Benefit-Risk Assessment of Tegaserod in Irritable Bowel Syndrome

Tegaserod: What's Old Is New Again

Irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC) are common gastrointestinal disorders imposing considerable impact on the quality of life and well-being of affected individuals. A paucity of evidence-based treatment options exist for CIC and IBS-C sufferers. Tegaserod, a 5-HT₄ agonist, has a substantial body of preclinical and clinical study evidence to support its beneficial role in modulating sensorimotor function of the luminal gastrointestinal tract. Tegaserod was first approved for use by the U.S. Food and Drug Administration for the management of IBS-C and CIC in 2002 and 2004, respectively. Tegaserod enjoyed a successful uptake in the management of these disorders during its first several years of availability in the United States, but was later withdrawn from the market in 2007 over concerns related to adverse cardiovascular events. Since then, additional safety data has been generated, and following a resubmission and review by the Food and Drug Administration, in April 2019, tegaserod was once again approved for use in IBS-C under a more restricted labeling, confining use to women under 65 years of age without heart disease or additional cardiovascular risk factors. This review summarizes the regulatory journey of tegaserod and details the existing pharmacokinetic, physiologic, clinical, and safety data of tegaserod generated over the last 2 decades. The discussion also examines the future of tegaserod in the treatment of these constipation disorders, as well as its potential role in other related disorders of brain-gut interaction.

A review of quantitative risk-benefit methodologies for assessing drug safety and efficacy-report of the ISPOR risk-benefit management working group

OBJECTIVE

Although regulatory authorities evaluate the risks and benefits of any new drug therapy during the new drug-approval process, quantitative risk-benefit assessment (RBA) is not typically performed, nor is it presented in a consistent and integrated framework when it is used. Our purpose is to identify and describe published quantitative RBA methods for pharmaceuticals.

METHODS

Using MEDLINE and other Internet-based search engines, a systematic literature review was performed to identify quantitative methodologies for RBA. These distinct RBA approaches were summarized to highlight the implications of their differences for the pharmaceutical industry and regulatory agencies.

RESULTS

Theoretical models, parameters, and key features were reviewed and compared for the 12 quantitative RBA methods identified in the literature, including the Quantitative Framework for Risk and Benefit Assessment, benefit-less-risk analysis, the quality-adjusted time without symptoms and toxicity, number needed to treat (NNT), and number needed to harm and their relative-value-adjusted versions, minimum clinical efficacy, incremental net health benefit, the risk-benefit plane (RBP), the probabilistic simulation method, multicriteria decision analysis (MCDA), the risk-benefit contour (RBC), and the stated preference method (SPM). Whereas some approaches (e.g., NNT) rely on subjective weighting schemes or nonstatistical assessments, other methods (e.g., RBP, MCDA, RBC, and SPM) assess joint distributions of benefit and risk.

CONCLUSIONS

Several quantitative RBA methods are available that could be used to help lessen concern over subjective drug assessments and to help guide authorities toward more objective and transparent decision-making. When evaluating a new drug therapy, we recommend the use of multiple RBA approaches across different therapeutic indications and treatment populations in order to bound the risk-benefit profile.

Systematic review: the efficacy of treatments for irritable bowel syndrome--a European perspective

BACKGROUND

Irritable bowel syndrome (IBS) is a common, chronic disorder, characterized by abdominal pain/discomfort, bloating and altered bowel habit.

AIM

To conduct a systematic evidence-based review of pharmacological therapies currently used, or in clinical development, for the treatment of IBS in Europe. The safety and tolerability of these therapies are the subject of an accompanying review.

METHODS

A literature search was completed for randomized controlled studies which included adult patients with IBS and an active or placebo control, assessed IBS symptoms, and were published in English between January 1980 and June 2005. The level of evidence for efficacy was graded according to the quality of the trial design and the study outcome.

RESULTS

There is some evidence for improvement of individual IBS symptoms with antidiarrhoeals (diarrhoea), antispasmodics (abdominal pain/discomfort), bulking agents (constipation), tricyclic antidepressants (abdominal pain/discomfort) and behavioural therapy. In contrast, there is strong evidence for the improvement of global IBS symptoms with two new serotonergic agents: the 5-HT4 selective agonist tegaserod (IBS with constipation) and the 5-HT3 antagonist alosetron (IBS with diarrhoea). Further data are required for the 5-HT3 antagonist, cilansetron, and the mixed 5-HT3 antagonist/5-HT4 agonist renzapride before their utility in IBS can be appraised.

CONCLUSIONS

There is limited evidence for the efficacy, safety and tolerability of therapies currently available in Europe for the treatment of IBS. Overall, there is an absence of pharmacological agents licensed specifically for the treatment of IBS subtypes, and new agents are awaited in Europe that will allow changes in clinical practice to focus on and improve global IBS symptoms.

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.

Emerging drugs for gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease is a common medical problem caused by the exposure of the distal oesophagus to gastric contents. Existing medical therapy is very effective, but symptomatic relief with acid suppressants is often delayed. Treatment focuses on the suppression of gastric acid rather than on the underlying pathophysiological abnormalities, such as transient non-swallow-related lower oesophageal sphincter relaxation. Current pharmacological developments concentrate on drugs with lasting acid suppression and a faster onset of action. Compounds interacting with the complex neuromuscular regulation of the gastro-oesophageal junction are also being developed and offer exciting prospects.