Influence of Demographic Factors on Clinical Outcomes in Adults With Chronic Idiopathic Constipation Treated With Plecanatide.

INTRODUCTION: Chronic idiopathic constipation (CIC) is a common condition that affects some patient groups more often. Demographic/clinical characteristics can differ in presentation and therapeutic response. The impact of these characteristics on plecanatide efficacy/safety was examined. METHODS: Data from 2 identically designed, randomized, phase 3 trials of adults with CIC receiving 3 mg of plecanatide, 6 mg of plecanatide, or placebo for 12 weeks were analyzed. Subgroups were baseline age, body mass index (BMI), race/ethnicity, and sex/gender. Endpoints included durable overall complete spontaneous bowel movement (CSBM) responder rate, weekly CSBMs and spontaneous bowel movements (SBMs), and adverse events. RESULTS: Overall (N = 2,639; 3 mg of plecanatide [n = 877]; 6 mg of plecanatide [n = 877]; and placebo [n = 885]), CSBM responder rates were significantly greater with 3 mg of plecanatide and 6 mg of plecanatide vs placebo in subgroups with those younger than 65 years ( P < 0.001), females ( P < 0.001), White individuals ( P < 0.001), and BMI <25 kg/m 2 ( P ≤ 0.004) and 25-30 kg/m 2 ( P < 0.001); as well, for 3 mg: 65 years or older ( P = 0.03), non-White individuals ( P < 0.001), and BMI ≥30 kg/m 2 ( P = 0.02). Improvement from baseline in weekly CSBM and SBM frequency occurred in all subgroups for both plecanatide doses vs placebo ( P ≤ 0.02) at week 12, except those aged 65 years or older for 6 mg of plecanatide. The most common adverse event was diarrhea (3 mg [4.9%]; 6 mg [5.4%]; and placebo [1.3%]). DISCUSSION: Pooled data from identically designed CIC trials strengthened the ability to identify meaningful subgroup comparisons regarding plecanatide efficacy and safety.

Plecanatide for the treatment of constipation-predominant irritable bowel syndrome.

Introduction: As an analogue of uroguanylin plecanatide binds to the Guanylate Cyclase-C receptor activating fluid and ion secretion in the small intestine with the same pH-dependent binding kinetics as the natural ligand. Plecanatide has been FDA approved as safe and effective for the indications of Chronic Idiopathic Constipation (CIC) and Irritable Bowel Syndrome with Constipation (IBS-C).Areas covered: All clinical trial results supporting approval of plecanatide in IBS-C are reported, evaluated and interpreted in the context of the complex pathophysiology of functional diseases and the barriers that must be overcome for appropriate protocol design and conduct.Expert opinion: The Expert Opinion section discusses safety and efficacy of plecanatide for IBS-C. Broader consideration of some of the inherent challenges in understanding and treating functional gastrointestinal disorders includes: 1. the difficulty of understanding diseases with complex pathophysiology that clinically present with a few simple symptoms, 2. exploring the pathophysiology of functional diseases using pharmacophysiology, 3. value of 'Set Theory' in the evaluation of complex clinical data and 4. physiologic and pathophysiologic insight gained by evaluation 'physiologic redundancy' and 'conservation of function'.

Benefit-Risk Assessment of Plecanatide in the Treatment of Chronic Idiopathic Constipation.

Plecanatide, a uroguanylin analog, activates the guanylate cyclase C receptors in the epithelial lining of the gastrointestinal tract in a pH-dependent fashion initiating (1) the conversion of intracellular guanosine triphosphate to cyclic guanosine monophosphate, which increases the activity of the cystic fibrosis transmembrane conductance regulator to increase chloride and bicarbonate secretion into the intestinal lumen and (2) a decrease in activity of the sodium-hydrogen ion exchanger. The resulting ionic shifts cause an increase in lumenal fluid to facilitate digestion. Plecanatide has been approved by the FDA for use in chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation. This manuscript is a critical assessment of the therapeutic efficacy and potential risks associated with the use of plecanatide in CIC. The discussion of CIC as a clinical and investigative disorder focuses on the importance of this problem as well and the difficulties involved in clinical management and scholarly investigation of a symptom arising from multiple pathophysiologic mechanisms. Clinical data from studies of recently approved drugs for CIC are utilized to construct a platform for thoughtful understanding of CIC and of how changes in investigation guidelines influence the interpretation of study data and guide symptom management. Plecanatide is a safe and effective medication for the management of adults with CIC.

