A phase IV clinical trial of gastrointestinal motility in adult patients with migraine before and after initiation of a calcitonin gene-related peptide ligand (galcanezumab) or receptor (erenumab) antagonist.

OBJECTIVE: To compare effects of an initial dose of calcitonin gene-related peptide (CGRP) monoclonal antibody (mAb) antagonists on gastrointestinal (GI) motility in patients with migraine and to explore if the mechanistic difference contributes to GI adverse events (AEs). BACKGROUND: Different frequencies of constipation have been observed between CGRP mAbs that target the ligand (galcanezumab [GMB]) or receptor (erenumab [ERE]). METHODS: Patients (n = 65) with migraine without significant GI symptoms were enrolled in a multi-center, single-blind phase IV clinical trial (NCT04294147) and randomized 1:1 to receive GMB (240 mg; n = 33) or ERE (140 mg; n = 32). GI whole and regional transit times were assessed using a wireless motility capsule 1 week before and 2 weeks after mAb administration. The primary endpoint was change from baseline in colonic transit time (CTT) within each treatment group. Other measures included GI Symptom Rating Scale (GSRS), Bristol Stool Form Scale (BSFS), and spontaneous bowel movement (SBM) evaluation. AEs were monitored throughout the study. RESULTS: Baseline characteristics indicated significant GI transit time variability with minimal GI reported symptoms. While not statistically significant, a numerical mean increase in CTT was observed in ERE patients (n = 28, mean [SD] at baseline: 33.8 [29.4] h; least square [LS] mean [SE] change: 5.8 [5.7] h, 95% confidence interval [CI] -5.7 to 17.2, p = 0.320), while GMB decreased CTT (n = 31, mean [SD] at baseline: 29.3 [24.5] h; LS mean [SE] change: -5.4 [5.4] h, 95% CI -16.2 to 5.5, p = 0.328) compared to baseline. No meaningful changes were observed in other regional transit times. ERE significantly reduced BSFS (LS mean [SE] score -0.5 [0.2], p = 0.004) and SBM (LS mean [SE] -1.2 [0.5], p = 0.0120), and increased GSRS-constipation compared to baseline (LS mean [SE] score 0.3 [0.1], p = 0.016). GMB increased GSRS-constipation (LS mean [SE] score 0.4 [0.1], p = 0.002). There were no discontinuations due to or serious AEs. A higher percentage of treatment-emergent AEs were reported with ERE than GMB (ERE: nine of 32 [28.1%] versus GMB: three of 33 [9.1%]), with constipation the most frequently reported (ERE: five of 32 [15.6%] versus GMB one of 33 [3.0%]). CONCLUSION: While the primary endpoint of this study was not met, secondary and tertiary endpoints support a within- and between-treatment change in GI effects suggesting possible mechanistic differences between ligand (GMB) and receptor (ERE) antagonism.

Intestinal pH and gastrointestinal transit profiles in cystic fibrosis patients measured by wireless motility capsule.

BACKGROUND AND AIMS: The effect of the cystic fibrosis transmembrane conductance regulator protein (CFTR) defect in pancreatic insufficient (PI) patients with cystic fibrosis (CF) on the gastrointestinal pH profile is poorly defined. Adequate and efficient neutralization of the gastric acidity in the duodenum is important for nutrient absorption and timely release of pancreatic enzyme replacement therapy (PERT). We utilized a wireless motility capsule (WMC) to study intestinal pH profile and gastrointestinal transit profile in CF subjects. METHODS: WMC studies were done on ten adult CF patients with PI while off acid suppression medication and ten age, gender and BMI matched healthy controls. Mean pH over 1 min increments and area under the pH curve over 5 min increments was calculated for the first hour post gastric emptying. Paired t-test was used to compare means of the pH recordings, transit profiles and analysis of time interval required to reach and maintain pH >5.5 and 6.0. RESULTS: A statistically significant difference was observed between mean pH values during the first 23 min of small bowel transit (p < 0.05). In CF subjects, there was a significant delay in time interval required to reach and sustain pH 5.5 and pH 6.0 (p < 0.001), which is required for PERT dissolution. Only small bowel transit in CF subjects was noted to be significantly delayed (p = 0.004) without a compensatory increase in whole gut transit time. CONCLUSIONS: We have demonstrated a significant delay in the small intestinal transit and a deficient buffering capacity required to neutralize gastric acid in the proximal small bowel of patients with CF.

