Clinical trial NCT03270085
Conditions: Chronic Diarrhea Irritable Bowel Syndrome With Diarrhea Bile Acid Malabsorption
Sponsor: Mayo Clinic
Start date: 2017-12-07; Completion date: 2019-05-31
Enrollment: 30 participants; Allocation: RANDOMIZED; Intervention model: PARALLEL

Brief summary:
To compare with a randomized trial (n=15 per treatment group), effects of colesevelam and placebo treatment, on colonic transit, bowel functions, permeability and tight junction expression in rectosigmoid mucosa of IBS-D with Bile Acid Malabsorption.

Detailed description:
Compare the effects of Colesevelam versus the placebo on diabetic subjects with chronic diarrhea. In this study, diabetic subjects will get either the Colesevelam or the placebo, not both.

The plan is to have about 30 subjects complete this study at Mayo Clinic.

Arms: arm 1: Once randomized, subjects will have baseline testing period, treatment period, and treatment testing period the study drug. This consists of nine visits and will be over a period of five to nine weeks.

Baseline testing period consists of: transit test, 4 day high fat diet with 48 hour stool collection, blood samples, rectosigmoid biopsies, one week stool diary, and medication pick up.

Treatment period will have subject take the study drug 1875 mg of medication orally twice daily with lunch and supper for 4-5 weeks.

The last period, is the treatment testing period. This consists of a full transit \& urine permeability test, 4 day high fat diet with 48 hour stool collection, blood samples, one week stool diary collection, and the return of the unused medication. arm 2: Once randomized, subjects will have a baseline testing period, treatment period and treatment testing period with the placebo. This consists of nine visits and will be over a period of five to nine weeks.

The last period, is the treatment testing period. This consists of a full transit \& urine permeability test, 4 day high fat diet with 48 hour stool collection, blood samples, one week stool diary collection, and the return of the unused placebo.
Interventions: intervention 1: Colesevelam intervention 2: Placebo
Intervention descriptions: intervention 1: Colesevelam (Welchol) is approved by the Food and Drug Administration (FDA) for the treatment of high blood cholesterol levels and to treat type 2 diabetes however, Colesevelam is not approved for the use proposed in this study and is considered investigational. intervention 2: A placebo looks exactly like the study drug, but it contains no active ingredient. This is used to learn if the effects seen in research participants are truly from the study drug.

Protocol documents:
Prot_SAP_000.pdf: 
 
Randomized, Double Blinded, 
Placebo Controlled Trial To 
Understand Efficacy Of 
Colesevelam In Diarrhea 
Predominant IBS Patients With 
Bile Acid Malabsorption 
 
NCT# 03270085 
 
October 15, 2018 


 
Study Title: 
Randomized, Double Blinded, Placebo controlled trial to understand efficacy of Colesevelam in 
diarrhea predominant IBS patients with Bile Acid Malabsorption  
 
Name of Principal Investigator (PI): Michael Camilleri, M.D. 
 
Version and date: Version 09 dated 10/15/2018 
Original protocol date: 07/03/2017 
 
 
 
SPECIFIC AIM  
     Irritable bowel syndrome (IBS) is the most common lower gastrointestinal (GI) disorder that affects 11% of 
adults (1). Currently, IBS and subgroups diarrhea-predominant IBS (IBS-D), and IBS-constipation (IBS-C), are 
defined by symptoms alone. Apart from central hypervigilance and psychological disturbances in IBS (2),48% 
of IBS-D patients have accelerated colonic transit, 21% have increased rectal sensation (3), and others have 
increased intestinal permeability, reduced barrier protein expression (4) and abnormal bile acid (BA) synthesis 
or excretion (5). These findings suggest that colonic “irritation” may be mediated by extrinsic factors (e.g. 
stress or prior GI infections) and intraluminal mediators [e.g. BAs and short chain fatty acids (SCFA)] which 
alter mucosal function, stimulate serotonin release, alter mucosal permeability, induce immune activation, and 
increase colonic motility.   
We have previously shown that colonic mucosal mRNA expression (first in 9 patients, then confirmed in 47 
other patients) showed that IBS-D is associated with changes in transcriptome which regulates mucosal 
functions, such as neurotransmitters (P2RY4 and VIP), ion channels [GUC2AB, and PDZD3) cytokines 
(CCL20), and immune function (C4BPA).  
Building on these preliminary observations, our overarching goal is to examine effects of BA sequestration in 
IBS-D with increased BA excretion on quantitative traits and mucosal mRNA expression in rectosigmoid colon. 
Hypothesis:  BA sequestration normalizes colonic functions in IBS-D with increased fecal BA excretion. 
Specific Aim: To compare with a randomized trial (n=15 per treatment group), effects of colesevelam 1.875g 
bid and placebo treatment, on colonic transit, bowel functions, permeability and tight junction expression in 
rectosigmoid mucosa of IBS-D with Bile Acid Malabsorption. 
 
This protocol addresses the third specific aim of a program on IBS-D with increased fecal BA excretion


 
ABBREVIATIONS used: ASBT: apical, Na-dependent bile acid transporter; ASIC: acid-sensing ion channel; ATP2C2: 
annotated as splice-site acceptor motif, and involved in Ca2+ encoding secretory pathway; BA: bile acids; C4BPA: 
complement component 4 binding protein, alpha; CA: cholic acid; CCL20: chemokine (C-C motif) ligand 20  CDCA 
chenodeoxycholic acid; CDH-1: cadherin 1; CLDN: claudin;CNR1: cannabinoid type 1 receptor;  C11orf30: chromosome 11, 
open-reading frame 30;  CYP, cytochrome P450; DCA deoxycholic acid; FAAH: fatty acid amide hydrolase; FABP6: fatty acid 
binding protein 6; FDR: false discovery rate; FXR: farnesoid X receptor; FGF19: fibroblast growth factor 19; FGFR4: FGF 
receptor 4; FN1: fibronectin 1;  GpBAR1:G protein coupled bile acid receptor 1; GUC: guanylate cyclase; 5-HT: serotonin; 5-
HTTLPR: 5-HT transporter, long polymorphic repeat; IL: interleukin; IBS: irritable bowel syndrome; IFIT3: interferon-induced 
protein with tetratricopeptide repeats 3;  KLB: klotho B;LRH1: liver receptor homolog-1 ; MAF: minor allele frequency; NaV: 
voltage gated sodium channel; NR1H4: Nuclear receptor subfamily 1, group H, member 4 ;OCLN: occluding; ORMDL3: 
Orosomucoid like 3; OST: organic solute transporter; OTU: operational taxonomic units; PRDM1: positive regulatory domain 
I-binding factor;   P2RY4: purinergic receptor P2Y, G-protein coupled, 4;  PDZD3: postsynaptic density-95, disks large, 
zonula occludens-1, domain 3; QTL: quantitative trait loci;  RBP2: retinal-binding protein 2;SHP: Small Heterodimer Partner; 
SLC solute carrier C; SNP: single nucleotide polymorphism; SNV: Single nucleotide variants;Th17: IL-17-producing CD4+ T 
cells; TGR5 =GpBAR1;  TFF1: trefoil factor 1 TJ: tight junctions; TNFSF15: tumor necrosis factor, superfamily 15; TLR9: toll-
like receptor 9; TRPV: transient receptor potential vanilloid; VIP: vasoactive intestinal peptide; XAF-1: X-Linked inhibitor of 
apoptosis-associated factor-1; ZO: zonula occludens 
A. INTRODUCTION 
A.1. Significance of the Problem. IBS affects ~11% and IBS-D affects ~5% of the US population (1) and 
often impairs quality of life (13). IBS is currently defined by symptoms (i.e., abdominal discomfort associated 
with bowel disturbances) in the absence of organic disease on routine testing. The few available therapeutic 
agents for IBS-D are of very limited efficacy. In contrast to this “one size fits all” approach, there is a large body 
of evidence that IBS-D symptoms are manifestations of peripheral mechanisms that perturb motor, 
mucosal and sensory functions (3,14). This application is founded on the concept that better understanding 
of the phenotypes in IBS-D will identify biomarkers that ultimately will support diagnosis and targeted 
(individualized) therapy for the disorder, significantly enhancing health. 
   