Pilot, Randomized, Blinded, Placebo-Controlled Trial Investigating the Correlation Between Acid Control and Heartburn Relief with 14 Days of Esomeprazole Treatment.

INTRODUCTION: Reflux symptoms are frequently associated with esophageal acid exposure. However, other potential causes unrelated to acid secretion are possible, and the relationship between acid control and symptomatic improvement remains unclear. This study investigated the correlation between individual intragastric pH control and heartburn relief among subjects with frequent heartburn who are likely to self-treat with over-the-counter (OTC) medications. We hypothesized that improved acid control would provide greater symptomatic improvement among individuals representative of an OTC population. METHODS: This phase 4, single-center, randomized, double-blind, placebo-controlled study was conducted in subjects without diagnosed gastroesophageal reflux disease or other gastrointestinal conditions who were experiencing frequent heartburn (≥ 3 episodes/week; ≥ 2 nighttime episodes/week over past 30 days) that was responsive to treatment. Subjects entered a 7-day run-in phase, received placebo BID (before breakfast and dinner), and completed symptom diaries. During the treatment phase, subjects received esomeprazole 20 mg BID, esomeprazole 20 mg then placebo, or placebo BID. Subjects underwent 24-h intragastric pH monitoring at baseline and day 14 and completed daily symptom diaries. RESULTS: In the per-protocol population (n = 39), mean (SD) change from baseline in percentage of time with intragastric pH > 4 was 58.7% (± 26.4%) versus 41.0% (± 30.4%) for those who did and did not achieve 24-h heartburn relief. Significant correlations were observed between change in percentage of time with intragastric pH > 4 and 24-h heartburn relief (OR 1.028; 95% CI 1.001, 1.055; P = 0.0442) and complete resolution (OR 1.034; 95% CI 1.003, 1.065; P = 0.0301). CONCLUSIONS: Individuals with greater improvements in duration of intragastric acid suppression had an increased likelihood of achieving heartburn relief and resolution. These results indicate that individuals not adequately controlling their intragastric pH may require an escalation in dose of their acid-suppressive therapy, assessment with 24-h pH monitoring, or a change in treatment regimen to address non-reflux-related etiologies of their heartburn. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02708355. FUNDING: Pfizer Consumer Healthcare, Madison, NJ, USA. Plain language summary available for this article.

Elobixibat, the first-in-class Ileal Bile Acid Transporter inhibitor, for the treatment of Chronic Idiopathic Constipation.

INTRODUCTION: Elobixibat is the first in class ileal bile acid transporter (IBAT) inhibitor. IBAT inhibitors block ileal absorption of bile acids by: (1) interrupting the enterohepatic circulation of bile resulting in a fall in serum cholesterol and (2) increasing the delivery of bile acids into the colon. Increasing colonic bile acids causes mucosal fluid secretion and enhances colonic motor activity. Changes in colonic physiology may be useful in treating constipation. Areas covered: In this review, the author reviews the prevalence and medical cost of Chronic Idiopathic Constipation (CIC) and the heterogeneity of the CIC patient population as a complicating factor in drug development and clinical care. He also reviews the history of Bile Acid cathartics and the complex pharmacophysiology of bile therapy with fluid and electrolyte shifts, colonic motor function changes and mucosal immunologic activation. Finally, the author reviews elobixabat development and the clinical trials that demonstrate improvement in constipation. Expert opinion: The early phases of elobixibat development provide confirmation of high IBAT binding affinity which translates into the expected inhibition of enterohepatic bile acid circulation and enhanced delivery of ileal bile acids to the colon associated with expected physiological changes. Elobixibat as a treatment of CIC appears promising.

Efficacy and safety of plecanatide in treating constipation predominant irritable bowel syndrome.

