A Phase 2 Study to Compare the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of 2 Dose Regimens of IW-1973 in Patients With Stable Type 2 Diabetes and Hypertension
Phase: PHASE2
Conditions: Diabetes Mellitus, Type 2, Hypertension
Sponsor: Cyclerion Therapeutics



IW-1973 Tablet 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
16 March 2017 
Confidential 
Page 2 of 78 
STUDY IDENTIFICATION 
A summary of key study participants is provided in Table 1. All study contact details will be 
provided prior to the Site Initiation Visit. 
Tab le 1. 
Key Study Par ticipants 
Role 
Contact Information 
Ironwood Contact: 
Ironwood Pharmaceuticals, Inc. 
301 Binney Street 
Cambridge, MA  02142 
Medical Monitor: 
Ironwood Pharmaceuticals, Inc 
301 Binney Street 
Cambridge, MA  02142 
Safety Officer: 
Ironwood Pharmaceuticals, Inc 
301 Binney Street 
Cambridge, MA  02142 
Serious Adverse Event (SAE) E-mail: 

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 3 of 78 
SYNOPSIS 
Sponsor 
Ironwood Pharmaceuticals, Inc. 
Name of Finished Product 
IW-1973 Tablet  
Name of Active Ingredient 
IW-1973 
Study Title 
A Phase 2 Study to Compare the Safety, Tolerability, Pharmacokinetics, and 
Pharmacodynamics of 2 Dose Regimens of IW-1973 in Patients with Stable Type 2 Diabetes 
and Hypertension  
Study Number 
C1973-202 
Study Phase: 2a 
Objectives  
To compare the safety, tolerability, pharmacokinetic (PK) profile, and pharmacodynamic (PD) 
effects of 2 treatment regimens of IW-1973 Tablet (40 mg per day) administered orally for 
2 weeks to patients with stable type 2 diabetes mellitus and hypertension 
Study Design 
This is a randomized, double-blind, placebo-controlled study consisting of 3 distinct periods 
(see Study Schematic). The study will enroll 26 patients (at least 11 male and 11 female) with 
stable type 2 diabetes and hypertension. Patients will be randomized in a 5:5:3 ratio to receive 
1 of 2 IW-1973 treatment regimens or placebo (all regimens will be masked) as outlined in the 
table. 
Treatment 
Arm 
Dose  
time 
Days 1 to 7 
Days 8 to 14 
QD/QD 
AM 
40 mg IW-1973 
40 mg IW-1973 
PM 
Placebo 
Placebo 
BID/QD 
AM 
20 mg IW-1973 
40 mg IW-1973 
PM 
20 mg IW-1973 
Placebo 
PBO/PBO 
AM 
Placebo 
Placebo 
PM 
Placebo 
Placebo 
 
Refer to Test Product, Dosage, and Mode of Administration for details on the number of 
IW-1973 and/or placebo tablets that will make up each dose. 

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 4 of 78 
Study Schematic 
 
Study Population  
The study will enroll 26 patients with  
• Type 2 diabetes with a hemoglobin A1c (HbA1c) level of ≤ 10.5% and a fasting 
(≥ 8 hours) serum glucose level of ≤ 240 mg/dL on a regimen of ≥ 1 medication for 
glycemic control with no change in medication for ≥ 12 weeks before Check-in and on a 
stable regimen (ie, same drug and same dose) for ≥ 28 days before Check-in 
• Hypertension with systolic BP of 120 to 160 mm Hg and diastolic BP of 70 to 100 mm Hg 
while on a stable regimen of ≥ 1 medication, which includes an angiotensin-converting 
enzyme inhibitor (ACEi) or angiotensin receptor blocking agent (ARB), for ≥ 28 days 
before Check-in 
 
See Eligibility Criteria for full inclusion and exclusion criteria. 
Screening
Visit
(Day -28 to -3)
End of Trial 
Visit
(Day 42 [ 3])
Screening Period 
Clinic Period
Follow-up Period
1 to 26 days
17 days
27 ( 3) days
Follow-up
Visit  
(Day 21 [ 2])
Check-in
(Day -2)
Discharge
(Day 15)
Dosing 
begins
(Day 1)
Last 
dose
(Day 14)
No treatment
IW-1973 QD (AM)
IW-1973 BID (AM/PM)
Placebo 
IW-1973 QD (AM)
IW-1973 QD (AM)
Placebo 
Days 1 to 14, all patients 
will receive 2 daily 8-tablet 
doses to mask treatment 
assignment
Days 1 to 7
Days 8 to 14

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 5 of 78 
Test Product, Dosage, and Mode of Administration 
Test product (IW-1973 Tablet, 5 mg) will be a 5-mg oral tablet  
On Days 1 to 14, all patients will receive 2 daily 8-tablet doses (AM and PM), 12 hours 
(± 30 minutes) apart. Matching placebo tablets will be administered with IW-1973 Tablets 
when required to mask treatment assignments. The table outlines study drug dosage by week 
and time for each regimen/treatment arm. 
Regimen/ 
Treatment arm 
Dose  
time 
Dosage  
Days 1 to 7 
Dosage  
Days 8 to 14 
QD/QD 
AM 
8 x IW-1973 Tablet 
8 x IW-1973 Tablet 
PM 
8 x placebo tablet 
8 x placebo tablet 
BID/QD 
AM 
4 x IW-1973 Tablet 
4 x placebo tablet 
8 x IW-1973 Tablet 
PM 
4 x IW-1973 Tablet 
4 x placebo tablet 
8 x placebo tablet 
PBO/PBO 
AM 
8 x placebo tablet 
8 x placebo tablet 
PM 
8 x placebo tablet 
8 x placebo tablet 
 
 
Reference Therapy, Dosage, and Mode of Administration 
Reference therapy will be placebo to match IW-1973 Tablet, 5 mg. 
Study Periods 
The 26 patients may be enrolled separately. Each patient will progress through 3 study 
periods.  
Screening Period:  The Screening Period will begin with the signature of the informed 
consent form (ICF) at the Screening Visit (which can occur from Day -28 to Day -3) and will 
last 1 to 26 days. At the Screening Visit, patients will undergo preliminary screening 
procedures to determine their eligibility for the study. The end of the Screening Period will 
coincide with the beginning of the Clinic Period at Check-in. 
Clinic Period:  The Clinic Period will begin at Check-in on Day -2 (2 days before dosing) and 
will end at the time of Discharge on Day 15. During the 17-day Clinic Period, patients will be 
confined to the Study Center and will receive a standard diet for diabetics. Patients who meet 
eligibility criteria based on Screening Visit assessments will be admitted to the Study Center 
on Day -2 for baseline procedures. On the morning of Day 1 (there is no Day 0), eligible 
patients (at least 11 male and 11 female) will be randomized in a 5:5:3 ratio to 1 of 3 masked 
treatment regimens: QD/QD, BID/QD, or PBO/PBO. On Days 1 to 14, patients will receive a 
morning (AM) dose and an evening (PM) dose.  
Safety, PK, and PD assessments, including blood collections, will be performed at specified 
times throughout the Clinic Period (see Criteria for Evaluation and Schedule of Events). On 
Day 15, after assessments have been completed, patients will be discharged from the Study 
Center at the Investigator’s discretion. 

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 6 of 78 
Follow-up Period:  The Follow-up Period will begin immediately after Discharge from the 
Study Center on Day 15 and will last for 27 (± 3) days. On Day 21 (± 2 days), 7 (± 2) days 
after the last dose of study drug, patients will return to the Study Center for the Follow-up 
Visit (see Schedule of Events). On Day 42 (± 3 days), 28 (± 3) days after the last dose of study 
drug, patients will return to the Study Center for the End of Trial Visit (see Schedule of 
Events). 
Study Drug Administration 
All patients will receive 2 orally administered doses per day: an AM dose and a PM dose. 
Except for Day 13, patients will receive the AM dose at approximately the same time 
(± 15 minutes) every day in the morning (8 to 10AM) following an overnight fast of ≥ 8 hours. 
(Note: For each patient, the first dose on Day 1 may be administered between 8 and 10AM; 
thereafter, AM doses on Days 2 to 12 and on Day 14 must be administered within 15 minutes 
of the time of dosing on Day 1.) On Day 13, if EndoPAT is planned, the first dose should be 
administered in the morning between 7 and 10:30AM, after the EndoPAT assessment. 
Breakfast should begin within 30 minutes after dosing. Each patient will receive their PM dose 
12 hours (± 30 minutes) after their AM dose and at least 30 minutes after completing a normal 
dinner.  
Patients may take multiple tablets together. Permitted concomitant medications may be taken 
at the same time as study drug. 
Stopping Criteria   
All dosing will be stopped if the Sponsor and Investigator determine that any of the following 
have occurred: 
• Drug-related serious adverse events (SAEs) in 2 or more patients on a given dosing 
regimen (per causality and SAE definitions in the protocol)  
• An overall pattern of clinically significant AEs or an overall pattern of patient tolerability 
issues, which may appear minor in terms of an individual event but, in the opinion of the 
Sponsor or Investigator, collectively represents a safety concern. 
Planned Number of Patients:   
Up to 26 patients may receive study drug in this trial. Additional patients may be checked into 
the Study Center on Day -2 as backups. If the backup patients are not needed, they will be 
discharged from the Study Center before Randomization. Patients withdrawing from the study 
after Randomization will not be replaced. 
Duration of Treatment  
Patients will be in the Study Center for 17 days, from Check-in on Day -2 to Discharge on 
Day 15. Patients will receive oral doses of study drug for 14 consecutive days and will be 
followed in the Study Center for 24 hours after the last dose. Total patient participation will be 
35 to 73 days, including the Screening, Clinic, and Follow-up Periods. 

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 7 of 78 
Criteria for Evaluation 
Pharmacodynamics 
Hemodynamics 
Cuff BP and pulse measurements and ambulatory BP and pulse monitoring will occur 
according to the Schedule of Events. BP effects will be assessed using the following 
parameters: 
• From supine measurements:  change from baseline in pulse and systolic and diastolic BP 
measurements; proportion of patients with supine BP < 120 mm Hg and diastolic 
BP < 70 mm Hg 
• From orthostatic measurements:  change in systolic and diastolic BP and pulse 
measurements after patient has gone from the supine to the standing position 
• From ambulatory monitoring:  change from baseline in 24-hour, 4-hour, daytime, and 
nighttime averages of systolic and diastolic BP, mean arterial pressure, and pulse 
measurements 
Endothelial Function Assessments  
If available at the Study Center, endothelial function in the finger will be measured according 
to the Schedule of Events using the noninvasive EndoPAT device. All measurements will be 
performed in a quiet, dimly lit, temperature-controlled (21–24°C) room to reduce vascular 
tone fluctuation. The procedure will begin after the patient has had the opportunity to void and 
has been resting quietly for ≥ 15 minutes. Endothelial function will be assessed using the 
Reactive Hyperemia Index (RHI) parameter. 
Platelet Function Testing  
Blood samples for platelet function assessments will be collected according to the Schedule of 
Events. 
Fasting plasma glucose and insulin 
Blood samples for determination of fasting plasma glucose and insulin levels will be collected 
according to the Schedule of Events. Values will be used in the Homeostatic Model 
Assessment to estimate insulin resistance (HOMA-IR). 
 