Current concepts on IBS focus on disturbances of colonic transit, mucosal immune function, visceral 
hypersensitivity, and central nervous system (CNS) hypervigilance (2,14,15). The current proposal focuses 
on IBS-D: in our series of 119 patients with IBS-D (3), 48% had accelerated transit, while 20.5% had increased 
and 16.5% had reduced rectal sensation. Since the pathophysiology and, possibly, genetic and expression 
mechanisms controlling (for example) motor and secretory functions, may differ significantly in IBS-D and IBS-
C, this proposal focuses on IBS-D. Recent research, detailed in New England Journal of Medicine (14) and 
Journal of Physiology (16), summarizes peripheral mechanisms in IBS: intraluminal irritants (such as mal-
digested carbohydrates (producing SCFA) or fats, excess of BAs, bioactive amines [e.g. serotonin (17)], 
mucosal barrier function (TJ proteins, e.g. ref. 18), immune activation, increased small intestinal and colonic 
permeability, and alterations in microbiome.  These factors activate local reflexes to alter intestinal motility or 
secretion, and stimulate sensation and pain (reviewed in ref. 4).  
We propose that these QUANTITATIVE traits, linked to underlying genetic mechanisms or to alterations in 
tissue expression of pivotal mechanisms, provide the basis for understanding IBS-D and optimizing treatment.  
Figure 1. Schema of 3 proposed aims of DK92179 application examining germ-line DNA, mucosal 
expression, and effect of BA sequestrant, Colesevelam, including numbers of participants in each aim. 
 This protocol addresses the third specific 
aim of a program on IBS-D with increased 
fecal BA excretion  
A third aim addresses the potential effects 
of bile acid sequestration on bowel 
function, transit, permeability and 
expression of barrier proteins in 
rectosigmoid mucosa and will thus 
confirm the relevance of mucosal 
alterations demonstrated in aim 2. To 
enhance the power of studies in IBS-D 
exploring gene quantitative trait loci 
(QTLs) and mucosal expression, it is 
essential to measure key quantitative 
traits. The relevance of the quantitative 
traits to subtypes of IBS and its symptoms 
are discussed elsewhere (14).    
 
Fig. 1 


 
A.2. Mucosal Expression of Factors Impacting Pathophysiology of IBS. IBS has been associated with 
changes in the rectosigmoid mucosal expression of immune mechanisms and non-immune protective factors. 
Table 1. Changes in Colonic Mucosal Expression in IBS in the Published Literature 
There are only a few 
examples of the inherited 
genotype that is associated 
with altered mucosal gene 
expression, e.g., 
differential expression of 
TNFSF15 genes (which 
are associated with IBS), 
has been linked with 
functional alterations of 
mucosal immune and 
protective functions (6,22).  
 
PRELIMINARY DATA  
1. A systematic review and meta-analysis (39) shows an average  28% of IBS-D patients have  
evidence of increased BA synthesis or fecal BA excretion (figure 2)   
2. Pilot Study of RNA-Seq of 
Rectosigmoid Mucosa:  
We examined RNA expression of 
rectosigmoid mucosa from 9 female IBS-D 
patients (36) by RNA-Seq (Illumina 
methods)(Fig. 3), and analyzed using the 
edgeR software. We identified [FDR 
corrected p<0.05] 21 genes (Fig. 4) with 
altered mRNA expression in that may be 
biologically relevant in IBS-D: 
neurotransmitters [P2RY4 (p=0.001), VIP 
[p=0.02)], cytokines [CCL20 (p=0.019)], 
immune function (C4BPA complement 
cascade  [p=0.0187]; TNFSF15 [p= 0.0098] 
and  IFIT3 which determines  expression of 
interferon-induced genes [p= 0.016), 
mucosal repair and cell adhesion (TFF1 
gastrointestinal trefoil protein,  [p= 0.012]; 
RBP2 retinol binding protein [p=0.017]; FN1 
fibronectin [p=0.009]), and ion transport 
functions with increased expression in: (i) GUC2AB (p= 0.017); guanylate cyclase activator 2B, which 
encodes uroguanylin which causes enterocyte chloride secretion through guanylate cycles C receptor [GC-C]); 
(ii).PDZD3 (p=0.029); PDZ protein associates with GC-C and regulates cGMP production, leading to chloride 
secretion (36). After validating RNA-Seq data with RT-PCR of same samples, we proposed in a model of 
barrier, ion secretory and immune dysfunctions, based on mucosal transcriptome changes in IBS-D.        
 Figure 3:  Summary model (based on RNA-Seq) of increased 
mucosal expression of ion secretory mechanisms (GUCA2B, 
PDZD3), barrier dysfunction (FN1, RBP2), transmitters 
(P2RY4, VIP), and immune regulation (TNF) in IBS-D.   
 
3. Replication of abnormal mucosal mRNA expression in 
IBS-D and novel observations in IBS-C (38). The initial 
observations by RNA-Seq were replicated using RT-PCR in 
rectosigmoid mucosal biopsies from a cohort of 47 IBS-D patients 
and contrasted findings in 10 IBS-C and 17 healthy controls. 


 
 Figure 4. Expression of mRNA (vs. healthy) in IBS-D, IBS-C (blue histograms) showing the specificity 
of the increased expression of guanylin and PDZD3 ion transport and immune mechanisms in IBS-D.    
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 5. Western blots for protein 
expression of PDZD3 in colonic 
mucosa (left) from IBS-D (n=10) (38), 
and PPP2R5C (n=7 IBS-D) in small 
bowel mucosa (43). Note the increased 
protein expressions relative to vinculin or 
actin (as control) compared to healthy 
controls. 
Figure 6. Immunofluorescence of 
colorectal mucosa showing increased 
expression of PDZD3 protein in 
epithelial cells in IBS-D patient 
compared to control. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fig 4 
Fig 5 
Fig 6 


 
Open-label study of the BA sequestrant, Colesevelam, in 12 patients with IBS-D and high fecal bile acid 
excretion demonstrated biological relevance of increased fecal BA excretion (27).   
Figure 7. Effects of colesevelam on 
sequestration of bile acid (methanol extraction 
of stool released the bile acids showing that 
increased amounts were bound) and reduced 
stool form.  Colesevelam improved stool 
consistency, sequestering and inactivating BA 
(shown by increased BA in stool after methanol 
extraction).  
 
 
 
 
 
 
 
 
 
METHODS 
Participants: Eligibility of 30 patients with IBS-D and evidence of BAM. Through the application of natural 
language processing and the electronic medical record, we have an established database of ~8000 patients 
with IBS who reside within ~100 miles, and have been evaluated at Mayo Clinic in Rochester, Minnesota; 
about ~2000 have been identified with IBS-D. All participants with IBS-D will be selected by computer-based 
random selection to be invited to participate. The randomly selected 300 patients with IBS-D will complete a 
validated bowel disease questionnaire, including Somatic Symptom Checklist [BDQ corresponding to Rome III 
criteria (58)], IBS quality of life [IBS-QOL (59)], and the Hospital Anxiety and Depression Scale [HAD (60)]. 
Ethnicity and race information is available in >90% of patients at Mayo Clinic.  
Consideration of Sex as a Biological Variable: Scientific premise for inclusion of both genders includes: 
(i) IBS-D affects both genders; (ii) there is no a priori evidence that mechanisms or pathobiology of IBS-D 
differs between genders. We shall set up special efforts to recruit males with IBS using REDCAP to identify 
male patients through the electronic health records (established 17 years ago at Mayo Clinic). 
Participants with IBS-D will be screen for BAM 3 ways with either fasting serum alpha C4 or FGF19 taken 
before 10 am. If C4 ≥ 40 ng/mL or FGF19 ≤ 80 pg/mL either in the past or at the time of screen, the patient will 
be included in the trial and subsequently randomized. Also IBS-D with a fecal BA >2000µmoles/48h either in 
the past or at the time of screen will be included in the trial or subsequently randomized. 
Quantitative Traits 
Colonic permeability is measured by urinary excretion of mannitol and lactulose after oral ingestion (44). We 
refined a previous HPLC-tandem mass spectrometry technique (45). We validated measurement of colonic 
permeability after oral delivery by direct instillation of sugars into the colon (46). We have published data 
showing significantly increased small bowel (P<.001) and colonic (P=0.10) permeability in IBS-D (35); and 
effects of dietary gluten on small bowel permeability, especially in HLA DQ2/8 +ve (P=0.02) patients with non-
celiac IBS-D (35). We validated 13C-mannitol to avoid confounding by dietary 12C-mannitol (47).  
Rectosigmoid mucosal expression of tight junction (TJ) proteins, a measure of barrier function: IBS-D 
patients have lower mRNA expression of TJ proteins [ZO-1 
and occludin (both P<.001)], but not claudin proteins (35) 
relative to healthy controls; values show fold change vs. mean 
in controls (Table 2). 
Table 2. TJ protein expressions in rectosigmoid mucosa 
in IBS D and healthy controls (mean ± SD).    
In addition, gluten-containing diet was associated with 
significant decreases in ZO-1 and occludin mRNA expression in rectosigmoid mucosa (48).       
 