SmartPill™ Administration to Assess Gastrointestinal Function after Spinal Cord Injury in a Porcine Model-A Preliminary Study.

Gastrointestinal (GI) complications, including motility disorders, metabolic deficiencies, and changes in gut microbiota following spinal cord injury (SCI), are associated with poor outcomes. After SCI, the autonomic nervous system becomes unbalanced below the level of injury and can lead to severe GI dysfunction. The SmartPill™ is a non-invasive capsule that, when ingested, transmits pH, temperature, and pressure readings that can be used to assess effects in GI function post-injury. Our minipig model allows us to assess these post-injury changes to optimize interventions and ultimately improve GI function. The aim of this study was to compare pre-injury to post-injury transit times, pH, and pressures in sections of GI tract by utilizing the SmartPill™ in three pigs after SCI at 2 and 6 weeks. Tributyrin was administered to two pigs to assess the influences on their gut microenvironment. We observed prolonged GET (Gastric Emptying Time) and CTT (Colon Transit Time), decreases in contraction frequencies (Con freq) in the antrum of the stomach, colon, and decreases in duodenal pressures post-injury. We noted increases in Sum amp generated at 2 weeks post-injury in the colon, with corresponding decreases in Con freq. We found transient changes in pH in the colon and small intestine at 2 weeks post-injury, with minimal effect on stomach pH post-injury. Prolonged GETs and CTTs can influence the absorptive profile in the gut and contribute to pathology development. This is the first pilot study to administer the SmartPill™ in minipigs in the context of SCI. Further investigations will elucidate these trends and characterize post-SCI GI function.

Accurate localization of a fall in pH within the ileocecal region: validation using a dual-scintigraphic technique.

Stereotypical changes in pH occur along the gastrointestinal (GI) tract. Classically, there is an abrupt increase in pH on exit from the stomach, followed later by a sharp fall in pH, attributed to passage through the ileocecal region. However, the precise location of this latter pH change has never been conclusively substantiated. We aimed to determine the site of fall in pH using a dual-scintigraphic technique. On day 1, 13 healthy subjects underwent nasal intubation with a 3-m-long catheter, which was allowed to progress to the distal ileum. On day 2, subjects ingested a pH-sensitive wireless motility capsule labeled with 4 MBq (51)Chromium [EDTA]. The course of this, as it travelled through the GI tract, was assessed with a single-headed γ-camera using static and dynamic scans. Capsule progression was plotted relative to a background of 4 MBq ¹¹¹Indium [diethylenetriamine penta-acetic acid] administered through the catheter. Intraluminal pH, as recorded by the capsule, was monitored continuously, and position of the capsule relative to pH was established. A sharp fall in pH was recorded in all subjects; position of the capsule relative to this was accurately determined anatomically in 9/13 subjects. In these nine subjects, a pH drop of 1.5 ± 0.2 U, from 7.6 ± 0.05 to 6.1 ± 0.1 occurred a median of 7.5 min (1-16) after passage through the ileocecal valve; location was either in the cecum (n = 5), ascending colon (n = 2), or coincident with a move from the cecum to ascending colon (n = 2). This study provides conclusive evidence that the fall in pH seen within the ileocolonic region actually occurs in the proximal colon. This phenomenon can be used as a biomarker of transition between the small and large bowel and validates assessment of regional GI motility using capsule technology that incorporates pH measurement.

Do stool form and frequency correlate with whole-gut and colonic transit? Results from a multicenter study in constipated individuals and healthy controls.