 
 
 
  
 
 
 

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 8 of 78 
Pharmacokinetics  
Blood samples for determination of plasma concentrations of IW-1973 will be collected 
according the Schedule of Events and the following PK parameters will be calculated, when 
possible: 
• AUClast:  Area under the plasma concentration time curve from time zero to Tlast, the time 
at which the last measurable plasma concentration (Clast) is observed 
• AUCtau:  Area under the plasma concentration time curve during a dosing interval (tau) 
• AUCinf:  Area under the plasma concentration time curve extrapolated to infinity 
• Cmax:  Maximum observed plasma concentration, occurring at Tmax 
• Ctrough:  Trough plasma concentration observed at the end of a dosing interval (collected 
before the next administration) 
• CL/F:  Apparent total body clearance after oral administration  
• t1/2:  Apparent terminal phase half-life 
• Tmax:  Time of maximum observed plasma concentration 
• Vz/F:  Apparent volume of distribution during the terminal phase after oral administration 
Safety  
Physical examination, vital sign parameters, 12-lead electrocardiograms (ECGs), clinical 
laboratory evaluations (including clinical chemistry, hematology, coagulation, urinalysis), and 
patient- and Investigator-reported AEs will be evaluated. Estimated glomerular filtration rate 
(eGFR) by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine 
equation and urine albumin creatinine ratio (UACR; urine albumin [mg/dL] / urine creatinine 
[g/dL]) will be calculated. 

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 9 of 78 
Statistical Methods:  
Sample Size Determination 
Sample size for this trial was determined outside statistical considerations.  
Analysis Populations: 
All patients who receive at least 1 dose of study drug will be included in the Safety 
Population. 
All patients who receive at least 1 dose of study drug and have at least 1 postdose PK 
parameter assessment will be included in the PK Population. 
All patients who receive at least 1 dose of study drug and have at least 1 postdose PD 
assessment will be included in the PD Population. 
Statistical Analysis 
Descriptive statistics (n, mean, standard deviation, minimum, median, interquartile range, and 
maximum) will be calculated to summarize continuous variables. Frequency and percent of 
patients in each category will be calculated to summarize categorical variables. 
Pharmacodynamic Analyses 
Summary statistics will be provided by treatment for supine and ambulatory BP and pulse rate 
values, endothelial function testing (RHI value), platelet function assessment results, and 
HOMA-IR values; changes from baseline in these variables will be compared across treatment 
groups. Summary statistics will be provided by treatment for the proportion with postdose 
supine BP less than 130/80 mm Hg. 
Pharmacokinetic Analyses 
If plasma concentrations of IW-1973 are detected, the PK parameters will be determined and 
tabulated, and summary statistics will be reported by treatment group. 
Safety Analyses 
Adverse events (AEs) will be summarized by system organ class (SOC), preferred term (PT), 
and treatment. Listings will be provided for severe AEs, drug-related AEs, SAEs, and AEs 
leading to study discontinuation. Descriptive statistics will be calculated on the safety 
parameters (ECG, vital signs, and clinical laboratory tests, eGFR, UACR) by treatment. 

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 10 of 78 
ELIGIBILITY CRITERIA 
INCLUSION CRITER IA 
Patients must meet all of the following criteria to be eligible for enrollment in this study: 
1. Patient has signed an ICF before any study-specific procedures are performed.  
2. Patient is an ambulatory male or female aged 30 to 75 years at the Screening Visit. 
3. Female patient is not pregnant or breastfeeding at the time of the Screening Visit and 
Check-in. Negative serum pregnancy tests must be documented at the Screening Visit and at 
Check-in before dosing. 
4. Female patients must be postmenopausal (no menses for 12 consecutive months), surgically 
sterile (ie, bilateral oophorectomy, hysterectomy, or tubal ligation), or, if of childbearing 
potential, agree to use 1 of the following methods of birth control from the date they sign the 
ICF until after the End of Trial Visit: 
a. Combination of 2 highly effective birth control methods (eg, condom with spermicide 
plus intrauterine device, condom with spermicide plus a diaphragm or cervical cap, 
hormonal contraceptive [including progesterone implant] combined with a barrier 
method) 
b. Maintenance of a monogamous relationship with a male partner who has been surgically 
sterilized by vasectomy (vasectomy procedure must have been conducted ≥ 60 days 
before the Screening Visit or confirmed via sperm analysis) plus a hormone or barrier 
method 
5. Patient’s body mass index (BMI) score is > 20 and < 40 kg/m2 at the Screening Visit. 
6. Patient’s health is stable with no clinically significant findings on a physical examination, 
12-lead ECG, alcohol breathalyzer, and clinical laboratory tests (serum chemistry, 
hematology, coagulation, urine drug screen, and urinalysis) that would prevent participation 
in the trial. (Note: The Investigator will determine if a particular finding is clinically 
significant. In making this determination, the Investigator will consider whether the 
particular finding could prevent the patient from performing any of the protocol-specified 
assessments, could represent a condition that would exclude the patient from the study, could 
represent a safety concern if the patient participates in the study, or could confound the 
study-specified assessments.) 
7. Patient has type 2 (ie, adult onset) diabetes mellitus diagnosed by a physician or nurse 
practitioner ≥ 6 months before the Screening Visit and meets all of the following: 
a. Has been on a regimen of ≥ 1 medication for glycemic control, which may include long-
acting insulin, with no change in medication for ≥ 12 weeks before Check-in and on a 
stable regimen (ie, same drug and same dose) for ≥ 28 days before Check-in with no 

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 11 of 78 
indication that the regimen will need to be changed for the duration of the study. 
Modification of short-acting insulin throughout the Screening Period will not affect 
eligibility. During the Clinic Period, per Investigator discretion, doses of supplemental 
short-acting insulin may be varied as needed to achieve adequate glycemic control. 
b. Has HbA1c level ≤ 10.5% and fasting (≥ 8 hours) serum glucose level ≤ 240 mg/dL at the 
Screening Visit and at Check-in. Glucose value from serum chemistry panel; at 
Investigator discretion, if fasting serum glucose is > 240 mg/dL, the test may be repeated 
for determination of eligibility 
c. Has, in the clinical judgement of the Investigator, sufficient diabetes stability to 
participate in the trial 
8. Patient has hypertension diagnosed by a physician or nurse practitioner ≥ 6 months before the 
Screening Visit and meets all of the following: 
a. Has been on a stable regimen of ≥ 1 medication to control hypertension for ≥ 28 days 
before Check-in with no indication that the regimen will need to be changed for the 
duration of the study. The medication(s) must include an angiotensin-converting enzyme 
inhibitor (ACEi) or angiotensin receptor blocking agent (ARB) and may include diuretics 
and/or calcium channel blockers. Other antihypertensive agents may be acceptable per 
the Investigator’s discretion. (See Exclusion Criteria for prohibited medications.) 
b. Has supine systolic blood pressure (BP) of 120 to 160 mm Hg and supine diastolic BP of 
70 to 100 mm Hg at the Screening Visit. Eligibility will be based on the average of 3 
measurements. 
c. Has, in the clinical judgement of the Investigator, sufficient hypertension stability to 
participate in the trial. 
9. Patient agrees to adhere to the study requirements. 
10. Patient has a negative hepatitis panel (hepatitis B surface antigen [HBsAg] and 
antihepatitis C virus [HCV]) and human immunodeficiency virus (HIV) antibody at the 
Screening Visit. 
11. Patient agrees to refrain from making any major lifestyle changes (eg, changing his or her 
exercise pattern) from the time of signature of the ICF to the End of Trial Visit. 

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 12 of 78 
EXCLUSION CRITER IA 
Patients who meet any of the following criteria will not be eligible to participate in the study: 
1. Patient has a clinically significant active or unstable medical condition that, in the opinion of 
the Investigator, would preclude trial participation, including active or unstable metabolic; 
hepatic; renal; hematological; pulmonary; cardiovascular; gastrointestinal; musculoskeletal; 
dermatological; urogenital; eye, ear, nose, and throat; psychiatric; or neurological conditions. 
2. Patient is on medication(s) that when co-administered with a soluble guanylate cyclase (sGC) 
stimulator, could increase the risk of hypotension. These include (but may not be limited to) 
nitrates, nitroglycerin, direct vasodilators (including hydralazine or systemic minoxidil), 
phosphodiesterase (PDE) 5 inhibitors (including sildenafil, tadalafil, and vardenafil), alpha 
adrenergic blockers, riociguat, and sodium-glucose co-transporter 2 (SGLT2) inhibitors. 
Patients should not take these medications from 6 days before Check-in to the End of Trial 
Visit.  
3. Patient has evidence of severe or active end-organ damage attributable to diabetes (eg, active 
diabetic nephropathy, retinopathy, or neuropathy) at the Screening Visit or Check-in. 
4. Patient has evidence of active end-organ morbidity associated with uncontrolled hypertension 
(eg, progressive kidney insufficiency, myocardial infarction, or stroke) at the Screening Visit 
or Check-in. Patient has had an in-patient hospitalization for a cardiovascular, renal, or 
metabolic cause in the 6 months before the Screening Visit. 
5. Patient has orthostatic decrease in systolic BP of > 20 mm Hg or orthostatic decrease in 
diastolic BP of > 15 mm Hg.  
6. Patient has severe renal insufficiency (eg, current or past need for dialysis) has undergone 
renal transplantation, or has planned renal transplantation.  
7. Patient has a history of malignancy, diagnosed or known to be active or actively treated 
within the past 5 years, other than resected lesions of low malignant potential, such as basal 
cell skin cancers. 
8. Patient has bleeding diathesis or history of clinically significant bleeding episodes (eg, 
gastrointestinal bleed) in the 12 months before the Screening Visit. 
9. Patient has a 12-lead ECG demonstrating severe bradycardia (heart rate < 40 beats per 
minute) or QTcF is ≥ 450 msec for male patients or is ≥ 470 msec for female patients at the 
Screening Visit. (Note: If on initial ECG, QTcF exceeds the limit, the ECG will be repeated 2 
more times, and the average of the 3 QTcF values will be used to determine the patient's 
eligibility). 
10. Patient has alanine aminotransferase (ALT) or aspartate aminotransferase (AST) level 
> 2 times the upper limit of normal as defined by the laboratory or creatinine level 
> 1.5 times the normal as defined by the laboratory at the Screening Visit. 

