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Sendzischew Shane MA, Ruddy J, Cline M, Rosenbaum DP, Edelstein S, Moshiree B. Review of the Patient Burden and Therapeutic Landscape of Irritable Bowel Syndrome with Constipation in the United States. Clin Exp Gastroenterol 2024; 17:227-253. [PMID: 39114809 PMCID: PMC11303673 DOI: 10.2147/ceg.s464375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 06/25/2024] [Indexed: 08/10/2024] Open
Abstract
Irritable bowel syndrome (IBS) is a common disorder of the gut-brain axis. IBS with constipation (IBS-C) accounts for approximately one-third of IBS cases and is associated with substantial burden of illness and decreased quality of life. This narrative review provides an overview of the current and upcoming treatment options and disease management for IBS-C from a US perspective and discusses the importance of the relationship between patient and health care provider in diagnosis and treatment. A positive diagnostic strategy for IBS-C is recommended, based on clinical history, physical examination, and minimal laboratory tests. An effective communication strategy between patients and health care professionals is essential to ensure early diagnosis and reduce both health care costs and overall disease burden. Treatment typically begins with lifestyle interventions and nonpharmacologic options, such as dietary interventions, fiber supplements, and osmotic laxatives. In patients with inadequate response to these therapies, 4 currently available therapies (lubiprostone, linaclotide, plecanatide, and tenapanor) approved by the US Food and Drug Administration may relieve IBS-C symptoms. These agents are generally well tolerated and efficacious in improving IBS-C symptoms, including constipation and abdominal pain. In patients with persistent abdominal pain and/or psychological symptoms, brain-gut behavioral therapy or neuromodulator therapy may be beneficial.
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Affiliation(s)
| | | | - Michael Cline
- Department of Gastroenterology, Cleveland Clinic, Cleveland, OH, USA
| | | | | | - Baharak Moshiree
- Division of Gastroenterology, Advocate Health Wake Forest Medical University, Charlotte, NC, USA
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Lacy BE, Rosenbaum D, Edelstein S, Kozuka K, Williams LA, Kunkel DC. Intestinal Permeability, Irritable Bowel Syndrome with Constipation, and the Role of Sodium-Hydrogen Exchanger Isoform 3 (NHE3). Clin Exp Gastroenterol 2024; 17:173-183. [PMID: 38860153 PMCID: PMC11164200 DOI: 10.2147/ceg.s455101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 05/19/2024] [Indexed: 06/12/2024] Open
Abstract
Increased intestinal permeability has been identified as one of the many pathophysiological factors associated with the development of irritable bowel syndrome (IBS), a common disorder of gut-brain interaction. The layer of epithelial cells that lines the intestine is permeable to a limited degree, and the amount of paracellular permeability is tightly controlled to enable the absorption of ions, nutrients, and water from the lumen. Increased intestinal permeability to macromolecules can be triggered by a variety of insults, including infections, toxins from food poisoning, or allergens, which in turn cause an inflammatory response and are associated with abdominal pain in patients with IBS. This review article discusses increased intestinal permeability in IBS, focusing on IBS with constipation (IBS-C) through the lens of a patient case with a reported prior diagnosis of "leaky gut syndrome" upon initial contact with a gastrointestinal specialist. We review advantages and disadvantages of several methods of measuring intestinal permeability in patients and discuss when measuring intestinal permeability is appropriate in the therapeutic journey of patients with IBS-C. Furthermore, we discuss a possible mechanism of restoring the intestinal barrier to its healthy state through altering intracellular pH by inhibiting sodium-hydrogen exchanger isoform 3 (NHE3). Tenapanor is a minimally absorbed, small-molecule inhibitor of NHE3 that has been approved by the US Food and Drug Administration for the treatment of IBS-C in adults. Preclinical studies showed that tenapanor may restore the intestinal barrier in IBS-C by affecting the conformation of tight junction proteins via NHE3 inhibition to block the paracellular transport of macromolecules from the intestinal lumen. Testing for increased permeability in patients with IBS-C who experience abdominal pain may help inform the choice of therapeutics and alter patients' misconceptions about "leaky gut syndrome".
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Affiliation(s)
- Brian E Lacy
- Division of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, FL, USA
| | | | | | | | | | - David C Kunkel
- Division of Gastroenterology, University of California San Diego, La Jolla, CA, USA
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Lembo AJ, Chey WD, Harris LA, Frazier R, Brenner DM, Chang L, Lacy BE, Edelstein S, Yang Y, Zhao S, Rosenbaum DP. Abdominal Symptom Improvement During Clinical Trials of Tenapanor in Patients With Irritable Bowel Syndrome With Constipation: A Post Hoc Analysis. Am J Gastroenterol 2024; 119:937-945. [PMID: 38294158 PMCID: PMC11062617 DOI: 10.14309/ajg.0000000000002685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 12/20/2023] [Indexed: 02/01/2024]
Abstract
INTRODUCTION This post hoc analysis evaluated the efficacy of tenapanor on abdominal symptoms in patients with irritable bowel syndrome with constipation. Abdominal symptoms assessed included pain, discomfort, bloating, cramping, and fullness. METHODS The abdominal symptom data were pooled from 3 randomized controlled trials (NCT01923428, T3MPO-1 [NCT02621892], and T3MPO-2 [NCT02686138]). Weekly scores were calculated for each abdominal symptom, and the Abdominal Score (AS) was derived as the average of weekly scores for abdominal pain, discomfort, and bloating. The overall change from baseline during the 12 weeks was assessed for each symptom weekly score and the AS. The AS 6/12-week and 9/12-week response rates (AS improvement of ≥2 points for ≥6/12- or ≥9/12-week) were also evaluated. The association of weekly AS response status (reduction of ≥30%) with weekly complete spontaneous bowel movement (CSBM) status (=0 and >0) was assessed. RESULTS Among 1,372 patients (684 tenapanor [50 mg twice a day] and 688 placebo), the least squares mean change from baseline in AS was -2.66 for tenapanor vs -2.09 for placebo ( P < 0.0001). The 6/12-week AS response rate was 44.4% for tenapanor vs 32.4% for placebo ( P < 0.0001), and for 9/12-week AS, 30.6% for tenapanor vs 20.5% for placebo ( P < 0.0001). A significant association between weekly CSBM status and weekly AS response status was observed each week ( P < 0.0001), with a greater proportion achieving an AS reduction in patients with >0 CSBMs in a week. DISCUSSION Tenapanor significantly reduced abdominal symptoms in patients with irritable bowel syndrome with constipation, particularly pain, discomfort, and bloating measured by AS, compared with placebo.
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Affiliation(s)
- Anthony J. Lembo
- Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - William D. Chey
- Division of Gastroenterology, Department of Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA
| | - Lucinda A. Harris
- Division of Gastroenterology & Hepatology, Mayo Clinic, Scottsdale, Arizona, USA
| | - Rosita Frazier
- Division of Gastroenterology & Hepatology, Mayo Clinic, Scottsdale, Arizona, USA
| | - Darren M. Brenner
- Division of Gastroenterology and Hepatology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Lin Chang
- Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, California
| | - Brian E. Lacy
- Division of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, Florida, USA
| | | | - Yang Yang
- Ardelyx, Waltham, Massachusetts, USA
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King AJ, Chang L, Li Q, Liu L, Zhu Y, Pasricha PJ, Wang J, Siegel M, Caldwell JS, Edelstein S, Rosenbaum DP, Kozuka K. NHE3 inhibitor tenapanor maintains intestinal barrier function, decreases visceral hypersensitivity, and attenuates TRPV1 signaling in colonic sensory neurons. Am J Physiol Gastrointest Liver Physiol 2024; 326:G543-G554. [PMID: 38252683 PMCID: PMC11376972 DOI: 10.1152/ajpgi.00233.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/04/2024] [Accepted: 01/17/2024] [Indexed: 01/24/2024]
Abstract
The pathogenesis of irritable bowel syndrome (IBS) is multifactorial, characterized in part by increased intestinal permeability, and visceral hypersensitivity. Increased permeability is associated with IBS severity and abdominal pain. Tenapanor is FDA-approved for the treatment of IBS with constipation (IBS-C) and has demonstrated improvements in bowel motility and a reduction in IBS-related pain; however, the mechanism by which tenapanor mediates these functions remains unclear. Here, the effects of tenapanor on colonic pain signaling and intestinal permeability were assessed through behavioral, electrophysiological, and cell culture experiments. Intestinal motility studies in rats and humans demonstrated that tenapanor increased luminal sodium and water retention and gastrointestinal transit versus placebo. A significantly reduced visceral motor reflex (VMR) to colonic distension was observed with tenapanor treatment versus vehicle in two rat models of visceral hypersensitivity (neonatal acetic acid sensitization and partial restraint stress; both P < 0.05), returning VMR responses to that of nonsensitized controls. Whole cell voltage patch-clamp recordings of retrogradely labeled colonic dorsal root ganglia (DRG) neurons from sensitized rats found that tenapanor significantly reduced DRG neuron hyperexcitability to capsaicin versus vehicle (P < 0.05), an effect not mediated by epithelial cell secretions. Tenapanor also attenuated increases in intestinal permeability in human colon monolayer cultures caused by incubation with proinflammatory cytokines (P < 0.001) or fecal supernatants from patients with IBS-C (P < 0.005). These results support a model in which tenapanor reduces IBS-related pain by strengthening the intestinal barrier, thereby decreasing permeability to macromolecules and antigens and reducing DRG-mediated pain signaling.NEW & NOTEWORTHY A series of nonclinical experiments support the theory that tenapanor inhibits IBS-C-related pain by strengthening the intestinal barrier. Tenapanor treatment reduced visceral motor responses to nonsensitized levels in two rat models of hypersensitivity and reduced responses to capsaicin in sensitized colonic nociceptive dorsal root ganglia neurons. Intestinal permeability experiments in human colon monolayer cultures found that tenapanor attenuates increases in permeability induced by either inflammatory cytokines or fecal supernatants from patients with IBS-C.