 
Mucosal morphology will assess intra-epithelial lymphocytes, mast cells and immunocytes in lamina propria, 
and immunohisto-chemistry of TJ proteins (35). GI pathologist will ensure correct orientation.    


 
     Colonic transit: Extensive experience over 28 years with validation of colonic transit by radioscintigraphy 
(49) .  
Gallbladder size measurement: Studies have demonstrated that patients with hormones that regulate bile 
acid synthesis (FGF15 in mice and FGF19 in humans) facilitate gallbladder filling. We want to determine if 
there is any difference of baseline and post treatment gallbladder measurements. Gallbladder measurement 
will be conducted fasting both pre and post treatment with a 2-D ultrasound. Patients will be in the supine 
position with the transducer placed in a sagittal plane in the right upper quadrant of the supine patients and 
positioned until the greatest length of the gallbladder is obtained. The image will be captured and the length will 
be measured. The probe will then be rotated 90 degrees to obtain the short axis and obtain the greatest 
dimension in that window. 
    BA kinetics: Assessment of BA synthesis and fecal excretion (uniquely available in USA at Mayo Clinic) 
Serum 7α-hydroxy-4-cholesten-3-one (7α-HCO or C4) measures hepatic cholesterol synthesis, and is a 
validated method for BA malabsorption [BAM (51,52)]. Serum C4 (ref. 53, assay based on ref. 54) is positively 
correlated with fecal BA excretion [rs=0.61, p<0.001 (5)].  
Serum fibroblast growth factor 19 (FGF19), a measure of feedback regulation of BA synthesis (54B), will be 
measured by ELISA (R&D Systems, Minneapolis, MN).     
Fecal BA excretion: Using HPLC/tandem mass spectrometry, we adapted a method (55) to measure fecal total 
and individual BAs. We have previously shown that fecal total BA (5), and secretory primary and secondary 
BAs [chenodeoxycholic (CDCA) and deoxycholic acids (DCA)] are higher in IBS-D, whereas CDCA is 
decreased and non-secretory lithocholic acid increased in IBS-C (56)]. 
    Short chain fatty acids (SCFAs) in stool by gas chromatography-mass spectrometry (Mayo CTSA ICL Lab) 
The method is adapted from Tangerman et al. (57) and permits analysis of 8 SCFAs, from C2 to C6, plus an 
internal standard, 2-ethyl butyric acid using a Thermo Trace GC Ultra Gas Chromatograph (San Jose, CA) 
fitted with a flame ionization detector (FID). Fecal samples are extracted using acetonitrile and injected without 
dilution; components were identified according to their retention times compared to standards. 
Studies on Sigmoid Mucosal Biopsies: Tight Junction Proteins, Morphology, RNA-Seq. With informed 
consent, 8 samples will be acquired from the rectum and sigmoid colon and 4 from terminal ileum, for each 
patient. Biopsies will be immediately preserved in formalin (histopathology), or in a solution of RNAlater 
(Ambion, Austin, TX), stored at -80°C. RNA extraction will be performed as in the manufacturer’s instructions 
(RNeasy mini kit, Qiagen, Valencia, CA). The quantity and quality of the extracted RNA will be determined by 
the NanoDrop 2000 spectrophotometer (Thermo Scientific, Wilmington, DE) and the Bioanalyzer 2100 (Agilent 
Technologies, Inc., Santa Clara, CA). All RINs will be determined using the Agilent Bioanalyzer. RNA-Seq 
analysis will be conducted as in section C.1.e and as in Camilleri et al. (36). Ileal mRNA of ASBT (SLC10A2) 
and FXR (NR1H4) in ileal mucosa will be measured by RT-PCR (see C.2.9.i.).  
     Quantitation of Tight Junction (TJ) Proteins in Sigmoid Mucosa Using Real-Time PCR.  
TJ proteins [zonula occludens 1 (ZO-1), occludin (OCLN), claudin-1 (CLDN-1), and glyceraldehyde 3-
phosphate dehydrogenase (GAPDH, control)] will be assayed in rectosigmoid biopsies. cDNA synthesis will be 
performed using 0.2 μg of total RNA with the High Capacity Reverse Transcription Kit (Applied Biosystems, 
Foster City, CA). Taqman gene expression assays for ZO-1, OCLN, CLDN-1, and GAPDH will be carried out in 
triplicate for each gene on an ABI Prism 7300 Real-time PCR System (Applied Biosystems) according to 
manufacturer's instructions using the comparative ΔΔCT method for relative quantification.  mRNA expression 
of each gene (normalized to GAPDH) will be compared by statistical analysis(35,48). 
    Colonic Mucosal Morphology. The colonic biopsies will be stained with H&E and tryptase to assess 
intraepithelial lymphocytes (IEL) and mast cells.  Immuno-histochemical staining of 5μ-thick paraffin sections 
will be performed using a commercial kit; primary antibodies used will be CD3, CD4, CD8, CD68, CD79, 
tryptase (Dako, Carpenteria, CA) and ZO-1 (Invitrogen Corporation, Camarillo, CA). Biopsies will be assessed 
by one experienced GI pathologist (T. Smyrk, MD) who will be blinded to IBS-D/C subtype. Dr. T. Smyrk, co-
investigator, has expertise and experience from our prior collaborative studies (48, DK86182). IEL will be 
counted on the H&E slides and expressed as IEL/100 epithelial cells. Immune cells stained for CD3 and CD8 
will be counted on semi-quantitative scale of 1-4. ZO-1 will be scored as percentage of epithelial cells positive, 
and semi-quantitative assessment of stain intensity [on scale 0-3 (48)]. 
     In Depth RNA Sequencing of Colonic Mucosa (analysis by E.W. Klee, Ph.D., Bioinformatics). 
Assay Protocol:  Total RNA will be isolated from mucosal biopsies (Qiagen RNeasy Mini Kit). RNA-Seq will be 
performed on the Illumina Hi-Seq 4000, using the RNA-Seq protocol with 101 base, paired-end reads. 


 
Samples will be multiplexed 6 per lane, averaging >100 million reads-per-sample, with 60.4% of reads 
mapping to the gene regions. Bioinformatics tools for pathway analysis will also be utilized (Dr. E. Klee Ph.D.). 
Library preparation and sample sequencing will be performed by the Mayo Clinic Advanced Genomic 
Technology Center Core Facility.  Special techniques for analysis, ensuring uniformity in cross-gene and 
sample set comparisons and pathway analysis are detailed in the section on laboratory facilities available.  
      In Depth Proteomics of colonic mucosal biopsies in duplicate by a label-free LC-MS/MS method 
(see letter of support from Dr. Daniel J. McCormick Ph.D., Proteomics Core, Mayo).   
Extraction and separation: Proteins from the biopsy will be extracted in SDS buffer containing protease 
inhibitors using a bead beater to disrupt tissue. Extracted proteins will be run on a gel, proteins separated by 
size, segmented, and in-gel trypsin digested to obtain peptides to compare across samples. 
Liquid chromatography is used to load peptide sample onto a C8 cartridge, which is then placed in-line with 
a C18 analytical column. Peptides are sorted by ionic strength using a mobile phase gradient of acidic low to 
high organic solvent, eluted off the column, captured into mass spectrometer (MS) via electrospray ionization, 
followed by data dependent ms/ms data for peak identification. D. We also have access to single reaction 
monitoring (SRM) mass spectrometry on QExactive and triple quad instruments in the Proteomics Core for 
more accurate quantification of proteins if necessary.   
Data analysis from high resolution MS will use MaxQuant, a quantitative proteomics software to compare 
high resolution MS data. Database searching within MaxQuant assigns amino acid sequence to peptides and 
assembles peptide information back to proteins. Quantified values of proteins between groups are compared. 
 
