The gut microbiota participates in the effect of linaclotide in patients with irritable bowel syndrome with constipation (IBS-C): a multicenter, prospective, pre-post study

BACKGROUND

Interindividual variation characterizes the relief experienced by constipation-predominant irritable bowel syndrome (IBS-C) patients following linaclotide treatment. Complex bidirectional interactions occur between the gut microbiota and various clinical drugs. To date, no established evidence has elucidated the interactions between the gut microbiota and linaclotide. We aimed to explore the impact of linaclotide on the gut microbiota and identify critical bacterial genera that might participate in linaclotide efficacy.

METHODS

IBS-C patients were administered a daily linaclotide dose of 290 µg over six weeks, and their symptoms were then recorded during a four-week posttreatment observational period. Pre- and posttreatment fecal samples were collected for 16S rRNA sequencing to assess alterations in the gut microbiota composition. Additionally, targeted metabolomics analysis was performed for the measurement of short-chain fatty acid (SCFA) concentrations.

RESULTS

Approximately 43.3% of patients met the FDA responder endpoint after taking linaclotide for 6 weeks, and 85% of patients reported some relief from abdominal pain and constipation. Linaclotide considerably modified the gut microbiome and SCFA metabolism. Notably, the higher efficacy of linaclotide was associated with enrichment of the Blautia genus, and the abundance of Blautia after linaclotide treatment was higher than that in healthy volunteers. Intriguingly, a positive correlation was found for the Blautia abundance and SCFA concentrations with improvements in clinical symptoms among IBS-C patients.

CONCLUSION

The gut microbiota, especially the genus Blautia, may serve as a significant predictive microbe for symptom relief in IBS-C patients receiving linaclotide treatment.

TRIAL REGISTRATION

This trial was registered with the Chinese Clinical Trial Registry (Chictr.org.cn, ChiCTR1900027934).

Comparative profiles of lubiprostone, linaclotide, and elobixibat for chronic constipation: a systematic literature review with meta-analysis and number needed to treat/harm

OBJECTIVE

To comprehensively evaluate the efficacy, safety, patient symptoms, and quality-of-life (QoL) of lubiprostone, linaclotide, and elobixibat as treatment for chronic constipation (CC).

DESIGN

Systematic literature review (SLR) and meta-analysis (MA). Literature searches were conducted on PubMed and Embase using the Ovid platform.

METHODS

SLR including randomized controlled trials (RCTs) and observational studies was conducted to identify the overall efficacy and safety of lubiprostone, linaclotide, and elobixibat. Thereafter, MA was performed using only RCTs. The number needed to treat (NNT) and number needed to harm (NNH) analyses were additionally conducted.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was efficacy regarding change in spontaneous bowel movements. Secondary outcomes included safety, constipation-related symptoms, and QoL.

RESULTS

Twenty-four studies met the inclusion criteria for the SLR: 17 RCTs, 4 observational studies, and 3 single-arm trials. Feasibility assessment for the MA resulted in 14 studies available for safety data analysis, and 8 available for efficacy analysis, respectively. Three drugs showed similar efficacy in the MA and NNT analysis. However, the NNH analysis revealed distinct safety profiles: lubiprostone, linaclotide, and elobixibat were linked to the highest risk of nausea, diarrhea, and abdominal pain, respectively.

CONCLUSION

The current study provides an updated overview of the efficacy, safety, patient symptoms, and QoL of the three drugs with different mechanisms of action for CC treatment.The findings could help physicians adopt an individualized approach for treating patients with CC in clinical practice.

Linaclotide combined with polyethylene glycol regimen for bowel preparation in patients with chronic constipation: A prospective randomized controlled study

BACKGROUND

The standard of bowel preparation sometimes is not met by using the 3 L polyethylene glycol electrolyte (PEG) method in patients with chronic constipation, which significantly impacts the diagnosis of colorectal diseases. Linaclotide can be utilized for the treatment of chronic idiopathic constipation. It is worth investigating whether linaclotide combined with 3 L PEG regimen can further optimize intestinal preparation in patients with chronic constipation.

AIM

To evaluate the efficacy and comfort of linaclotide combined with PEG for bowel preparation in patients with chronic constipation by comparing with PEG.

METHODS

From July 2021 to December 2022, 120 patients with chronic constipation who underwent colonoscopy at the Department of Gastroenterology, the Second Affiliated Hospital of Wenzhou Medical University were selected as research subjects. Using the random number table method, the patients were randomly divided into either a control group or an observation group. Both groups were given 3 L PEG and methylene silicone oil, and the observation group was additionally given three linaclotide capsules. The score of Boston Bowel Preparation Scale (BBPS), colonoscopy entry time, the detection rate of polyps or adenomas, and the incidence of adverse reactions were compared between two groups. Independent sample t test and χ² test were used for statistical comparisons.