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Affiliation(s)
- Andrew J King
- Ardelyx, Inc., Waltham, Massachusetts, United States
| | - Lin Chang
- Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States
| | - Qian Li
- Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Liansheng Liu
- Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Yaohui Zhu
- Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Pankaj J Pasricha
- Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Ji Wang
- Ardelyx, Inc., Waltham, Massachusetts, United States
| | | | | | | | | | - Kenji Kozuka
- Ardelyx, Inc., Waltham, Massachusetts, United States
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Singh P, Sayuk GS, Rosenbaum DP, Edelstein S, Kozuka K, Chang L. An Overview of the Effects of Tenapanor on Visceral Hypersensitivity in the Treatment of Irritable Bowel Syndrome with Constipation. Clin Exp Gastroenterol 2024; 17:87-96. [PMID: 38617992 PMCID: PMC11016248 DOI: 10.2147/ceg.s454526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 03/22/2024] [Indexed: 04/16/2024] Open
Abstract
Background Patients with irritable bowel syndrome with constipation (IBS-C) experience persistent abdominal pain, a common symptom leading to greater healthcare utilization and reports of treatment non-response. Clinically significant improvements in abdominal pain were observed in clinical trials of tenapanor, a first-in-class inhibitor of sodium/hydrogen exchanger isoform 3 (NHE3), for the treatment of IBS-C in adults. Aim This narrative review reports the current knowledge about visceral hypersensitivity as a mechanism for abdominal pain in patients with IBS-C and explores the published evidence for hypothesized mechanisms by which tenapanor may reduce visceral hypersensitivity leading to the observed clinical response of decreased abdominal pain. Findings Abdominal pain is experienced through activation and signaling of nociceptive dorsal root ganglia that innervate the gut. These sensory afferent neurons may become hypersensitized through signaling of transient receptor potential cation channel subfamily V member 1 (TRPV1), resulting in reduced action potential thresholds. TRPV1 signaling is also a key component of the proinflammatory cascade involving mast cell responses to macromolecule exposure following permeation through the intestinal epithelium. Indirect evidence of this pathway is supported by observations of higher pain in association with increased intestinal permeability in patients with IBS. Tenapanor reduces intestinal sodium absorption, leading to increased water retention in the intestinal lumen, thereby improving gastrointestinal motility. In animal models of visceral hypersensitivity, tenapanor normalized visceromotor responses and normalized TRPV1-mediated nociceptive signaling. Conclusion By improving gastrointestinal motility, decreasing intestinal permeability and inflammation, and normalizing nociception through decreased TRPV1 signaling, tenapanor may reduce visceral hypersensitivity, leading to less abdominal pain in patients with IBS-C. Therapies that have demonstrated effects on visceral hypersensitivity may be the future direction for meaningful abdominal pain relief for patients with IBS-C.
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Affiliation(s)
- Prashant Singh
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Gregory S Sayuk
- Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
| | | | | | | | - Lin Chang
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
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Lin YC, Yan HT. Impact of dietary sodium restriction on falls among middle-aged and older adults: Results of an 8-year longitudinal study. Geriatr Gerontol Int 2024; 24 Suppl 1:292-299. [PMID: 37718504 DOI: 10.1111/ggi.14669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/14/2023] [Accepted: 08/30/2023] [Indexed: 09/19/2023]
Abstract
AIM This study aimed to understand the relationship between dietary sodium restriction (DSR) and falling experiences in middle-aged and older adults. METHODS The 8-year follow-up data from the Taiwan Longitudinal Study on Aging, covering 5131 individuals aged ≥50 years, were analyzed using random-effects panel logit models. Participants were asked to indicate whether they were told by a physician to reduce or avoid sodium intake from food and whether they had had fall experiences during the past year. We modelled falling experiences as a function of DSR (independent variable), involuntary body weight loss and walking difficulty (mediators), and chronic diseases (moderator), adjusting for individual-level characteristics. RESULTS Individuals with DSR were at a higher risk of falls compared with those with no DSR (adjusted odds ratio [AOR] = 1.30, 95% confidence interval [CI] = 1.11-1.53). This effect was more prevalent in individuals with a history of stroke (AOR = 1.85, 95% CI = 1.19-2.87). Those told to reduce sodium intake by a physician were likely to lose weight involuntarily (AOR = 1.20, 95% CI = 1.05-1.36) and had difficulty walking up two or three flights of stairs alone (AOR = 2.38, 95% CI = 1.73-3.27), which mediated the effect of DSR on increased fall risk (AOR = 1.15, 95% CI = 0.95-1.38). We found a temporal effect: participant reactions to short- and mid-term DSR were significant. CONCLUSIONS DSR was associated with a greater likelihood of falls among middle-aged and older adults, particularly those with a history of stroke. Geriatr Gerontol Int 2024; 24: 292-299.
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Affiliation(s)
- Yu-Chun Lin
- Department of Chinese Medicine, China Medical University Hospital, Taichung City, Taiwan
- Graduate Institute of Integrated Medicine, China Medical University, Taichung City, Taiwan
| | - Huang-Ting Yan
- Institute of Political Science, Academia Sinica, Taipei City, Taiwan
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Patel D, Jose F, Baker J, Moshiree B. Neurogastroenterology and Motility Disorders of the Gastrointestinal Tract in Cystic Fibrosis. Curr Gastroenterol Rep 2024; 26:9-19. [PMID: 38057499 DOI: 10.1007/s11894-023-00906-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2023] [Indexed: 12/08/2023]
Abstract
PURPOSE OF REVIEW To discuss all the various motility disorders impacting people with Cystic Fibrosis (PwCF) and provide diagnostic and management approaches from a group of pediatric and adult CF and motility experts and physiologists with experience in the management of this disease. RECENT FINDINGS Gastrointestinal (GI) symptoms coexist with pulmonary symptoms in PwCF regardless of age and sex. The GI manifestations include gastroesophageal reflux disease, esophageal dysmotility gastroparesis, small bowel dysmotility, small intestinal bacterial overgrowth syndrome, distal idiopathic obstruction syndrome, constipation, and pelvic floor disorders. They are quite debilitating, limiting the patients' quality of life and affecting their nutrition and ability to socialize. This genetic disorder affects many organ systems and is chronic, potentially impacting fertility and future family planning, requiring a multidisciplinary approach. Our review discusses the treatments of motility disorders in CF, their prevalence and pathophysiology. We have provided a framework for clinicians who care for these patients that can help to guide their clinical management.
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Affiliation(s)
- Dhiren Patel
- Department of Pediatrics, Pediatric Gastroenterology, Hepatology and Nutrition, SSM Cardinal Glennon Children's Medical Center, Saint Louis University, St Louis, MO, USA
| | - Folashade Jose
- Pediatric Gastroenterology, Hepatology, and Nutrition, Clinical Associate Professor, Levine Childrens Hospital, Carolina Pediatric Gastroenterology, Charlotte, NC, USA
| | | | - Baha Moshiree
- Division of Gastroenterology, Atrium Health Wake Forest Medical University, Charlotte, NC, USA.
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Stamatopoulos K, Mistry N, Fotaki N, Turner DB, Swift B. Physiologically Based Biopharmaceutics Model (PBBM) of Minimally Absorbed Locally Acting Drugs in the Gastrointestinal Tract-Case Study: Tenapanor. Pharmaceutics 2023; 15:2726. [PMID: 38140067 PMCID: PMC10747343 DOI: 10.3390/pharmaceutics15122726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 11/23/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023] Open
Abstract
A physiologically based biopharmaceutics model (PBBM) was developed to predict stool and urine sodium content in response to tenapanor administration in healthy subjects. Tenapanor is a minimally absorbed small molecule that inhibits the sodium/hydrogen isoform 3 exchanger (NHE3). It is used to treat irritable bowel syndrome with constipation (IBS-C). Its mode of action in the gastrointestinal tract reduces the uptake of sodium, resulting in an increase in water secretion in the intestinal lumen and accelerating intestinal transit time. The strategy employed was to perform drug-drug interaction (DDI) modelling between sodium and tenapanor, with sodium as the "victim" administered as part of daily food intake and tenapanor as the "perpetrator" altering sodium absorption. Food effect was modelled, including meal-induced NHE3 activity using sodium as an inducer by normalising the induction kinetics of butyrate to sodium equivalents. The presented model successfully predicted both urine and stool sodium content in response to tenapanor dosed in healthy subjects (within 1.25-fold error) and provided insight into the clinical observations of tenapanor dosing time relative to meal ingestion. The PBBM model was applied retrospectively to assess the impact of different forms of tenapanor (free base vs. HCl salt) on its pharmacodynamic (PD) effect. The developed modelling strategy can be effectively adopted to increase confidence in using PBBM models for the prediction of the in vivo behaviour of minimally absorbed, locally acting drugs in the gastrointestinal tract, when other approaches (e.g., biomarkers or PD data) are not available.
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Affiliation(s)
| | - Nena Mistry
- Biopharmaceutics, DPD, MDS, GSK, Ware SG12 0DP, UK;
| | - Nikoletta Fotaki
- Centre for Therapeutic Innovation, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK;
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Currò D, Ianiro G, Gasbarrini A. A pharmacokinetic evaluation of tenapanor for the treatment of irritable bowel syndrome with constipation: an update of the literature. Expert Opin Drug Metab Toxicol 2023; 19:889-894. [PMID: 38108081 DOI: 10.1080/17425255.2023.2294937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 12/11/2023] [Indexed: 12/19/2023]
Abstract
INTRODUCTION Tenapanor is the latest addition to the second-line pharmacotherapeutic options for the treatment of irritable bowel syndrome with constipation. It is a first-in-class inhibitor of type 3 sodium/hydrogen exchanger (NHE3), characterized by very low oral absorption. Its pharmacological properties are discussed here based on the latest literature. AREAS COVERED A general description of tenapanor is provided, highlighting those pharmacokinetic and pharmacodynamic characteristics of the drug which may be of major importance for tolerability and safety. This description is associated with a summary and analysis of currently available toxicological data. EXPERT OPINION Plasma concentrations of free tenapanor after oral administration are well below the half maximal inhibitory concentration for NHE3, so that systemic effects of the drug are minimal. Therefore, the action of tenapanor is limited to NHE3 located on the apical membrane of enterocytes. The consequent reduction in intestinal sodium absorption increases the intraluminal content by osmosis, which in turn enhances the propulsive activity of the colon. Diarrhea is the most frequent adverse effect of tenapanor. Increased fecal sodium and water excretion do not appear to expose patients to short- and long-term hydro-electrolyte imbalances.