Biological Samples Collected 
1. Venous Blood Sample (fasting) will be collected for serum FGF19 and C4. Venous blood DNA will 
be stored for future genetic studies.  
2. Fecal Sample for Fecal Organic Acids: Gas chromatography-mass spectrometry for SCFA in stool 
and HPLC tandem MS for total and individual fecal BAs. Samples will now be a random stool sample 
without a required dietary change unless they have not had a qualifying diagnosis of BAM as noted in 
the Research Plan below. Samples will then be processed for total fat (routine van de Kamer method at 
Mayo Medical Laboratory), total BAs, and primary and secondary BAs [by LC/MS as previously 
described from our lab (56)], and SCFA by GC-MS  
3. Additional stool and rectosigmoid mucosa samples will be stored for future microbiome studies. 
4.  Urine Samples to quantitate Excretion of Lactulose and 13C-Mannitol after Oral Ingestion of 
lactulose and 13C mannitol (5:1 ratio by mass) (47). The 0-2h urine most closely reflects small intestinal 
permeability and 8-24h urine reflects colonic permeability (46). HPLC-tandem mass spectrometry will 
be used for detection of the sugars (Mayo Clinic CTSA Lab). Baseline and post treatment small bowel 
and colonic permeability will be performed for every patient. 
Cumulative (Cum) excretion (0-2h and 8-24h) = Concentration of sugar (µg/mL)] * total urine volume (mL).   
 
Lactulose: mannitol ratio (L:M R) is: 0.2 x (Cum excretion lactulose) / (Cum excretion 13C-mannitol). 
       5.  Sigmoidoscopy and Mucosal Biopsies from sigmoid will now be optional. Participants will have 
the option to complete sigmoidoscopy at the beginning, end, both time points or refrain from completing this 
portion of the study. If participants agree to perform the sigmoidoscopy, it will be performed in all fasting 
participants in the Clinical Research unit, and in the same time of day (7-8am), with the patients’ medications 
stopped 48 hours before the biopsies for the baseline studies. The biopsies will be collected in formalin or 
RNAlater solution (Ambion, Austin, TX) and stored at -80°C until further analyzed.    
 
RESEARCH PLAN for Randomized controlled trial of colesevelam in IBS-D with high fecal BA. 
Hypotheses: BA sequestration normalizes colonic functions in IBS-D with increased fecal BA excretion. 
Specific Aim: To compare with a randomized trial (n=15 per treatment group), effects of colesevelam 1.875g 
bid and placebo treatment, on colonic transit, bowel functions, permeability and tight junction expression in 
rectosigmoid mucosa  of IBS-D with fecal BA>2000 µmoles/48h (upper limit of normal).  
Rationale: BA diarrhea is increasingly recognized as a subtype of IBS-D (39,41). In an open-label study (27), 
we identified beneficial effects of colesevelam in the treatment of IBS symptoms in patients with high total fecal 
BA excretion (>2000µmoles/48h), elevated primary bile acids (>4%) with elevated total fecal bile acids (>1,000 
µmol/48h), or primary bile acids > 10%, elevated C4 (> 40 ng/mL), and decreased FGF19 (<80 pg/mL) (section 
C.1.g and figure 7)).  


 
Human subjects and design: 30 IBS-D patients with BAM will be randomized (15/group) in 4-week double-
blind, parallel-group trial to Colesevelam, 1.875g b.i.d. or placebo. Patients will be stratified on gender and 
BMI; we anticipate 90% female and 75% BMI >30kg/m2.     
Experimental procedures: Effects of colesevelam/placebo on symptoms (daily stool diaries), as well as 
colonic transit, fecal bile acid and fat excretion and fasting serum C4 and FGF-19, intestinal permeability and 
TJ expression in rectosigmoid mucosal biopsies at baseline and at end of 28 days’ treatment.  
Primary endpoints: 1. Bowel movements/week; 2. Stool consistency based on Bristol Stool Form Scale, BSFS. 
Secondary endpoints: 1. Quantitative total fecal BAs; 2. Proportion of secretory BA (CDCA, DCA) in stool; 3. 
Fasting serum C4 and FGF-19 levels; 4. Colonic transit, geometric center at 24 and 48 hours; 5. Intestinal and 
colonic permeability (mannitol, lactulose excretion); 6. TJ expression in rectosigmoid mucosa.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
This study consists of ten visits to Mayo Clinic at the Charlton 7 Clinical Research Trials Unit (CRTU). Some of 
the visits can be combined.  
Visit 1 (Screen visit) Volunteers will be asked to come to the Charlton 7 to review and sign this informed 
consent form and all have all their questions answered. This visit will require about 90 minutes.  
• 
QUESTIONNAIRES: Volunteers will be asked to complete two questionnaires.  
1. Bowel Disease Questionnaire, which asks questions about their bowel symptoms  
2. Hospital Anxiety and Depression Inventory, which asks about any anxiety or depression they are 
currently feeling  
3. Quality of Life Questionnaire, which ask you how your bowel symptoms are affecting your life 
4. Symptom Checklist, which ask you about any symptoms you are currently feeling 
• 
VITAL SIGNS, HEIGHT AND WEIGHT: A nurse will take your height, weight and vital signs (pulse, 
blood pressure, respiration rate and temperature).  
• 
HISTORY AND BRIEF PHYSICAL EXAM: A study physician will review their medical history, current 
medications and supplements and perform a physical exam.  
• 
POSSIBLE BLOOD DRAW: A small amount of blood may be taken if the study physician determines 
that blood tests need to be run to see if they qualify for the study.  Such as serum alphaC4 or FGF19. 
If the study physician finds the volunteer eligible for the study, they will be asked to participate in the rest of the 
study. 
• STOOL COLLECTION: You will be given a stool kit and will be asked to return a stool sample before 
your Flexible Sigmoidoscopy. 
• If the patient has not had previous qualifying FGF19, C4, primary to total fecal bile acids in the past, 
then fasting serum blood work for FGF19 and C4 will be completed at the Screen visit. A 48 hour stool 
Colesevelam Study Design 
Screen 
Visit 
Within  
4 weeks 
VISIT: 
Baseline Testing 
 1) Transit for GC24 & urine 
permeability; gallbladder 
measurement 
2) 4 day High Fat diet with  
48 hour stool collection* 
3) Blood samples (DNA, C4 & FGF19) 
4) Rectosigmoid biopsies** 
5) 1 week stool diary collected 
6) Medication pickup 
 
6-10 
Day 1 
2-5 
Day 28+2-7 
Treatment Testing  
1) Full Transit & Urine Permeability; 
gallbladder measurement  
2) 4 day High Fat diet with  
48 hour stool collection* 
3) Blood samples (C4 & FGF19) 
4) Rectosigmoid biopsies** 
5) treatmentstool diary collected 
6) Unused medication returned 
4-5 week Treatment with 
Colesevelam/Placebo 
Within  
1 week 
* Fecal Bile Acids (total and individual), Short Chain Fatty Acids & Microbiome 
** TJ protein expression, proteomics, morphology & RNA sequencing 


 
test to evaluate for primary and total fecal bile acids will be conducted first. The remaining study 
examinations, abbreviated colonic transit test, permeability test, random stool sample, flexible 
sigmoidoscopy, and gallbladder ultrasound will be postponed by at least one week. 
 
Visit 2 (Pretreatment testing) Participants will be asked to report to the desk on Charlton 7 after an 8 hour 
fast (no food/drink, a small amount of water is OK), and the avoidance of artificial sweeteners 48 hours before 
and during the permeability testing (Visits 2-3).  The visit should take approximately 45-60 minutes. 
• 
PREGNACY TEST, if needed: A urine sample will be collected for a pregnancy test from women who 
can get pregnant if it was not done within 48 hours of this study day. The results of this test must be 
negative in order for participants to continue the study.  
• 
FASTING BLOOD DRAW: Participants will be asked to give a small amount of blood for DNA, serum 
alpha C4 and FGF19 testing if not done previously. 
DIARY RETURN: Participants will be asked to return the completed 7-day Pretreatment Diary. 
• 
ABREVIATED COLONIC TRANSIT TEST/Permeability test: : Participants will be asked to swallow a 
small capsule containing a small amount of a radioactive substance with a liquid containing a small 
amount of naturally occurring sugars: lactulose and mannitol. The sugars allow the measurement of the 
permeability of the small intestine and colon.  The participants will be instructed to have breakfast one 
hour later.  
VISITS 3-5 MAY BE COMBINED 
Visit 3 (24 hour image) Participants will be asked to report to the desk on Charlton 7 (fasting required) 
approximately 24 hours after they ingested the capsule containing radioisotope during Visit 2. Ultrasound 
measurement can be performed before or after the 24 hour image is obtained. The ultrasound gallbladder 
measurement should take ~ 10-15 minutes. This visit should take approximately 25 minutes.  
Visit 4 (Flexible sigmoidoscopy) [OPTIONAL]  Participants will be asked to report to the desk on Charlton 7 
(no fasting required). The visit should take approximately 75 minutes.  
• 
ENEMA: Participants will need to prepare the colon for the sigmoidoscopy by means of a tap water 
enema at the CRTU. A CRTU nurse will give a tap water enema. Two enemas may be given if needed. 
• 
FLEXIBLE SIGMOIDOSCOPY WITH BIOPSIES: A sigmoidoscopy is a lower endoscopy that uses a 
flexible endoscope to visually inspect the lining of the sigmoid colon. Several biopsies of the lining of 
the colon will be removed for examination under a microscope, TJ protein expression, proteomics and 
RNA sequencing.. No sedation is needed. The nurse will review information regarding post-endoscopy 
care and the participant will be dismissed. 
 