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 13 of 78 
11. Patient has a history of clinically significant hypersensitivity or allergies to any of the 
inactive ingredients contained in the active or placebo drug products. 
12. Patient has a history of active alcoholism or drug addiction during the year before the 
Screening Visit, or has a positive drug screen at the Screening Visit or at Check-in.  
13. Patient has previously received IW-1973 in a study or has received an investigational drug 
during the 30 days or 5 half-lives of that investigational drug (whichever is longer) before the 
Screening Visit or is planning to receive another investigational drug at any time during the 
study. 
14. Patient is an active smoker or has used any nicotine-containing products (cigarettes, 
e-cigarettes, vape pens, cigars, chewing tobacco, gum, patches) during the 6 months before 
Check-in. Use of nicotine is excluded during the study until after the End of Trial Visit. All 
positive nicotine tests will result in screen failure. 
15. Patient has consumed grapefruit or grapefruit juice during the 72 hours before Check-in, 
taken vitamins or herbal supplements during the 7 days before Check-in, or taken any 
supplements for the treatment of erectile dysfunction during the 14 days before Check-in. 
Grapefruit, grapefruit juice, vitamins, herbal supplements, or any supplements for the 
treatment of erectile dysfunction are excluded during the study until after the End of Trial 
Visit. 
16. Patient has consumed any alcohol-containing foods or beverages during the 7 days before 
Check-in. Use of alcohol-containing foods or beverages is prohibited from 7 days before 
Check-in through Discharge. In the clinic, patient may consume up to 2 cups of coffee or tea 
per day but not within 1 hour of study drug administration or within 3 hours before EndoPAT 
assessment.  
17. Patient has donated blood products (including plasma and platelet donation) during the 6 
weeks before Check-in. 
18. Patient has received blood products during the 2 months before Check-in. 
19. Patient has undergone a surgical procedure during the 30 days before Check-in, other than 
minor dermatologic procedures. 
20. Patient has an acute or chronic condition that, in the Investigator’s opinion, would limit the 
patient’s ability to complete or participate in this clinical study. 
21. Patient is involved in the conduct and administration of this study as an Investigator, 
sub-Investigator, study coordinator, other study staff, or Sponsor member. 
22. Patient will not be able to adhere to the trial assessment schedule, or, in the clinical judgment 
of the Investigator, the patient is otherwise not suitable for trial participation. 
 
NOTE: Patients may be rescreened should they discontinue in the Screening Period due to 
visit window deviations or other administrative reasons. In addition, laboratory values, 
ECG values, or BPs that are outside the range specified in the protocol may be repeated to 
confirm eligibility during the Screening period at the Investigator’s discretion after 
consultation with the Medical Monitor. 

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 14 of 78 
SCHEDULE OF EVENTS 
Study Period→ 
Screening Period  
Clinic Period 
Visit Days → 
Study Procedure ↓ 
Screening  
Visit  
Day -28 to -3 
Check-in 
Day -2 
Day -1 
Day 1 
Day 2 
Days 
3-6 
ICF Signed 
X 
 
 
 
 
 
Demographics 
X 
 
 
 
 
 
Medical History 
X 
 
 
 
 
 
Inclusion/Exclusion Evaluation 
X 
X 
 
 
 
 
Physical Exam 
X 
X 
 
 
 
 
Hepatitis (HBsAg, HCV) & HIV Screen 
X 
 
 
 
 
 
Drug & Alcohol Screen (a) 
X 
X 
 
 
 
 
Pregnancy Test (b) 
X 
X 
 
 
 
 
Weight (W) & Height (H) (c) 
W, H 
 
W 
 
 
 
12-lead electrocardiogram (d) 
X 
X 
 
preAM: 0 (≤30m) 
pdAM:  4 (±15m) 
 
 
Respiratory rate (R) &  
oral temperature (T) 
X 
X 
X 
T,R preAM:  0 (≤30m) 
T pdAM:  1, 4 h 
(±15m) 
X 
X 
Supine/standing BP & pulse (e) 
3 indicates triplicate supine BPs 
supine only 
AM 
X 3 
X 
preD1: 0 (≤30m) 3 
pdD1:  1, 4h (±5m) 
pre: 0 (≤30m) 
pd:  1, 4, 8h (±5m) 
pre: 0 (≤15m) 
pd:  1, 4h (±5m) 
pre: 0 
(≤15m) 
PM 
preD1: 0 (≤15m) 
pdD1:  1, 4h (±5m) 
pre: 0 (≤15m) 
pd:  1, 4h (±5m) 
pre: 0 (≤15m) 
pd:  1, 4h (±5m) 
 
Hemoglobin A1c 
X 
X 
 
preAM: 0 (≤15m) 
 
 
Fasting plasma glucose & serum insulin 
(f) 
X 
X 
 
preAM: 0 (≤15m) 
 
 
Clinical chemistry, coagulation, 
hematology, urinalysis (f) 
X 
X 
 
serum creatinine only  
preAM: 0 (≤15m) 
 
 
Urine albumin & creatinine (g) 
X 
 
first void 
 
 
 
AE Evaluations 
X 
X 
X 
X 
X 
X 

IW-1973 Tablet 
 
Ironwood Pharmaceuticals, Inc. 
Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
 
Confidential 
Page 15 of 78 
Study Period→ 
Screening Period  
Clinic Period 
Visit Days → 
Study Procedure ↓ 
Screening  
Visit  
Day -28 to -3 
Check-in 
Day -2 
Day -1 
Day 1 
Day 2 
Days 
3-6 
Prior & concomitant medications 
X 
X 
X 
X 
X 
X 
 
 
 
 
 
 
 
Ambulatory BP monitoring (i) 
 
 
Start: 
preD1: 0 (≤ 15m) 
Continue 
End: pd 12h  
[= preAM: 
0(≤15m)] 
 
EndoPAT (j) 
 
 
pre D13: 0  
(end ≥30 m) 
 
 
 
 
 
 
 
 
 
 
Randomization 
 
 
 
X 
 
 
Study drug administration (l) 
AM 
 
 
 
X 
X 
X 
PM 
X 
X 
X 
PK blood samples (m) 
AM 
 
 
 
pre: 0 (≤ 15m) 
pd:  1, 3, 6h (± 5m) 
…pd 6h (  5m)  
pre: 0 (≤ 5m) 
 
PM 
pre: 0 (≤ 5m) 
pd: 1, 3h (± 5m)…  
pre:  0 (≤ 5m) 
 
 
Platelet function (n) 
 
 
 
preAM: 0 (≤15m) 
 
 
Confined to clinic 
 
X 
X 
X 
X 
X 
Discharge from clinic  
 
 
 
 
 
 
Study completion 
 
 
 
 
 
 
AM = morning; BP = blood pressure; h = hour; H = height; HBsAg = hepatitis B surface antigen; HCV = hepatitis C virus; HIV = human immunodeficiency 
virus; ICF = informed consent form; m = minute; msec = millisecond; pd = postdose; pdD1 = corresponding to postdose Day 1; PM = evening; pre = predose; 
preD1 = corresponding to predose Day 1; R = respiratory rate; T = oral temperature; W = weight 
a. 
Urine drug screen for selected drugs of abuse and alcohol breathalyzer screen 
b. For female patients, a negative serum pregnancy test must be documented at the Screening Visit, at Check-in with results available before randomization, 
and at the Follow-up Visit. A urine pregnancy test must be documented at the End of Trial Visit. 
c. 
On in-clinic days, in the morning after voiding, before any water or food intake 
d. Patients must be supine for ≥ 5 minutes before the ECG recording (Note:  If on initial ECG, QTcF is ≥ 450 msec for male patients or is ≥ 470 msec for 
female patients, the ECG will be repeated 2 more times, and the average of the 3 QTcF values will be used to determine the patient's eligibility). 
e. 
Triplicate supine to standing assessment (Screening Visit, predose on Day -1, and on Day 15) after the subject has been lying quietly for ≥ 5 m supine BP 
and pulse is the average of 3 measurements obtained at 2-m intervals, after final supine measurement subject assume sitting position for 1 m, and finally 
assume standing position for 2 m before standing measurements are taken Note: The change in blood pressure from supine to standing will be determined 

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using the third supine blood pressure and pulse measurements in comparison to the standing blood pressure and pulse measurements. Single supine to 
standing measurement assessed after the patient has been lying quietly for ≥ 5 m before supine measurements are taken, then assume sitting position for 1 m, 
and finally assume standing position for 2 m before standing measurements are taken.  Single supine measurements are assessed after the subject has been 
laying quietly for ≥ 5 m.  Predose measurements should precede all oral and any antihypertensive concomitant medications. All measurements before blood 
draws where applicable. Note: Supine-only (without standing) pulse and BP may be taken at the 4-h post PM dose timepoints (approximately midnight) if, in 
the Investigator’s clinical opinion, earlier postdose orthostatic (supine and standing) pulse and BPs for the given dosing and for previous dosings at the 4-
hour postdose timepoint indicate it is safe to eliminate the standing (orthostatic) pulse and BP measurement. 
f. 
After ≥ 8-h fast, after EndoPAT (when applicable) and BP/pulse measurements and before dosing, where applicable.  Does not apply to urine collection. 
g. At the Screening and Follow-up Visit, single urine sample, which may not be first void; during Clinic Period, first-void urine sample 
 
 
i. 
ABPM assessments should be performed on the same arm of the subject throughout the study; non-dominant arm is preferred. 
j. 
If EndoPAT is available at the Study Center, for each patient, the Day -1 and Day 13 assessments should be at approximately the same time of day (± 15 m).  
Before all oral and any antihypertensive concomitant medications and study drug, BP/pulse measurements (for PD/Safety), and blood collections; after 
opportunity to void and then resting quietly in a temperature-controlled room for ≥ 15 m; occlusion/finger measurement right arm/hand. See Section 3.7.4.2 
 
  
 
l. 
2 orally administered 8-tablet doses: an AM 8-tablet dose at ~ same time (± 15 m) every day after overnight fast of ≥ 8 hours on Days 1 to 12 and on Day 14. 
On Day 13, first dose may be administered in the morning between 7 and 10:30AM, after the EndoPAT assessment (if applicable). Breakfast should begin 
within 30 m after dosing. PM 8-tablet dose, 12 hours (± 30 minutes) after AM dose and ≥ 30 minutes after completing dinner. May take multiple tablets 
together. Permitted concomitant medications may be taken at the same time as study drug. 
m. ≈ 2-mL blood sample in one K2EDTA tube at each timepoint; each sample divided into 2 equal plasma aliquots 
n. CPRS assessment ≈ 1.8-mL blood sample in one 3.2% citrate tube at each timepoint as well as ≈ 4.5-mL blood sample in one 3.2% citrate tube at each 
timepoint; VerifyNow Aspirin Test and VerifyNow PRU Test ≈ 2-mL blood sample in 3.2% citrate tube at each timepoint for each test. 