RESULTS

The BBPS scores of the right segment, the middle segment, and the left segment, as well as the BBPS score of the overall bowel were higher in the observation group (P < 0.05). The colonoscopy entry time was shorter in the observation group (P < 0.05). The detection rates of polyps and adenomas (22% [11/50] vs 46% [23/50]; 14% [7/50] vs 32% [16/50]) differed significantly between the control group and observation group (P < 0.05). The incidence of adverse reactions in the observation group was significantly shorter than that of the control group (P < 0.05).

CONCLUSION

Compared with the 3 L PEG method, linaclotide combined with 3 L PEG regimen can achieve better bowel preparation effect, reduce the incidence of adverse reactions, and has higher safety, which is worthy of further clinical promotion.

American Gastroenterological Association-American College of Gastroenterology Clinical Practice Guideline: Pharmacological Management of Chronic Idiopathic Constipation

INTRODUCTION

Chronic idiopathic constipation (CIC) is a common disorder associated with significant impairment in quality of life. This clinical practice guideline, jointly developed by the American Gastroenterological Association and the American College of Gastroenterology, aims to inform clinicians and patients by providing evidence-based practice recommendations for the pharmacological treatment of CIC in adults.

METHODS

The American Gastroenterological Association and the American College of Gastroenterology formed a multidisciplinary guideline panel that conducted systematic reviews of the following agents: fiber, osmotic laxatives (polyethylene glycol, magnesium oxide, lactulose), stimulant laxatives (bisacodyl, sodium picosulfate, senna), secretagogues (lubiprostone, linaclotide, plecanatide), and serotonin type 4 agonist (prucalopride). The panel prioritized clinical questions and outcomes and used the Grading of Recommendations Assessment, Development, and Evaluation framework to assess the certainty of evidence for each intervention. The Evidence to Decision framework was used to develop clinical recommendations based on the balance between the desirable and undesirable effects, patient values, costs, and health equity considerations.

RESULTS

The panel agreed on 10 recommendations for the pharmacological management of CIC in adults. Based on available evidence, the panel made strong recommendations for the use of polyethylene glycol, sodium picosulfate, linaclotide, plecanatide, and prucalopride for CIC in adults. Conditional recommendations were made for the use of fiber, lactulose, senna, magnesium oxide, and lubiprostone.

DISCUSSION

This document provides a comprehensive outline of the various over-the-counter and prescription pharmacological agents available for the treatment of CIC. The guidelines are meant to provide a framework for approaching the management of CIC; clinical providers should engage in shared decision making based on patient preferences as well as medication cost and availability. Limitations and gaps in the evidence are highlighted to help guide future research opportunities and enhance the care of patients with chronic constipation.

AGA Clinical Practice Guideline on the Pharmacological Management of Irritable Bowel Syndrome With Constipation

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction associated with significant disease burden. This American Gastroenterological Association guideline is intended to support practitioners in decisions about the use of medications for the pharmacological management of IBS-C and is an update of a prior technical review and guideline.

METHODS

The Grading of Recommendations Assessment, Development and Evaluation framework was used to assess evidence and make recommendations. The technical review panel prioritized clinical questions and outcomes according to their importance for clinicians and patients and conducted an evidence review of the following agents: tenapanor, plecanatide, linaclotide, tegaserod, lubiprostone, polyethylene glycol laxatives, tricyclic antidepressants, selective serotonin reuptake inhibitors, and antispasmodics. The Guideline Panel reviewed the evidence and used the Evidence-to-Decision Framework to develop recommendations.

CONCLUSIONS

The panel agreed on 9 recommendations for the management of patients with IBS-C. The panel made a strong recommendation for linaclotide (high certainty) and conditional recommendations for tenapanor, plecanatide, tegaserod, and lubiprostone (moderate certainty), polyethylene glycol laxatives, tricyclic antidepressants, and antispasmodics (low certainty). The panel made a conditional recommendation against the use of selective serotonin reuptake inhibitors (low certainty).

Cost-Effectiveness of Linaclotide Compared to Osmotic Laxatives in the Treatment of Irritable Bowel Syndrome with Constipation in China

INTRODUCTION

Linaclotide, a selective agonist of guanylate cyclase C, was highly recommended for the treatment of irritable bowel syndrome with constipation (IBS-C). However, the cost-effectiveness of linaclotide in Chinese is not known, and this study aimed to assess the cost-effectiveness of linaclotide for patients with IBS-C.

