Definition of factor Xa inhibitor-related, life-threatening gastrointestinal bleeding and guidance on when to use reversal therapy: A Delphi panel.

Objective: To define and contextualize life-threatening gastrointestinal (GI) bleeding in the setting of factor Xa (FXa) inhibitor therapy and to derive a consensus-based, clinically oriented approach to the administration of FXa inhibitor reversal therapy. Methods: We convened an expert panel of clinicians representing specialties in emergency medicine, gastroenterology, vascular medicine, and trauma surgery. Consensus was reached among the clinician panelists using the Delphi technique, which consisted of 2 survey questionnaires followed by virtual, real-time consensus-building exercises. Results: Hypovolemia and hemodynamic instability were considered the most important clinical signs of FXa inhibitor-related, life-threatening GI bleeds. Clinician panelists agreed that potentially life-threatening GI bleeding should be determined on the basis of hemodynamic instability, signs of shock, individual patient characteristics, and clinical judgment. Last, the panel agreed that all patients with life-threatening, FXa inhibitor-associated GI bleeding should be considered for FXa inhibitor reversal therapy; the decision to reverse FXa inhibition should be individualized, weighing the risks and benefits of reversal; and when reversal is elected, therapy should be administered within 1 h after initial emergency department evaluation, when possible. Conclusions: Consensus-based definitions of life-threatening GI bleeding and approaches to FXa inhibitor reversal centered on hemodynamic instability, signs of shock, individual patient characteristics, and clinical judgment. The results from this Delphi panel may inform clinical decision-making for the treatment of patients experiencing GI bleeding associated with FXa inhibitor use in the emergency department setting.

CNS sites controlling the gastric pyloric sphincter: Neuroanatomical and functional study in the rat.

The pyloric sphincter receives parasympathetic vagal innervation from the dorsal motor nucleus of the vagus (DMV). However, little is known about its higher-order neurons and the nuclei that engage the DMV neurons controlling the pylorus. The purpose of the present study was twofold. First, to identify neuroanatomical connections between higher-order neurons and the DMV. This was carried out by using the transneuronal pseudorabies virus PRV-152 injected into rat pylorus torus and examining the brains of these animals for PRV labeling. Second, to identify the specific sites within the DMV that functionally control the motility and tone of the pyloric sphincter. For these studies, experiments were performed to assess the effect of DMV stimulation on pylorus activity in urethane-anesthetized male rats. A strain gauge force transducer was sutured onto the pyloric tonus to monitor tone and motility. L-glutamate (500 pmol/30 nL) was microinjected unilaterally into the rostral and caudal areas of the DMV. Data from the first study indicated that neurons labeled with PRV occurred in the DMV, hindbrain raphe nuclei, midbrain Edinger-Westphal nucleus, ventral tegmental area, lateral habenula, and arcuate nucleus. Data from the second study indicated that microinjected L-glutamate into the rostral DMV results in contraction of the pylorus blocked by intravenously administered atropine and ipsilateral vagotomy. L-glutamate injected into the caudal DMV relaxed the pylorus. This response was abolished by ipsilateral vagotomy but not by intravenously administered atropine or L-NG-nitroarginine methyl ester (L-NAME). These findings identify the anatomical and functional brain neurocircuitry involved in controlling the pyloric sphincter. Our results also show that site-specific stimulation of the DMV can differentially influence the activity of the pyloric sphincter by separate vagal nerve pathways.

Development of a novel patient-reported outcome measure to assess signs and symptoms of COVID-19.