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SCHEDULE OF EVENTS (…CONTINUED) 
Study Period→ 
Clinic Period 
Follow-up Period 
Visit Days → 
Study Procedure ↓ 
Day 7 
Days 8-13 
Day 14 
Discharge 
Day 15 
Follow-up 
Visit 
Day 21 (± 2) 
End of 
Trial Visit 
Day 42 (± 3) 
ICF Signed 
 
 
 
 
 
 
Demographics 
 
 
 
 
 
 
Medical History 
 
 
 
 
 
 
Inclusion/Exclusion Evaluation 
 
 
 
 
 
 
Physical Exam 
 
 
 
X 
 
X 
Hepatitis (HBsAg, HCV) & HIV Screen 
 
 
 
 
 
 
Drug & Alcohol Screen (a) 
 
 
 
 
X 
 
Pregnancy Test (b) 
 
 
 
 
X 
X 
Weight (W) & Height (H) (c) 
 
Day 13 W 
 
W 
W 
W 
12-lead electrocardiogram (d) 
 
 
 
X 
 
 
Respiratory rate (R) &  
oral temperature (T) 
X 
X 
X 
X 
X 
X 
Supine/standing BP & pulse (e) 
3 indicates triplicate supine BPs 
supine only 
AM 
pre:  0 (≤15m) 
pd:   1, 4h (±5m) 
Days 8 & 13  pre: 0 (≤ 15m) 
                      pd: 1, 4 (± 5m) 
Days 9-12      pre: 0 (≤15m) 
pre: 0 (≤15m) 
pd: 12h 
(±15m) 3 
X 
X 
PM 
 
Day 8 & 13   pre: 0 (≤15m) 
 
Hemoglobin A1c 
 
Day 8  preAM: 0 (≤15m) 
preAM:0 
(≤15m) 
X 
 
X 
Fasting plasma glucose & serum insulin 
(f) 
 
Day 8 
preAM: 0 (≤15m) 
 
X 
 
 
Clinical chemistry, coagulation, 
hematology, urinalysis; (f) 
 
 
 
X 
 
X 
Urine albumin & creatinine (g) 
 
 
 
first void 
 
X 
AE Evaluations 
X 
X 
X 
X 
X 
X 
Prior & concomitant medications 
X 
X 
X 
X 
X 
X 

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Study Period→ 
Clinic Period 
Follow-up Period 
Visit Days → 
Study Procedure ↓ 
Day 7 
Days 8-13 
Day 14 
Discharge 
Day 15 
Follow-up 
Visit 
Day 21 (± 2) 
End of 
Trial Visit 
Day 42 (± 3) 
 
 
 
 
 
 
 
Ambulatory BP monitoring 
Start: 
pre: 0 (≤15m) 
End: Day 8  
preAM: 0 (≤15m) 
Start: 
preAM: 0 
(≤15m) 
End: 
pd: 12h 
(±15m) 
 
 
EndoPAT (j) 
 
Day 13 preAM 0  
 
 
(end ≥30m) 
 
 
 
 
 
 
 
 
 
 
 
 
Randomization 
 
 
 
 
 
 
Study drug administration (l) 
AM 
X 
X 
X 
 
 
 
PM 
X 
X 
X 
PK blood samples (m) 
AM 
 pre: 0 (≤5m) 
pd:  1, 3, 6h 
(±5m) 
Day 8 
pre: 0 (≤5m) 
 
 
pd:  1, 3, 6h (±5m) 
pre: 0 (≤5m) 
pd:  1,3,6h 
(±5m) 
pd:  12h 
(±15m) 
X 
X 
PM 
pre:  0 (≤5m) 
Day 8 
pre: 0 (≤5m) 
pre:  0 (≤5m) 
Platelet function (n) 
 
Day 8 
 preAM: 0 (≤15m) 
preAM: 0 
(≤15m) 
 
 
 
Confined to clinic 
X 
X 
X 
 
 
 
Discharge from clinic  
 
 
 
X 
 
 
Study completion 
 
 
 
 
 
X 
 

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TABLE OF CONTENTS 
STUDY IDENTIFICATION ...........................................................................................................2 
SYNOPSIS .......................................................................................................................................3 
ELIGIBILITY CRITERIA.............................................................................................................10 
INCLUSION CRITERIA.........................................................................................................10 
EXCLUSION CRITERIA .......................................................................................................12 
SCHEDULE OF EVENTS ............................................................................................................14 
LIST OF ABBREVIATIONS AND DEFINITIONS OF TERMS ................................................25 
1. 
INTRODUCTION .................................................................................................................28 
1.1 
BACKGROUND AND STUDY RATIONALE .........................................................28 
1.2 
IW-1973 BACKGROUND ..........................................................................................29 
2. 
STUDY OBJECTIVES ..........................................................................................................30 
3. 
INVESTIGATIONAL PLAN ................................................................................................31 
3.1 
OVERALL STUDY DESIGN AND PLAN ................................................................31 
3.2 
DISCUSSION OF STUDY DESIGN INCLUDING THE CHOICE OF 
CONTROL GROUPS ..................................................................................................33 
3.3 
STUDY DURATION ..................................................................................................34 
3.4 
STUDY POPULATION SELECTION .......................................................................34 
3.4.1 
Study Population ................................................................................................34 
3.4.1.1 
Type 2 Diabetes Requirement ..................................................................34 
3.4.1.2 
Hypertension Requirement ......................................................................34 
3.4.2 
Removal of Patients from Therapy or Assessment ............................................35 
3.4.3 
Replacement Procedures ....................................................................................36 
3.5 
STUDY TREATMENT(S) ..........................................................................................36 
3.5.1 
Study Drug .........................................................................................................36 
3.5.1.1 
Investigational Product ............................................................................36 
3.5.1.2 
Placebo .....................................................................................................36 
3.5.1.3 
Packaging and Labeling ...........................................................................36 
3.5.1.4 
Storage and Accountability ......................................................................36 
3.5.2 
Method of Assigning Patients to Treatment Groups..........................................37 
3.5.3 
Selection of Dosage in the Study .......................................................................37 
3.5.4 
Selection and Timing of Dose for Each Patient .................................................37 
3.5.5 
Dosage................................................................................................................38 
3.5.6 
Blinding..............................................................................................................38 
3.5.7 
Concomitant Medications ..................................................................................39 
3.5.8 
Restrictions ........................................................................................................39 
3.5.8.1 
Prior Therapy and Prohibited Medications ..............................................39 

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3.5.8.2 
Vitamins and Supplements ......................................................................40 
3.5.8.3 
Fluid and Food Intake and Nicotine-containing Product Use ..................40 
3.5.8.4 
Patient Activity Restrictions ....................................................................41 
3.6 
STOPPING CRITERIA ...............................................................................................41 
3.7 
STUDY PROCEDURES .............................................................................................41 
3.7.1 
Informed Consent...............................................................................................41 
3.7.2 
Medical History .................................................................................................42 
3.7.3 
Safety Assessments ............................................................................................42 
3.7.3.1 
Physical Examination...............................................................................42 
3.7.3.2 
Vital Signs ................................................................................................42 
3.7.3.3 
Electrocardiograms ..................................................................................43 
3.7.3.4 
Clinical Laboratory Tests .........................................................................44 
3.7.3.5 
Urine Creatinine Ratio (UACR) ..............................................................45 
3.7.3.6 
Estimated Glomerular Filtration Rate (eGFR) .........................................45 
3.7.3.7 
Adverse Events ........................................................................................46 
3.7.3.8 
Serious Adverse Events ...........................................................................47 
3.7.3.9 
Recording Adverse Events .......................................................................48 
3.7.3.10 
Reporting Serious Adverse Events ..........................................................49 
3.7.4 
Pharmacodynamic Assessments ........................................................................50 
3.7.4.1 
Hemodynamics ........................................................................................50 
3.7.4.2 
Endothelial Function ................................................................................50 
3.7.4.3 
Platelet Function Assessment ..................................................................51 
3.7.4.4 
HOMA-IR ................................................................................................51 
3.7.4.5 
 ...............................................................................................51 
3.7.4.6 
 
3.7.5 
Pharmacokinetic Assessments ...........................................................................52 
3.8 
STUDY ACTIVITIES .................................................................................................52 
3.8.1 
Screening Period (Days –28 to Day -3) .............................................................52 
3.8.1.1 
Screening Visit (Days –28 to Day -3) ......................................................52 
3.8.2 
Clinic Period (Day -2 to Day 15) .......................................................................53 
3.8.2.1 
Check-in (Day -2) ....................................................................................53 
3.8.2.2 
Day -1.......................................................................................................54 
3.8.2.3 
Day 1 ........................................................................................................54 
3.8.2.4 
Day 2 ........................................................................................................55 
3.8.2.5 
Day 3-6.....................................................................................................56 
3.8.2.6 
Day 7 ........................................................................................................56 
3.8.2.7 
Day 8 ........................................................................................................57 
3.8.2.8 
Days 9 to 12 .............................................................................................57 

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3.8.2.9 
Day 13 ......................................................................................................58 
3.8.2.10 
Day 14 ......................................................................................................58 
3.8.2.11 
Discharge (Day 15) ..................................................................................58 
3.8.3 
Follow-up Period (Day 16 to Day 42 ±3) ..........................................................60 
3.8.3.1 
Follow-up Visit (Day 21 ±2)....................................................................60 
3.8.3.2 
End of Trial Visit (Day 42 ± 3) ................................................................60 
3.9 
STATISTICAL METHODS ........................................................................................61 
3.9.1 
Determination of Sample Size ...........................................................................61 
3.9.2 
Analysis Populations ..........................................................................................61 
3.9.2.1 
 Safety Population ....................................................................................61 
3.9.2.2 
PK Population ..........................................................................................61 
3.9.2.3 
PD Population ..........................................................................................61 
3.9.3 
Statistical Methods .............................................................................................61 
3.9.3.1 
General Considerations ............................................................................61 
3.9.3.2 
Patient Disposition, Demographics, and Baseline Characteristics ..........62 
3.9.3.3 
Pharmacodynamic Analyses ....................................................................62 
3.9.3.4 
Safety Analyses ........................................................................................63 
3.9.3.5 
Pharmacokinetic Analyses .......................................................................64 
3.9.3.6 
Interim Analysis .......................................................................................64 
3.9.3.7 
Computer Methods...................................................................................64 
3.10 
CHANGES IN THE CONDUCT OF THE STUDY OR PLANNED ANALYSES ...64 
4. 
ETHICAL CONSIDERATIONS ...........................................................................................66 
4.1 
 INSTITUTIONAL REVIEW BOARD.......................................................................66 
4.2 
PATIENT INFORMATION AND INFORMED CONSENT .....................................66 
5. 
INVESTIGATORS AND STUDY ADMINISTRATIVE STRUCTURE ............................68 
5.1 
GENERATION OF STUDY RECORDS ....................................................................68 
5.2 
DATA QUALITY ASSURANCE ...............................................................................69 
5.3 
ELECTRONIC CASE REPORT FORMS AND DATA MANAGEMENT ...............69 
5.4 
STUDY MONITORING .............................................................................................69 
6. 
STUDY SPONSORSHIP.......................................................................................................71 
6.1 
INVESTIGATOR AND STUDY TERMINATION ...................................................71 
6.2 
REPORTING AND PUBLICATION ..........................................................................71 
7. 
INVESTIGATOR OBLIGATIONS ......................................................................................72 
7.1 
DOCUMENTATION ..................................................................................................72 
7.2 
PERFORMANCE ........................................................................................................74 
7.3 
ACCOUNTABILITY ..................................................................................................74 
7.4 
RETENTION AND REVIEW OF RECORDS ...........................................................74 
7.5 
PATIENT CONFIDENTIALITY ................................................................................75 