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Affiliation(s)
- Diego Currò
- Pharmacology Section, Department of Health Care Surveillance and Bioethics, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Gianluca Ianiro
- Department of Translational Medicine and Surgery, Università Cattolica del Sacro Cuore, Rome, Italy
- Department of Medical and Surgical Sciences, UOC CEMAD Centro Malattie dell'Apparato Digerente, Medicina Interna e Gastroenterologia, Fondazione Policlinico Universitario Gemelli IRCCS, Rome, Italy
| | - Antonio Gasbarrini
- Department of Translational Medicine and Surgery, Università Cattolica del Sacro Cuore, Rome, Italy
- Department of Medical and Surgical Sciences, UOC CEMAD Centro Malattie dell'Apparato Digerente, Medicina Interna e Gastroenterologia, Fondazione Policlinico Universitario Gemelli IRCCS, Rome, Italy
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Han Y, Srinivasan S, Yun CC. Inhibition of protein kinase C-α and activation of ezrin by Lactobacillus acidophilus restore Na +/H + exchange activity and fluid absorption in db/db mice. Am J Physiol Endocrinol Metab 2023; 325:E214-E226. [PMID: 37467022 PMCID: PMC10511175 DOI: 10.1152/ajpendo.00145.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/03/2023] [Accepted: 07/03/2023] [Indexed: 07/20/2023]
Abstract
Gastrointestinal (GI) complications, including diarrhea, constipation, and gastroparesis, are common in patients with diabetes. Dysregulation of the Na+/H+ exchanger NHE3 in the intestine is linked to diarrhea and constipation, and recent studies showed that NHE3 expression is reduced in type 1 diabetes and metformin causes diarrhea in the db/db mouse model of type 2 diabetes (T2D) via inhibition of NHE3. In this study, we investigated whether NHE3 expression is altered in type 2 diabetic intestine and the underlying mechanism that dysregulates NHE3. NHE3 expression in the brush border membrane (BBM) of the intestine of diabetic mice and humans was decreased. Protein kinase C (PKC) activation is associated with pathologies of diabetes, and immunofluorescence (IF) analysis revealed increased BBM PKCα abundance. Inhibition of PKCα increased NHE3 BBM abundance and NHE3-mediated intestinal fluid absorption in db/db mice. Previous studies have shown that Lactobacillus acidophilus (LA) stimulates intestinal ion transporters. LA increased NHE3 BBM expression and mitigated metformin-mediated inhibition of NHE3 in vitro and in vivo. To understand the underlying mechanism of LA-mediated stimulation of NHE3, we used Caco-2bbe cells overexpressing PKCα that mimic the elevated state of PKCα in T2D. LA diminished PKCα BBM expression, increased phosphorylation of ezrin, and the interaction of NHE3 with NHE regulatory factor 2 (NHERF2). In addition, inhibition of PKCι blocked phosphorylation of ezrin and activation of NHE3 by LA. These findings demonstrate that NHE3 is downregulated in T2D, and LA restores NHE3 expression via regulation of PKCα, PKCι, and ezrin.NEW & NOTEWORTHY We used mouse models of type 2 diabetes (T2D) and human patient-derived samples to show that Na+/H+ exchanger 3 (NHE3) expression is decreased in T2D. We show that protein kinase C-α (PKCα) is activated in diabetes and inhibition of PKCα increased NHE3 expression and mitigates diarrhea. We show that Lactobacillus acidophilus (LA) stimulates NHE3 via inhibition of PKCα and phosphorylation of ezrin.
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Affiliation(s)
- Yiran Han
- Gastroenterology Research, Atlanta Veterans Administration Medical Center, Decatur, Georgia, United States
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Shanthi Srinivasan
- Gastroenterology Research, Atlanta Veterans Administration Medical Center, Decatur, Georgia, United States
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
| | - C Chris Yun
- Gastroenterology Research, Atlanta Veterans Administration Medical Center, Decatur, Georgia, United States
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, United States
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11
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Herekar A, Shimoga D, Jehangir A, Shahsavari D, Yan Y, Karunaratne TB, Sharma A. Tenapanor in the Treatment of Irritable Bowel Syndrome with Constipation: Discovery, Efficacy, and Role in Management. Clin Exp Gastroenterol 2023; 16:79-85. [PMID: 37309470 PMCID: PMC10257918 DOI: 10.2147/ceg.s384251] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 05/29/2023] [Indexed: 06/14/2023] Open
Abstract
Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction (DGBI). IBS significantly impacts the quality of life of patients. Since its pathogenesis is unclear and can be multifactorial, it highlights the need for new and improved pharmaceutical drugs that not only improve bowel symptoms, but also address global IBS symptoms, such as abdominal pain. Tenapanor, a recently Food & Drug Administration (FDA)-approved medication for IBS with constipation (IBS-C), is a small molecule inhibitor of the sodium/hydrogen exchanger isoform 3 (NHE3) that inhibits the absorption of sodium and phosphate in the gastrointestinal tract, resulting in fluid retention and softer stool. Furthermore, tenapanor reduces intestinal permeability to improve visceral hypersensitivity and abdominal pain. Due to its recent approval, tenapanor was not included in the recent IBS guidelines, however, it may be considered for IBS-C patients failing first-line treatment of soluble fiber. In this review article, we aim to provide in-depth information to the reader regarding the design of tenapanor, its development through Phase I, II and III randomized clinical trials, and its role in the treatment of IBS-C.
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Affiliation(s)
- Anam Herekar
- Department of Medicine, Augusta University, Augusta, GA, USA
| | - Dhanush Shimoga
- Department of Medicine, Augusta University, Augusta, GA, USA
| | - Asad Jehangir
- Department of Medicine, Augusta University, Augusta, GA, USA
| | | | - Yun Yan
- Department of Medicine, Augusta University, Augusta, GA, USA
| | | | - Amol Sharma
- Department of Medicine, Augusta University, Augusta, GA, USA
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12
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Dorel R, Wong AR, Crawford JJ. Trust Your Gut: Strategies and Tactics for Intestinally Restricted Drugs. ACS Med Chem Lett 2023; 14:233-243. [PMID: 36923921 PMCID: PMC10009798 DOI: 10.1021/acsmedchemlett.3c00001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 02/02/2023] [Indexed: 02/24/2023] Open
Abstract
Non-absorbable small-molecule drugs targeted to the gut represent an alternative approach to safe, non-systemic therapeutics. Such drugs remain confined to the gastrointestinal tract upon oral dosing by virtue of their limited passive permeability, increasing the local concentration at the site of action while minimizing exposure elsewhere in the body. Herein we review the latest advances in the field of gut-restricted therapeutics, highlighting the different strategies and tactics that medicinal chemists have employed in pursuit of drugs with minimal intestinal absorption.
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Affiliation(s)
- Ruth Dorel
- Genentech, Inc., South San Francisco, California 94080, United States
| | - Alice R. Wong
- Genentech, Inc., South San Francisco, California 94080, United States
| | - James J. Crawford
- Genentech, Inc., South San Francisco, California 94080, United States
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13
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Cil O, Anderson MO, de Souza Goncalves L, Tan JA, Haggie PM, Verkman AS. Small molecule inhibitors of intestinal epithelial anion exchanger SLC26A3 (DRA) with a luminal, extracellular site of action. Eur J Med Chem 2023; 249:115149. [PMID: 36724632 PMCID: PMC10124120 DOI: 10.1016/j.ejmech.2023.115149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/13/2023] [Accepted: 01/22/2023] [Indexed: 01/30/2023]
Abstract
The anion exchanger protein SLC26A3 (down-regulated in adenoma, DRA) is expressed in the luminal membrane of intestinal epithelial cells in colon, where it facilitates the absorption of Cl- and oxalate. We previously identified a 4,8-dimethylcoumarin class of SLC26A3 inhibitors that act from the SLC26A3 cytoplasmic surface, and demonstrated their efficacy in mouse models of constipation and hyperoxaluria. Here, screening of 50,000 new compounds and 1740 chemical analogs of active compounds from the primary screen produced five novel classes of SLC26A3-selective inhibitors (1,3-dioxoisoindoline-amides; N-(5-sulfamoyl-1,3,4-thiadiazol-2-yl)acetamides; thiazolo-pyrimidin-5-ones; 3-carboxy-2-phenylbenzofurans and benzoxazin-4-ones) with IC50 down to 100 nM. Kinetic washout and onset of action studies revealed an extracellular site of action for the thiazolo-pyrimidin-5-one and 3-carboxy-2-phenylbenzofuran inhibitors. Molecular docking computations revealed putative binding sites for these inhibitors. In a loperamide model of constipation in mice, orally administered 7-(2-chloro-phenoxymethyl)-3-phenyl-thiazolo [3,2-a]pyrimidin-5-one (3a) significantly increased stool weight, pellet number and water content. SLC26A3 inhibitors with an extracellular site of action offer the possibility of creating non-absorbable, luminally acting inhibitors with minimal systemic exposure following oral administration. Our findings also suggest that inhibitors of related SLC26 anion transporters with an extracellular site of action might be identified for pharmacological modulation of selected epithelial ion transport processes.