Visit 5 (Study Medication pickup) Participants will be asked to report to the desk on Charlton 7 (no fasting 
required).The visit should take approximately 15-30 minutes.  
 
• 
PREGNACY TEST, if needed: A urine sample will be collected for a pregnancy test from women who 
can get pregnant if it was not done within 48 hours of this study day. The results of this test must be 
negative in order to continue the study.  
• 
STUDY MEDICATION: The nurse will dispense a 5 week supply of the Colesevelam/placebo and 
instruct participants to take 3 tablets orally twice daily with lunch and supper.  
• 
 SINGLE RANDOMSTOOL SPECIMENS: Returned as instructed 
• 
DIARIES RETURN: Participants will be asked to return the completed 7-day Pretreatment Bowel diary  
• 
 
 
TREATMENT: Participants will take 1875 mg (3 tablets [625 mg/tablet]) of the medication orally twice daily 
with lunch and supper for 4-5 weeks. They also will be asked to complete the following visits after 21 days of 
treatment with the treatment fat diet and stool collections completed after the transit/permeability and flex 
sig/biopsy tests. A separate stool sample collection kit will be provided on Visit 6 to be returned before the 
flexible sigmoidoscopy. No special diet is required with this particular stool collection.  
Note: Treatment Bowel diary will not be completed by participants during high fat diet. 
 


 
Visit 6 (Treatment testing) Participants will be asked to report to the desk on Charlton 7 after an 8 hour fast 
(no food/drink, a small amount of water is OK). And the avoidance of artificial sweeteners 48 hours before and 
during the permeability testing (Visits 6-7).  This visit will require about 9-10 hours total.  
• 
PREGNACY TEST, if needed: A urine sample will be collected for a pregnancy test from women who 
can get pregnant if it was not done within 48 hours of this study day. The results of this test must be 
negative in order to continue the study.  
• 
VITAL SIGNS: A nurse will take vital signs (pulse, blood pressure, respiration rate and temperature).  
• 
FASTING BLOOD DRAW: Participants will be asked to give a small amount of blood for serum alpha 
C4 and FGF19 testing. 
• 
FULL COLONIC TRANSIT/PERMEABILITY TEST: Participants will be asked to swallow a small 
capsule containing a small amount of a radioactive substance with a liquid containing a small amount of 
naturally occurring sugars: lactulose and mannitol. The sugars allow the measurement of the 
permeability of the small intestine and colon. Approximately one hour later, the transit test starts with a 
scrambled egg breakfast (with toast and a glass of milk). The eggs also contain a small amount of 
radioactive substance. Participants will eat two additional meals, a lunch of chicken breast (4 hours 
after the egg breakfast) and a dinner of a roast beef sandwich (8 hours after the egg breakfast). These 
meals are not radioactive, they are supplied only so all participants in this study will eat the same type 
and same amount of food this day. They will be asked not to eat or drink anything except for water 
while undergoing testing today other than what they are given. At the completion of the breakfast test 
meal they will be instructed to stand in front of a special camera and pictures will be taken immediately 
after the egg breakfast and then 1, 2, 3, 4, 6 and 8 hours later. Participants will be asked to collect urine 
samples at scheduled intervals for the next eight hours. After the 8 hour image is taken, they will collect 
all urine until the next morning. A urine collection kit will be provided to then for this. After they leave the 
CRTU, they may eat or drink your own foods, but ingestion of alcohol and drinks containing any 
sweeteners must continue being avoided until after Visit 7 as they interfere with the measurements of 
the research study. 
• 
STUDY MEDICATION ADMINISTRATION: The CRTU nurse will administer a dose of the study 
medication with the lunch and snack meals provided during this visit. 
• 
STOOL COLLECTION: You will be given a stool kit and will be asked to return a stool sample before 
your Flexible Sigmoidoscopy. 
• 
 
Visit 7 (24 hour image) Participants will be asked to report to the desk on Charlton 7 (fasting required) for the 
24 hour image. Ultrasound measurement can be performed before or after the 24 hour image is obtained. The 
ultrasound gallbladder measurement should take ~ 10-15 minutes. The visit should take approximately 25 
minutes. 
VISITS 8 AND 9 MAY BE COMBINED 
Visit 8 (48 hour image and urine collection return) Participants will be asked to report to the desk on 
Charlton 7 (no fasting required) to drop off their 8-24 hour urine collection and have the 48 hour image taken. 
The visit should take approximately 10 minutes. 
Visit 9 (Flexible sigmoidoscopy) [OPTIONAL] Participants will be asked to report to the desk on Charlton 7 
(no fasting required). The visit should take approximately 75 minutes. 
• 
ENEMA: same as Visit 4 
• 
FLEXIBLE SIGMOIDOSCOPY WITH BIOPSIES: same as Visit 4 
Visit 10: End of Study: 
• 
DIARIES RETURN: Participants will be asked to return the completed Treatment Bowel diary  
• 
MEDICATION RETURN: On the last visit participants will be asked to return any unused medication. 
Statistical analyses: Effects of treatment will be compared (using Intention-To-Treat principles) using 
ANCOVA with BMI, gender, baseline colonic transit and baseline fecal BA excretion as covariates.  
November 1 2018: at least 75% of the participants will have completed all study procedures. We plan to 
complete an interim analysis in order to submit an abstract for a national gastroenterology meeting in May 
2019. We anticipate completing all studies in all participants by the time the data need to be presented.  At that 
time, we shall present the data from the ENTIRE patient cohort; that analysis will be used for the one full 
manuscript emanating from these data. 
 


 
A senior statistician will review the interim analysis results and analyze the data related to the previously 
determined primary endpoints. All members of the study team and the investigative team will remain blinded to 
treatment arm assignment and treatment arm results until the completion of the study. Thus, this would not 
affect the p value when the study is completed.  
Statistical power: Based on our previous open-label study, the proposed sample size (15 per group) has 
~80% power (2-sided α=0.05) to detect clinically 
relevant effect sizes in stool frequency and form 
(expressed as detectable difference [Δ] in 2 groups:  in 
Table 3: Detectable differences based on 80% 
power. 
Anticipated results and significance: Colesevelam 
will reduce stool frequency, decrease stool consistency 
and slow colonic transit in IBS-D with high BA 
excretion.  
Precautions and alternative approaches:  
1. The RCT has sufficient power based on directly relevant open-label trial data with same drug and disease. 
2. Other agents that reduce hepatic BA synthesis and are in development will be alternatives for BA 
sequestrants, e.g. FXR agonists, FGF-19 analogs.  
 
PLANNED ENROLLMENT REPORT     
 
Comments:   30 patients IBS-D with BAM 
 
Racial Categories 
Ethnic Categories 
Not Hispanic or Latino Hispanic or Latino Total 
Female 
Male 
Female 
Male 
American Indian / Alaska Native 
1 
0 
0 
0 
1 
Asian 
2 
1 
0 
0 
3 
Native Hawaiian or Other Pacific Islander 
0 
0 
0 
0 
0 
Black or African American 
2 
1 
0 
0 
3 
White 
13 
7 
2 
1 
23 
More Than One Race 
0 
0 
0 
0 
0 
Total 
18 
9 
2 
1 
30 
 
Inclusion of Children  
Children, 18-21 years of age, and adults 21 years or older will be eligible for participation in the study as active 
participants or as healthy controls. However, children below 18 years of age will be excluded, since there are 
differences in the criteria of diagnosis in adults and children, and insufficient quantitative pediatric data on the 
traits to be analyzed in order to assess the phenotypes of IBS, e.g. transit, permeability, etc.   
 