INTRODUCTION: Uroguanylin interacting with intestinal Guanylate Cyclase C (GC-C) receptors plays an important role in gastrointestinal fluid and electrolyte homeostasis. Plecanatide is the first uroguanylin analog that stimulates GC-C receptors on gastrointestinal mucosa with pH-sensitive receptor binding. Binding to the GC-C receptor activates intracellular conversion of GTP to cGMP resulting in the stimulation of intestinal fluid secretion. Areas covered: Herein, all published research regarding the development of and clinical experience with plecanatide is reviewed. Clinical study results in patients with Chronic Idiopathic Constipation (CIC) and Irritable Bowel Syndrome with Constipation (IBS-C) are also reviewed. Success in the treatment of CIC and IBS-C is supported by beneficial effects on stool viscosity, Complete Spontaneous Bowel Movements and visceral sensation. Finally, the discussion within focuses on the importance of plecanatide in understanding the physiology of uroguanylin, the pathophysiology of IBS-C and the potential for development of uroguanylin and guanylin analogs. Expert opinion: Given this broad spectrum of potential activity for GC-C agonists, it would not be surprising to see that the use of agents such as plecanatide in new areas grow to a level even greater than the use for the present CIC and IBS-C indications.

Epitope-specific immunotherapy targeting CD4-positive T cells in coeliac disease: two randomised, double-blind, placebo-controlled phase 1 studies.

BACKGROUND: A gluten-free diet is the only means to manage coeliac disease, a permanent immune intolerance to gluten. We developed a therapeutic vaccine, Nexvax2, designed to treat coeliac disease. Nexvax2 is an adjuvant-free mix of three peptides that include immunodominant epitopes for gluten-specific CD4-positive T cells. The vaccine is intended to engage and render gluten-specific CD4-positive T cells unresponsive to further antigenic stimulation. We assessed the safety and pharmacodynamics of the vaccine in patients with coeliac disease on a gluten-free diet. METHODS: We did two randomised, double-blind, placebo-controlled, phase 1 studies at 12 community sites in Australia, New Zealand, and the USA, in HLA-DQ2·5-positive patients aged 18-70 years who had coeliac disease and were on a gluten-free diet. In the screening period for ascending dose cohorts, participants were randomly assigned (1:1) by central randomisation with a simple block method to a double-blind crossover, placebo-controlled oral gluten challenge. Participants with a negative interferon γ release assay to Nexvax2 peptides after the screening oral gluten challenge were discontinued before dosing. For the biopsy cohorts, the screening period included an endoscopy, and participants with duodenal histology who had a Marsh score of greater than 1 were discontinued before dosing. Participants were subsequently randomly assigned to either Nexvax2 or placebo in ascending dose cohorts (2:1) and in biopsy cohorts (1:1) by central randomisation with a simple block method. In the three-dose study, participants received either Nexvax2 60 µg, 90 µg, or 150 µg weekly, or placebo over 15 days; in a fourth biopsy cohort, patients received either Nexvax2 at the maximum tolerated dose (MTD) or placebo. In the 16-dose study, participants received Nexvax2 150 µg or 300 µg or placebo twice weekly over 53 days; in a third biopsy cohort, patients also received either Nexvax2 at the MTD or placebo. In the 4-week post-treatment period, ascending dose cohorts underwent a further double-blind crossover, placebo-controlled oral gluten challenge, which had a fixed sequence, and biopsy cohorts had a gastroscopy with duodenal biopsies and quantitative histology within 2 weeks without oral gluten challenge. Participants, investigators, and study staff were masked to the treatment assignment, except for the study pharmacist. The primary endpoint was the number and percentage of adverse events in the treatment period in an intention-to-treat analysis. Both trials were completed and closed before data analysis. Trials were registered with the Australian New Zealand Clinical Trials Registry, numbers ACTRN12612000355875 and ACTRN12613001331729. FINDINGS: Participants were enrolled from Nov 28, 2012, to Aug 14, 2014, in the three-dose study, and from Aug 3, 2012, to Sept 10, 2013, in the 16-dose study. Overall, 62 (57%) of 108 participants were randomly assigned after oral gluten challenge and 20 (71%) of 28 participants were randomly assigned after endoscopy. In the three-dose study, nine participants were randomly allocated to Nexvax2 60 µg and three to placebo (first cohort), nine were allocated to Nexvax2 90 µg and four to placebo (second cohort), eight were allocated to Nexvax2 150 µg and four to placebo (third cohort), and three were allocated to Nexvax2 150 µg and three to placebo (biopsy cohort). In the 16-dose study, eight participants were randomly allocated to Nexvax2 150 µg and four to placebo (first cohort), ten were allocated to Nexvax2 300 µg and three to placebo (second cohort), and seven were allocated to Nexvax2 150 µg and seven to placebo (biopsy cohort). The MTD for Nexvax2 was 150 µg because of transient, acute gastrointestinal adverse events with onset 2-5 h after initial doses of the vaccine, similar to those caused by gluten ingestion. In the ascending dose cohorts in the three-dose study, six (55%) of 11 placebo recipients, five (56%) of nine who received Nexvax2 60 µg, seven (78%) of nine who received Nexvax2 90 µg, and five (63%) of eight who received Nexvax2 150 µg had at least one treatment-emergent adverse event, as did all three (100%) placebo recipients and one (33%) of three Nexvax2 150 µg recipients in the biopsy cohort. In the ascending dose cohorts of the 16-dose study, five (71%) of seven placebo-treated participants, six (75%) of eight who received Nexvax2 150 µg, and all ten (100%) who received Nexvax2 300 µg had at least one treatment-emergent adverse event, as did six (86%) of seven placebo recipients and five (71%) of seven Nexvax2 150 µg recipients in the biopsy cohort. Vomiting, nausea, and headache were the only treatment-emergent adverse events that occurred in at least 5% of participants in either study. Among participants given the MTD, eight gastrointestinal treatment-emergent adverse events occurred in four (50%) of eight participants in the third cohort and none (0%) of three participants in the biopsy cohort in the three-dose study, and five events occurred in five (63%) of eight participants in the first cohort and three events in two (29%) of seven participants in the biopsy cohort of the 16-dose study. Median villous height to crypt depth ratio in distal duodenal biopsies was not significantly different between those who received the vaccine at the MTD on either schedule and those who received placebo. Of the participants who completed the post-treatment oral gluten challenge per protocol, interferon γ release assay to Nexvax2 peptides was negative (responders to treatment) in two (22%) of nine placebo-treated participants in the three-dose study versus two (33%) of six who received Nexvax2 60 µg, five (63%) of eight who received Nexvax2 90 µg, and six (100%) of six who received Nexvax2 150 µg (p=0·007); in the 16-dose study, none (0%) of five placebo-treated participants had a negative assay versus six (75%) of eight who received Nexvax2 150 µg (p=0·021). INTERPRETATION: The MTD of Nexvax2 was 150 µg for twice weekly intradermal administration over 8 weeks, which modified immune responsiveness to Nexvax2 peptides without deterioration in duodenal histology. The gastrointestinal symptoms that followed the first intradermal administration of the vaccine resembled those associated with oral gluten challenge. These findings support continued clinical development of this potential therapeutic vaccine for coeliac disease. FUNDING: ImmusanT.