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Affiliation(s)
- Onur Cil
- Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA.
| | - Marc O Anderson
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, CA, USA
| | | | - Joseph-Anthony Tan
- Departments of Medicine and Physiology, University of California San Francisco, San Francisco, CA, USA
| | - Peter M Haggie
- Departments of Medicine and Physiology, University of California San Francisco, San Francisco, CA, USA
| | - Alan S Verkman
- Departments of Medicine and Physiology, University of California San Francisco, San Francisco, CA, USA
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Pergola PE. Phosphate Frustration: Treatment Options to Complement Current Therapies. Int J Nephrol 2022; 2022:9457440. [PMID: 36045900 PMCID: PMC9424003 DOI: 10.1155/2022/9457440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 07/16/2022] [Indexed: 11/18/2022] Open
Abstract
Hyperphosphatemia eventually develops in almost all patients with advanced chronic kidney disease and is associated with negative clinical outcomes. Thus, guidelines recommend targeting treatment to normal phosphate levels in patients with chronic kidney disease. Despite low phosphorus diets, clearance by dialysis, and phosphate binder use, many patients with chronic kidney disease on dialysis are unable to consistently achieve and maintain serum phosphate concentrations <5.5 mg/dL. A chart audit of patients on dialysis receiving phosphate binders showed that 74 to 86% were unable to consistently achieve serum phosphate ≤5.5 mg/dL over 6 months. Furthermore, although there is evidence that serum phosphate concentrations <4.5 mg/dL are associated with improved survival and cardiovascular outcomes, real-world phosphate control data suggest achieving and maintaining this goal for most patients would be extremely challenging, if not near impossible, using current therapies. As phosphate binders can only remove approximately 300 mg of the 2,500 mg or more daily dietary phosphate intake, therapeutic innovations are necessary to improve phosphate management. We present treatment options to complement current therapies including tenapanor, a novel sodium/hydrogen exchanger isoform 3 inhibitor that blocks the dominant paracellular phosphate absorption pathway and has been shown to reduce phosphate levels in several clinical trials.
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15
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Jacobs JW, Leadbetter MR, Bell N, Koo-McCoy S, Carreras CW, He L, Kohler J, Kozuka K, Labonté ED, Navre M, Spencer AG, Charmot D. Discovery of Tenapanor: A First-in-Class Minimally Systemic Inhibitor of Intestinal Na +/H + Exchanger Isoform 3. ACS Med Chem Lett 2022; 13:1043-1051. [PMID: 35859876 PMCID: PMC9290029 DOI: 10.1021/acsmedchemlett.2c00037] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
![]()
We present herein
the design, synthesis, and optimization of gut-restricted
inhibitors of Na+/H+ exchanger isoform 3 (NHE3).
NHE3 is predominantly expressed in the kidney and gastrointestinal
tract where it acts as the major absorptive sodium transporter. We
desired minimally systemic agents that would block sodium absorption
in the gastrointestinal tract but avoid exposure in the kidney. Starting
with a relatively low-potency highly bioavailable hit compound (1), potent and minimally absorbed NHE3 inhibitors were designed,
culminating with the discovery of tenapanor (28). Tenapanor
has been approved by the U.S. Food and Drug Administration (FDA) for
the treatment of irritable bowel syndrome with constipation in adults.
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Affiliation(s)
- Jeffrey W. Jacobs
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Michael R. Leadbetter
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Noah Bell
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Samantha Koo-McCoy
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | | | - Limin He
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Jill Kohler
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Kenji Kozuka
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Eric D. Labonté
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Marc Navre
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Andrew G. Spencer
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
| | - Dominique Charmot
- Ardelyx, Inc., 400 Fifth Avenue, Suite 210, Waltham, Massachusetts 02451, United States
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16
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Kovesdy CP, Adebiyi A, Rosenbaum D, Jacobs JW, Quarles LD. Novel Treatments from Inhibition of the Intestinal Sodium-Hydrogen Exchanger 3. Int J Nephrol Renovasc Dis 2021; 14:411-420. [PMID: 34880650 PMCID: PMC8646223 DOI: 10.2147/ijnrd.s334024] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 11/11/2021] [Indexed: 12/31/2022] Open
Abstract
Plasma membrane sodium–hydrogen exchangers (NHE) transport Na+ into cells in exchange for H+. While there are nine isoforms of NHE in humans, this review focuses on the NHE3 isoform, which is abundantly expressed in the gastrointestinal tract, where it plays a key role in acid–base balance and water homeostasis. NHE3 inhibition in the small intestine results in luminal sodium and water retention, leading to a general decrease in paracellular water flux and diffusional driving force, reduced intestinal sodium absorption, and increased stool sodium excretion. The resulting softer and more frequent stools are the rationale for the development of tenapanor as a novel, first-in-class NHE3 inhibitor to treat irritable bowel syndrome with constipation. NHE3 also has additional therapeutic implications in nephrology. Inhibition of intestinal NHE3 also lowers blood pressure by reducing intestinal sodium absorption. Perhaps, the most novel effect is its ability to decrease intestinal phosphate absorption by inhibiting the paracellular phosphate absorption pathway. Therefore, selective pharmacological inhibition of NHE3 could be a potential therapeutic strategy to treat not only heart failure and hypertension but also hyperphosphatemia. This review presents an overview of the molecular and physiological functions of NHE3 and discusses how these functions translate to potential clinical applications in nephrology.
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Affiliation(s)
- Csaba P Kovesdy
- Division of Nephrology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Adebowale Adebiyi
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | | | | | - L Darryl Quarles
- Division of Nephrology, University of Tennessee Health Science Center, Memphis, TN, USA
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17
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Block GA, Bleyer AJ, Silva AL, Weiner DE, Lynn RI, Yang Y, Rosenbaum DP, Chertow GM. Safety and Efficacy of Tenapanor for Long-term Serum Phosphate Control in Maintenance Dialysis: A 52-Week Randomized Phase 3 Trial (PHREEDOM). KIDNEY360 2021; 2:1600-1610. [PMID: 35372979 PMCID: PMC8785778 DOI: 10.34067/kid.0002002021] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 08/25/2021] [Indexed: 12/17/2022]
Abstract
Background Treating hyperphosphatemia is a tenet of dialysis care. This trial assessed the safety and efficacy of tenapanor for the management of hyperphosphatemia. Methods In this 52-week phase 3 study (NCT03427125), participants receiving maintenance dialysis with both hyperphosphatemia (serum phosphate 6.0-10.0 mg/dl) and a 1.5 mg/dl increase after phosphate binder washout were randomized (3:1) to tenapanor 30 mg twice daily for 26 weeks (randomized treatment period) or sevelamer carbonate (52-week safety control). Participants completing 26 weeks of treatment with tenapanor were rerandomized (1:1) to tenapanor or placebo for 12 weeks (randomized withdrawal period), and were eligible to enter the 14-week safety extension period. With input from the US Food and Drug Administration, the primary efficacy end point was the difference in the change in serum phosphate from the end of the randomized treatment period to the end of the randomized withdrawal period, among participants who achieved ≥1.2 mg/dl decrease in serum phosphate during the randomized treatment period (efficacy analysis set). Efficacy was also evaluated in the intention-to-treat (ITT) analysis set. Results Of 564 eligible participants randomized to receive tenapanor (n=423) or sevelamer carbonate (n=141) during the randomized treatment period, 255 (60%) in the tenapanor group subsequently were rerandomized to tenapanor (n=128) or placebo (n=127) during the randomized withdrawal period. In the efficacy analysis set (n=131), the difference in estimated mean change in serum phosphate level between tenapanor and placebo from the beginning to the end of the randomized withdrawal period was -1.4 mg/dl (P<0.0001); in the ITT analysis set (n=243), the estimated mean difference was -0.7 mg/dl (P=0.002). Loosened stools were the most frequently reported adverse event (53% during the randomized treatment period). Serious adverse events were reported more frequently for participants treated with sevelamer carbonate (16%-23% across the three study periods) compared with tenapanor (11%-17%). Conclusions Tenapanor reduced serum phosphate concentrations and maintained control of serum phosphate in participants receiving maintenance dialysis, with an acceptable safety and tolerability profile.
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Affiliation(s)
- Geoffrey A Block
- Clinical Research and Medical Affairs, US Renal Care, Inc., Plano, Texas
| | - Anthony J Bleyer
- Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Arnold L Silva
- Boise Kidney and Hypertension Institute, Meridian, Idaho
| | - Daniel E Weiner
- Division of Nephrology, Tufts Medical Center, Boston, Massachusetts
| | - Robert I Lynn
- Department of Medicine, Albert Einstein College of Medicine, New York, New York.,Kidney Medical Associates, New York, New York
| | - Yang Yang
- Biometrics, Ardelyx, Inc., Fremont, California
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18
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Yee J, Rosenbaum D, Jacobs JW, Sprague SM. Small Intestinal Phosphate Absorption: Novel Therapeutic Implications. Am J Nephrol 2021; 52:522-530. [PMID: 34515051 DOI: 10.1159/000518110] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 06/24/2021] [Indexed: 01/19/2023]
Abstract
BACKGROUND Chronic kidney disease (CKD) affects approximately 15% of adults in the USA. As CKD progresses, urinary phosphate excretion decreases and results in phosphate retention and, eventually, hyperphosphatemia. As hyperphosphatemia is associated with numerous adverse outcomes, including increased cardiovascular mortality, reduction in phosphorus concentrations is a guideline-recommended, established clinical practice. Dietary phosphate restriction, dialysis, and phosphate binders are currently the only options for phosphate management. However, many patients with hyperphosphatemia have phosphorus concentrations >5.5 mg/dL, despite treatment. SUMMARY This review pre-sents recent advances in the understanding of intestinal phosphate absorption and therapeutic implications. Dietary phosphate is absorbed in the intestine through two distinct pathways, paracellular absorption and transcellular transport. Recent evidence indicates that the paracellular route accounts for 65-80% of total phosphate absorbed. Thus, the paracellular pathway is the dominant mechanism of phosphate absorption. Tenapanor is a first-in-class, non-phosphate binder that inhibits the sodium-hydrogen exchanger 3 or solute carrier family 9 member 3 (SLC9A3) encoded by the SLC9A3 gene, and blocks paracellular phosphate absorption. Key Messages: Targeted inhibition of sodium-hydrogen exchanger 3 effectively reduces paracellular permeability of phosphate. Novel therapies that target the paracellular pathway may improve phosphate control in chronic kidney disease.