Inclusion of Women and Minorities 
In advertisements for patients and healthy subjects, we shall specifically solicit participation of women and 
minorities. We anticipate that there will be a majority of whites and representation of blacks and Asians, 
consistent with the ethnic constitution of communities in southeastern Minnesota, which is approximately 90% 
Caucasian, 5% Southeast Asian, and 5% other minorities. The prevalence of IBS among whites, blacks and 
Hispanics in the U.S. is very similar. 
 
Consideration of Sex as a Biological Variable  
We plan to recruit approximately 2 females to one male patient for these studies. We shall set up special 
efforts to recruit males with IBS using REDCAP to identify male patients through the electronic health records 


 
(established 17 years ago at Mayo Clinic.  Thus, we have identified through search of electronic medical 
records that there are: 
a. 2000 IBS patients residing within 100 miles of Rochester, MN.  
b. 350 patients with IBS-constipation residing within 100 miles of Rochester, MN  
Scientific premise for inclusion of both genders includes:  
IBS-D affects both genders; there is no a priori evidence that mechanisms or pathobiology of IBS-D differ 
between genders.  Therefore, our study will assess mucosal mRNA and protein expression and response to 
colesevelam treatment in both genders.  
  
PROTECTION OF HUMAN SUBJECTS 
 
1.    Risks to the Subjects 
 
       a.   Human subject involvement and characteristics 
 
 
We shall recruit 30 patients with IBS-D, and BAM, residing in an area with a radius of 100 miles from 
Rochester, MN.  We have an established database of ~2000  patients with IBS-D within 100 miles of Mayo 
Clinic in MN. Patients will have been evaluated by the investigators in the Division of Gastroenterology at Mayo 
Clinic, Rochester, MN.  Healthy subjects residing in southeastern Minnesota will be recruited without 
restrictions for gender, race or ethnic group.  We anticipate that among healthy participants there will be a 
majority of whites, and representation of blacks and Asians, consistent with the ethnic constitution of 
communities in southeastern Minnesota, which is approximately 90% Caucasian, 5% Southeast Asian, and 5% 
other minorities.  Given the ratio of females to males in irritable bowel syndrome in gastroenterology clinics, we 
anticipate recruiting 2 females to 1 male. We shall set up special efforts to recruit males with IBS using 
REDCAP to identify male patients through the electronic health records (established 17 years ago at Mayo 
Clinic). Therefore the proposal addresses the requirement for relevant inclusion of both genders in the 
research proposal. 
To avoid tertiary referral bias, at least 50% of patients selected will reside within 100 miles of Mayo 
Clinic.  
The racial and ethnic characteristics of the study cohort will be characterized in ~90% of participants. 
This is information that has to be collected on a voluntary basis in the medical record, and patients cannot 
legally be coerced into providing this information. 
 
Participants:  Eligibility of Patients with IBS 
We have a database of ~900 patients with functional gastrointestinal diseases who reside within ~150 
miles from Mayo Clinic which is located in Olmsted County, MN.   
All participants will complete the validated Bowel Disease Questionnaire [BDQ, including questions to 
correspond to Rome criteria (58)], the Symptom Checklist-90 [SCL-90 (59)] and the Hospital Anxiety and 
Depression Scale [HAD (60)]. The BDQ also includes a psychosomatic symptom checklist intended to identify 
somatization disorders.  We have used these questionnaires extensively in several studies. 
A positive diagnosis of IBS will be based on the Rome III criteria (83): At least 3 months, with onset at 
least 6 months previously, of recurrent abdominal pain or discomfort associated with 2 or more of the following:  
a) Improvement with defecation; and/or b) Onset associated with a change in frequency of stool; and/or c) 
Onset associated with a change in form (appearance) of stool (discomfort means an uncomfortable sensation 
not described as pain). 
 
 
Inclusion criteria  
                                  IBS patients 
Age (yr) 
 
 
 
 
18-75  
 
 
 
Gender (F:M)  
 
 
 
2:1 
 
 
 
BDQ - IBS symptoms  
 
             +ve by Rome III criteria 
Hospital Anxiety/Depression score 
 
No restrictions 
Abdominal surgery (except appy or choly) 
None  
 
            
GI medications 
 
 
            None past 48h  


 
BAM 
serum alpha C4 ≥ 40 ng/mL or FGF19 ≤ 80 pg/mL, fecal BA 
>2000 µmoles/48h, total fecal BA > 1000 µmoles/48h + >4% 
primary BA, or >10% primary BA 
 
Note: If a score of ≥11 for either anxiety or depression is obtained from the Hospital Anxiety Depression Scale, 
these finding will be documented in their medical record, the volunteer is informed of the findings and their 
primary care physician is contacted about the score. If the volunteer is experiencing active suicidal/homicidal 
ideations, they will be sent to the emergency room. 
 
Exclusion criteria 
In all patients diagnosed with IBS, we apply rigorous standards to exclude clinically-relevant 
inflammation. Patients with known bleeding diathesis will be excluded, given the need for sigmoid mucosal 
biopsies.  
 
PROHIBITED MEDICATIONS 
Patients participating will not take any of the following disallowed medications for at least 7 days prior to 
and during the remainder of the study: 
1. 
Any treatment specifically taken for IBS-D, including loperamide, cholestyramine, alosetron  
2. 
Drugs with a known pharmacological activity at 5-HT4, 5-HT2b or 5-HT3 receptors (e.g, tegaserod, 
ondansetron, tropisetron, granisetron, dolasetron, mirtazepine, cilansetron); 
3. 
All narcotics (e.g, codeine, morphine, and propoxyphene, either alone or in combination) 
4. 
Anti-cholinergic agents (e.g, dicyclomine, hyoscyamine, propantheline). 
5.  
Tramadol 
6. 
GI preparations: 
•  Anti-nausea agents (e.g, trimethobenzamide, promethazine, prochlorperazine, dimenhydrinate, 
hydroxyzine); 
•  Osmotic laxative agents (e.g, lactulose, sorbitol or PEG solutions as Miralax and Glycolax); 
•  Prokinetic agents (e.g, cisapride, metoclopramide, prucalopride, domperidone); 
•  5-HT3 antagonists (e.g. alosetron) 
 7. 
Oral anticoagulants 
 8. 
Antimuscarinics 
 9. 
Peppermint oil 
10. 
Systemic antibiotics, as well as antibiotics directed at colonic flora such as rifaximin and metronidazole  
 
In advertisements for patients, we shall specifically solicit participation of women and minorities.  The 
prevalence of IBS among whites, blacks and Hispanics in the U.S. is very similar.  Children, 18-21 years of 
age, will be eligible for participation in the study as patients or as healthy controls. However children below 18 
years of age will be excluded since it is unethical to expose healthy children to the potential risks of rectal 
intubation and radiation, and studies of IBS children in these age groups will be uninterpretable without age 
and gender matched controls from healthy individuals. 
 
Dietary, Fluid and Other Restrictions 
During recruitment, informed consent review, and baseline period, the subjects will be informed and 
reminded of the following restrictions: 
• 
No alcohol for 48 hours before each and during each test. 
• 
Patients must fast for at least 8 hours before visiting the clinic for the colonic permeability test and colonic 
transit tests. 
• 
No artificial sweeteners for 48 hours [Splenda (sucralose), NutraSweet (aspartame), lactulose or mannitol] 
before the permeability testing. Examples of foods to avoid are sugar free gums, mints and diet soda 
• 
Avoid taking any additional over-the-counter or prescription medications or herbal supplements that have 
not been reviewed and approved by the physician or the study coordinator until the study has been 
completed.   
 