BACKGROUND: Given the urgent need for vaccines and treatments for coronavirus disease 2019 (COVID-19), the Symptoms of Infection with Coronavirus-19 (SIC), a comprehensive, patient-reported outcome (PRO) measure of signs and symptoms associated with COVID-19, was developed in full alignment with current US regulatory guidance to support evaluations of vaccines and treatments in development. METHODS: An initial version of the SIC was developed to address concepts identified through a targeted literature review and consultation with experts in infectious diseases and clinicians routinely managing COVID-19 in a hospital setting. A qualitative study was conducted in sites in the United States among 31 participants aged ≥ 18 years who were English-speaking and willing and able to provide informed consent and a self-reported history by telephone or online method. The measure was refined based on additional feedback from the clinicians and three iterative rounds of combined concept elicitation and cognitive debriefing interviews conducted with patients, caregivers, and healthy volunteers. RESULTS: Among 39 scientific articles identified in the literature review, 35 COVID-19 signs and symptoms were reported and confirmed during interviews with clinicians, patients, and caregivers. Patients and healthy participants suggested changes for refining the draft SIC to ensure consistent interpretation and endorsed both the 24-h recall period and use of an 11-point numeric rating scale (NRS) for capturing change in symptom severity. The final version of the SIC captures the daily presence or absence of 30 symptoms and a rating of severity for 25 of the 30 symptoms using an NRS for those symptoms reported as present. CONCLUSIONS: The SIC comprehensively addresses observations described in the literature, by clinicians, and by patients, and captures patients' experiences with COVID-19 in a manner that minimizes complexity and facilitates completion for both patients and healthy volunteers. This measure is thus appropriate for use in clinical trials of both therapeutics and vaccines for COVID-19.

Cost-effectiveness analysis of universal noninvasive testing for post-treatment confirmation of Helicobacter pylori eradication and the impact of patient adherence.

BACKGROUND: The treatment failure rate for Helicobacter pylori eradication therapy is ~20% due to poor patient compliance and increased antibiotic resistance. This analysis assessed the cost-effectiveness of universal post-treatment testing to confirm eradication of H. pylori infection in adults. METHODS: Decision-analytic models evaluated the cost-effectiveness of universal post-treatment testing (urea breath test [UBT] or monoclonal fecal antigen test [mFAT]) vs no testing (Model 1), and UBT vs mFAT after adjusting for patient adherence to testing (Model 2) in adults who previously received first-line antimicrobial therapy. Patients testing positive received second-line quadruple therapy; no further action was taken for those testing negative or with no testing (Model 1) or for those nonadherent to testing (Model 2). In addition to testing costs, excess lifetime costs and reduced quality-adjusted life-years (QALYs) due to continuing H. pylori infection were considered in the model. RESULTS: Expected total costs per patient were higher for post-treatment testing (UBT: US$325.76; mFAT: US$242.12) vs no testing (US$182.41) in Model 1 and for UBT (US$336.75) vs mFAT (US$326.24) in Model 2. Expected QALYs gained per patient were 0.71 and 0.72 for UBT and mFAT, respectively, vs no testing (Model 1), and the same was 0.37 for UBT vs mFAT (Model 2). The estimated incremental costs per QALY gained for post-treatment testing vs no testing were US$82.90-US$202.45 and, after adjusting for adherence, US$28.13 for UBT vs mFAT. CONCLUSION: Universal post-treatment testing was found to be cost-effective for confirming eradication of H. pylori infection following first-line therapy. Better adherence to UBT relative to mFAT was the key to its cost-effectiveness.

Impact of patient adherence on the cost-effectiveness of noninvasive tests for the initial diagnosis of Helicobacter pylori infection in the United States.

OBJECTIVE: Previous US-based economic models of noninvasive tests for diagnosis of Helicobacter pylori infection did not consider patient adherence or downstream costs of continuing infection. This analysis evaluated the long-term cost-effectiveness of the urea breath test (UBT), fecal antigen test (FAT), and serology for diagnosis of H. pylori infection after incorporating information regarding test adherence. MATERIALS AND METHODS: A decision-analytic model incorporating adherence information evaluated the cost-effectiveness of the UBT, FAT, and serology for diagnosis of H. pylori infection. Positive test results led to first-line triple therapy; no further action was taken for nonadherence or negative results. Excess lifetime costs and reduced quality-adjusted life-years (QALYs) were estimated for patients with continuing H. pylori infection. RESULTS: In the base-case scenario with estimated adherence rates of 86%, 48%, and 86% for the UBT, monoclonal FAT, and serology, respectively, corresponding expected total costs were US$424.99, $466.41, and $404.98/patient. Test costs were higher for the UBT, but were fully or partially offset by higher excess lifetime costs for the monoclonal FAT and serology. The QALYs gained/patient with the UBT vs monoclonal FAT and serology were 0.86 and 0.27, respectively. The UBT was dominant vs the monoclonal FAT, leading to lower costs and higher QALYs; the UBT was cost-effective vs serology (incremental cost/QALY gained $74). CONCLUSION: Based on a comprehensive modeled analysis that included consideration of patient test adherence and long-term consequences resulting from continuing H. pylori infection, the UBT provided the greatest economic value among noninvasive tests for diagnosis of H. pylori infection, because of high patient adherence and excellent test performance.