METHODS

An economic evaluation was conducted with a Markov model from a societal perspective. The Markov model was structured to simulate the discontinuation and continuation of medication in IBS-C patients in clinical practice, as well as the revisit and non-visit of non-responding patients. The cycle of the model was 4 weeks, and the time horizon was 1 year. The efficacy data in the model was from the risk ratios obtained by the meta-analysis and the calculation of the response rate of the three medications. The utility, discontinuation rate of the medication, and revisit rate data were from published literature, while the cost data were obtained from experts' opinions and published literature. A series of sensitivity analyses was performed on parameters potentially having impact on the model outputs.

RESULTS

The QALYs (quality-adjusted life years) gained for 1-year treatment with linaclotide, polyethylene glycol, and lactulose were 0.821, 0.795, and 0.781, respectively. The corresponding total costs were CNY 7,721 (USD 1,120), CNY 8,797 (USD 1,276) and CNY 9,481 (USD 1,375). In both comparisons, linaclotide was dominant. Compared with polyethylene glycol and lactulose, the likelihood of linaclotide being cost-effective was 100% for both, using 1 times per capita GDP per QALY as willingness-to-pay threshold.

CONCLUSIONS

IBS-C seriously affects the quality of life of patients with IBS-C, and linaclotide can improve symptoms and quality of life at less cost.

Constipation in Cancer Patients - an Update of Clinical Evidence

OPINION STATEMENT

Constipation is one of the most frequent problems in cancer patients, and its etiology is multifactorial. It leads to decreased quality of life and impedes optimal pain treatment. Despite the high prevalence, constipation is frequently underdiagnosed mainly because of lack of validated diagnostic criteria or widely accepted definition of constipation in cancer patients. All cancer patients should be evaluated regularly for constipation, and concomitant causes and risk factors were assessed. Opioids are responsible for a much of the secondary constipation in cancer patients. The management of constipation in cancer patients should be multifaceted, addressing dietary and behavioral issues and optimizing pharmacological interventions. Prevention of opioid-induced constipation (OIC) is pivotal, as treatment is often unsatisfactory or inefficient. Dietary and behavioral interventions should be considered. Non-pharmacological measures include hydration and nutrition, ensuring privacy during defecation, using a commode or footstool, and the availability of a caregiver. Abdominal massage may be of value. Traditional laxatives are recommended in prevention but not in the treatment of OIC. Peripherally acting mu-opioid receptor antagonists (PAMORA) appear the first choice in the treatment and an alternative to laxatives in some recent clinical practice guidelines in preventing OIC. Naldemedine, naloxegol, and methylnaltrexone are supported by quality evidence for OIC management. Naloxone or naltrexone, taken orally in combined formulations with opioids, may be valuable in preventing or reducing OIC symptoms.

Irritable bowel syndrome

Irritable bowel syndrome is one of the most common functional bowel disorders, and has a substantial impact on patients' daily lives, as well as a big economic impact on society. It is characterised by abdominal pain, bloating and abdominal distention and altered bowel movements, with a predominance of diarrhoea, constipation, or alternation of these signs, which cannot be explained by a structural or biochemical abnormality. Its aetiopathogenesis and pathophysiological mechanism are unknown. The disease affects 5%-10% of healthy individuals at any given time and, in most people, has a relapsing-remitting course. This article reviews some of the main and most current evidence on its epidemiology, risk factors, pathophysiology, clinical manifestations, diagnostic approach, and therapeutic options, both dietary, pharmacological and psychotherapeutic.

Linaclotide for the treatment of refractory lower bowel manifestations of systemic sclerosis

Background

Lower gastrointestinal (GI) tract involvement can affect up to 50% of systemic sclerosis (SSc) patients, and may result in malabsorption, pseudo-obstruction, hospitalization, and death. We report our experience with linaclotide, a selective agonist of guanylate cyclase C (GC-C), for SSc patients with refractory lower GI disease.

Methods

We performed an analysis of patients seen at the Johns Hopkins Scleroderma Center and identified patients prescribed linaclotide for refractory lower GI manifestations. Patients had clinical data collected in our longitudinal database. Linaclotide responders were on medication for at least 12 months with documented effectiveness by the treating physician.