Sites Where Research Will Be Performed 


 
Mayo Clinic Rochester will be the only site where the research is performed; the human studies will be 
conducted in the CRTU of the Mayo Clinic CTSA; all analyses of biological samples in the Molecular 
Genotyping core facilities or the Immunochemistry Core Lab (CTSA) at Mayo Clinic and the functional 
genomics studies in the Department of Physiology and Biomedical Engineering at Mayo Clinic.  
      
b.   Sources of research materials 
      
 
Research material will be the medical records (of those who authorize review of the records for 
research purposes), prospectively acquired measurements of gastrointestinal and colonic transit with an 
external gamma camera, observations obtained at flexible sigmoidoscopy, mucosal biopsy mRNA expressions 
of interest (tight junction proteins and mRNA sequencing), measurements of fecal BAs and short chain fatty 
acids, and in vivo permeability measurements. There will also be venous blood samples from which DNA will 
be extracted and stored and subsequently analyzed using whole gene sequencing.  Results of studies will be 
accessed by a secure password available only to study personnel.  Data will be merged for studies of 
associations by the study biostatisticians. 
All of the information collected in this study will be for research purposes only. 
 
c.   Potential risks 
The potential risks associated with the study are radiation exposure from scintigraphy, 
sigmoidoscopy, and rectosigmoid mucosal biopsies. The precautions associated with minimizing these risks 
are discussed below under 2 b, protection against risk, and under 5, the Data and Safety Monitoring Plan. 
 
2.     Adequacy of Protection against Risks 
 
        a.   Recruitment and Informed Consent  
 
 
Prior to initiating the study, all subjects will provide written informed consent using forms. The consent 
form becomes a permanent part of the medical record at Mayo Clinic. All subjects will be given a verbal 
explanation of the study, provided time to read and study the written consent form approved by Mayo’s 
Institutional Review Board and its information, given opportunities to ask questions and a copy of the consent 
form.  Participants will be informed of their right to withdraw from the study at any time without prejudice to their 
clinical management now or in the future.  Consent will be sought by one of the members of the investigative 
team (physician or study coordinator) properly trained in the consent process.  The consent will be 
documented by the participant’s signature on the consent form.  Specific information is provided in the Mayo 
consent form regarding storage and future use of the DNA sample.  The participants will be informed that since 
this genetic information is not yet pertinent to clinical practice, the information will not be included in the 
medical record, but will be maintained in a coded fashion accessible only to study personnel.  
 
 
All recruitment or contact information will be approved by Mayo Clinic Institutional Review Board. 
 
 b.   Protection against risk 
 
Responsible Conduct of Human Research by Study Personnel    
 
Mayo Clinic has established a formal program entitled the Mayo Investigator Training Program or MITP.  
The MITP is a web based educational course designed to provide all personnel involved in human subject 
research with training about human subject protection.   All Mayo personnel engaged in human subject 
research are required to complete the course.  The primary objectives of the course are to provide the 
historical framework for current human subject protection regulations and to explore the evolving issues related 
to human subject research.   The course is divided into four sections: 
* 
Course introduction and general overview 
* 
History section with examples of unethical behavior in human subject research 
* 
Review of major human subject protection issues 
* 
Discussion of the various roles and responsibilities of individuals involved in human subject 
research 
At the conclusion of the instruction, individuals are required to complete a thirty-question assessment. All Mayo 
investigators have completed the Mayo IRB's mandated certification in the responsible conduct of research.   
 


 
Specific Risks and Precautions Proposed 
i. Radiation exposure  
 
Radiation exposure results from 99mTc (sulfur colloid, SF) and 111In used to measure gut transit. These 
exposures conform to previously approved levels of radiation exposure approved by the Radiation Control 
Committee at Mayo Clinic.   
 
The radiation dosimetry and organ exposures (in mrad) are listed below: 
GASTRIC, SMALL BOWEL AND COLONIC TRANSIT 
Radiophar- Activity  Body Gonads Breast Red     Lung Thyroid Bone ULI Colon Stom   Blad   Liv Esoph Oth   
maceutical    mCi 
 
                marrow 
 
                                 -ach     -der   -er  -agus -er 
111In Cl3             0.1          20       140                 20                                   380     740     60    40     10      160 
99mTc  S.C.    1.0          20         90                  20                                   420     300    130   20     10      220 
(mrad= radiation absorbed dose to organs; S.C. = sulfur colloid)) 
 
He or the radiation effective dose to the body summarizes the risk to the whole body as the individual doses to 
each of the organs; effective dose is used to compare risks among various types of x ray and radionuclide 
studies: 111InCl3  0.1 mCi: He 142 mrem; 99mTcDTPA 1.0 mCi, He 90 mrem; (where mrem= radiation equivalent 
dose). 
In view of the radiation exposure, all females of childbearing age will be required to have a negative urine 
pregnancy test within 48 hours of the radioisotope studies.   
 
 
ii. Flexible Sigmoidoscopy has very low risk of bowel perforation, estimated at ~1 in 10,000.  
To date, these studies have not been associated with any perforation or mucosal damage that resulted in any 
clinically important issues such as local hemorrhage or abscess formation.  
 
iii. Medications: 
No unapproved medications are being tested: 
 
Colesevelam will be used for an unapproved indication, but there is no intention to develop plans to acquire 
approval to market the medication for the indication IBS-diarrhea with increased fecal BA excretion.  Mayo 
Clinic Research Pharmacy will over-encapsulate commercially available medication, produce identical placebo 
capsules and will be responsible for maintaining the randomization code and study blinding. 
  
Flexible sigmoidoscopy and rectosigmoid biopsies will be performed without conscious sedation. 
 
iv. Genetic information 
Results of the studies will be maintained in summaries in computer-secured files protected by a personal 
password.  In the latter files, participants will be identified only by a 7 digit Mayo Clinic registration number 
rather than by name to ensure confidentiality. Since genetic information collected is not yet pertinent to clinical 
practice, the information will not be included in the medical record, but will be maintained in a coded fashion 
and is accessible only to IRB-approved study personnel.  Many of the principles described by Beskow et al. 
(84) with respect to the exploratory analysis of gene-disease associations apply, so the consent process for 
genetic analysis will not require exhaustive genetic counseling. 
 
Plans for ensuring necessary interventions to protect participants are included in the data safety monitoring 
plan (see under 5 below)  
 
Given the prior track record with use of all of the intubations, measurement devices, secure protection of 
information on genetic information, there is a very high likelihood that the studies will be conducted safely and 
the participants will be protected from harm. 
 
3.    Potential Benefits of the Proposed Research to the Subjects and Others 
 
 
The PROPOSED RESEARCH has the potential to develop a new approach to the treatment of 
gastrointestinal diseases, grouped as irritable bowel syndrome with diarrhea, which is recognized as a 
spectrum of disorders with significant unmet clinical need.  The participants have the potential to benefit from 


 
the information regarding their gastrointestinal and colonic transit rate, serum C4, fecal BA excretion and 
potentially in future studies, the microbial flora.   
The benefits to participants may include recommendations on medications to retard colonic transit or to 
bind BAs in the colon for those patients with evidence of BA malabsorption.  By the time the study is 
conducted, or possible considerations will be fecal bacteriotherapy, probiotics or non-absorbable antibiotics, 
such as rifaximin which was recently approved for marketing for IBS-D.   
The current state of knowledge about the role of increased mucosal permeability and immune activation 
is too rudimentary to justify consideration of treatment for those pathophysiological changes.  There are, 
however, medications in development for both potential pathophysiological disorders in association with IBS 
including the dietary supplement glutamine (85). Therefore, there is potential to propose therapy if such 
treatments become approved during the “life cycle” of this application. 
 
Given the anticipated mechanistic insights to the participants in this research proposal, and to others 
with irritable bowel syndrome, and the track record of the investigators in the conduct of such research, the 
benefits outweigh the risks in the studies proposed.    
 
4.    Importance of the knowledge to be gained 
 
The PROPOSED RESEARCH has the potential to develop a new approach to the treatment of 
gastrointestinal diseases, specifically irritable bowel syndrome with diarrhea and increased fecal bile acid 
excretion, a disorder with unclear relationship to increased mucosal permeability or immune activation or 
secretory mechanisms. This disorder is associated with significant unmet clinical need.  Understanding the 
potential role of factors leading to motor and sensory dysfunction of the small bowel and colon in patients with 
IBS will provide mechanistic information that may lead to novel biomarkers that may assist in subtype 
identification in IBS and therapeutic approaches for IBS. 
 
 
The risks to the participants are reasonable since many procedures are noninvasive (other than 
sigmoidoscopy with biopsies), the research team has vast experience in the proposed testing, there is no risk 
of any significant morbidity or mortality, and precautions are taken to minimize discomfort or adverse effects.  
Radiation exposure is being kept to the minimum that allows successful completion and data acquisition.  
There is a high likelihood (e.g., investigator’s record and expertise, validated methods, statistical power) of 
obtaining meaningful, useful information in each specific aim.    
 
5.      Data and Safety Monitoring Plan (DSMP)  
 
Name of Principal Investigator (PI) – Michael Camilleri, M.D. 
 