Rhythmic Aortic Contractions Induced by Electrical Stimulation In Vivo in the Rat.

For over a century, the behavior of the aorta and other large arteries has been described as passive elastic tubes in which no active contraction occurs in the smooth muscle wall. In response to pulsatile pressure changes, the vessels undergo a 'passive' elastic dilatation-contraction cycle, described as a "Windkessel" effect. However, Mangel and colleagues have presented evidence that is contrary to this view. They reported that in the rabbit, the aorta undergoes rhythmic 'active' (contraction) during the cardiac cycle; but these findings have been largely ignored. In the present study, we observed spontaneous contractions in synchrony with the heartbeat in another species (rat). In addition we demonstrate that aorta contractions are of neurogenic origin. Electrical stimulation of the aorta evoked contractions that occur at a rate that is in the range of the animal's heartbeat and are suppressed by tetrodotoxin and the alpha-adrenergic receptor blocker, phentolamine. Altogether, these findings indicate that aortic contractions are under neural control from the heart.

Assessment of treatment response in chronic constipation clinical trials.

BACKGROUND: While chronic constipation (CC) clinical trials have focused primarily on bowel symptoms (symptoms directly related to bowel movements), abdominal symptoms are also prevalent among patients. The United States Food and Drug Administration's (FDA's) guidance on the use of patient-reported outcome measures to support product approvals or labeling claims recommends that endpoints be developed with direct patient input and include all symptoms important to patients. AIM: To identify a comprehensive set of CC symptoms that are important to patients for measurement in clinical trials. METHODS: Following a targeted literature review to identify CC symptoms previously reported by patients, 28 patient interviews were conducted consistent with the FDA's guidance on patient-reported outcomes. Subsequent to open-ended questions eliciting descriptions of all symptoms, rating and ranking methods were used to identify those of greatest importance to patients. RESULTS: All 67 studies reviewed included bowel symptoms; more than half also addressed at least one abdominal symptom. Interview participants reported 62 potentially distinct concepts: 12 bowel symptoms; 21 abdominal symptoms; and 29 additional symptoms/impacts. Patients' descriptions revealed that many symptom terms were highly related and/or could be considered secondary to CC. The rating and ranking task results suggest that both bowel (for example, stool frequency and consistency) and abdominal symptoms (for example, bloating, abdominal pain) comprise patients' most important symptoms. Further, improvements in both bowel and abdominal symptoms would constitute an improvement in patients' CC overall. CONCLUSION: Abdominal symptoms in CC patients are equal in relevance to bowel symptoms and should also be addressed in clinical trials to fully evaluate treatment benefit.

From depolarization-dependent contractions in gastrointestinal smooth muscle to aortic pulse-synchronized contractions.