Results

Thirty-one patients with SSc were treated with linaclotide. At the time of linaclotide initiation, 23 of these patients (74%) were classified as having severe GI disease, as defined by recurrent pseudo-obstruction, malabsorption, and/or need for artificial nutrition (Medsger GI severity score ≥ 3). The majority of patients (90.3%; 28/31) had a treatment response, while only three patients (9.7%) reported ineffectiveness or intolerable side effects. Low-dose linaclotide (≤ 145 mcg daily) was used in 18 patients and was effective in 94%. High-dose therapy (> 145 mcg daily) was effective in 11 of 13 patients (85%). Common side effects were diarrhea, cramping, or bloating (11/31, 35%). Ineffectiveness, cost, and abdominal pain were complaints cited among those who discontinued therapy.

Conclusion

Linaclotide is a well-tolerated and efficacious pro-secretory and pro-motility agent that can be used to manage refractory lower GI manifestations in SSc. We found that low-dose linaclotide is an effective option and may be better tolerated, though a subset of patients may require high dose regimens.

Evaluation and Treatment of Constipation in the Geriatric Population

Chronic constipation affects one-third of the US population and occurs disproportionately in the elderly and female individuals, increasing in older individuals who are institutionalized. This condition has a significant impact on health care costs and quality of life. Clinicians need to consider primary as well as secondary causes of constipation in elderly individuals because the cause is often multifactorial. Diagnostic algorithms should eliminate red-flag symptoms that may indicate a malignancy but also consider pelvic floor dysfunction, which is more common in this age group. An appropriate treatment plan is tailored to the severity of the patient's symptoms.

Tadalafil versus linaclotide in gastrointestinal dysfunction and depressive behavior in constipation-predominant irritable bowel syndrome

BACKGROUND

Intestinal GC-C/cGMP pathway may be involved in visceral hypersensitivity and fluid secretion in irritable bowel syndrome (IBS). The guanylcyclase C agonist linaclotide, approved for IBS- constipation, is contraindicated in children as it may cause severe diarrhea. In contrast, drugs increasing cGMP by inhibiting phosphodiesterase 5 (PDE-5) are well tolerated in children with pulmonary hypertension. Accordingly, we investigated whether beneficial effects of linaclotide in IBS might be shared by PDE-5inhibitor tadalafil without the severe diarrhea reported for linaclotide. Since depression is commonly comorbid with IBS and is implicated in its pathophysiology; and since tadalafil is absorbed systemically and crosses blood brain barrier, whereas linaclotide does not, impact of both drugs on behavioral changes in IBS was also investigated.

METHODS

72 rats were divided into 6groups (control naive, control tadalafil, control linaclotide, untreated IBS, IBS tadalafil, and IBS linaclotide-treated). IBS was induced by 0 to 4 °C intragastric saline for 14 days.

RESULTS

Both drugs reduced visceral hypersensitivity and colonic C fos. Tadalafil, and to a greater extent, linaclotide increased colonic cGMP, fecal pellets (8.66 ± 4.6 (IBS),versus14.8 ± 3.3(tadalafil), 20 ± 1.2(linaclotide), fecal water content (29.8 ± 5.5 (IBS), versus 47.83 ± 12.6 (tadalafil), 63.58 ± 11.6 (linaclotide) and reduced intestinal transit time (% distance travelled: 29 ± 6.1(IBS), versus 40.58 + 7.5(tadalafil), 51.83 ± 8.3(linaclotide). Tadalafil, but not linaclotide, increased hippocampal cGMP, and improved behavioral tests scores compared to linaclotide (immobility time: 97.3 ± 12.5 s (IBS) versus 68 ± 12.8(tadalafil), 80 ± 17.06 (linaclotide).

CONCLUSION

Systemic PDE-5 inhibitors might be alternatives to locally acting guanyl cyclase agonists in IBS, inducing less severe diarrhea and more beneficial effects on the associated behavioral changes.

Oral Pharmacological Activation of Hypothalamic Guanylate Cyclase 2C Receptor Stimulates Brown Fat Thermogenesis to Reduce Body Weight

Linaclotide is a synthetic peptide approved by the FDA for the treatment of constipation-predominant irritable bowel syndrome and chronic constipation. Linaclotide binds and activates the transmembrane receptor guanylate cyclase 2C (Gucy2c). Uroguanylin (UGN) is a 16 amino acid peptide that is mainly secreted by enterochromaffin cells in the duodenum and proximal small intestine. UGN is the endogenous ligand of Gucy2c and decreases body weight in diet-induced obese (DIO) mice via the activation of the thermogenic program in brown adipose tissue. Therefore, we wanted to evaluate whether oral linaclotide could also improve DIO mice metabolic phenotype. In this study, we have demonstrated that DIO mice orally treated with linaclotide exhibited a significant reduction of body weight without modifying food intake. Linaclotide exerts its actions through the central nervous system, and more specifically, via Gucy2c receptors located in the mediobasal hypothalamus, leading to the activation of the sympathetic nervous system to trigger the thermogenic activity of brown fat stimulating energy expenditure. These findings indicate for first time that, in addition to its effects at intestinal level to treat irritable bowel syndrome with constipation and chronic constipation, linaclotide also exerts a beneficial effect in whole body metabolism.

