod reduces the facilitatory effects of rectal distension on the RIII reflex in women with IBS-C.

Neurogastroenterology of tegaserod (HTF 919) in the submucosal division of the guinea-pig and human enteric nervous system

Actions of the 5-HT(4) serotonergic receptor partial agonist, tegaserod, were investigated on mucosal secretion in the guinea-pig and human small intestine and on electrophysiological behaviour of secretomotor neurons in the guinea-pig small intestinal submucosal plexus. Expression of 5-HT(4) receptor protein and immunohistochemical localization of the 5-HT(4) receptor in the submucosal plexus in relation to expression and localization of choline acetyltransferase and the vesicular acetylcholine (ACh) transporter were determined for the enteric nervous system of human and guinea-pig small intestine. Immunoreactivity for the 5-HT(4) receptor was expressed as ring-like fluorescence surrounding the perimeter of the neuronal cell bodies and co-localized with the vesicular ACh transporter. Exposure of mucosal/submucosal preparations to tegaserod in Ussing chambers evoked increases in mucosal secretion reflected by stimulation of short-circuit current. Stimulation of secretion had a relative high EC(50) of 28.1 +/- 1.3 mumol L(-1), was resistant to neural blockade and appeared to be a direct action on the secretory epithelium. Tegaserod acted at presynaptic 5-HT(4) receptors to facilitate the release of ACh at nicotinic synapses on secretomotor neurons in the submucosal plexus. The 5-HT(2B) receptor subtype was not involved in actions at nicotinic synapses or stimulation of secretion.

Guidelines on the irritable bowel syndrome: mechanisms and practical management

BACKGROUND

IBS affects 5-11% of the population of most countries. Prevalence peaks in the third and fourth decades, with a female predominance.

AIM

To provide a guide for the assessment and management of adult patients with irritable bowel syndrome.

METHODS

Members of the Clinical Services Committee of The British Society of Gastroenterology were allocated particular areas to produce review documents. Literature searching included systematic searches using electronic databases such as Pubmed, EMBASE, MEDLINE, Web of Science, and Cochrane databases and extensive personal reference databases.

RESULTS

Patients can usefully be classified by predominant bowel habit. Few investigations are needed except when diarrhoea is a prominent feature. Alarm features may warrant further investigation. Adverse psychological features and somatisation are often present. Ascertaining the patients' concerns and explaining symptoms in simple terms improves outcome. IBS is a heterogeneous condition with a range of treatments, each of which benefits a small proportion of patients. Treatment of associated anxiety and depression often improves bowel and other symptoms. Randomised placebo controlled trials show benefit as follows: cognitive behavioural therapy and psychodynamic interpersonal therapy improve coping; hypnotherapy benefits global symptoms in otherwise refractory patients; antispasmodics and tricyclic antidepressants improve pain; ispaghula improves pain and bowel habit; 5-HT(3) antagonists improve global symptoms, diarrhoea, and pain but may rarely cause unexplained colitis; 5-HT(4) agonists improve global symptoms, constipation, and bloating; selective serotonin reuptake inhibitors improve global symptoms.

CONCLUSIONS

Better ways of identifying which patients will respond to specific treatments are urgently needed.

Guidelines on the irritable bowel syndrome: mechanisms and practical management

BACKGROUND

IBS affects 5-11% of the population of most countries. Prevalence peaks in the third and fourth decades, with a female predominance.

AIM

To provide a guide for the assessment and management of adult patients with irritable bowel syndrome.

METHODS

Members of the Clinical Services Committee of The British Society of Gastroenterology were allocated particular areas to produce review documents. Literature searching included systematic searches using electronic databases such as Pubmed, EMBASE, MEDLINE, Web of Science, and Cochrane databases and extensive personal reference databases.