For decades, it was believed that the diameter of gastrointestinal smooth muscle cells is sufficiently narrow, and that the diffusion of calcium across the plasma membrane is sufficient, to support contractile activity. Thus, depolarization-triggered release of intracellular calcium was not believed to be operative in gastrointestinal smooth muscle. However, after the incubation of muscle segments in solutions devoid of calcium and containing the calcium chelator ethylene glycol tetraacetic acid, an alternative electrical event occurred that was distinct from normal slow waves and spikes. Subsequently, it was demonstrated in gastrointestinal smooth muscle segments that membrane depolarization associated with this alternative electrical event triggered rhythmic contractions by release of intracellular calcium. Although this concept of depolarization-triggered calcium release was iconoclastic, it has now been demonstrated in multiple gastrointestinal smooth muscle preparations. On the basis of these observations, we investigated whether a rhythmic electrical and mechanical event would occur in aortic smooth muscle under the same calcium-free conditions. The incubation of aortic segments in a solution with no added calcium plus ethylene glycol tetraacetic acid induced a fast electrical event without corresponding tension changes. On the basis of the frequency of these fast electrical events, we pursued, contrary to what has been established dogma for more than three centuries, the question of whether the smooth muscle wall of the aorta undergoes rhythmic activation during the cardiac cycle. As with depolarization-triggered contractile activity in gastrointestinal smooth muscle, it was "well known" that rhythmic activation of the aorta does not occur in synchrony with the heartbeat. In a series of experiments, however, it was demonstrated that rhythmic contractions occur in the aortic wall in synchrony with the heartbeat and share a common pacemaker with the heart. We conclude that important observations in the vascular system became derivative from those in the gastrointestinal system. The challenging of scientific dogma potentially leads to the expansion of our fundamental knowledge base.

Clinical trials in irritable bowel syndrome: a review.

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders and it is characterized by episodes of abdominal pain and altered bowel functions. The specific bowel disturbances of diarrhea, constipation or an alternation between the two defines the IBS subtypes of diarrhea-predominant, constipation-predominant, and mixed or alternating IBS. Because of the abnormalities in bowel states associated with each IBS subtype, it is not likely that one agent would successfully treat all three subtypes. As a result, clinical trials have focused, for the most part, on one IBS subtype. Over the past 2 decades very few agents have achieved regulatory approval for the treatment of IBS. In the present article we review publications reporting on phase 2 and phase 3 studies evaluating agents to potentially be used in the treatment of patients with IBS.

Asimadoline and its potential for the treatment of diarrhea-predominant irritable bowel syndrome: a review.

Irritable bowel syndrome (IBS) is a multifactorial condition with principal symptoms of pain and altered bowel function. The kappa-opioid agonist asimadoline is being evaluated in Phase III as a potential treatment for IBS. Asimadoline, to date, has shown a good safety profile and the target Phase III population - diarrhea-predominant IBS patients with at least moderate pain - was iteratively determined in a prospective manner from a Phase II dose-ranging study. The clinical data in support of this population are reviewed in this article. Furthermore, the scientific rationale for the use of asimadoline in the treatment of IBS is reviewed. Considering the high patient and societal burdens of IBS, new treatments for IBS represent therapeutic advances.

Depolarization-stimulated contractility of gastrointestinal smooth muscle in calcium-free solution: a review.

The membrane of most gastrointestinal smooth muscles shows slow waves, slow rhythmic changes in membrane potential. Slow waves serve to bring the membrane potential of smooth muscle cells to a threshold level that elicits a second electrical event known as the spike or action potential. The inward current of the spike, in most gastrointestinal smooth muscle preparations, is carried, at least in part, by calcium. Indeed, considering the narrow diameter of smooth muscle cells, some have hypothesized that the influx of calcium during the spike is sufficient for activation of the contractile machinery. Findings consistent with this include marked reduction in contractility during exposure of muscle segments to blockers of L-type calcium channels or following reductions in external calcium levels. However, it has also been observed that following exposure of muscle segments to external bathing solutions containing no added calcium plus 5 mM EGTA to remove any remaining extracellular calcium, contractions can be triggered following membrane depolarization. It is noteworthy that in isolated smooth muscle cells or in small muscle segments, during incubation in calcium-free solution, depolarization does not induce contractions. The present paper discusses the evidence in support of depolarization-mediated contractions occurring in gastrointestinal smooth muscle segments during incubation in solutions devoid of calcium.

Urgency as an Endpoint in Irritable Bowel Syndrome.