A Randomized Phase III Clinical Trial of Plecanatide, a Uroguanylin Analog, in Patients With Chronic Idiopathic Constipation.

OBJECTIVES: This study assessed the efficacy and safety of plecanatide, a guanylate cyclase-C (GC-C) agonist and the first uroguanylin analog approved for the treatment of chronic idiopathic constipation (CIC). METHODS: This phase III, multicenter, double-blind, placebo-controlled study randomized 1,394 patients with CIC. Patients received either plecanatide (3 or 6 mg) or placebo, orally, once daily, for 12 weeks. The primary efficacy endpoint was the percentage of patients who were durable overall complete spontaneous bowel movement (CSBM) responders over the 12-week treatment period. Patients were instructed to record their daily bowel movements, stool consistency scores, and abdominal symptoms in an electronic diary. Treatment-emergent adverse events (AEs) were collected. RESULTS: Each dose of plecanatide resulted in a significantly greater percentage of durable overall CSBM responders (21.0%, 3 mg; 19.5%, 6 mg) as compared with placebo (10.2%; P<0.001 for both). Plecanatide (3 and 6 mg) also significantly increased mean weekly CSBM frequency from baseline (increase of 2.5 and 2.2/week, respectively) vs. placebo (1.2/week; P<0.001 for both) and mean weekly spontaneous bowel movement frequency (increase of 3.2 and 3.1/week, respectively) vs. placebo (1.3/week; P<0.001, for both) over the 12-week treatment period. Both plecanatide doses significantly improved all secondary and additional efficacy endpoints. The most common AE, diarrhea, occurred in 1.3% (placebo), 5.9% (3 mg) and 5.7% (6 mg) of patients. CONCLUSIONS: Plecanatide significantly improved constipation and its related symptoms with a low rate of adverse events. These results suggest that plecanatide will be a useful treatment option in the management of CIC. ClinicalTrials.gov: NCT01982240.