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Affiliation(s)
- Jerry Yee
- Nephrology and Hypertension, Henry Ford Hospital, Detroit, Michigan, USA
| | | | | | - Stuart M Sprague
- Division of Nephrology and Hypertension, NorthShore University Health System, Evanston, Illinois, USA
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19
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McCullough PA. Phosphate Control: The Next Frontier in Dialysis Cardiovascular Mortality. Cardiorenal Med 2021; 11:123-132. [PMID: 34120113 DOI: 10.1159/000516286] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 03/24/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Cardiovascular disease (CVD) is a major cause of death in patients with chronic kidney disease (CKD) on dialysis. Mortality rates are still unacceptably high even though they have fallen in the past 2 decades. Hyperphosphatemia (elevated serum phosphate levels) is seen in almost all patients with advanced CKD and is by far the largest remaining modifiable contributor to CKD mortality. SUMMARY Phosphate retention drives multiple physiological mechanisms linked to increased risk of CVD. Fibroblast growth factor 23 and parathyroid hormone (PTH) levels, both of which have been suggested to have direct pathogenic CV effects, increase in response to phosphate retention. Phosphate, calcium, and PTH levels are linked in a progressively worsening cycle. Maladaptive upregulation of phosphate absorption is also likely to occur further exacerbating hyperphosphatemia. Even higher phosphate levels within the normal range may be a risk factor for vascular calcification and, thus, CV morbidity and mortality. A greater degree of phosphate control is important to reduce the risk of CV morbidity and mortality. Improved phosphate control and regular monitoring of phosphate levels are guideline-recommended, established clinical practices. There are several challenges with the current phosphate management approaches in patients with CKD on dialysis. Dietary restriction of phosphate and thrice-weekly dialysis alone are insufficient/unreliable to reduce phosphate to <5.5 mg/dL. Even with the addition of phosphate binders, the only pharmacological treatment currently indicated for hyperphosphatemia, the majority of patients are unable to achieve and maintain phosphate levels <5.5 mg/dL (or more normal levels) [PhosLo® gelcaps (calcium acetate): 667 mg (prescribing information), 2011, VELPHORO®: (Sucroferric oxyhydroxide) (prescribing information), 2013, FOSRENAL®: (Lanthanum carbonate) (prescribing information), 2016, AURYXIA®: (Ferric citrate) tablets (prescribing information), 2017, RENVELA®: (Sevelamer carbonate) (prescribing information), 2020, RealWorld dynamix. Dialysis US: Spherix Global Insights, 2019]. Phosphate binders do not target the primary pathway of phosphate absorption (paracellular), have limited binding capacity, and bind nonspecifically [PhosLo® gelcaps (calcium acetate): 667 mg (prescribing information). 2013, VELPHORO®: (Sucroferric oxyhydroxide) (prescribing information), 2013, FOSRENAL®: (Lanthanum carbonate) (prescribing information), 2016, AURYXIA®: (Ferric citrate) tablets (prescribing information), 2017, RENVELA®: (Sevelamer carbonate) (prescribing information) 2020]. Key Messages: Despite current phosphate management strategies, most patients on dialysis are unable to consistently achieve target phosphate levels, indicating a need for therapeutic innovations [RealWorld dynamix. Dialysis US: Spherix Global Insights, 2019]. Given a growing evidence base that the dominant mechanism of phosphate absorption is the intestinal paracellular pathway, new therapies are investigating ways to reduce phosphate levels by blocking absorption through the paracellular pathway.
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Affiliation(s)
- Peter A McCullough
- Baylor University Medical Center, Dallas, Texas, USA.,Department of Internal Medicine, Texas A & M College of Medicine, Baylor Heart and Vascular Institute, Dallas, Texas, USA.,Baylor Jack and Jane Hamilton Heart and Vascular Hospital, Dallas, Texas, USA
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20
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Shigematsu T, Une Y, Ikejiri K, Kanda H, Fukagawa M, Akizawa T. Therapeutic Effects of Add-On Tenapanor for Hemodialysis Patients with Refractory Hyperphosphatemia. Am J Nephrol 2021; 52:496-506. [PMID: 34098559 PMCID: PMC8491508 DOI: 10.1159/000516156] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/25/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Phosphate binders are used to treat hyperphosphatemia. Some patients have inappropriately controlled serum phosphorus levels, which may occur for many reasons, including a high pill burden and adverse events (AEs). Tenapanor selectively inhibits the passive paracellular transfer of phosphate in the gastrointestinal tract, thereby reducing serum phosphorus levels. This novel mechanism of action may contribute to improved phosphate management. The efficacy and safety of tenapanor have not been evaluated in Japanese patients with high serum phosphorus levels despite treatment with phosphate binders. This study aimed to assess the efficacy and safety of add-on tenapanor therapy for reducing serum phosphorus levels in this population. METHODS This multicenter, double-blind, randomized, placebo-controlled trial enrolled patients with refractory hyperphosphatemia undergoing hemodialysis. Patients were randomly assigned in a 1:1 ratio to receive tenapanor or placebo as an add-on to their phosphate binder regimen for 6 weeks. Change in serum phosphorus levels at week 6 (day 43) compared with the baseline value (day 1, week 0) (primary endpoint), achievement of target serum phosphorus levels (serum phosphorus level ≤6.0 or ≤5.5 mg/dL), and safety, based on all AEs and drug-related AEs, were among the outcomes evaluated. RESULTS In total, 24 patients were randomly assigned to the placebo group and 23 to the tenapanor group. The mean serum phosphorus level decreased from 7.01 mg/dL on day 1 to 6.69 mg/dL on day 43 in the placebo group and from 6.77 mg/dL on day 1 to 4.67 mg/dL on day 43 in the tenapanor group. In the placebo and tenapanor groups (modified intent-to-treat population), the mean (standard deviation) change in the serum phosphorus level at day 43 (last observation carried forward [LOCF]) was 0.08 (1.52) mg/dL and -1.99 (1.24) mg/dL, respectively, with a between-group difference of -2.07 (95% confidence interval: -2.89, -1.26; p < 0.001). The target achievement rate (serum phosphorus level ≤6.0 mg/dL at week 6 [LOCF]) was 37.5 and 87.0% in the placebo and tenapanor groups, respectively. Diarrhea was the most common drug-related AE, and it occurred in 8.3 and 65.2% of patients in the placebo and tenapanor groups, respectively. No specific AEs were observed with add-on tenapanor or with phosphate binders. DISCUSSION/CONCLUSION Therapy with existing phosphate binders and add-on tenapanor resulted in a significant decrease in serum phosphorus level compared with the placebo group in patients with refractory hyperphosphatemia despite treatment with phosphate binders. No new safety signals were raised, and add-on tenapanor was generally well tolerated.
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Affiliation(s)
| | - Yotaro Une
- Research and Development Division, Kyowa Kirin Co., Ltd., Tokyo, Japan
| | - Kazuaki Ikejiri
- Research and Development Division, Kyowa Kirin Co., Ltd., Tokyo, Japan
| | - Hironori Kanda
- Research and Development Division, Kyowa Kirin Co., Ltd., Tokyo, Japan
| | - Masafumi Fukagawa
- Division of Nephrology, Department of Internal Medicine, Endocrinology, and Metabolism, Tokai University School of Medicine, Isehara, Japan
| | - Tadao Akizawa
- Division of Nephrology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan
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21
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Efficacy of Tenapanor in Treating Patients With Irritable Bowel Syndrome With Constipation: A 26-Week, Placebo-Controlled Phase 3 Trial (T3MPO-2). Am J Gastroenterol 2021; 116:1294-1303. [PMID: 33337659 PMCID: PMC8183489 DOI: 10.14309/ajg.0000000000001056] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/13/2020] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Tenapanor is a first-in-class, minimally absorbed, small-molecule inhibitor of the gastrointestinal sodium/hydrogen exchanger isoform 3. This phase 3 trial assessed the long-term efficacy and safety of tenapanor 50 mg b.i.d. for the treatment of patients with irritable bowel syndrome with constipation (IBS-C). METHODS In this randomized double-blind study (ClinicalTrials.gov identifier: NCT02686138), patients with IBS-C received tenapanor 50 mg b.i.d. or placebo b.i.d. for 26 weeks. The primary endpoint was the proportion of patients who had a reduction of ≥30.0% in average weekly worst abdominal pain and an increase of ≥1 weekly complete spontaneous bowel movement from baseline, both in the same week, for ≥6 of the first 12 treatment weeks (6/12-week combined responder). RESULTS Of the 620 randomized patients with IBS-C, 593 (95.6%) were included in the intention-to-treat analysis set (tenapanor: n = 293; placebo: n = 300) and 481 patients (77.6%) completed the 26-week treatment period. In the intention-to-treat analysis set (mean age: 45.4 years; 82.1% women), a significantly greater proportion of patients treated with tenapanor were 6/12-week combined responders than those treated with placebo (36.5% vs 23.7%; P < 0.001). Abdominal symptoms and global symptoms of IBS were significantly improved with tenapanor compared with placebo. Diarrhea, the most common adverse event, was typically transient and mild to moderate in severity. Diarrhea led to study drug discontinuation for 19 (6.5%) and 2 patients (0.7%) receiving tenapanor and placebo, respectively. DISCUSSION Tenapanor 50 mg b.i.d. improved IBS-C symptoms over 26 weeks and was generally well tolerated, offering a potential new long-term treatment option for patients with IBS-C (see Visual abstract, Supplementary Digital Content 1, http://links.lww.com/AJG/B797).