BACKGROUND: The choice of endpoints is crucial for proper evaluation of agents in clinical trials of irritable bowel syndrome (IBS). In a recently published draft guidance for IBS from the United States Food and Drug Administration (FDA), urgency was not considered an appropriate primary endpoint. The FDA's position is that it is not clear how patients with diarrhea-predominant IBS (D-IBS) "define or describe urgency". The aims of this study were to evaluate the association of urgency with stool frequency and consistency in patients with D-IBS and to describe results from patient interviews on their understanding of the term urgency. METHODS: A retrospective analysis of clinical trial data in patients with D-IBS was conducted. Analyses focused on the relationship of urgency to stool frequency and consistency. Interviews were conducted with patients with D-IBS to test their understanding of the term urgency. RESULTS: On the days that patients reported urgency, as compared to the days that patients did not report urgency, they had more frequent bowel movements (3.9 versus 1.8) and looser stools (Bristol Stool Score: 5.4 versus 4.2). The differences for both parameters, evaluated on the days with or without urgency, were statistically significant. In patient interviews, patients with D-IBS had a clear understanding of the concept and terminology of urgency and considered it one of their two most bothersome symptoms. CONCLUSIONS: Urgency should be considered a suitable co-primary endpoint in D-IBS studies.

Asimadoline in the treatment of irritable bowel syndrome.

IMPORTANCE OF THE FIELD: Irritable bowel syndrome (IBS) represents one of the most common gastrointestinal disorders, with the diarrhea-predominant form (D-IBS) representing an area of high unmet medical need. One difficulty in identifying suitable treatments for IBS is that although there are animal models for the components of IBS, it is not clear whether animals are afflicted by the disease. In a recently completed Phase II study, the kappa-opioid agonist, asimadoline, was shown to be efficacious in a prospectively defined subgroup of D-IBS patients. This study confirmed a good safety profile for asimadoline. AREAS COVERED IN THIS REVIEW: The chemistry, pharmacology, pharmacokinetics, pharmacodynamics and clinical safety and efficacy of asimadoline in relationship to IBS is reviewed. Papers were searched over the past 20 years using the PubMed database and key words 'asimadoline', 'kappa-opioid agonist' and 'irritable bowel syndrome'. Abstracts were reviewed and appropriate full papers were then evaluated. WHAT THE READER WILL GAIN: The reader will gain an appreciation of kappa-opioid agonists as IBS treatments. TAKE HOME MESSAGE: In a prospectively defined, clinically relevant patient subgroup, asimadoline shows efficacy in the treatment of D-IBS.

Does Timing of Colon Procedures Affect Outcomes in D-IBS Trials?

BACKGROUND: Sigmoidoscopy/colonoscopy is usually performed prior to enrollment into clinical trials of irritable bowel syndrome (IBS). Two main reasons are to rule out alternative diagnoses and to ensure that colitis is not present. However, the possible impact of a recent versus remote colon procedure on symptoms in IBS trials has not been evaluated. The aim of this study was to evaluate the effect of timing of colon procedures on symptoms in IBS trials. METHODS: Post hoc analyses were conducted using placebo patients with diarrhea-predominant IBS in a phase 2 trial. Pain, frequency, consistency, and urgency were analyzed using repeated measures models during the first 7 days of treatment and over the entire 12-week treatment period. RESULTS: Fifty-two placebo patients were grouped by whether they had a colon exam performed between screening and randomization (Group 1) or had a normal colon procedure during the 3 years prior to screening for this trial (Group 2). Average screening symptom scores were comparable between the two groups. Evaluation of various symptoms showed that there were no consistent significant differences between the two groups in pain, frequency, consistency, or urgency. CONCLUSIONS: After the required 3-day post-procedure recovery period, there was no evidence that colonoscopy timing affected subsequent IBS symptoms.

Psychometric evaluation of patient-reported outcomes in irritable bowel syndrome randomized controlled trials: a Rome Foundation report.