New pharmacological treatment options for irritable bowel syndrome with constipation.

INTRODUCTION: Constipation predominant irritable bowel syndrome (IBS-C) is a common disorder and accounts for a large number of ambulatory visits. Sensory abnormalities, that is, presence of abdominal pain and discomfort, distinguish IBS-C from chronic idiopathic constipation. AREA COVERED: This review focuses on the pharmacology, efficacy, safety, and future of prucalopride, YKP-10811, DSP-6952, dexloxiglumide, linaclotide, plecanatide, tenapanor, and elobixibat. EXPERT OPINION: It is now well established that treatment focusing only on bowel transit provides incomplete relief to patients with IBS-C. Improved understanding of pathophysiology of IBS-C has led to use of sensory end points like complete spontaneous bowel movements and the FDA combined end point (abdominal pain and complete spontaneous bowel movements) in clinical trials. A number of drugs are in development and provide hope for this challenging group of patients. However, because of recent failures secondary to ineffectiveness and/or adverse events, we cautiously await how clinical data play out in larger studies and in clinical practice.

Dose-dependent effects of lesogaberan on reflux measures in patients with refractory gastroesophageal reflux disease: a randomized, placebo-controlled study.

BACKGROUND: The γ-aminobutyric acid type B-receptor agonist lesogaberan (AZD3355) has been developed for use in patients with gastroesophageal reflux disease (GERD) symptoms despite proton pump inhibitor (PPI) therapy (partial responders). This study aimed to explore the dose-response effect of lesogaberan on reflux episodes in partial responders. METHODS: In this randomized, single-centre, double-blind, crossover, placebo-controlled study, partial responders taking optimised PPI therapy were given 30, 90, 120 and 240 mg doses of lesogaberan. Each dose was given twice (12 h apart) during a 24-h period, during which impedance-pH measurements were taken. RESULTS: Twenty-five patients were included in the efficacy analysis and 27 in the safety analysis. The effect of lesogaberan on the mean number of reflux episodes was dose-dependent, and all doses significantly reduced the mean number of reflux episodes relative to placebo. Lesogaberan also dose-dependently reduced the mean number of acid reflux episodes (except the 30 mg dose) and weakly acid reflux episodes (all doses) significantly, relative to placebo. Regardless of dose, lesogaberan had a similar effect on the percentage of time with esophageal pH < 4 [mean reduction: 68.5% (30 mg), 54.2% (90 mg), 65.9% (120 mg), 72.1% (240 mg); p < 0.05 except 90 mg dose]. No adverse events led to discontinuation and no serious adverse events occurred during active treatment. CONCLUSIONS: Lesogaberan inhibited reflux in a dose-dependent manner in partial responders taking optimised PPI therapy, and these effects were significant versus placebo. All lesogaberan doses were well tolerated and were not associated with clinically relevant adverse events. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01043185.

Exploring the physiologic role of human gastroesophageal reflux by analyzing time-series data from 24-h gastric and esophageal pH recordings.

Our previous finding of a fractal pattern for gastric pH and esophageal pH plus the statistical association of sequential pH values for up to 2 h led to our hypothesis that the fractal pattern encodes information regarding gastric acidity and that depending on the value of gastric acidity, the esophagus can signal the stomach to alter gastric acidity by influencing gastric secretion of acid or bicarbonate. Under our hypothesis values of gastric pH should provide information regarding values of esophageal pH and vice versa. We used vector autoregression, a theory-free set of inter-related linear regressions used to measure relationships that can change over time, to analyze data from 24-h recordings of gastric pH and esophageal pH. We found that in pH records from normal subjects, as well as from subjects with gastroesophageal reflux disease alone and after treatment with a proton pump inhibitor, gastric pH values provided important information regarding subsequent values of esophageal pH and values of esophageal pH provided important information regarding subsequent values of gastric pH. The ability of gastric pH and esophageal pH to provide information regarding subsequent values of each other was reduced in subjects with gastroesophageal reflux disease compared to normal subjects. Our findings are consistent with the hypothesis that depending on the value of gastric acidity, the esophagus can signal the stomach to alter gastric acidity, and that this ability is impaired in subjects with gastroesophageal reflux disease.