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22
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Arokiadoss A, Weber HC. Targeted pharmacotherapy of irritable bowel syndrome. Curr Opin Endocrinol Diabetes Obes 2021; 28:214-221. [PMID: 33481423 DOI: 10.1097/med.0000000000000618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Irritable bowel syndrome (IBS) is a highly prevalent functional gastrointestinal (GI) disorder with negative impact on quality of life and it represents a substantial economic burden on healthcare cost. The medical management of IBS is symptom directed. This review provides an update related to clinical trial data for novel treatment modalities in IBS targeting the gut epithelium secretagogue receptors and channels. RECENT FINDINGS The new Rome IV criteria define functional gastrointestinal disorders (FGID) as disorders of the gut-brain interaction. Pharmacological treatment modalities for IBS target gastrointestinal receptors and ion channels, peripheral opioid receptor, gut serotonin receptors, and the gut microbiome. New targeted pharmacotherapies have shown efficacy and safety in the treatment of patients with IBS. SUMMARY Diagnostic criteria for FGID, including IBS, have been revised in Rome IV and are defined as gut-brain disorders. Newly approved pharmacotherapy options with proven efficacy and acceptable side-effect profiles are available for the symptom-based management of IBS.
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Affiliation(s)
| | - H Christian Weber
- Boston University School of Medicine, Section of Gastroenterology
- VA Boston Healthcare System, Section of Gastroenterology and Hepatology, Boston, Massachusetts, USA
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23
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Tan Q, di Stefano G, Tan X, Renjie X, Römermann D, Talbot SR, Seidler UE. Inhibition of Na + /H + exchanger isoform 3 improves gut fluidity and alkalinity in cystic fibrosis transmembrane conductance regulator-deficient and F508del mutant mice. Br J Pharmacol 2021; 178:1018-1036. [PMID: 33179259 DOI: 10.1111/bph.15323] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 11/01/2020] [Accepted: 11/02/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE Constipation and intestinal obstructive episodes are major health problems in cystic fibrosis (CF) patients. Three FDA-approved drugs against constipation-prone irritable bowel syndrome were tested for their ability to increase luminal fluidity and alkalinity in cystic fibrosis transmembrane conductance regulator (CFTR) null (cftr-/- ) and F508del mutant (F508delmut/mut ) murine intestine. EXPERIMENTAL APPROACH Guanylate cyclase C agonist linaclotide, PGE1 analogue lubiprostone and intestine-specific NHE3 inhibitor tenapanor were perfused through a ~3 cm jejunal, proximal or mid-distal colonic segment in anaesthetized cftr-/- , F508delmut/mut and WT mice. Net fluid balance was determined gravimetrically and alkaline output by pH-stat back titration. KEY RESULTS Basal jejunal fluid absorptive rates were significantly higher and basal HCO3 - output was significantly lower in cftr-/- and F508delmut/mut compared to WT mice. In cftr-/- and F508delmut/mut mice, all three drugs significantly inhibited the fluid absorptive rate and increased alkaline output in the jejunum and tenapanor and lubiprostone, but not linaclotide, in the colon. After tenapanor pre-incubation, linaclotide elicited a robust fluid secretory response in WT jejunum, while no further change in absorptive rates was observed in cftr-/- and F508delmut/mut jejunum, suggesting that the increase in gut fluidity and alkalinity by linaclotide in CF gut is mediated via NHE3 inhibition. Lubiprostone also inhibited fluid absorption in cftr-/- and F508delmut/mut jejunum via NHE3 inhibition but had a residual NHE3-independent effect. CONCLUSION AND IMPLICATIONS Linaclotide, lubiprostone and tenapanor reduced fluid absorption and increased alkaline output in the CF gut. Their application may ameliorate constipation and reduce obstructive episodes in CF patients.
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Affiliation(s)
- Qinghai Tan
- Department of Gastroenterology, Hannover Medical School, Hanover, Germany
| | | | - Xinjie Tan
- Department of Gastroenterology, Hannover Medical School, Hanover, Germany
| | - Xiu Renjie
- Department of Gastroenterology, Hannover Medical School, Hanover, Germany
| | - Dorothee Römermann
- Department of Gastroenterology, Hannover Medical School, Hanover, Germany
| | - Steven R Talbot
- Institute of Veterinary Research, Hannover Medical School, Hanover, Germany
| | - Ursula E Seidler
- Department of Gastroenterology, Hannover Medical School, Hanover, Germany
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Linz B, Saljic A, Hohl M, Gawałko M, Jespersen T, Sanders P, Böhm M, Linz D. Inhibition of sodium-proton-exchanger subtype 3-mediated sodium absorption in the gut: A new antihypertensive concept. IJC HEART & VASCULATURE 2020; 29:100591. [PMID: 32760780 PMCID: PMC7390783 DOI: 10.1016/j.ijcha.2020.100591] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/24/2020] [Accepted: 07/07/2020] [Indexed: 12/22/2022]
Abstract
Arterial hypertension is one of the main contributors to cardiovascular diseases, including stroke, heart failure, and coronary heart disease. Salt plays a major role in the regulation of blood pressure and is one of the most critical factors for hypertension and stroke. At the individual level, effective salt reduction is difficult to achieve and available methods for managing sodium balance are lacking for many patients. As part of the ingested food, salt is absorbed in the gastrointestinal tract by the sodium proton exchanger subtype 3 (NHE3 also known as Slc9a3), influencing extracellular fluid volume and blood pressure. In this review, we discuss the beneficial effects of pharmacological inhibition of NHE3-mediated sodium absorption in the gut and focus on the effect on blood pressure and end-organ damage.
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Affiliation(s)
- Benedikt Linz
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Arnela Saljic
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mathias Hohl
- Kardiologie, Angiologie und Internistische Intensivmedizin, Universitätsklinikum des Saarlandes
| | - Monika Gawałko
- 1st Department of Cardiology, Medical University of Warsaw, Warsaw, Poland
- Department of Cardiology, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Thomas Jespersen
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Prashanthan Sanders
- Centre for Heart Rhythm Disorders, Royal Adelaide Hospital, University of Adelaide, Adelaide, Australia
| | - Michael Böhm
- Kardiologie, Angiologie und Internistische Intensivmedizin, Universitätsklinikum des Saarlandes
| | - Dominik Linz
- Department of Cardiology, Maastricht University Medical Centre, Maastricht, the Netherlands
- Centre for Heart Rhythm Disorders, Royal Adelaide Hospital, University of Adelaide, Adelaide, Australia
- University Maastricht, Cardiovascular Research Institute Maastricht (CARIM), the Netherlands
- Corresponding author at: Maastricht UMC+, Maastricht Heart+Vascular Center, 6202 AZ Maastricht, the Netherlands.
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Sinagra E, Rossi F, Raimondo D, Conoscenti G, Anderloni A, Guarnotta V, Maida M. Tenapanor for the treatment of irritable bowel syndrome with constipation. Expert Rev Clin Pharmacol 2020; 13:473-479. [PMID: 32478632 DOI: 10.1080/17512433.2020.1762570] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Irritable bowel syndrome with constipation is associated with higher rates of functional impairment, as compared to other subtypes of the syndrome. Conventional laxative-based pharmacologic therapy of IBS-C, which is mostly symptom-based, is often unsatisfactory. Tenapanor represents a first-in-class orally available inhibitor of NHE3, which is minimally absorbed in the GI tract, what constitutes a significant therapeutic benefit, as it may act on the drug target. AREAS COVERED Aim of this article is to sum up the evidences about pharmacodynamics and pharmacokinetics of tenapanor, focusing on animal models and in vitro studies, but also discuss clinical trials on tenapanor's safety and efficacy in view of its important potential role in IBS-C treatment. EXPERT OPINION In the challenging setting of irritable bowel syndrome with constipation, tenapanor represents a novel strategy in the pipeline of the therapies of IBS-C. Its pharmacokinetic and pharmacodynamic profile provides that it is minimally absorbed from the intestinal lumen and that its action is local, but not systemic action, therefore guaranteeing the reduction of drug-drug interactions, toxicity and severe adverse effects. Phase 2b and 3 trials showed an optimal satisfaction of primary and secondary endpoints.
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Affiliation(s)
- Emanuele Sinagra
- Gastroenterology and Endoscopy Unit, Fondazione Istituto G. Giglio, Contrada Pietra Pollastra Pisciotto , Cefalù, Italy.,Section of Nutrition, Euro-Mediterranean Institute of Science and Technology (IEMEST) , Palermo, Italy
| | - Francesca Rossi
- Gastroenterology and Endoscopy Unit, Fondazione Istituto G. Giglio, Contrada Pietra Pollastra Pisciotto , Cefalù, Italy
| | - Dario Raimondo
- Gastroenterology and Endoscopy Unit, Fondazione Istituto G. Giglio, Contrada Pietra Pollastra Pisciotto , Cefalù, Italy
| | - Giuseppe Conoscenti
- Gastroenterology and Endoscopy Unit, Fondazione Istituto G. Giglio, Contrada Pietra Pollastra Pisciotto , Cefalù, Italy
| | - Andrea Anderloni
- Digestive Endoscopy Unit, Division of Gastroenterology, Humanitas Research Hospital , Rozzano Italy
| | - Valentina Guarnotta
- Dipartimento Di Promozione Della Salute, Materno-Infantile, Medicina Interna E Specialistica Di Eccellenza "G. D'Alessandro" (PROMISE), Sezione Di Malattie Endocrine, Del Ricambio E Della Nutrizione, Università Di Palermo , Italy
| | - Marcello Maida
- Section of Gastroenterology, S.Elia - Raimondi Hospital , Caltanissetta, Italy
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Abstract
The selective sodium hydrogen exchanger 3 (NHE3) inhibitor tenapanor is being developed by Ardelyx Inc. for the treatment of constipation-predominant irritable bowel syndrome (IBS-C) [under the tradename IBSRELA®] and for hyperphosphataemia in patients with chronic kidney disease (CKD) on dialysis or with end stage renal disease (ESRD). Based on positive results from the phase III T3MPO trial program, tenapanor was recently approved in the USA for the treatment of IBS-C in adults. This article summarises the milestones in the development of tenapanor leading to this first approval.
