The effects of withdrawing tegaserod treatment in comparison with continuous treatment in irritable bowel syndrome patients with abdominal pain/discomfort, bloating and constipation: a clinical study

Tegaserod for the Treatment of Irritable Bowel Syndrome

Background: Tegaserod (Zelnorm®) is a 5-hydroxytryptamine (serotonin) type 4 receptor agonist for the treatment of hypomotility disorders of the lower gastrointestinal tract associated with the irritable bowel syndrome with constipation (IBS-C).

Objective: The authors provide the reader with a better understanding on tegaserod mechanism of action, on its pharmacodynamics and pharmacokinetic properties, on safety and tolerability, with a summary of the key published clinical trials conducted in patients with irritable bowel syndrome (IBS). Its effects on colon inflammation have also been described.

Results: Tegaserod was withdrawn in 2007 due to increased risks of cardiovascular adverse effects. The manufacturer denied this, because pre-existing cardiovascular disease or risk factors were attributed to all affected patients. Thus, no causal relationship between tegaserod use and cardiovascular events was clearly shown. A matched case-control study of tegaserod-treated with untreated patients found no association between tegaserod and adverse cardiovascular outcomes. Despite its adverse effects, tegaserod resulted to be effective in treating chronic constipation in adult women aged < 65 years with IBS-C, while the safety and effectiveness of tegaserod in men with IBS-C have not been established.

Conclusion: Tegaserod was resubmitted to the Food and Drug Administration in 2018 for use in a low-risk population. Moreover, tegaserod has also been shown to improve symptoms, enhance gastric accommodation and significantly attenuate visceral pain arising from the colon in functional dyspepsia patients. Treatment with tegaserod seems also to exert a protective effect in inflamed colons, reducing the severity of colitis in animal models.

The management of adult patients with severe chronic small intestinal dysmotility

Adult patients with severe chronic small intestinal dysmotility are not uncommon and can be difficult to manage. This guideline gives an outline of how to make the diagnosis. It discusses factors which contribute to or cause a picture of severe chronic intestinal dysmotility (eg, obstruction, functional gastrointestinal disorders, drugs, psychosocial issues and malnutrition). It gives management guidelines for patients with an enteric myopathy or neuropathy including the use of enteral and parenteral nutrition.

Ex vivo study of human visceral nociceptors

OBJECTIVE

The development of effective visceral analgesics free of deleterious gut-specific side effects is a priority. We aimed to develop a reproducible methodology to study visceral nociception in human tissue that could aid future target identification and drug evaluation.

DESIGN

Electrophysiological (single unit) responses of visceral afferents to mechanical (von Frey hair (VFH) and stretch) and chemical (bradykinin and ATP) stimuli were examined. Thus, serosal afferents (putative nociceptors) were used to investigate the effect of tegaserod, and transient receptor potential channel, vanilloid 4 (TRPV₄) modulation on mechanical responses.

RESULTS

Two distinct afferent fibre populations, serosal (n=23) and muscular (n=21), were distinguished based on their differences in sensitivity to VFH probing and tissue stretch. Serosal units displayed sensitivity to key algesic mediators, bradykinin (6/14 units tested) and ATP (4/10), consistent with a role as polymodal nociceptors, while muscular afferents are largely insensitive to bradykinin (0/11) and ATP (1/10). Serosal nociceptor mechanosensitivity was attenuated by tegaserod (-20.8±6.9%, n=6, p<0.05), a treatment for IBS, or application of HC067047 (-34.9±10.0%, n=7, p<0.05), a TRPV₄ antagonist, highlighting the utility of the preparation to examine the mechanistic action of existing drugs or novel analgesics. Repeated application of bradykinin or ATP produced consistent afferent responses following desensitisation to the first application, demonstrating their utility as test stimuli to evaluate analgesic activity.

CONCLUSIONS

Functionally distinct subpopulations of human visceral afferents can be demonstrated and could provide a platform technology to further study nociception in human tissue.

Disorders of gastrointestinal hypomotility

Ingestion and digestion of food as well as expulsion of residual material from our gastrointestinal tract requires normal propulsive, i.e. motor, function. Hypomotility refers to inherited or acquired changes that come with decreased contractile forces or slower transit. It not only often causes symptoms but also may compromise nutritional status or lead to other complications. While severe forms, such as pseudo-obstruction or ileus, may have a tremendous functional impact, the less severe forms of hypomotility may well be more relevant, as they contribute to common disorders, such as functional dyspepsia, gastroparesis, chronic constipation, and irritable bowel syndrome (IBS). Clinical testing can identify changes in contractile activity, defined by lower amplitudes or abnormal patterns, and the related effects on transit. However, such biomarkers show a limited correlation with overall symptom severity as experienced by patients. Similarly, targeting hypomotility with pharmacological interventions often alters gut motor function but does not consistently improve symptoms. Novel diagnostic approaches may change this apparent paradox and enable us to obtain more comprehensive information by integrating data on electrical activity, mechanical forces, patterns, wall stiffness, and motions with information of the flow of luminal contents. New drugs with more selective effects or more specific delivery may improve benefits and limit adverse effects. Lastly, the complex regulation of gastrointestinal motility involves the brain-gut axis as a reciprocal pathway for afferent and efferent signaling. Considering the role of visceral input in emotion and the effects of emotion on visceral activity, understanding and managing hypomotility disorders requires an integrative approach based on the mind-body continuum or biopsychosocial model of diseases.

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.