Single-Dose Linaclotide Is Equal in Efficacy to Polyethylene Glycol for Bowel Preparation Prior to Capsule Endoscopy

BACKGROUND

Video capsule endoscopy provides noninvasive visualization of the small bowel, but yield is often limited by debris. At our institution, preparation with polyethylene glycol (PEG) and simethicone is used to improve visualization.

AIMS

We hypothesized that linaclotide and simethicone would yield equal to better results.

METHODS

We enrolled 29 subjects for the experimental regimen of linaclotide and simethicone. We maintained standard NPO status, clear liquid period, and simethicone dose. Subjects received 290 μg of linaclotide 1 h prior to capsule. We randomly selected 30 historical PEG controls. Two blinded gastroenterologists graded visualization as ideal/excellent, good, fair, or poor and measured small bowel transit time.

RESULTS

Thirteen men and 16 women were enrolled with an average age of 61. There was no significant difference in exam quality between linaclotide and control. Preparation was rated as ideal/excellent or good in 19 of 28 of linaclotide and 18 of 28 PEG subjects when recorder entered the small bowel (p = 0.78, chi-square). Median small bowel transit was 192 min (linaclotide) versus 202 min (PEG), respectively (p = 0.93, t test). Three studies (1 linaclotide and 2 PEG) failed to leave the stomach; 1 linaclotide subject had recorder failure. Diagnostic yield was similar (18/29 for linaclotide and 16/30 for PEG, p = 0.50, chi-square). There were no serious side effects. No differences in age, sex, BMI, or frequency of diabetes, GERD, or gastroparesis were measured between the groups.

CONCLUSIONS

Single-dose linaclotide 1 h before capsule endoscopy was equally effective when compared to PEG in terms of visualization and transit time. This trial was registered at ClincialTrials.gov, number NCT02465385.

Targeting the paracrine hormone-dependent guanylate cyclase/cGMP/phosphodiesterases signaling pathway for colorectal cancer prevention

Colorectal cancer (CRC) is one of the leading causes of cancer related-deaths. The risk of development of CRC is complex and multifactorial, and includes disruption of homeostasis of the intestinal epithelial layer mediated though dysregulations of tumor suppressing/promoting signaling pathways. Guanylate cyclase 2C (GUCY2C), a membrane-bound guanylate cyclase receptor, is present in the apical membranes of intestinal epithelial cells and maintains homeostasis. GUCY2C is activated upon binding of paracrine hormones (guanylin and uroguanylin) that lead to formation of cyclic GMP from GTP and activation of downstream signaling pathways that are associated with normal homeostasis. Dysregulation/suppression of the GUCY2C-mediated signaling promotes CRC tumorigenesis. High-calorie diet-induced obesity is associated with deficiency of guanylin expression and silencing of GUCY2C-signaling in colon epithelial cells, leading to tumorigenesis. Thus, GUCY2C agonists, such as linaclotide, exhibit considerable role in preventing CRC tumorigenesis. However, phosphodiesterases (PDEs) are elevated in intestinal epithelial cells during CRC tumorigenesis and block GUCY2C-mediated signaling by degrading cyclic GMP to 5`-GMP. PDE5-specific inhibitors, such as sildenafil, show considerable anti-tumorigenic potential against CRC by amplifying the GUCY2C/cGMP signaling pathway, but cannot achieve complete anti-tumorigenic effects. Hence, dual targeting the elevation of cGMP by providing paracrine hormone stimuli to GUCY2C and by inhibition of PDEs may be a better strategy for CRC prevention than alone. This review delineates the involvement of the GUCY2C/cGMP/PDEs signaling pathway in the homeostasis of intestinal epithelial cells. Further, the events are associated with dysregulation of this pathway during CRC tumorigenesis are also discussed. In addition, current updates on targeting the GUCY2C/cGMP/PDEs pathway with GUCY2C agonists and PDEs inhibitors for CRC prevention and treatment are described in detail.