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8. 
REFERENCE LIST ...............................................................................................................76 
9. 
SPONSOR SIGNATURE ......................................................................................................77 
10. INVESTIGATOR’S SIGNATURE .......................................................................................78 
 

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LIST OF IN-TEXT TABLES 
Table 1. 
Key Study Participants.........................................................................................2 
Table 2. 
Treatment Arm Dosing Regimens .....................................................................31 
Table 3. 
Dosage by Week and Time for Each Treatment Arm .......................................38 
Table 4. 
Clinical Laboratory Tests...................................................................................44 
 
 
 

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LIST OF IN-TEXT FIGURES 
Figure 1. 
Study Schematic ................................................................................................32 
 

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LIST OF ABBREVIATIONS AND DEFINITIONS OF TERMS 
Abbreviation 
Term 
ABPM 
ambulatory blood pressure monitoring 
ACEi 
angiotensin-converting enzyme inhibitor 
AE 
adverse event 
ALT 
alanine aminotransferase 
ARB 
angiotensin receptor blocking agent 
AST 
aspartate aminotransferase 
AUCinf 
area under the plasma concentration time curve extrapolated to infinity 
(whenever possible) 
AUClast 
area under the plasma concentration time curve from time zero to the last 
observation 
AUCtau 
area under the plasma concentration time curve during a dosing interval (tau) 
BMI 
body mass index (kg/m2) 
BP 
blood pressure 
BUN 
blood urea nitrogen 
CBC 
complete blood count 
 
 
CKD-EPI 
Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 
CL/F 
apparent clearance (clearance relative to bioavailability) 
Cmax 
maximum observed plasma concentration 
Ctrough 
trough plasma concentration observed at the end of a dosing interval 
DNA 
deoxyribonucleic acid 
ECG 
electrocardiogram 
eCRF 
electronic case report form 
EDC 
electronic data capture 
eGFR 
estimated glomerular filtration rate (mg/mL/1.73 m2) 
eNOS 
endothelial nitric oxide synthase 
FDA 
Food and Drug Administration 
FPG 
fasting plasma glucose 
FPI 
fasting plasma insulin  

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Abbreviation 
Term 
GCP 
good clinical practice 
GGT 
gamma glutamyl transferase   
GLP 
good laboratory practice 
HbA1c 
hemoglobin A1c (glycated hemoglobin) 
HBsAG 
hepatitis B surface antigen 
HCV 
hepatitis C virus 
HDPE 
high-density polyethylene 
HEK 
human embryonic kidney  
hERG 
ether-a-go-go related gene 
HIV 
human immunodeficiency virus 
HOMA-IR 
homeostatic model assessment to quantify insulin resistance 
HPF 
high power field 
IC50 
half maximal inhibitory concentration 
ICF  
informed consent form 
ICH 
International Conference on Harmonization 
IRB 
Institutional Review Board 
kg 
kilogram 
kg/m2 
kilograms/meters squared (body mass index) 
LDH 
lactate dehydrogenase  
MAD 
multiple ascending dose 
MCH 
mean corpuscular hemoglobin 
MCHC 
mean corpuscular hemoglobin concentration 
MCV 
mean corpuscular volume 
MedDRA 
Medical Dictionary for Regulatory Activities 
mg 
milligram 
mL 
milliliter 
mm Hg 
millimeters of mercury 
MPV 
mean platelet volume 
msec 
millisecond 
NO 
nitric oxide 

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Abbreviation 
Term 
pd 
postdose 
PD 
pharmacodynamic(s) 
PDE 
phosphodiesterase 
PID 
patient identification 
PK 
pharmacokinetic(s) 
PT 
preferred term 
QTcF 
QT interval corrected using Fridericia’s formula 
RBC 
red blood cell 
RDW 
red blood cell distribution width 
RHI 
reactive hyperemia index 
SAD 
single ascending dose 
SAE 
serious adverse event 
SAS® 
Statistical Analysis System 
Scr 
serum creatinine 
sGC 
soluble guanylate cyclase 
SGLT2 
sodium-glucose co-transporter 2 
 
 
SOC 
system organ class 
tau 
dosing interval 
t1/2 
apparent terminal phase half-life 
Tmax 
time of maximum observed plasma concentration 
UACR 
urine albumin creatinine ratio 
UGT 
uridine diphosphate–glucuronosyl transferase 
Vz/F 
apparent volume of distribution (volume of distribution relative to 
bioavailability) 
WBC 
white blood cell 
 

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1. 
INTRODUCTION 
1.1 
BACKGROUND AND STUDY RATIONALE 
The NO-sGC-cGMP (nitric oxide – soluble guanylate cyclase – cyclic guanosine 3’,5’-
monophosphate) pathway plays a critical role in the cardiovascular system. In the vascular 
endothelium, sGC is stimulated by NO to produce cGMP, which acts on downstream targets 
including cGMP-dependent protein kinases, phosphodiesterases, and ion channels. This leads to 
relaxation of the vascular smooth muscle and vasodilation. In addition, intracellular cGMP is 
involved in processes that affect vascular proliferation, fibrosis, and inflammation. Impaired 
NO-sGC-cGMP signaling, has been implicated in the pathogenesis of cardiovascular diseases 
such as systemic and pulmonary hypertension, coronary artery disease, congestive heart failure, 
peripheral vascular disease, atherosclerosis, and kidney disease. Agents that stimulate sGC to 
increase cGMP production (1,2) may be useful for treating and/or preventing a broad range of 
diseases that may ensue from dysfunction in the fundamental NO-sGC-cGMP pathway.(3,4) 
 
 
 
 
 
 
 
 
 
 
This exploratory, proof-of-concept study will evaluate the safety, tolerability, PK, and PD of 
2 dosing regimens of daily 40 mg IW-1973 administered orally for 2 weeks to patients with 
type 2 diabetes mellitus and hypertension. This study is designed to explore the tolerability 
profile of the MAD MTD, 40 mg IW-1973, in a patient population, and to explore whether 
tolerability can be improved with an initial week of BID dosing.  

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In addition to safety, tolerability, and PK, this study will evaluate the PD effects (hemodynamics 
and endothelial function) of daily 40 mg IW-1973 in patients with type 2 diabetes and 
hypertension, a population with likely dysfunction in the NO-cGMP-sGC pathway. Type 2 
diabetes is a chronic metabolic disorder in which the body does not use insulin effectively, 
leading to hyperglycemia and glucose intolerance. The prevalence of diabetes in the United 
States (US) is 9.3%, or about 29.1 million people, and 95% of diagnosed cases are type 2.(5) 
This multifactorial disease is associated with numerous comorbidities, including hypertension, 
obesity, hyperlipidemia, chronic kidney disease, and cardiovascular disease. Nearly all diabetic 
patients have at least 1 comorbidity and almost 90% have at least 2.(6) Hypertension is the most 
common comorbid condition and may affect over 80% of patients with type 2 diabetes.(6) 
Hypertension in diabetic patients increases the risk of cardiovascular disease and associated 
complications such as stroke, coronary artery disease, and peripheral vascular disease. In 
addition, hypertension in diabetic patients also increases the risk of microvascular diseases 
including retinopathy, nephropathy, and neuropathy.(7,8) Many of the common comorbid 
disorders in diabetic patients are related to impairment in the NO-sGC-cGMP pathway; 
therefore, improving dysfunction in the NO-cGMP-sGC pathway could be useful in treating 
multiple disorders in these patients.   
1.2 
IW-1973 BACKGROUND 
For a detailed description of the properties of IW-1973 and the results of the nonclinical and 
clinical studies conducted thus far, please refer to the most recent Investigator’s Brochure.   
. 

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2. 
STUDY OBJE CTIVES 
To compare the safety, tolerability, PK profile, and PD effects of 2 treatment regimens of 
IW-1973 Tablet (40 mg per day) administered orally for 2 weeks to patients with stable type 2 
diabetes mellitus and hypertension. 

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3. 
INVESTIGATIONAL PLAN 
3.1 
OVERALL STUDY DESIGN AND PLAN 
This is a randomized, double-blind, placebo-controlled study consisting of 3 distinct periods (see 
Figure 1). The study will enroll 26 patients (at least 11 male and 11 female) with stable type 2 
diabetes and hypertension (see Eligibility Criteria). Additional patients may be checked into the 
Study Center on Day -2 as backups. If the backup patients are not needed, they will be 
discharged from the Study Center before Randomization. Patients withdrawing from the study 
after Randomization will not be replaced. Patients will be randomized in a 5:5:3 ratio to 1 of 2 
IW-1973 treatment regimens or placebo (all regimens will be masked) as outlined in Table 2. 
Tab le 2. 
Tr eatm ent Arm Dosing Regimens 
Treatment 
Arm 
Dose  
time 
Days 1 to 7 
Days 8 to 14 
QD/QD 
AM 
40 mg IW-1973 
40 mg IW-1973 
PM 
Placebo 
Placebo 
BID/QD 
AM 
20 mg IW-1973 
40 mg IW-1973 
PM 
20 mg IW-1973 
Placebo 
PBO/PBO 
AM 
Placebo 
Placebo 
PM 
Placebo 
Placebo 
 
Refer to Section 3.5.5 for details on the number of IW-1973 and/or placebo tablets that will make 
up each dose. 

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Follow-up Period:  The Follow-up Period will begin immediately after Discharge from the 
Study Center on Day 15 and will last for 27 (± 3) days. On Day 21 (± 2 day), 7 (± 2) days after 
the last dose of study drug, patients will return to the Study Center for the Follow up Visit (see 
Schedule of Events). On Day 42 (± 3 days), 28 days after the last dose of study drug, patients 
will return to the Study Center for the End of Trial Visit. 
3.2 
DISCUSSION OF STUDY DESIGN INCLUDING THE CHOICE OF 
CONTROL GROUPS 
A double-blind, placebo-controlled, randomized study design was chosen to investigate the 
safety PK, PD, and tolerability of 2 daily 40-mg IW-1973 dosing regimens. Patients will be 
randomized to ensure that the treatment groups are comparable and to minimize the potential for 
selection bias. The study will be double blind and treatments will be masked to ensure that the 
subjects and clinic staff are unaware of the dosing assignment and to minimize potential for bias 
in study assessments or in reporting of AEs. Placebo was chosen as the control so that the rate of 
spontaneously occurring AEs can be determined and to reduce the potential for bias in the 
reporting of AEs. Randomization will occur so that, within a particular cohort, an optimal 
number of subjects can be exposed to a particular dose of IW-1973, while at the same time 
ensuring that a reasonable number of subjects across the cohorts receive placebo for AE and PD 
comparisons. This design is in accordance with the concepts in International Conference on 
Harmonisation (ICH) E10, Choice of Control Groups and Related Issues in Clinical Trials 
(International Conference on Harmonisation of Technical Requirements for Registration of 
Pharmaceuticals for Human Use, 2001).  
Patients will be confined to the Study Center for the full duration of dosing through 24 hours 
after the final dose to allow monitoring of safety parameters and assessment of any PD effects of 
IW-1973. In addition, Stopping Criteria (Section 3.6) have been established to ensure that dosing 
will stop should a safety signal be detected. Patients will have a Follow-up Visit 7 (± 2) days 
after the final dose of study drug and an End of Trial Visit 28 (± 3) days after the final dose to 
determine if any AEs have developed and if any AEs that were ongoing at the time of Discharge 
have resolved.  