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Affiliation(s)
- Anthony Markham
- Springer Nature, Private Bag 65901, Mairangi Bay, Auckland, 0754, New Zealand.
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Efficacy of Tenapanor in Treating Patients With Irritable Bowel Syndrome With Constipation: A 12-Week, Placebo-Controlled Phase 3 Trial (T3MPO-1). Am J Gastroenterol 2020; 115:281-293. [PMID: 31934897 PMCID: PMC7771640 DOI: 10.14309/ajg.0000000000000516] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVES Tenapanor is a first-in-class, minimally absorbed, small-molecule inhibitor of the gastrointestinal sodium/hydrogen exchanger isoform 3. This phase 3 trial assessed the efficacy and safety of tenapanor 50 mg b.i.d. for the treatment of patients with constipation-predominant irritable bowel syndrome (IBS-C). METHODS In this phase 3, double-blind study (ClinicalTrials.gov identifier NCT02621892), patients with IBS-C were randomized to tenapanor 50 mg b.i.d. or placebo b.i.d. for 12 weeks followed by a 4-week randomized withdrawal period. The primary efficacy variable was the proportion of patients who reported a reduction in average weekly worst abdominal pain of ≥30.0% and an increase of ≥1 complete spontaneous bowel movement from baseline, both in the same week, for ≥6 weeks of the 12-week treatment period. RESULTS Of the 629 randomized patients with IBS-C, 606 (96.3%) were included in the intention-to-treat analysis set (tenapanor: n = 307; placebo: n = 299) and 533 (84.7%) completed the 12-week treatment period. In the intention-to-treat analysis set (mean age 45 years, 81.4% women), a significantly greater proportion of patients treated with tenapanor met the primary endpoint than patients treated with placebo (27.0% vs 18.7%, P = 0.020). Abdominal symptoms and global symptoms of IBS also improved with tenapanor (P < 0.05 vs placebo). Diarrhea was the most commonly reported adverse event, resulting in study drug discontinuation in 6.5% and 0.7% of patients receiving tenapanor and placebo, respectively, during the 12-week treatment period. DISCUSSION Tenapanor 50 mg b.i.d. improved IBS-C symptoms and was generally well tolerated, offering a potential new treatment option for patients with IBS-C.
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Niewinna K, Zielińska A, Fichna J. Recent advances in the pharmacological management of constipation predominant irritable bowel syndrome. Expert Opin Pharmacother 2019; 21:73-84. [PMID: 31724881 DOI: 10.1080/14656566.2019.1688784] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Introduction: Irritable bowel syndrome (IBS) is a complex functional gut disorder that typically manifests in early adult years. More than a third of IBS patients are diagnosed with predominant constipation subtype (IBS-C). This syndrome has a distressing impact on the quality of life and is challenging both for patients and physicians.Areas covered: This review focuses on the pathophysiology of constipation in IBS and presents current management options. It also covers the latest findings that may lead to novel pharmacological options in IBS-C management. The authors intend to highlight the results of published research including abstracts, records from the clinicaltrials.gov database (second and third phases of the study) and information from original FDA documents.Expert opinion: Current therapeutic options for IBS-C treatment are based on linaclotide, lubiprostone, plecanatide, and the reintroduced tegaserod. Drugs present on the market as well as those in pre-clinical development should increase the lower esophageal sphincter pressure, promote gastric motility, accelerate gastric emptying and improve gastro-duodenal coordination. Most significantly, they shall not induce severe side effects.
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Affiliation(s)
- Karolina Niewinna
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
| | - Anna Zielińska
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
| | - Jakub Fichna
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
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Camilleri M. What's in the pipeline for lower functional gastrointestinal disorders in the next 5 years? Am J Physiol Gastrointest Liver Physiol 2019; 317:G640-G650. [PMID: 31460793 PMCID: PMC6879894 DOI: 10.1152/ajpgi.00205.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 08/13/2019] [Accepted: 08/21/2019] [Indexed: 01/31/2023]
Abstract
The overall objectives of this review are to summarize actionable biomarkers for organic etiology of lower functional gastrointestinal disorders (FGIDs) that lead to individualized treatment for their FGIDs and to assess the pipeline for novel approaches to the management of constipation, diarrhea, and chronic abdominal pain in lower FGIDs. The new approaches to therapy include ion exchangers/transporters for functional constipation (sodium-glucose cotransporter 1, Na+/H+ exchanger 3, and solute carrier family 26 member 3 inhibitors), bile acid modulators for constipation such as ileal bile acid transporter inhibitors and fibroblast growth factor 19 analog for functional constipation, and bile acid sequestrants or farnesoid X receptor agonists for functional diarrhea. Treatment for chronic abdominal pain remains an unmet need in patients with lower FGIDs, and promising novel approaches include delayed-release linaclotide, nonclassical opioid visceral analgesics, and selective cannabinoid receptor agonists. The role of probiotics, fecal microbial transplantation, and possible future microbiome therapies is discussed.
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
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Azzam O, Kiuchi MG, Ho JK, Matthews VB, Gavidia LML, Nolde JM, Carnagarin R, Schlaich MP. New Molecules for Treating Resistant Hypertension: a Clinical Perspective. Curr Hypertens Rep 2019; 21:80. [PMID: 31506798 DOI: 10.1007/s11906-019-0978-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW To review the findings of trials evaluating pharmacological treatment approaches for hypertension in general, and resistant hypertension (RH) in particular, and propose future research and clinical directions. RECENT FINDINGS RH is defined as blood pressure (BP) that remains above target levels despite adherence to at least three antihypertensive medications, including a diuretic. Thus far, clinical trials of pharmacological approaches in RH have focused on older molecules, with spironolactone being demonstrated as the most efficacious fourth-line agent. However, the use of spironolactone in clinical practice is hampered by its side effect profile and the risk of hyperkalaemia in important RH subgroups, such as patients with moderate-severe chronic kidney disease (CKD). Clinical trials of new molecules targeting both well-established and more recently elucidated pathophysiologic mechanisms of hypertension offer a multitude of potential treatment avenues that warrant further evaluation in the context of RH. These include selective mineralocorticoid receptor antagonists (MRAs), aldosterone synthase inhibitors (ASIs), activators of the counterregulatory renin-angiotensin-system (RAS), vaccines, neprilysin inhibitors alone and in combined formulations, natriuretic peptide receptor agonists A (NPRA-A) agonists, vasoactive intestinal peptide (VIP) agonists, centrally acting aminopeptidase A (APA|) inhibitors, antimicrobial suppression of central sympathetic outflow (minocycline), dopamine β-hydroxylase (DβH) inhibitors and Na+/H+ Exchanger 3 (NHE3) inhibitors. There is a paucity of data from trials evaluating newer molecules for the treatment of RH. Emergent novel molecules for non-resistant forms of hypertension heighten the prospects of identifying new, effective and well-tolerated pharmacological approaches to RH. There is a glaring need to undertake RH-focused trials evaluating their efficacy and clinical applicability.
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Affiliation(s)
- Omar Azzam
- Department of Internal Medicine, Royal Perth Hospital, Perth, Western Australia, Australia.,Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Level 3, MRF Building, Rear 50 Murray St, Perth, WA, 6000, Australia
| | - Marcio G Kiuchi
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Level 3, MRF Building, Rear 50 Murray St, Perth, WA, 6000, Australia
| | - Jan K Ho
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Level 3, MRF Building, Rear 50 Murray St, Perth, WA, 6000, Australia
| | - Vance B Matthews
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Level 3, MRF Building, Rear 50 Murray St, Perth, WA, 6000, Australia
| | - Leslie Marisol Lugo Gavidia
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Level 3, MRF Building, Rear 50 Murray St, Perth, WA, 6000, Australia
| | - Janis M Nolde
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Level 3, MRF Building, Rear 50 Murray St, Perth, WA, 6000, Australia
| | - Revathy Carnagarin
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Level 3, MRF Building, Rear 50 Murray St, Perth, WA, 6000, Australia
| | - Markus P Schlaich
- Dobney Hypertension Centre, School of Medicine - Royal Perth Hospital Unit / Medical Research Foundation, University of Western Australia, Level 3, MRF Building, Rear 50 Murray St, Perth, WA, 6000, Australia. .,Departments of Cardiology and Nephrology, Royal Perth Hospital, Perth, Australia. .,Neurovascular Hypertension & Kidney Disease Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia.
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Abstract
PURPOSE OF REVIEW Hypertension (HTN) is a widespread and growing disease, with medication intolerance and side-effect present among many. To address these obstacles novel pharmacotherapy is an active area of drug development. This review seeks to explore future drug therapy for HTN in the preclinical and clinical arenas. RECENT FINDINGS The future of pharmacological therapy in HTN consists of revisiting old pathways to find new targets and exploring wholly new approaches to provide additional avenues of treatment. In this review, we discuss the current status of the most recent drug therapy in HTN. New developments in well trod areas include novel mineralocorticoid antagonists, aldosterone synthase inhibitors, aminopeptidase-A inhibitors, natriuretic peptide receptor agonists, or the counter-regulatory angiotensin converting enzyme 2/angiotensin (Ang) (1-7)/Mas receptor axis. Neprilysin inhibitors popularized for heart failure may also still hold HTN potential. Finally, we examine unique systems in development never before used in HTN such as Na/H exchange inhibitors, vasoactive intestinal peptide agonists, and dopamine beta hydroxylase inhibitors. SUMMARY A concise review of future directions of HTN pharmacotherapy.