Medical Therapy of Constipation: Current Standards and Beyond

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

[Pharmacotherapy in Patients with Chronic Constipation]

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

Intractable Constipation in the Elderly

OPINION STATEMENT

Chronic constipation is a common gastrointestinal disorder disproportionately affecting the elderly. Immobility, polypharmacy, and physiologic changes contribute to its increased prevalence in this population. Unidentified and undertreated constipation leads to a significant negative impact on quality of life and an increase in healthcare spending. Careful physical examination and exploration of the clinical history can unmask primary and secondary forms of constipation, guiding diagnostic and therapeutic considerations. Non-pharmacologic treatment options include bowel training and biofeedback as well as the addition of fiber. Laxatives are safe and can be used long term; thus, they remain the mainstay of therapy. Newer agents with specific physiologic targets have proven to be effective in adults with chronic constipation, but data is lacking for safety profile in the elderly. Consideration for surgery in medically refractory cases should be entertained, while use of neuromodulation is not ready for prime time. This is a review of the currently available treatment options for chronic constipation in adults and specifically tailored towards the elderly.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Update on the Management of Chronic Constipation

OPINION STATEMENT

Chronic constipation (CC) is a highly prevalent disorder encountered by health care providers of all specialties. The diagnosis can be confidently made by taking a careful history, evaluating for warning signs and symptoms, performing an examination, including a digital rectal exam, and using the Rome IV criteria. Treatment should begin at the first visit; most patients require few diagnostic tests to make, or confirm, the diagnosis of CC. Assuming that the patient has persistent symptoms of constipation, despite using traditional therapy (fiber, osmotic agents), then patients should be offered one of the newer treatments, rather than repeating prior treatments, which is a common practice. Lubiprostone, a chloride channel activator, has been shown to safely improve symptoms of CC. Its proven track record of success over the last decade is a common reason why many health care providers choose this as a first-line agent. Alternatively, linaclotide, which stimulates guanylate cyclase C receptors, and which has also been shown to improve symptoms of CC in large, randomized trials, is another logical choice. The decision of which agent to use first often depends upon the patient's co-payment or insurance plan. Either medication should be given a trial of at least 4-6 weeks. If a patient does not respond, then the patient should be treated with the other agent. If symptoms persist, the clinician should consider the possibility of overlapping, or predominant, pelvic floor dysfunction (PFD). The combination of high-resolution anorectal manometry and a balloon expulsion test can be used to make the diagnosis of PFD. If present, patients should be referred to a knowledgeable physical therapist for pelvic floor retraining. New treatment options are available to treat the multiple symptoms of CC. Co-existing pelvic floor dysfunction should be considered in those patients who fail medical therapy.

Cost-effectiveness of linaclotide compared to antidepressants in the treatment of irritable bowel syndrome with constipation in Scotland

Presently, linaclotide is the only EMA-approved therapy indicated for the treatment of irritable bowel syndrome with constipation (IBS-C). This study sought to determine the cost-effectiveness of linaclotide compared to antidepressants for the treatment of adults with moderate to severe IBS-C who have previously received antispasmodics and/or laxatives. A Markov model was created to estimate costs and QALYs over a 5-year time horizon from the perspective of NHS Scotland. Health states were based on treatment satisfaction (satisfied, moderately satisfied, not satisfied) and mortality. Transition probabilities were based on satisfaction data from the linaclotide pivotal studies and Scottish general all-cause mortality statistics. Treatment costs were calculated from the British National Formulary. NHS resource use and disease-related costs for each health state were estimated from Scottish clinician interviews in combination with NHS Reference costs. Quality of life was based on EQ-5D data collected from the pivotal studies. Costs and QALYs were discounted at 3.5 % per annum. Uncertainty was explored through extensive deterministic and probabilistic sensitivity analyses. Over a 5-year time horizon, the additional costs and QALYs generated with linaclotide were £659 and 0.089, resulting in an incremental cost-effectiveness ratio of £7370 per QALY versus antidepressants. Based on the probabilistic sensitivity analysis, the likelihood that linaclotide was cost-effective at a willingness to pay of £20,000 per QALY was 73 %. Linaclotide can be a cost-effective treatment for adults with moderate-to-severe IBS-C who have previously received antispasmodics and/or laxatives in Scotland.

New Options in Constipation Management

Constipation is common in the general population and for those on opioids and/or who are suffering from advanced cancer. Self-management consists of dietary changes, exercise, and laxatives. However, responses to self-management efforts are often inadequate to relieve the subjective and objective experience of constipation. Multiple new anti-constipating medications have recently been tested in randomized trials and the following are available commercially: probiotics, prucalopride, lubiprostone, linaclotide, elobixibat, antidepressants, methylnaltrexone, alvimopan, and naloxegol. This review will discuss the evidence-based benefits of these medications and outline an approach to managing constipation.