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3.3 
STUDY DURATION  
Patients will be in the Study Center for 17 days, from Check-in on Day -2 to Discharge on 
Day 15. Patients will receive oral doses of study drug for 14 consecutive days and will be 
followed in the Study Center for 24 hours after the last dose. Total patient participation will be 
35 to 73 days, including the Screening, Clinic, and Follow-up Periods. 
3.4 
STUDY POPULATION SELECTION 
3.4.1 
Study Population 
This study will enroll 26 patients (at least 11 male and 11 female) with type 2 diabetes and 
hypertension as defined below. Refer to Eligibility Criteria for full inclusion and exclusion 
requirements. 
3.4.1.1 
Type 2 Diabetes Requirement 
Patients must have type 2 diabetes diagnosed by a physician or nurse practitioner no fewer than 
6 months before the Screening Visit and must have been on a regimen of at least 1 medication 
specifically for control of glycemia, either oral or injectable, with no change in medication for at 
least 12 weeks before Check-in and have been on a stable regimen (ie, same drug and same dose) 
for at least 28 days before Check-in. To be eligible, patients must have a hemoglobin A1c 
(HbA1c) level of ≤ 10.5% and a fasting (≥ 8 hours) serum glucose level of ≤ 240 mg/dL.    
All screened patients with HbA1c or serum glucose levels in the abnormal range (as defined by 
the laboratory) at any point during the trial will be informed of these abnormal lab values, and 
with the patient’s permission, this information will be shared with a designated healthcare 
provider at the conclusion of their participation in the trial. 
3.4.1.2 
Hypertension Requirement 
In addition to type 2 diabetes, patients must have hypertension diagnosed by a physician or nurse 
practitioner no fewer than 6 months before the Screening Visit and must have been on a stable 
medical regimen of at least 1 medication for BP control for at least 28 days before the Screening 
Visit; the medication(s) must include an angiotensin-converting enzyme inhibitor (ACEi) or 
angiotensin receptor blocking agent (ARB). Patients must have systolic BP of 120 to 160 mm Hg 
and diastolic BP of 70 to 100 mm Hg. 

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All patients with systolic pressures ≥ 140 mm Hg or diastolic pressures ≥ 90 mm Hg at the end 
of trial visit will be referred to their healthcare provider. All patients with systolic pressure 
≥ 160 mm Hg or diastolic pressure ≥ 100 mm Hg at any point during the study, who, in the 
clinical judgement of the Investigator, are experiencing or at immediate risk for end-organ events 
will be immediately referred to an appropriate healthcare provider.    
3.4.2 
Removal of Patients from Therapy or Assessment 
A premature discontinuation will occur when a patient who has signed the ICF and has been 
randomized ceases participation in the study, regardless of circumstances, before completion of 
Clinic Period. Patients who prematurely discontinue dosing should remain in the clinic for at 
least 24 hours after their final dose of study drug and should complete all Discharge day 
assessments. In addition, these patients should return to the Study Center for their Follow-up and 
End of Trial Visits, 7 (± 2) and 28 (± 3) days, respectively, after their final dose of study drug. 
A patient will be considered to have completed the study after completing the End of Trial Visit. 
Patients will be informed that they are free to withdraw from the study at any time and for any 
reason. The Investigator may remove a patient from the study if, in the Investigator’s opinion, it 
is not in the best interest of the patient to continue the study. Patients may also be discontinued 
from the study by the Investigator or the Sponsor at any time for any reason, including the 
following: 
• Adverse event(s) 
• Protocol violation, including lack of compliance 
• Lost to follow-up (every effort must be made to contact the patient; a certified letter must be 
sent) 
• Withdrawal of consent (attempts should be made to determine the reason for the patient 
withdrawing consent if possible) 
• Study termination by the Sponsor 
• Other reasons (eg, administrative reasons or pregnancy) 
 

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The Sponsor will be notified of any patient discontinuation after Randomization. The date the 
patient is withdrawn from the study and the reason for discontinuation will be recorded on the 
study termination form of the electronic case report form (eCRF). Patients who discontinue from 
the study will be followed until resolution of all of their AEs or until the unresolved AEs are 
judged by the Investigator to have stabilized. 
If a patient does not return for a scheduled visit, the study center should contact the patient. An 
effort must be made to contact the patient, including sending a certified letter. In every case, the 
patient outcome, including lost to follow-up information, will be documented. 
3.4.3 
Replacement Procedures 
Patients withdrawing from the study after Randomization will not be replaced. 
3.5 
STUDY TREATMENT(S) 
3.5.1 
Study Drug 
3.5.1.1 
Investigational Product 
The investigational product, IW-1973 Tablet, is a 5 mg oral tablet.  
3.5.1.2 
Placebo 
Placebo will match the IW-1973 Tablet in appearance. 
3.5.1.3 
Packaging and Labeling 
IW-1973 Tablet and placebo to match will be supplied to the site(s) in 60cc high-density 
polyethylene (HDPE) induction sealed bottles, 35 tablets per bottle. Bottles will be supplied as 
open label to the clinical site(s). 
3.5.1.4 
Storage and Accountability 
IW-1973 Tablet and placebo to match will be shipped under refrigerated conditions, 2°C - 8°C 
(36 - 46°F). 
IW-1973 Tablet and placebo to match must be stored under refrigerated conditions, 2°C - 8°C 
(36°F - 46°F) per the instructions in the study’s Pharmacy Manual. Once opened the bottles will 

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be kept at room temperature storage (15 -30°C/59-86°F) for up to 30 days. Any deviation from 
these storage conditions must be reported to Ironwood and use of the study drug suspended until 
authorization for its continued use has been provided by Ironwood. 
The Investigator must ensure that the receipt and use of all study drug supplied is recorded and 
must supervise the storage and allocation of these supplies. All study drug supplies must be 
retained in a locked room that may only be accessed by the pharmacist, Investigator, or other 
duly designated persons. Study drug must not be used outside the context of this protocol, and 
under no circumstances should the Investigator or study center personnel allow the supplies to be 
used other than as directed by this protocol without prior authorization from Ironwood. 
3.5.2 
Method of Assigning Patients to Tr eatm ent Groups 
Patients who meet all of the inclusion criteria and none of the exclusion criteria will be 
randomized to treatment on Day 1. Patients will be randomized in a 5:5:3 ratio to receive 
QD/QD IW-1973, BID/QD IW-1973, or placebo.  
The computer-generated randomization schedule will be prepared by an independent statistician 
not otherwise associated with the study. 
3.5.3 
Selection of Dosage in the Study 
This Phase 2a exploratory study will evaluate 40 mg IW-1973 administered daily for 2 weeks 
according to 2 different regimens: QD for both weeks or BID for the 1st week and QD the 
2nd week. In the Phase 1b MAD study (ICP-1973-102), 40 mg IW-1973 was considered the 
maximum tolerated repeat dose, therefore, 40 mg was chosen for evaluation in this patient 
population.  
3.5.4 
Selection and Timing of Dose for Each Patient 
All patients will receive 2 orally administered doses per day: an AM dose and a PM dose. Except 
for Day 13, patients will receive the AM dose at approximately the same time (± 15 minutes) 
every day in the morning (8 to 10AM) following an overnight fast of ≥ 8 hours. (Note: For each 
patient, the first dose on Day 1 may be administered between 8 and 10AM; thereafter, AM doses 
on Days 2 to 12 and on Day 14 must be administered within 15 minutes of the time of dosing on 
Day 1.) On Day 13, first dose should be administered in the morning between 7 and 10:30AM, 

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after the EndoPAT assessment (when applicable). Breakfast should begin within 30 minutes after 
dosing. Each patient will receive their PM dose 12 hours (± 30 minutes) after their AM dose and 
at least 30 minutes after completing a normal dinner.  
Patients may take multiple tablets together. Permitted concomitant may be taken at the same time 
as study drug. 
3.5.5 
Dosage 
On Days 1 to 14, all patients will receive 2 daily 8-tablet doses (AM and PM), 12 hours 
(± 30 minutes) apart. 
Matching placebo tablets will be administered with IW-1973 Tablets when required to mask 
treatment assignments. Table 3 outlines study drug dosage by week and time, for each 
regimen/treatment arm. 
Tab le 3. 
Dosage by Week and Time for Each Tr eatm ent Arm 
Regimen/ 
Treatment arm 
Dose  
time 
Dosage  
Days 1 to 7 
Dosage  
Days 8 to 14 
QD/QD 
AM 
8 x IW-1973 Tablet 
8 x IW-1973 Tablet 
PM 
8 x placebo tablet 
8 x placebo tablet 
BID/QD 
AM 
4 x IW-1973 Tablet 
4 x placebo tablet 
8 x IW-1973 Tablet 
PM 
4 x IW-1973 Tablet 
4 x placebo tablet 
8 x placebo tablet 
PBO/PBO 
AM 
8 x placebo tablet 
8 x placebo tablet 
PM 
8 x placebo tablet 
8 x placebo tablet 
 
3.5.6 
Blinding 
This study is double blind and placebo controlled. The patients and Sponsor will be blinded to 
treatment assignments. Except for specifically designated unblinded Study Center pharmacy 
staff, the Investigator and remaining site study staff will be blinded as to treatment. The 
investigational product and placebo will be matching oral tablets.  

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Site unblinding of a subject’s treatment assignment is restricted to emergency situations. In the 
scenario that the Investigator must unblind a subject, the Investigator, or person designated by 
the Investigator, should contact Ironwood’s Medical Monitor directly to discuss the need for 
emergency unblinding. Individual sealed unblinding envelopes, which can be opened to identify 
the treatment assignment for an individual subject in an emergency, will be provided to the Study 
Center pharmacist. The reason for breaking the blind must be documented in the subject’s source 
documentation and eCRF. 
3.5.7 
Concomitan t Medications 
At the Screening Visit, the following information will be recorded for each patient: 
• All medications the patient is taking (ongoing)  
• All prior medications taken during the 30 days before the Screening Visit 
 
Permitted concomitant medications should be taken at the same time (± 15 minutes) each day and 
may be taken at the same time as study drug. All oral and any antihypertensive concomitant 
medications should be taken after EndoPAT (when applicable) and after predose BP 
assessments. 
Any medication taken by a patient during the course of the study (beginning at the Screening 
Visit and including any new medications added or changes in medications previously reported), 
will be documented in the source documents and the eCRF along with the time of use and the 
reason for use. 
3.5.8 
Restr ictions 
3.5.8.1 
Prior Therapy and Prohibited Medications 
Medication(s) that when co-administered with an sGC stimulator could increase the risk of 
hypotension are prohibited from 6 days before Check-in through the End of Trial Visit. These 
medications include (but may not be limited to) nitrates, nitroglycerin, direct vasodilators 
(including hydralazine or systemic minoxidil), phosphodiesterase (PDE) 5 inhibitors (including 
sildenafil, tadalafil, and vardenafil), alpha adrenergic blockers, riociguat, and sodium-glucose co-
transporter 2 (SGLT2) inhibitors.  