RESULTS

Patients can usefully be classified by predominant bowel habit. Few investigations are needed except when diarrhoea is a prominent feature. Alarm features may warrant further investigation. Adverse psychological features and somatisation are often present. Ascertaining the patients' concerns and explaining symptoms in simple terms improves outcome. IBS is a heterogeneous condition with a range of treatments, each of which benefits a small proportion of patients. Treatment of associated anxiety and depression often improves bowel and other symptoms. Randomised placebo controlled trials show benefit as follows: cognitive behavioural therapy and psychodynamic interpersonal therapy improve coping; hypnotherapy benefits global symptoms in otherwise refractory patients; antispasmodics and tricyclic antidepressants improve pain; ispaghula improves pain and bowel habit; 5-HT(3) antagonists improve global symptoms, diarrhoea, and pain but may rarely cause unexplained colitis; 5-HT(4) agonists improve global symptoms, constipation, and bloating; selective serotonin reuptake inhibitors improve global symptoms.

CONCLUSIONS

Better ways of identifying which patients will respond to specific treatments are urgently needed.

Standardized concept for the treatment of gastrointestinal dysmotility in critically ill patients--current status and future options

Inhibition of gastrointestinal motility is a major problem in critically ill patients. Motor stasis gives rise to subsequent complications including intolerance to enteral feeding, enhanced permeability of the atrophic intestinal mucosa and conditions as severe as systemic inflammatory response syndrome, sepsis and multiple organ failure. Although the diagnosis of motility disturbances in critically ill patients is difficult, the type and site of the disturbance are important to consider in the analysis of the condition and in the choice of therapeutic approach. The pharmacological treatment of impaired gastrointestinal motility is difficult to handle for the clinician, because the underlying mechanisms are complex and not fully understood and the availability of pharmacological treatment options is limited. In addition, there is a lack of controlled studies on which to build an evidence-based treatment concept for critically ill patients. Notwithstanding this situation, there has been remarkable progress in the understanding of the integrated regulation of gastrointestinal motility in health and disease. These advances, which largely relate to the organization of the enteric nervous system and its signaling mechanisms, enable the intensivist to develop a standardized concept for the use of prokinetic agents in the treatment of impaired gastrointestinal motility in critically ill patients.

Tegaserod for the treatment of irritable bowel syndrome and chronic constipation

BACKGROUND

IBS is a complex disorder that encompasses a wide profile of symptoms. The symptoms of chronic constipation frequently resemble those of constipation-predominant IBS. Current drug treatments for irritable bowel syndrome (IBS) are of limited value. Many target specific symptoms only. Tegaserod, a 5HT(4) partial agonist, represents a novel mechanism of action in the treatment of IBS and chronic constipation.

OBJECTIVES

The objective of this review was to evaluate the efficacy and tolerability of tegaserod for the treatment of IBS and chronic constipation in adults and adolescents aged 12 years and above.

SEARCH STRATEGY

MEDLINE 1966-December 2006 and EMBASE 1980 to December 2006 were searched. The text and key words used included "tegaserod", "HTF 919", "irritable bowel", "constipation" and "colonic diseases, functional". The Cochrane Central Register of Controlled Trials, and the Inflammatory Bowel Disease Review Group Specialized Trials Register were also searched. Searches stopped on 15th December 2006. Relevant articles were retrieved, and their reference lists were also reviewed.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing tegaserod with placebo, no treatment or any other intervention (pharmacological or non-pharmacological) in subjects aged 12 years and above with a diagnosis of IBS or chronic constipation, focusing on clinical endpoints were considered for review.

DATA COLLECTION AND ANALYSIS

Study inclusion and exclusion, data extraction and quality assessment was undertaken by two authors independently. Meta-analysis was performed where study populations, designs, outcomes, and statistical reporting allowed combination of data in a valid way, using the summary statistics relative risk for dichotomous data and weighted mean difference for continuous data, both with 95% CI. Thirteen short-term placebo-controlled studies fulfilled the inclusion criteria. These were predominantly conducted in women. Ten studies evaluated the efficacy of tegaserod on global gastrointestinal (GI) symptoms in patients with constipation-predominant IBS (C-IBS). One small study evaluated safety in patients with diarrhoea-predominant IBS. Two studies evaluated the effectiveness of tegaserod for the treatment of chronic constipation.