Review of efficacy and safety of laxatives use in geriatrics

AIM: To study the efficacy and safety of pharmacological treatment of constipation in geriatrics.

METHODS: PubMed, MEDLINE, google scholar, and Ovid were searched to identify human studies performed on the use of laxatives in elderly with constipation, which were conducted between January 1990 and January 2013 using the specified keywords. Controlled studies that enrolled geriatric patients with a diagnosis of constipation and addressed the efficacy and/or the safety of pharmacological treatments were included. Studies were excluded from this review if they were non-controlled trials, case series, or case reports.

RESULTS: Out of twenty three studies we initially retrieved in our search, only nine studies met the eligibility criteria of being controlled trials within geriatrics. The laxatives examined in the nine studies were senna, lactulose, sorbital, polyethylene glycol (PEG), lubiprostone, linaclotide, and prucalopride. In those studies, senna combinations had a higher efficacy than sorbitol or lactulose as well as, a very good adverse effect profile. PEG was also shown to be safe and effective in geriatric population. Furthermore, it has been shown that PEG is as safe in geriatrics as in general population. New agents like lubiprostone and prucalopride show promising results but the data about these agents in geriatrics are still limited which warrants further investigation.

CONCLUSION: Senna combinations and PEG appear to have a more favorable profile over the other traditionally used laxatives in elderly patients with constipation.

[Current issues on the treatment of chronic constipation]

Chronic constipation is a very common clinical problem with its prevalence of up to 14% in the general population. It is not a life-threatening disease, but since patient's satisfaction to the treatment is known to be as low as 50%, chronic constipation still remains a clinically challenging problem. Fortunately, many new treatments have been introduced or are to be introduced in the near future. This article will review the basic concepts and the results of recent studies on the new treatments for chronic constipation.

Recent Updates on the Treatment of Constipation

The treatment of constipation aims to regulate the frequency and quantity of stool in order to promote successful defecation. Numerous studies on pharmacologic treatments and non-pharmacologic therapies for constipation have attempted to overcome limitations such as temporary and insufficient efficacy. Conventional laxatives have less adverse effects and are inexpensive, but often have limited efficacy. Recently developed enterokinetic agents and intestinal secretagogues have received attention owing to their high efficacies and low incidences of adverse events. Studies on biofeedback and surgical treatment have focused on improving symptoms as well as quality of life for patients with refractory constipation.

Comparison of adequate relief with symptom, global, and responder endpoints in linaclotide phase 3 trials in IBS-C

BACKGROUND

Optimal clinical trial endpoints for irritable bowel syndrome with constipation (IBS-C) are uncertain.

OBJECTIVE

The objective of this article is to compare adequate relief (AR) to abdominal/bowel symptoms, global endpoints, and FDA and EMA responder criteria; and to use AR as an anchor to assess clinically meaningful change (CMC) in IBS-C symptoms.

METHODS

Using pooled 12-week data from two phase 3 linaclotide clinical trials, daily abdominal/bowel symptoms and weekly global assessments were correlated with AR. Symptom CMC thresholds were estimated using AR as an anchor. Agreement between AR and FDA/EMA responder criteria was assessed.

RESULTS

Correlations of AR with percentage change in abdominal symptoms, bowel symptoms, and global endpoints ranged from 0.48-0.54, 0.32-0.39, and 0.61-0.71, respectively. Using AR as an anchor, CMC thresholds were 29% improvement in abdominal pain, 29% improvement in abdominal discomfort, and 0.7/week increase in CSBMs, similar to thresholds for IBS-C responder endpoints recommended by the FDA and EMA. There was considerable agreement of weekly responder rates between AR and the FDA and EMA endpoints (on average, 70%-76% and 71%-82% of weeks with agreement, respectively).

CONCLUSIONS

AR bridges IBS-C clinical trials, putting into perspective the disparate primary endpoints recommended by professional societies and regulatory authorities, and allowing researchers, practitioners, and regulators to compare trial results.

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

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

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

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

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

Irritable bowel syndrome: a concise review of current treatment concepts

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders causing patients to seek medical treatment. It is relatively resource intensive and the source of significant morbidity. Recent insights into the pathophysiology and treatment of IBS has given clinicians more options than ever to contend with this disorder. The purpose of our paper is to review older, "classic" treatments for IBS as well as newer agents and "alternative" therapies. We discuss the evidence base of these drugs and provide context to help develop appropriate treatment plans for IBS patients.