Evaluation of esophageal sensation.

Dramatic progress has been made over the past decade in the sophistication and availability of equipment to test esophageal motility and sensation. High-resolution esophageal manometry and impedance have moved from the research clinic into clinical practice. Some of the testing is costly and time consuming, and requires extensive experience to perform the testing and properly interpret the results. These sensory studies are valuable in the interpretation of clinical problems, and provide important research information. Clinicians should evaluate the research studies to advance their understanding of the pathophysiology of the esophagus.

Histamine2-receptor antagonists: Rapid development of tachyphylaxis with repeat dosing.

Histamine2-receptor antagonists (H2RAs) are available over-the-counter (OTC) for the treatment and prevention of heartburn, but more than occasional, single-dose use can lead to rapid development of tachyphylaxis. The aim of this review is to assess the published evidence regarding the development of tachyphylaxis with repeat usage of H2RAs. PubMed and SCOPUS were searched across all years to identify clinical studies that examined the development of tachyphylaxis with repeated dosing of H2RAs. Although a single (first) dose of an H2RA can be effective for controlling gastric acid and preventing or relieving food-related heartburn, numerous studies confirm that tachyphylaxis, also known as tolerance, is consistently detected at the first time point assessed after the first dose, including the second day and/or second dose. Even if symptom relief is achieved with an H2RA, it may be due to desensitization of the esophagus to acid exposure, potentially providing symptom relief without significantly decreasing esophageal acid exposure. When recommending OTC drugs for treatment of frequent heartburn, clinicians should be aware of the potential for rapid development of tachyphylaxis in patients who use H2RAs for 2 or more consecutive days. Even if symptom relief is achieved, it may be due to desensitization of the esophagus to acid by the H2RA, potentially providing symptom relief without significantly decreasing esophageal acid exposure. Other strategies, such as an OTC proton pump inhibitor, may be needed to optimize management of frequent heartburn.

Evidence-based treatment of frequent heartburn: the benefits and limitations of over-the-counter medications.

PURPOSE: This review summarizes the pharmacological effects of over-the-counter (OTC) heartburn drugs, and the implications for treating frequent heartburn. DATA SOURCES: PubMed and SCOPUS were searched across all years to identify well-controlled, randomized clinical studies that assessed mechanism of action and efficacy. CONCLUSIONS: Antacids can transiently neutralize acid in the esophagus, but do not significantly affect gastric pH or prevent subsequent heartburn episodes. Histamine-2 receptor antagonists (H2 RAs) rapidly develop tolerance with repeat dosing, and exhibit an analgesic effect that may provide heartburn relief while leaving the esophagus exposed to acid. Proton pump inhibitors (PPIs) provide a sustained inhibition of gastric acid production, and are superior to antacids and H2 RAs for control of gastric acid and treatment of frequent heartburn. IMPLICATIONS FOR PRACTICE: When recommending therapies for frequent heartburn, it is of particular importance to understand the strengths and weaknesses of available OTC medications. Antacids and H2 RAs are not recommended for treatment of frequent heartburn, while OTC PPIs are both indicated for, and effective for, treatment of frequent heartburn. A PPI dose of 20 mg is optimal for empiric treatment of frequent heartburn, and consistent with the 2013 treatment guidelines established by the American College of Gastroenterology (ACG) for treatment with a minimum effective dose.

Determination of serum antibodies to Clostridium difficile toxin B in patients with inflammatory bowel disease.