Tegaserod in the treatment of irritable bowel syndrome (IBS) with constipation as the prime symptom

Irritable bowel syndrome with constipation (IBS-C) as the predominant bowel symptom is a prevalent disorder, characterized by recurring abdominal pain/discomfort, bloating, and constipation, and imposes a significant socio-economic burden. Traditional treatments generally address just one of the multiple IBS symptoms. The efficacy and safety profile of tegaserod, a serotonin 5-HT(4) receptor agonist, has been demonstrated in several randomized, placebo-controlled, and open-label trials. This review discusses the major clinical trials of tegaserod, which have involved 8948 IBS patients. Overall, data reveal that tegaserod is an effective treatment for IBS-C, providing statistically significant relief of overall and multiple individual IBS-C symptoms (abdominal pain/discomfort, bloating, and constipation) in both placebo-controlled and "real-life" open-label settings. Repeat treatments with tegaserod were also shown to be effective, which is noteworthy given the chronic and episodic nature of IBS. Moreover, tegaserod was associated with improvements in patients' quality of life and work productivity. Data also indicate that tegaserod is well tolerated over the short-term (4 weeks), long-term (12 months), and repeated treatments. Diarrhea is the only adverse event consistently associated with tegaserod and was generally mild and transient. Overall, tegaserod has been demonstrated to offer effective and well-tolerated treatment of IBS-C, providing patients with meaningful symptom relief.

Systematic review: the safety and tolerability of pharmacological agents for treatment of irritable bowel syndrome--a European perspective

AIM

To use an evidence-based approach to evaluate the safety and tolerability of the treatments available for irritable bowel syndrome (IBS), or in clinical development, in Europe. A separate review appraises the evidence for the efficacy of these therapies.

METHODS

A literature search (for 1980 to 2005) was completed for all relevant clinical trial data and other articles which included safety information on the use of pharmacological IBS therapies. Clinical trials were scored according to the level of safety information, and adverse event incidence reported when possible.

RESULTS

The tolerability of many of the agents used to treat IBS in Europe is poorly understood. However, serotonergic agents, such as tegaserod and alosetron, which are currently unavailable in Europe, have undergone rigorous assessment in IBS and their benefits have been established. Following initial marketing of alosetron for use in patients with IBS with diarrhoea, concerns about severe constipation and ischaemic colitis resulted in restriction of its use to women with severe IBS symptoms. This highlights the importance of post-marketing surveillance and post-marketing studies in refining the therapeutic indication of new IBS therapies, which will help to identify appropriate recipients for the drug and establish the impact of adverse reactions in clinical practice.

CONCLUSIONS

There is a significant lack of data on the safety and tolerability of the therapies currently used routinely to treat IBS in Europe. The newer agents have undergone rigorous assessment, such that their benefits and risks in treating IBS are established. Defining their place among the spectrum of available therapies remains challenging when the benefits and risks of the older treatments are so poorly characterized.

Tegaserod in the treatment of irritable bowel syndrome with constipation

Tegaserod, a novel serotonin receptor agonist, has gained acceptance and widespread use for the treatment of women with irritable bowel syndrome and constipation. Development of this therapy evolved from the emerging role of serotonin in gastrointestinal motor, secretory and sensory functions. The efficacy and safety of tegaserod has been well established in women suffering from irritable bowel syndrome with constipation. Large, randomized, double-blind, placebo-controlled trials involving more than 3500 predominantly female patients with irritable bowel syndrome and constipation have demonstrated the superiority of tegaserod over placebo in improving global and individual symptoms. The most common side effects of tegaserod in clinical trials were diarrhea and headache. Recent data suggest that retreatment with tegaserod after a drug holiday is efficacious, opening the door to the possibility of intermittent therapy for patients with irritable bowel syndrome and constipation. Areas in need of further investigation include the role of tegaserod in the treatment of pain and bloating in irritable bowel syndrome, whether tegaserod has a role in male patients, the long-term efficacy of tegaserod, whether tolerance develops in a subset of patients with extended therapy and whether tegaserod is beneficial for the treatment of other functional gastrointestinal disorders.

Tegaserod is effective in the initial and retreatment of irritable bowel syndrome with constipation

BACKGROUND

Symptoms of irritable bowel syndrome are often cyclical and thus may require repeated rather than continuous therapy. Tegaserod is effective and well-tolerated for irritable bowel syndrome with constipation but data on retreatment are lacking.

AIM

To assess whether tegaserod retreatment is as efficacious and well-tolerated as initial treatment in a primary care setting.

METHODS

This open-label trial was designed to evaluate the effectiveness of tegaserod under real-life conditions. Irritable bowel syndrome with constipation patients received tegaserod 6 mg b.d. for 12 weeks; response was assessed at weeks 4 and 12. Responders (those achieving satisfactory relief for at least 2 of the previous 4 weeks) at weeks 4 and/or 12 entered an 8-week withdrawal period where symptom recurrence was assessed. Patients experiencing recurrence could receive tegaserod 6 mg b.d. for another 4 weeks (retreatment phase) and on completion, could choose to continue tegaserod in a 6-month extension study.

RESULTS

A total of 513 patients received initial treatment with tegaserod; 85.0% (436 of 513) responded. 403 responders entered the withdrawal period; symptoms recurred in 83.9% (338 of 403) after a mean of 38 days. Of the 307 patients who subsequently entered retreatment 89.3% (274 of 307) responded. Among patients entering the retreatment period, 269 (87.6%) had responded within the first 4 weeks of initial treatment. Of these, 243 (90.3%) responded to tegaserod retreatment. Adverse events were infrequent and similar during 4 weeks of the initial treatment period (11.1%) and on retreatment (10.4%). The extension study, completed by 188 of 232 (81.0%) patients, demonstrated good long-term tolerability of tegaserod.

CONCLUSIONS

Irritable bowel syndrome with constipation patients can be successfully treated, and retreated, with tegaserod 6 mg b.d. Tegaserod was well-tolerated during initial and retreatment periods.