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Abstract
PURPOSE OF REVIEW Irritable bowel syndrome (IBS) is a functional GI disorder that affects a large percentage of the population and presents a significant socio-economic burden on the society. In this article, we reviewed the evidence supporting various pharmacological treatment options for IBS. RECENT FINDINGS Rifaximin, eluxadoline, and alosetron have demonstrated that they reduce symptom severity improving quality of life in patients with IBS-diarrhea. Ramosetron is a promising agent in development. Peppermint oil has also demonstrated a positive impact on some symptoms of IBS. For IBS with constipation, traditional laxatives have failed to demonstrate significant benefit. However, lubiprostone, linaclotide, and plecanatide have demonstrated improvement of IBS with constipation in large, placebo-controlled trials. Tenapanor, a sodium/hydrogen exchanger 3 inhibitor, appears to be a promising treatment option in the pipeline. There are multiple pharmacologic agents with a variety of mechanisms that have demonstrated efficacy in IBS with diarrhea and constipation. There are no established pharmacologic agents for IBS with a mixed bowel pattern. There is a promising pipeline for additional novel therapies for IBS.
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Affiliation(s)
- Akhil Munjal
- Department of Internal Medicine, University of Texas Health Science Center at Houston/McGovern Medical School, 6431 Fannin Street, Houston, TX, 77030, USA
| | - Bhavtosh Dedania
- Division of Gastroenterology, University of Texas Health Science Center at Houston/McGovern Medical School, 6431 Fannin Street, MSB 4.234, Houston, TX, 77030, USA
| | - Brooks Cash
- Division of Gastroenterology, University of Texas Health Science Center at Houston/McGovern Medical School, 6431 Fannin Street, MSB 4.234, Houston, TX, 77030, USA.
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33
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Block GA, Rosenbaum DP, Yan A, Chertow GM. Efficacy and Safety of Tenapanor in Patients with Hyperphosphatemia Receiving Maintenance Hemodialysis: A Randomized Phase 3 Trial. J Am Soc Nephrol 2019; 30:641-652. [PMID: 30846557 DOI: 10.1681/asn.2018080832] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 01/24/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Guidelines recommend reducing elevated serum phosphate in patients with CKD. Tenapanor, a minimally absorbed inhibitor of gastrointestinal sodium/hydrogen exchanger 3 (NHE3), reduces paracellular phosphate transport. METHODS In this phase 3 randomized, double-blind trial, we randomly assigned patients with hyperphosphatemia receiving maintenance hemodialysis to receive twice-daily oral tenapanor (3, 10, or 30 mg [the latter down-titrated, if needed]) for 8 weeks. Patients were then rerandomized 1:1 to receive either their previously assigned dose or placebo for a 4-week 'withdrawal' period. We measured serum phosphate levels over the course of the trial. The primary end point was mean change in serum phosphate over the 4-week withdrawal period for the tenapanor group (using pooled data) versus the placebo group. RESULTS Of 219 patients randomized, 152 completed both study phases. During the initial 8-week treatment period, all three treatment groups experienced significant decreases in mean serum phosphate (reductions of 1.00, 1.02, and 1.19 mg/dl, corresponding to the 3, 10, and 30 mg [down-titrated] dose groups, respectively). Tenapanor also showed a significant benefit over placebo during the withdrawal period, with a mean increase of 0.85 mg/dl in the placebo group versus a mean increase of 0.02 mg/dl in the pooled tenapanor group. Adverse events were largely limited to softened stool and a modest increase in bowel movement frequency, resulting from increased stool sodium and water content, stemming from tenapanor's mechanism of action. CONCLUSIONS Tenapanor significantly reduced elevated serum phosphate in patients with hyperphosphatemia receiving maintenance hemodialysis. Adverse effects were limited to those induced by its known mechanism of action, which increases stool sodium and water content.
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Affiliation(s)
- Geoffrey A Block
- Denver Nephrology Research Division, Denver Nephrology, Denver, Colorado;
| | | | | | - Glenn M Chertow
- Division of Nephrology, Stanford University School of Medicine, Stanford, California
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34
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Abstract
PURPOSE OF THE REVIEW Pharmacology remains the mainstay of treatment for hypertension across the globe. In what may seem like a well-trodden field, there are actually an exciting array of new pathways for the treatment of hypertension on the horizon. This review seeks to discuss the most recent research in ongoing areas of drug development in the field of hypertension. RECENT FINDINGS Novel areas of research in the field of hypertension pharmacology include central nervous system regulators, peripheral noradrenergic inhibitors, gastrointestinal sodium modulators, and a counter-regulatory arm of the renin-angiotensin-aldosterone system. This review discusses these pathways in a look into the current status of emerging pharmacological therapies for hypertension.
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Affiliation(s)
- Merrill H Stewart
- John Ochsner Heart and Vascular Institute, Ochsner Clinical School, The University of Queensland School of Medicine, 1514 Jefferson Highway, New Orleans, LA, 70121, USA.
| | - Carl J Lavie
- John Ochsner Heart and Vascular Institute, Ochsner Clinical School, The University of Queensland School of Medicine, 1514 Jefferson Highway, New Orleans, LA, 70121, USA
| | - Hector O Ventura
- John Ochsner Heart and Vascular Institute, Ochsner Clinical School, The University of Queensland School of Medicine, 1514 Jefferson Highway, New Orleans, LA, 70121, USA
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35
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Abstract
Constipation, a condition characterized by heterogeneous symptoms, is common in Western society. It is associated with reduced physical health, mental health, and social functioning. Because constipation is rarely due to a life-threatening disease (for example, colon cancer), current guidelines recommend empiric therapy. Limited surveys suggest that fewer than half of treated individuals are satisfied with treatment, perhaps because the efficacy of drugs is limited, they are associated with undesirable side effects, or they may not target the underlying pathophysiology. For example, although a substantial proportion of constipated patients have a defecatory disorder that is more appropriately treated with pelvic floor biofeedback therapy than with laxatives, virtually no pharmacological trials formally assessed for anorectal dysfunction. Recent advances in investigational tools have improved our understanding of the physiology and pathophysiology of colonic and defecatory functions. In particular, colonic and anorectal high-resolution manometry are now available. High-resolution anorectal manometry, which is increasingly used in clinical practice, at least in the United States, provides a refined assessment of anorectal pressures and may uncover structural abnormalities. Advances in our understanding of colonic molecular physiology have led to the development of new therapeutic agents (such as secretagogues, pro-kinetics, inhibitors of bile acid transporters and ion exchangers). However, because clinical trials compare these newer agents with placebo, their efficacy relative to traditional laxatives is unknown. This article reviews these physiologic, diagnostic, and therapeutic advances and focuses particularly on newer therapeutic agents.
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Affiliation(s)
- David O. Prichard
- Division of Gastroenterology and Hepatology, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA
| | - Adil E. Bharucha
- Clinical Enteric Neuroscience Translational and Epidemiological Research Program and Division of Gastroenterology and Hepatology, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA
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36
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Major G, Murray K, Singh G, Nowak A, Hoad CL, Marciani L, Silos-Santiago A, Kurtz CB, Johnston JM, Gowland P, Spiller R. Demonstration of differences in colonic volumes, transit, chyme consistency, and response to psyllium between healthy and constipated subjects using magnetic resonance imaging. Neurogastroenterol Motil 2018; 30:e13400. [PMID: 30062794 DOI: 10.1111/nmo.13400] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 05/28/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND In functional gastrointestinal disorders a lack of objective biomarkers limits evaluation of underlying mechanisms. We aimed to demonstrate the utility of magnetic resonance imaging for this task using psyllium, an effective constipation treatment, in patients and controls. METHODS Two crossover studies: (i) adults without constipation (controls, n = 9) took three treatments in randomized order for 6 days - maltodextrin (placebo), psyllium 3.5 g t.d.s and 7 g t.d.s., (ii) adults with chronic constipation (patients, n = 20) took placebo and psyllium 7 g t.d.s. for 6 days. MRI was performed fasting and postprandially on day 6. Measurements included small bowel and ascending colon water content, colonic volume, transit time, and MR relaxometry (T1, T2) to assess colonic chyme. Stool water percentage was measured. RESULTS 7 g psyllium t.d.s. increased fasting colonic volumes in controls from median 372 mL (IQR 284-601) to 578 mL (IQR 510-882), and in patients from median 831 mL (IQR 745-934) to 1104 mL (847-1316), P < .05. Mean postprandial small bowel water was higher in controls and patients after 7 g psyllium t.d.s. vs placebo. Whole gut transit was slower in patients than controls (P < .05). T1 of the descending colon chyme (fasting) was lower in patients (213 ms, 176-420) than controls (440 ms, 352-884, P < .05) on placebo, but increased by 7 g psyllium t.d.s. (590 ms, 446-1338), P < .001. Descending colon T1 correlated with baseline stool water content and stool frequency on treatment. CONCLUSIONS AND INFERENCES MRI measurements can objectively demonstrate the mode of action of therapy targeting intestinal fluid content in constipation.
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Affiliation(s)
- G Major
- Nottingham Digestive Diseases Centre and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, UK
| | - K Murray
- Nottingham Digestive Diseases Centre and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, UK.,Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - G Singh
- Nottingham Digestive Diseases Centre and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, UK
| | - A Nowak
- Nottingham Digestive Diseases Centre and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, UK
| | - C L Hoad
- Nottingham Digestive Diseases Centre and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, UK.,Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - L Marciani
- Nottingham Digestive Diseases Centre and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, UK
| | | | - C B Kurtz
- Ironwood Pharmaceuticals Inc., Cambridge, MA, USA
| | - J M Johnston
- Ironwood Pharmaceuticals Inc., Cambridge, MA, USA
| | - P Gowland
- Nottingham Digestive Diseases Centre and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, UK.,Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, UK
| | - R Spiller
- Nottingham Digestive Diseases Centre and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, UK
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