Linaclotide: A new drug for the treatment of chronic constipation and irritable bowel syndrome with constipation

INTRODUCTION

Linaclotide is the first member of a novel class of drugs to be extensively evaluated for the treatment of chronic constipation (CC) and irritable bowel syndrome with constipation (IBS-C).

AIM

To provide a comprehensive overview of the current state of knowledge on linaclotide, its pharmacological properties, mode of action and efficacy in clinical trials to date.

METHODS

We conducted a systematic review of the literature.

RESULTS

The survey revealed that linaclotide is a minimally absorbed, 14-amino acid peptide which acts in the intestinal lumen on guanylate cyclase-C (GC-C). This results in generation of cyclic guanosine monophosphate (cGMP), which stimulates chloride secretion, resulting in increased luminal fluid secretion and an acceleration of intestinal transit. In animal models, linaclotide also decreased visceral hypersensitivity. Linaclotide softened stool and increased transit in CC and in IBS-C. Phase II and phase III clinical studies established efficacy of linaclotide in CC (linaclotide 145 µg daily approved in the United States for CC) and in IBS-C (linaclotide 290 µg daily US Food and Drug Administration-approved for IBS-C, with favourable recommendation for the European Medicines Agency Committee for Medicinal Products for Human Use (CHMP). Linaclotide showed a favourable safety profile, and the main treatment-emerging adverse event was diarrhea, leading to discontinuation rates of up to 5%. Linaclotide is an important addition to the therapeutic possibilities for treating IBS-C and CC.

Novel therapies for constipation

Constipation is a common medical problem and when standard laxatives fail it can be difficult to treat. Different aetiologies require tailored therapeutic approaches. Simple constipation may only require dietary manipulation while severe neurological or slow transit constipation may need pharmacologic intervention. Recently new drug therapies have been introduced. PubMed and Ovid were searched for reviews, systematic reviews and meta-analysis published since 2003 using the terms: constipation, prucalopride, linaclotide and lubiprostone. This review summarizes potential novel therapies identified as effective in the management of chronic constipation. Prucalopride is a selective 5-hydroxytryptamine receptor agonist. The prucalopride study was in patients, largely women with idiopathic constipation showed improved spontaneous complete bowel movement (SCBM) at a dose of 2 mg a day with few adverse events reported. Linaclotide is a 14-amino acid peptide guanylate cyclase-C agonist. The linaclotide study was carried out in patients with irritable bowel syndrome, constipation group (IBS-C). There was significant improvement of bowel evacuation and symptom resolution in patients on the active treatment arm. Lubiprostone activates type-2 chloride channels, increasing intestinal fluid secretion. In the trials of this drug, the lubiprostone arms had a greater mean number of SCBM. The novel therapies, prucalopride, lubiprostone, and linaclotide had very different modes of action yet, all three have been shown to be efficacious and safe in the treatment dose for constipation.

Gastrointestinal pain: unraveling a novel endogenous pathway through uroguanylin/guanylate cyclase-C/cGMP activation

The natural hormone uroguanylin regulates intestinal fluid homeostasis and bowel function through activation of guanylate cyclase-C (GC-C), resulting in increased intracellular cyclic guanosine-3',5'-monophosphate (cGMP). We report the effects of uroguanylin-mediated activation of the GC-C/cGMP pathway in vitro on extracellular cGMP transport and in vivo in rat models of inflammation- and stress-induced visceral hypersensitivity. In vitro exposure of intestinal Caco-2 cells to uroguanylin stimulated bidirectional, active extracellular transport of cGMP into luminal and basolateral spaces. cGMP transport was significantly and concentration dependently decreased by probenecid, an inhibitor of cGMP efflux pumps. In ex vivo Ussing chamber assays, uroguanylin stimulated cGMP secretion from the basolateral side of rat colonic epithelium into the submucosal space. In a rat model of trinitrobenzene sulfonic acid (TNBS)-induced visceral hypersensitivity, orally administered uroguanylin increased colonic thresholds required to elicit abdominal contractions in response to colorectal distension (CRD). Oral administration of cGMP mimicked the antihyperalgesic effects of uroguanylin, significantly decreasing TNBS- and restraint stress-induced visceromotor response to graded CRD in rats. The antihyperalgesic effects of cGMP were not associated with increased colonic spasmolytic activity, but were linked to significantly decreased firing rates of TNBS-sensitized colonic afferents in rats in response to mechanical stimuli. In conclusion, these data suggest that the continuous activation of the GC-C/cGMP pathway along the intestinal tract by the endogenous hormones guanylin and uroguanylin results in significant reduction of gastrointestinal pain. Extracellular cGMP produced on activation of GC-C is the primary mediator in this process via modulation of sensory afferent activity.