BACKGROUND & AIMS: There is debate about how best to measure patient-reported outcomes (PROs) in irritable bowel syndrome (IBS). We pooled data to measure the psychometric properties of IBS end points, including binary responses (eg, "adequate relief") and 50% improvement in symptom severity. METHODS: We pooled data from 12 IBS drug trials involving 10,066 participants. We tested the properties of binary response and 50% improvement end points, including the impact of baseline severity on performance, and measured construct validity using clinical anchors. RESULTS: There were 9044 evaluable subjects (age, 44 years; 85% female; 58% IBS constipation-prominent [IBS-C]; 31% IBS diarrhea-prominent [IBS-D]). Using the binary end point, the proportion responding in the mild, moderate, and severe groups was 42%, 40%, and 38%, respectively (P = .0008). There was no effect of baseline severity on binary response (odds ratio [OR], 0.99; 95% confidence interval [CI], 0.99-1.0; P = .07). The proportions reaching 50% improvement in pain were 45%, 41%, and 41%, respectively; there was a small, yet significant, impact of baseline severity (OR, 1.04; 95% CI, 1.03-1.05; P < .0001) that did not meet clinical relevance criteria. Both end points revealed strong construct validity and detected "minimally clinically important differences" in symptoms. Both provided better discriminant spread in IBS-D than IBS-C. CONCLUSIONS: Both the traditional binary and 50% improvement end points are equivalent in their psychometric properties. Neither is impacted by baseline severity, and both demonstrate excellent construct validity. They are optimized for the IBS-D population but also appear valid in IBS-C.

Evaluation of crofelemer in the treatment of diarrhea-predominant irritable bowel syndrome patients.

BACKGROUND: Crofelemer improves bowel function in several conditions characterized by states of prominent secretory diarrhea. AIM: This double-blind, randomized, placebo-controlled trial evaluated the effects of 3 dose levels of crofelemer in patients with diarrhea-predominant irritable bowel syndrome (D-IBS). METHODS: Male and female patients were randomly assigned to receive crofelemer 125, 250 or 500 mg or placebo twice daily for 12 weeks. The primary efficacy measure was a responder for improvement in stool consistency. In addition, abdominal pain- and discomfort-free days, pain and discomfort scores as well as other bowel function parameters (such as stool frequency and consistency, urgency, bloating) were evaluated. RESULTS: Two hundred and forty-two D-IBS patients were randomized. Crofelemer did not produce significant improvement in stool consistency (primary endpoint), stool frequency, urgency or adequate relief. However, female D-IBS patients showed improvement in the proportion of pain- and discomfort-free days during treatment with 500 mg crofelemer: month 1 (crofelemer vs. placebo: 17.7 vs. 10.2%, p = 0.098); month 2 (23.5 vs. 13.3%, p = 0.076); month 3 (26.1 vs. 10.6%, p = 0.0076). No benefit was seen in male D-IBS patients. Crofelemer was well tolerated. CONCLUSIONS: Crofelelmer did not produce benefit on bowel function; an increase in the number of pain- and discomfort-free days in female D-IBS patients was seen. Further studies with crofelemer are warranted to evaluate it as a potential visceral analgesic.

Primary endpoints for irritable bowel syndrome trials: a review of performance of endpoints.

The choice of primary endpoint for a clinical trial is one of the most important determinants of the ability of a clinical trial to demonstrate efficacy of therapeutic agents. Although there are still no clear, universally accepted guidelines on the definition of clinical benefit for irritable bowel syndrome (IBS), consensus guidelines stress the importance of using validated endpoints. This article reviews the evidence available in the literature on the psychometric validation and performance of the 3 endpoints recommended by the Rome III Committee for use as primary endpoints in treatment trials of IBS. The Rome III Committee recommends 2 types of measures: binary endpoints addressing the construct of relief (that is, adequate relief and satisfactory relief) and an integrative symptom questionnaire that addresses the change in severity of a representative group of symptoms of IBS (that is, the IBS Severity Scale). The current evidence suggests that at present, adequate relief should be recognized by regulatory authorities as an acceptable primary endpoint in clinical trials. This analysis also suggests that data from individual clinical trials should be pooled and undergo meta-analysis, and that prospective studies should be considered to further characterize the performance of available endpoints as outcome measures in pharmacotherapeutic trials in IBS.