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3.5.8.2 
Vitamins and Supplements 
All vitamins and herbal supplements are prohibited within 7 days before Check-in through the 
End of Trial Visit. Supplements for the treatment of erectile dysfunction are prohibited within 
14 days before Check-in through the End of Trial Visit. 
3.5.8.3 
Fluid and Food Intake and Nicotine-containing Product Use 
The following food, fluid, and tobacco restrictions apply: 
• All nicotine-containing products (eg, cigarettes, e-cigarettes, vape pens, cigars, chewing 
tobacco, gum, patches) are prohibited within 6 months before Check-in through the End of 
Trial Visit. 
• All alcohol-containing foods or beverages are prohibited within the 7 days before Check-in 
through Discharge. 
• Patients may consume up to 2 cups of coffee or tea per day but not within 1 hour of study 
drug administration or within 3 hours before EndoPAT assessments (when applicable). 
• Grapefruit and grapefruit juice are prohibited within 72 hours before Check-in through the 
End of Trial Visit. 
• Food is not allowed for 8 hours before AM study drug administration. Breakfast should begin 
within 30 minutes of AM study drug administration.  Dinner should be completed at 
least 30 minutes before PM dose. 
• Food is not allowed 8 hours before clinical laboratory sample collections.  
• While in clinic, patients will follow a standard diet for diabetics. 
 
Because poppy seeds can sometimes cause a positive result on the drugs of abuse test, subjects 
are advised to avoid eating poppy seeds or foods containing poppy seeds for at least 48 hours 
before the drug screen at the Screening Visit, Check-in, and Follow-up Visit. 
The subject’s food consumption will be recorded in the subject’s source documentation. 

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3.5.8.4 
Patient Activity Restrictions 
The following subject activity restrictions apply: 
• Subjects are not to donate blood within the 6 weeks before Check-in. 
• Subjects are not to have received blood products within the 2 months before Check-in. 
• Subjects are not to have undergone a surgical procedure (other than minor dermatologic 
procedures) during the 30 days before Check-in. 
• Subjects should refrain from making any major lifestyle changes (eg, changing his or her 
exercise pattern) from the time of signature of the ICF to the End of Trial Visit. 
• Female subjects are not breastfeeding. 
 
3.6 
STOPPING CRITER IA 
All dosing will be stopped if the Sponsor and Investigator determine that any of the following 
have occurred: 
• Drug-related serious adverse events (SAEs) in 2 or more patients on a given dosing regimen 
(per causality and SAE definitions in the protocol)  
• An overall pattern of clinically significant AEs or an overall pattern of patient tolerability 
issues, which may appear minor in terms of an individual event but, in the opinion of the 
Sponsor or Investigator, collectively represents a safety concern. 
 
3.7 
STUDY PROCEDURES 
3.7.1 
Informed Consent 
Informed consent procedures will comply with the Code of Federal Regulations (CFR) 21 CFR, 
Parts 50 and 312. 
The written ICF must be approved by the Institutional Review Board (IRB) for the purposes of 
obtaining and documenting consent. 
Before entry into the study, each patient will be provided with a written explanation of the study. 
It is the responsibility of the Investigator or appropriately trained health professional to give each 
patient full and adequate information regarding the objectives and procedures of the study and 

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the possible risks involved. Patients will then be given the opportunity to ask questions and the 
Investigator will be available to answer questions as needed. Patients will be informed of their 
right to withdraw from the study at any time without prejudice. After this explanation and before 
entering the study, the patient will voluntarily sign an ICF. The patient should receive a copy of 
the signed and dated ICF. The Investigator must retain each patient’s original signed ICF. 
If new information becomes available that may be relevant to the patient’s consent and 
willingness to participate in the study, the ICF will be revised. The revised ICF must be 
submitted to the IRB for review and approval prior to its use. 
3.7.2 
Medical Histor y 
A complete medical history will be recorded at the Screening Visit. 
3.7.3 
Safety Assessments 
3.7.3.1 
Physical Examination 
A complete physical examination will be performed according to the Schedule of Events. The 
physical examination of each patient should include examination and assessment of the 
following: 
General appearance 
Lymph nodes 
Skin  
Cardiovascular system 
Head, eyes, ears, nose, and throat 
Central nervous system 
Respiratory system 
Neck 
Peripheral nervous system 
Abdomen/liver/spleen 
Musculoskeletal system  
 
 
Breast, genitourinary, and rectal examinations are optional and may be performed at the 
discretion of the Investigator. Any new, clinically significant abnormal findings from the 
physical examination will be reported as an AE. 
Height will only be recorded at the Screening Visit; weight will be recorded according to the 
Schedule of Events. 
3.7.3.2 
Vital Signs 
Vital signs will be measured according to the Schedule of Events and documented on the eCRF. 
Vital sign measurements include oral temperature (°C), respiratory rate, and supine and standing 

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BP and pulse. Respiratory rate will be taken after the patient has been seated for at least 
5 minutes. At the Screening Visit, on Day -1, and on Day 15, the supine BP measurements will 
be the average of 3 measurements obtained at 2-minutes intervals after the patient has been lying 
quietly for at least 5 minutes; for supine-only BP and pulse measurements thereafter, patient 
must lie quietly for at least 5 minutes before measurements are taken. In addition, at the 
Screening Visit, these blood pressure assessments should be completed at medication trough 
level, ie, prior to subjects taking their hypertensive medications, for determination of eligibility. 
For supine and standing BP and pulse measurements, patient must lie quietly for at least 5 
minutes before supine measurements are taken, then assume a sitting position for 1 minute, and 
finally assume a standing position for 2 minutes before standing measurements are taken. All BP 
and pulse measurements should be taken before blood draws where applicable. All predose BP 
and pulse measurements should be taken before all oral and any antihypertensive concomitant 
medications.  
3.7.3.3 
Electrocardiograms 
A 12-lead ECG will be performed according to the Schedule of Events and documented on the 
eCRF. Electrocardiograms should be obtained after the patient has been supine for at least 
5 minutes. (Note: if on initial ECG, QTcF is ≥ 450 msec for male patients or is ≥ 470 msec for 
female patients, the ECG will be repeated 2 more times, and the average of the 3 QTcF values 
will be used to determine the patient's eligibility.) 

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3.7.3.4 
Clinical Laboratory Tests 
Blood and urine samples for clinical laboratory tests will be collected according to the laboratory 
study procedures at the days and times defined in the Schedule of Events. Patients must have 
fasted for at least 8 hours before sample collections. The clinical laboratory evaluations will 
include the serum chemistry, hematology, coagulation, and urinalysis panels and the additional 
tests presented in Table 4.  
Tab le 4. 
Clinical Lab orator y Tests 
Serum Chemistry Panel 
Hematology Panel (CBC) 
Complete Urinalysis  
Albumin 
Hematocrit 
Color and appearance 
Alkaline Phosphatase 
Hemoglobin 
pH and Specific Gravity 
ALT 
Platelet count 
Bilirubin 
AST 
RBC count 
Glucose 
Bicarbonate 
WBC count 
Ketones 
BUN 
WBC differential 
Leukocytes 
Calcium 
  (% & absolute): 
Nitrates 
Chloride 
Basophils 
Occult blood 
Cholesterol 
Eosinophils 
Protein 
Creatinine 
Lymphocytes 
Urobilinogen 
GGT 
Monocytes 
Microscopic  
Glucose 
Neutrophils 
Including bacteria, RBCs, WBCs 
HDL-c 
RBC indices 
per HPF if dipstick is abnormal 
LDH 
MCH 
 
LDL-c (calculated) 
MCHC 
 
Magnesium 
MCV 
 
Phosphorus 
RDW 
Additional tests 
Potassium 
 
Hemoglobin A1c 
Sodium 
 
Fasting plasma glucose 
Total Bilirubin 
Coagulation Panel 
Fasting plasma insulin 
Total Protein 
aPTT 
Urine albumin 
Triglycerides 
Prothrombin time 
Urine creatinine  
 Uric acid 
INR 
 
ALT = alanine aminotransferase; aPTT = activated partial thromboplastin time; AST = aspartate aminotransferase; BUN = 
blood urea nitrogen; CBC = complete blood count; GGT = gamma glutamyl transferase; HPF = high power field; INR = 
International Normalized Ratio; LDH = lactate dehydrogenase; MCH = mean corpuscular hemoglobin; MCHC = mean 
corpuscular hemoglobin concentration; MCV = mean corpuscular volume; MPV = mean platelet volume; RBC = red blood 
cell; RDW = red blood cell distribution width; WBC = white blood cell.  
 
For female patients, a negative serum pregnancy test must be documented at the Screening Visit, 
at Check-in with results available before dosing, and at the Follow-up Visit. A urine pregnancy 

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test must be documented at the End of Trial Visit. In the event of a positive pregnancy test, the 
test will be repeated. If pregnancy is confirmed, see Section 3.7.3.10. 
At the Screening Visit, blood will be collected for a hepatitis panel (including hepatitis B surface 
antigen [HBsAg] and antihepatitis C virus [HCV]) and human immunodeficiency virus (HIV) 
antibody screen. 
A urine drug screen for selected drugs of abuse and an alcohol breathalyzer screen will be 
performed at the Screening Visit, Check-in, and the Follow-up Visit. Patients will be screened 
for the following drugs of abuse: 
Amphetamines 
Cocaine 
Opiates 
Barbiturates 
Cotinine 
Phencyclidine (PCP) 
Benzodiazepines 
Marijuana 
Propoxyphene 
 
3.7.3.5 
Urine Creatinine Ratio (UACR) 
Urine creatinine ratio (UACR) will be calculated as urine albumin (mg/dL) / urine creatinine 
(g/dL), At the Screening and Follow-up Visits, single urine samples, which may not be first void, 
will be collected for determination of albumin and creatinine levels. During the Clinic Period, 
first-void urine samples will be collected according to the Schedule of Events for determination 
of albumin and creatinine levels.  
3.7.3.6 
Estimated Glomerular Filtration Rate (eGFR) 
Estimated glomerular filtration rate will be based on the serum creatinine level determined as 
part of the clinical laboratory tests (Table 4) and will be calculated according to the Chronic 
Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine equation.(9)  
The CKD-EPI equation, expressed as a single equation, is  
GFR = 141 × min(Scr/κ, 1)α × max(Scr/κ, 1) -1 209 × 0.993Age × 1.018 [if female] _ 1.159 [if black] 
 
where Scr is serum creatinine, κ is 0.7 for females and 0.9 for males, α is -0.329 for females and 
-0.411 for males, min indicates the minimum of Scr/κor 1, and max indicates the maximum of 
Scr/κ or 1. 