Study Overview 
 
Brief Description of the Purpose of the Study - This study assesses the effect of bile acid sequestration in 
patients with IBS-D and bile acid malabsorption in a randomized controlled trial and a study of the patient’s 
DNA and the transcriptome and proteome of the mucosa of the rectosigmoid colon. 
  
This study does not involve administration of any investigational agent and therefore poses minimal risk to 
participants.   Because of this low risk status, the Data Safety Monitoring Plan (DSMP) for this study focuses 
on close monitoring by the PI in conjunction with an Independent Monitor.  Adverse events will be reported to 
the NIH and to the Mayo Clinic IRB. 
 
Adherence Statement – The Data Safety Monitoring Plan (DSMP) outlined below will adhere to the protocol 
approved by the Mayo Clinic IRB.   
 
III. Confidentiality  
 
A.  Protection of Subject Privacy – During this study, medical history and physical examination will be 
performed, and questionnaires will be administered. Additional research material will be:  review of medical 
records (of those who authorize review of the records for research purposes), quantitation of gastrointestinal 
and colonic transit with an external gamma camera, venous blood samples from which DNA will be extracted 
and stored, venous blood samples for measurement of factors reflecting BA metabolism, urine and stool 


 
collections, colonic mucosal biopsy collections and expression of mRNA and proteins in biopsies, and 
measurements of rectal motility.  
Data will be kept in strict confidence. No information will be given to anyone without permission from the 
subject. This statement guarantees confidentiality. Confidentiality is assured by use of identification codes. All 
data, whether generated in the laboratory or at the bedside, will be identified with a randomly generated 
identification code unique to the subject. 
 
B. 
Database Protection – The database is secured with password protection. The technologist 
conducting DNA analyses provides the statistician with only coded information, which is entered into the 
research database using the generated identification code unique to each participant,  These precautions 
permit the objectives of the research to be conducted, specifically to determine the influence of susceptibility 
genes on the IBS and physiological/quantitative  endpoints, and to assess the association between the DNA 
and the quantitative traits and the expression of relevant mRNA in the sigmoid mucosa.  Specifically, it is to be 
noted that the DNA and RNA-seq data are not entered into the patients’ medical record, thus protecting the 
patients participating in the study from any impact of research (clinically unvalidated) information on the clinical 
management or insurability of the participant.   Electronic communication with outside collaborators involves 
only unidentifiable information.   
 
Sharing of DNA samples will be performed in accordance with NIH guidelines.   
 
Confidentiality during AE Reporting – Adverse Event reports and annual summaries will not include 
subject-identifiable material. Each will include the identification code only. 
 
IV. Adverse Event Information 
 
 Definition - An adverse event (AE) is any untoward medical occurrence in a subject temporally associated with 
participation in the clinical study.  An adverse finding can include a sign, symptom, abnormal assessment 
(laboratory test value, vital signs, electrocardiogram finding, etc.) or any combination of these. 
A Serious Adverse Event (SAE) is any adverse event that results in one or more of the following outcomes: 
• 
Death 
• 
A life-threatening event 
• 
Inpatient hospitalization or prolongation of existing hospitalization  
• 
A persistent or significant disability/incapacity 
• 
A congenital anomaly or birth defect 
• 
Important medical event based upon appropriate medical judgment 
Classification of AE Severity – AEs will be labeled according to severity which is based on their impact on the 
patient.  An AE will be termed  
• 
‘mild’ if it does not have a major impact on the patient, 
• 
‘moderate’ if it causes the patient some minor inconvenience and 
• 
‘severe’ if it causes a substantial disruption to the patient’s well-being.  
AE Attribution Scale – AEs will be categorized according to the likelihood that they are related to the study 
intervention.  Specifically, they will be labeled either definitely, probably, possibly or unrelated to the study 
intervention. 
 
D. 
Expected Risks –  
Risks and/or 
Anticipated 
Adverse Events 
Assessment 
measures 
Individual 
doing 
assessment 
Assessment 
intervals or 
frequency 
Interventions to decrease or respond 
to risks  
Bruising at 
venipuncture site 
Subject 
symptoms/ 
vital signs 
Study 
coordinator / 
RN 
Pt instructed 
to call study 
coordinator 
To be expected rarely; participant 
information; Decrease with pressure 
and ice applied  by trained personnel 
Endoscopy: 
Sigmoidoscopy 
Subject 
observation 
Study 
coordinator/ 
Endoscopy 
technologist, 
At time of 
procedure 
 
Some discomfort expected; instruction 
to pass gas 


 
RN and 
Physician 
Sigmoid colon 
biopsy 
Bleeding at 
biopsy site 
Endoscopy 
RN and 
Physician 
 
 
Exclusion of patients with hemorrhagic 
disorder 
Physician assessment of medical 
history and current 
medications/supplements 
   
E. 
SAE Reporting 
 
 
SAEs that are unanticipated, serious, and/or possibly related to the study intervention will be reported 
to the Independent Monitor, IRB, and Clinical Research Trials Unit in accordance with requirements.  
Anticipated SAEs or those unrelated to the study intervention will be reported to the same individuals/entities in 
accordance with requirements.” 
 
If abnormal lab values are discovered during the study, the study group shall address this issue and attempt to 
correct it as early as possible. 
 
V. 
Data Quality and Safety Review Plan and Monitoring 
 
 
A. 
Data Quality and Management 
Description of Plan for Data Quality and Management–The PI will review all data collection forms on an 
ongoing basis for data completeness and accuracy as well as protocol compliance.  A statement reflecting the 
results of the review will be sent to the IRB in the annual report.  
Frequency of Review  
 
Subject Accrual and Compliance 
1) 
Measurement and reporting of subject accrual, adherence to inclusion/exclusion criteria – Review of the 
rate of subject accrual, adherence to inclusion/exclusion criteria will occur yearly during the 4.5 year 
recruitment phase.  Review will occur at the end of each recruitment wave to assure that participants meet 
eligibility criteria and ethnic diversity goals outlined in the grant proposal.   
2) 
Measurement and reporting of participant compliance to treatment protocol – compliance will be 
measured by number of returned tablets at end of treatment phase.  
 
Justification of Sample Size – The application documents the justification of sample size for each specific 
aim in the proposal.  
 
Stopping Rules – This study will be stopped prior to its completion if adverse effects to the procedures that 
significantly impact the risk-benefit ratio have been observed  
 
     E. Designation of an Independent Monitor – Dr. David A. Katzka, M.D. (Mayo Clinic) will serve as 
independent monitor to perform an independent review of ongoing safety. In accordance with IRB review, we 
shall ask Dr. Katzka to constitute an independent DSMB if required. Colesevelam is an approved drug. Since 
we shall not be applying to FDA to market the drug for a new indication, an IND will not be required for the 
study.    
 
Data type 
Frequency of review 
Reviewer 
Subject accrual (adherence to protocol 
regarding demographics, inclusion/exclusion) 
Yearly 
 
Principal Investigator, 
Independent Monitor 
Adverse event rates (injuries) 
Yearly 
Principal Investigator, 
Independent Monitor 
Stopping rules report regarding statistical power 
implications of drop outs and missing data 
Yearly 
Principal Investigator, 
Independent Monitor 


 
Safety Review Plan – Study progress and safety will be reviewed monthly (and more frequently, if needed).  
Progress reports, including patient recruitment, retention/attrition, and AEs will be provided to the Independent 
Monitor every year.  An annual report will be compiled and will include a list and summarization of adverse 
events.  In addition, the annual report will address: 
(1) whether adverse event rates are consistent with pre-study assumptions; 
(2) reason for dropouts from the study;  
(3) whether all participants met entry criteria;  
(4) whether continuation of the study is justified on the basis that additional data are needed to accomplish the 
stated aims of the study; and 
(5) conditions whereby the study might be terminated prematurely.   
 
 
The annual report will be signed by the Independent Monitor and will be forwarded to the IRB and the 
CRTU on an annual basis.   
 
VI. 
Informed Consent 
Written informed consent will be obtained from each subject at entry into the study. Informed consent is 
obtained by the following process: 
 
•  
The subject will be asked to review the study consent form; 
 
•  
The PI or Co-Investigator (Co-I) approved as such by the IRB will meet with the subject to 
review the form, to confirm the subject’s understanding of the study, and to answer any questions that the 
subject might have; and 
•  
Once the subject demonstrates understanding of the study and agrees to participate in the 
study, the consent will be signed 
 


 
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