MAIN RESULTS

In patients with C-IBS, the relative risk (RR) of being a responder in terms of global relief of GI symptoms during the last 4 weeks of treatment was significantly higher with both tegaserod 12 mg and 4 mg doses compared with placebo. Although the pooled results indicate statistically significant benefit with tegaserod, the a priori minimal clinically important differences set in two of three studies were not reached. The responder rate for this endpoint was also higher when considered for the first 4 weeks of treatment (tegaserod 12 mg only). Tegaserod did not significantly improve the patients' individual symptoms of abdominal pain and discomfort although bowel habit showed a statistically significant improvement with tegaserod 4 mg and there was a non-significant trend in this outcome in favour of tegaserod 12 mg. In patients with chronic constipation, the RR of being a responder in terms of complete spontaneous bowel movements per week with tegaserod 12 mg was 1.54 (95% CI 1.35 to 1.75), WMD for this endpoint compared with placebo 0.6 (95% CI 0.42 to 0.78). Differences between tegaserod and placebo in increases in frequency of bowel movements were small (less than one per week). The proportion of patients with either diagnosis who experienced diarrhea was significantly higher in the tegaserod 12 mg group compared with placebo (RR 2.80, 95% CI 2.13 to 3.68), with a number needed to harm (NNH) of 20. Effects of tegaserod on GI symptoms such as bloating, stool consistency, and straining were not consistent across the studies.

AUTHORS' CONCLUSIONS

Tegaserod appears to improve the overall symptomatology of IBS, and the frequency of bowel movements in those with chronic constipation. The clinical importance of these modest improvements is not clear. There are currently few data on its effect on quality of life. In addition, more information is needed about its efficacy in men. It would also be of interest to know whether treatment with tegaserod leads either directly, or indirectly, to changes in visceral sensitivity or psychopathology, which are also considered important in the pathophysiology of these conditions.

Irritable bowel syndrome: current approach to symptoms, evaluation, and treatment

There are frequent advances in knowledge about the clinical presentation, pathophysiology, and treatment of irritable bowel syndrome. It is important for clinicians to be aware of available therapies and the supporting evidence for those therapies to increase patient satisfaction. This is best achieved with a collaborative and long-term clinician-patient relationship and mutual commitment to modify therapy and try new modalities until the greatest relief of symptoms and improvement in health-related quality of life is achieved. This article reviews symptoms, comorbidities, gender differences, and measure of severity in irritable bowel syndrome and current and evidence-based approaches to evaluation and treatment, and the new symptom-based Rome III diagnostic criteria are reviewed and explained.

Mechanisms of serotonergic agents for treatment of gastrointestinal motility and functional bowel disorders

Most of the body's serotonin is released in the gut where it plays an important role in the control of gastrointestinal (GI) motility, sensitivity and muscle tone by activating different receptor subtypes. This review focuses on the known effects of selective serotonin reuptake inhibitor and serotonin receptor agonists and antagonists on the sensorimotor function of the GI tract and describes the therapeutic potential of these actions for GI motility and functional bowel disorders.

Constipation

Chronic constipation is a common disorder manifested by a variety of symptoms. Assessments of colonic transit and anorectal functions are used to categorize constipated patients into three groups, i.e., normal transit or irritable bowel syndrome, pelvic floor dysfunction (i.e., functional defaecatory disorders) and slow transit constipation. 'Slow transit' constipation is a clinical syndrome attributed to ineffective colonic propulsion and/or increased resistance to propagation of colonic contents. Defaecatory disorders are caused by insufficient relaxation of the pelvic floor muscles or a failure to generate adequate propulsive forces during defaecation. Colonic transit is often delayed in patients with functional defaecatory disorders. Normal and slow transit constipation are generally managed with medications; surgery is necessary for a minority of patients with slow transit constipation. Functional defaecatory disorders are primarily treated with pelvic floor retraining using biofeedback therapy.