Clostridium difficile infection has increased in prevalence among patients with inflammatory bowel disease (IBD). Serum antibodies against C. difficile toxins have been detected in susceptible populations and may be protective; however, such antibodies have not been previously characterized in IBD patients. This study measured immunoglobulin G antibody levels to C. difficile toxin B in serum from IBD patients in remission and IBD patients in relapse. IBD patients demonstrated significantly higher antibody levels than non-IBD patients. In addition, a higher proportion of IBD patients in remission had positive antibody levels compared to IBD patients in relapse. Further characterization of antibody responses may elucidate understanding of susceptibility to C. difficile infection among IBD patients.

Long-term safety and effectiveness of lubiprostone, a chloride channel (ClC-2) activator, in patients with chronic idiopathic constipation.

BACKGROUND: Lubiprostone helps relieve constipation in short-term 4-week studies. There are limited data on long-term pharmacological treatment with lubiprostone for chronic idiopathic constipation. AIMS: To examine the long-term safety and effectiveness of lubiprostone in patients with chronic idiopathic constipation. METHODS: In this prospective, multicenter, open-labeled trial, 248 patients aged ≥18 years with chronic idiopathic constipation were directed to take lubiprostone 24 mcg BID as needed for 48 weeks. Patients were allowed to decrease the dose in response to the perceived severity of constipation and need for relief. Hematology and chemistry profiles and assessment of constipation symptoms and its severity were performed at all visits. Adverse events (AEs) were recorded. RESULTS: Of the 248 patients who entered the trial, 127 (51%) completed the trial. A dose reduction was observed in 17% of the patients, resulting in an average study medication exposure across the study of approximately 1.7 capsules (or approximately 40.8 mcg) per day. The most common treatment-related AEs were nausea (19.8%), diarrhea (9.7%), abdominal distension (6.9%), headache (6.9%), and abdominal pain (5.2%). No deaths were reported and of the 16 reported serious AEs, one was considered possibly treatment related. Average changes in serum electrolytes were not clinically relevant at any time point during the study. On average, lubiprostone significantly (p < 0.0001) reduced patient-reported constipation severity, abdominal bloating, and abdominal discomfort across 48 weeks when compared to baseline. CONCLUSIONS: During this 48-week open-label study, lubiprostone was well tolerated. Bowel symptoms consistently improved over 48 weeks in adult patients with chronic idiopathic constipation.

Safety aspects and rational use of a naproxen + esomeprazole combination in the treatment of rheumatoid disease.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely prescribed for reduction of pain and inflammation, particularly in the setting of rheumatologic disorders. While effective, they are associated with risks, including nephrotoxicity, gastrointestinal inflammation, peptic ulcer disease, and worsened cardiovascular outcomes. After development of cyclo-oxygenase 2 inhibitors to minimize gastrointestinal complications, early use revealed increased cardiovascular event rate risk, and retrospective analysis of traditional NSAIDs revealed similar concerns, with the exception of naproxen. PN400 is a fixed-dose combination formulation designed to provide sequential delivery of a nonenteric-coated, immediate-release esomeprazole 20 mg mantle followed by an enteric-coated naproxen 500 mg core. This review summarizes the pharmacokinetics, benefits, safety, and tolerability of PN400. Phase I trials demonstrated pharmacokinetics consistent with its formulation, and at different esomeprazole combination doses, PN400 containing esomeprazole 20 mg was the lowest dose that still resulted in substantial sustained increases of gastric pH > 4. In two Phase III trials (Study 301 and Study 302), PN400 resulted in a significant reduction in gastric ulcers relative to enteric-coated naproxen (4.1% to 23.1% in Study 301, 7.1% to 24.3% in Study 302). Discontinuation due to NSAID-associated upper gastrointestinal adverse events or duodenal ulcers was significantly less in PN400 patients (3.2% to 12%, P < 0.001, in Study 301; 4.8% to 11.9%, P = 0.009, in Study 302). Two subjective patient indices were utilized to assess tolerability, ie, the Severity of Dyspepsia Assessment (SODA) and Overall Treatment Evaluation of Dyspepsia (OTE-DP). Patients with PN400 had significantly better upper gastrointestinal tolerability compared with those treated with enteric-coated naproxen in terms of SODA scores, proportion of heartburn-free patients, and OTE-DP response. While no formal recommendations are available at this time for use of this new combination medication, it will likely become an important treatment option with application for many patients.