OBJECTIVES: Despite a lack of supportive data, stool form and stool frequency are often used as clinical surrogates for gut transit in constipated patients. The aim of this study was to assess the correlation between stool characteristics (form and frequency) and gut transit in constipated and healthy adults. METHODS: A post hoc analysis was performed on 110 subjects (46 chronic constipation) from nine US sites recording stool form (Bristol Stool Scale) and frequency during simultaneous assessment of whole-gut and colonic transit by wireless motility capsule (WMC) and radio-opaque marker (ROM) tests. Stool form and frequency were correlated with transit times using Spearman's rank correlation. Accuracy of stool form in predicting delayed transit was assessed by receiver operating characteristic analysis. RESULTS: In the constipated adults (42 females, 4 males), moderate correlations were found between stool form and whole-gut transit measured by WMC (r=-0.61, P<0.0001) or ROM (-0.45, P=0.0016), as well as colonic transit measured by WMC (-0.62, P<0.0001). A Bristol stool form value <3 predicted delayed whole-gut transit with a sensitivity of 85% and specificity of 82% and delayed colonic transit with a sensitivity of 82% and specificity of 83%. No correlation between stool form and measured transit was found in healthy adults, regardless of gender. No correlation was found between stool frequency and measured transit in constipated or healthy adults. The correlation between stool frequency and measured transit remained poor in constipated adults with <3 bowel movements per week. CONCLUSIONS: Stool form predicts delayed vs. normal transit in adults. However, only a moderate correlation exists between stool form and measured whole-gut or colonic transit time in constipated adults. In contrast, stool frequency is a poor surrogate for transit, even in those with reduced stool frequency.

Investigation of colonic and whole-gut transit with wireless motility capsule and radiopaque markers in constipation.

BACKGROUND & AIMS: Colonic transit time (CTT) traditionally is assessed with radiopaque markers (ROMs), which requires radiation and is hindered by lack of standardization and compliance. We assessed regional and CTT with the SmartPill (SmartPill Corporation, Buffalo, NY), a new wireless pH and pressure recording capsule, in constipated and healthy subjects and compared this with ROM. METHODS: Seventy-eight constipated (Rome II) and 87 healthy subjects ingested a 260-kcal meal, a ROM capsule, and the SmartPill. Subjects wore a data receiver and kept daily stool diaries for 5 days. SmartPill recordings assessed CTT, whole-gut transit time (WGTT), small-bowel transit time, and gastric emptying time. Abdominal radiographs on days 2 and 5 assessed ROM transit. Sensitivity/specificity and receiver operating characteristics (ROCs) of each technique and utility were compared. RESULTS: Gastric emptying time, CTT, and WGTT were slower (P < .01) in constipated subjects than controls. CTT was slower in women than men (P = .02). Day 2 and day 5 ROM transits were slower (P < .001) in constipated subjects. Correlation of the SmartPill CTT with ROMs expelled on day 2/day 5 was r = 0.74/r = 0.69 in constipation, and r = 0.70/r = 0.40 in controls, respectively. The diagnostic accuracy of the SmartPill CTT to predict constipation from ROC was 0.73, with a specificity of 0.95. These were comparable with those of day 5 ROM (ROC, 0.71; specificity, 0.95). CONCLUSIONS: The SmartPill is a novel ambulatory technique of assessing regional (gastric, small bowel, colonic) and WGTT without radiation. It reveals hitherto unrecognized gender differences and upper-gut dysfunction in constipation. It correlates well with ROM and offers a standardized method of discriminating normal from slow colonic transit.

Colonic motor response to wakening is blunted in slow transit constipation as detected by wireless motility capsule.

BACKGROUND: Chronic constipation may be categorized as normal transit (NTC), slow transit (STC), or outlet obstruction. Colonic wake response is a relative increase in colonic motility upon awakening. Colonic manometry studies have demonstrated attenuated wake response in STC. We sought to evaluate wake response among healthy (H), NTC, and STC patients using wireless motility capsule (WMC). METHODS: A retrospective study of WMC data from a multicenter clinical trial and a tertiary gastroenterology clinic was performed. WMC motility parameters of contraction frequency (Ct) and area under the contraction curve (AUC) were analyzed in 20-min windows 1-h before and after awakening. T-tests compared parameters between H, NTC, and STC. Linear regression analysis was performed to determine if outlet obstruction confounded data. A receiver operating characteristic curve demonstrated optimal Ct cut-offs to define blunted wake response. RESULTS: A total of 62 H, 53 NTC and 75 STC subjects were analyzed. At 20, 40, and 60 min after awakening, STC subjects had significantly lower mean Ct when compared to H (p < 0.001) and NTC (p < 0.01). Linear regression demonstrated that outlet obstruction was not associated with a decreased wake response (ß = 3.94, (CI -3.12-1.00), P = 0.27). Defined at the Ct threshold of 64 at 20-min post-wake, blunted wake response sensitivity was 84% and specificity was 32% for chronic constipation. CONCLUSION: Findings of an impaired wake response in subjects with STC and not NTC adds further evidence to neuronal dysfunction as an etiology of STC, and identifies a possible temporal target for pharmacologic intervention.