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3.7.3.7 
Adverse Events  
All patients will be monitored for AEs throughout the study. All AEs will be recorded in 
accordance with the procedures outlined in this section. 
An AE is any untoward medical occurrence in a patient or clinical investigation subject 
administered a pharmaceutical product and which does not necessarily have to have a causal 
relationship with this treatment.  
An AE, therefore, can be any unfavorable and unintended sign (including an abnormal laboratory 
finding, for example), symptom, or disease temporally associated with the use of a medicinal 
product, whether or not considered related to the medicinal product. 
An AE includes, but is not limited to, the following: 
• Any unfavorable changes in general condition 
• Any clinically significant worsening of a preexisting condition 
• Any intercurrent diseases and accidents 
 
Note: A procedure is not an AE, but the reason for a procedure may be an AE. 
3.7.3.7.1 
Causality Assessment 
For all AEs, the Investigator must provide an assessment of causal relationship to study drug. 
The causality assessment must be recorded in the patient’s source documentation and on the AE 
page of the subject’s eCRF. Causal relationship must be assessed according to the following: 
Related:   
An event where there is a reasonable possibility of a causal relationship between 
the event and the study drug 
Unrelated:   Any other event 

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3.7.3.7.2 
Severity Assessment 
The Investigator will provide an assessment of the severity of each AE by recording a severity 
rating in the patient’s source documentation and on the AE page of the patient’s eCRF. Severity, 
which is a description of the intensity of manifestation of the AE, is distinct from seriousness, 
which implies a patient outcome or AE-required treatment measure associated with a threat to 
life or functionality. Severity will be assessed according to the following scale: 
Mild: 
A type of AE that is usually transient and may require only minimal treatment or 
therapeutic intervention. The event does not generally interfere with usual 
activities of daily living. 
Moderate: 
A type of AE that is usually alleviated with additional specific therapeutic 
intervention. The event interferes with usual activities of daily living, causing 
discomfort but poses no significant or permanent risk of harm to the research 
participant. 
Severe: 
A type of AE that interrupts usual activities of daily living, or significantly affects 
clinical status, or may require intensive therapeutic intervention.  
 
3.7.3.8 
Serious Adverse Events 
An SAE is defined as any AE occurring at any dose that results in any of the following 
outcomes: 
• Death 
• Life-threatening:  the patient was at immediate risk of death from the reaction as it occurred 
(ie, it does not include a reaction that hypothetically might have caused death if it had 
occurred in a more severe form) 
• Hospitalization or prolongation of existing hospitalization 
• Persistent or significant disability/incapacity:  a substantial disruption of a person’s ability to 
conduct normal daily functions 
• Congenital anomaly/birth defect 
• Important medical events:  events that may not result in death, be life threatening, or require 
hospitalization. Such an event may be considered serious when, based on appropriate medical 
judgment, it may jeopardize the subject and may require medical or surgical intervention to 
prevent 1 of the outcomes listed in this definition. Examples of such medical events include 
allergic bronchospasm requiring intensive treatment in an emergency department or at home, 
blood dyscrasias or convulsions that do not result in inpatient hospitalization, or the 
development of drug dependency or drug abuse. 

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Emergency room visits that do not result in admission to the hospital should be evaluated for 1 of 
the other serious outcomes (eg, life-threatening, other serious [medically important] event). 
3.7.3.9 
Recording Adverse Events 
Adverse events will be collected and recorded from the time the patient signs the ICF at the 
Screening Visit through the End of Trial Visit. All AEs, regardless of the assumption of a causal 
relationship with study procedures or study medication, must be recorded in the patient’s source 
documentation and subsequently on the appropriate AE page of the patient’s eCRF. This record 
includes AEs the patient reports spontaneously, those observed by the Investigator, and those 
elicited by the Investigator in response to open-ended questions during the study, such as “Have 
you had any health problems since your last visit?” 
For every AE, the Investigator must 
• Provide an assessment of the severity, causal relationship to the study medication, and 
seriousness of the event 
• Document all actions taken with regard to the study medication (ie, no action taken, 
treatment temporarily interrupted, or treatment discontinued)  
• Detail any other treatment measures taken for the AE, including concomitant medications 
and/or procedures 
 
Pretreatment AEs will be collected from the time the patient signs the ICF until the patient 
receives study drug. Pretreatment AEs will be captured in the patient’s source documentation but 
will only be entered for patients who receive study drug on the AE page of the patient’s eCRF. 
Laboratory abnormalities and changes in vital signs, physical examination findings, and 12-lead 
ECG parameters should be considered AEs and reported on the AE page of the patient’s eCRF if 
the Investigator considers them clinically significant and/or they necessitate intervention. 
Any medical condition that is present when a patient is screened and does not worsen in severity 
and/or frequency should be reported as Medical History and not as an AE. However, if the 
condition does deteriorate in severity and/or frequency at any time during the study, it should be 
reported as an AE. 

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3.7.3.10 
Reporting Serious Adverse Events 
An AE that meets any of the serious criteria must be reported to Ironwood within 24 hours from 
the time that site personnel first learn of the event, using the SAE Report form provided for the 
study. Regardless of causality, all SAEs must be reported and will be collected and recorded 
from the time the subject signs ICF at the Screening Visit until the End of Trial Visit. All SAEs 
must also be recorded in the subject’s source documentation and on the AE page of the subject’s 
eCRF. 
The initial report should include at least the following information: 
• Patient identification number 
• Description and onset of the event 
• Serious criteria 
• Causality assessment to study drug 
 
Special Situation:  Exposure to Study Drug during Pregnancy 
In the event that a pregnancy occurs in a patient, the study drug must be stopped at once, and 
study personnel must report the pregnancy as soon as possible (within 24 hours after notification) 
on the pregnancy notification form provided for this study. The study personnel must follow the 
pregnancy until the end and report the pregnancy outcome on the pregnancy outcome form 
provided for this study. If the pregnancy is associated with an SAE (eg, if the mother is 
hospitalized), a separate SAE form must be completed. 
All relevant SAE or pregnancy information should be emailed to Ironwood Drug Safety and 
Pharmacovigilance. 
All SAE Report Forms should be emailed to: 
 
Clinical Drug Safety & Pharmacovigilance 
 
 
 
 

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If follow-up is obtained, or requested by Ironwood, the additional information should be emailed 
on an SAE Report Form to Ironwood, in a timely manner according to the procedures outlined 
above. Copies of discharge summaries, consultant reports, autopsy reports, and any other 
relevant documents may also be requested. 
Appropriate remedial measures should be taken by the Investigator using his/her best medical 
judgment to treat the SAE. These measures and the subject’s response to these measures should 
be recorded. All SAEs regardless of relationship to study drug will be followed by the 
Investigator until satisfactory resolution, until the Investigator deems the SAE to be chronic or 
stable, or until the subject is lost to follow-up. Clinical, laboratory, and diagnostic measures 
should be employed by the Investigator as needed to adequately determine the etiology of the 
event. 
The Investigator will be responsible for reporting all SAEs to the IRB. Ironwood will be 
responsible for reporting to the regulatory authorities. 
3.7.4 
Phar macodynamic Assessments 
Hemodynamic, endothelial function, and platelet function assessments will be used to determine 
the PD parameters for PD analyses. 
3.7.4.1 
Hemodynamics 
Blood pressure and pulse measurements for PD analyses will include supine and standing pulse 
and BP (for calculation of orthostatic pulse rate and BP) and ABPM assessed according to the 
Schedule of Events; refer to Section 3.7.3.2 for detailed instructions.  
3.7.4.2 
Endothelial Function 
If available at the Study Center, endothelial function in the finger will be measured according to 
the Schedule of Events using the noninvasive EndoPAT device. (Note: For each patient, the Day 
-1 and Day 13 assessments should occur at approximately the same time of day [±15 minutes].) 
All measurements will precede all antihypertensive concomitant medications and will be 
performed in a quiet, dimly lit, temperature-controlled (21–24°C) room to reduce vascular tone 
fluctuation. The procedure will begin after the patient has had the opportunity to void and has 
been resting quietly for at least 15 minutes. The right arm will be used for occlusion and finger 

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measurements. Endothelial function will be assessed using the reactive hyperemia index (RHI) 
parameter.  
The EndoPAT procedure requires data entry of height, weight, and BP assessments in the 
EndoPAT software as follows. The Screening Visit height will be used for all EndoPAT 
assessments. The weight assessments obtained on Day -1 and on Day 13 will be used for the 
Day -1 and Day 13 assessments, respectively. Blood pressure is required as part of the EndoPAT 
procedure to determine the range of occlusion pressure necessary to complete the procedure. 
Therefore, as part of the EndoPAT procedure, BP assessments will be taken at least 15 minutes 
prior to starting the EndoPAT recording.  
3.7.4.3 
Platelet Function Assessment 
Blood samples for platelet function assessment (VerifyNow®, Accriva Diagnostics, San Diego, 
CA) and Evaluation of Platelet Function Markers (Center for Platelet Research Studies, Boston, 
MA) will be collected according to the Schedule of Events. Additional platelet function tests 
may be performed.  
3.7.4.4 
HOMA-IR 
Blood samples for determination of fasting plasma glucose and insulin levels (Table 4) will be 
collected according to the Schedule of Events. Values will be used in the Homeostatic Model 
Assessment to estimate insulin resistance (HOMA-IR).(10,11)  
The HOMA-IR equation is  
HOMA-IR = (FSI × FPG)/22.5, 
where FSI is fasting serum insulin concentration (µU/l) and FPG is fasting plasma glucose 
(mmol/l) 
3.7.4.5 
 
 
 
 
  

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- 
Drug screen 
- 
HBsAg, HCV, and HIV screen 
• Alcohol breathalyzer  
• AE evaluation 
Note: Screening Visit assessments may take place over more than 1 day. 
Patients may be rescreened should they discontinue in the Screening Period due to visit window 
deviations or other administrative reasons. In addition, laboratory values, ECG values, or BPs 
that are outside the range specified in the protocol may be repeated to confirm eligibility during 
the Screening period at the Investigator’s discretion after consultation with the Medical Monitor. 
3.8.2 
Clinic Period (Day -2 to Day 15) 
Patients will be confined to the clinic from Check in on Day -2 until Discharge on Day 15. 
3.8.2.1 
Check-in (Day -2) 
• Review of inclusion and exclusion criteria  
• Physical examination 
• Respiratory rate and oral temperature  
• Prior (since the Screening Visit) and concomitant medications * 
• Supine-to-standing (orthostatic) pulse and BP * 
• 12-lead ECG 
• Collection of blood and urine samples for: 
- 
Clinical chemistry, hematology (CBC), coagulation (including fasting serum glucose *) 
- 
Urinalysis 
- 
Serum pregnancy test for all females (must be confirmed negative) * 
- 
Hemoglobin A1c * 
- 
Fasting plasma glucose 
- 
Fasting plasma insulin 
- 
Drug screen * 
- 
 
• Alcohol breathalyzer * 

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• AE evaluation 
* must meet Eligibility Criteria at Check-in 
 
3.8.2.2 
Day -1 
• Weight 
• If planned, EndoPAT assessment completed > 30 minutes before the time corresponding to 
AM dose on Day 13 and before all oral and any antihypertensive concomitant medications 
(Note: For each patient, the Day -1 and Day 13 assessments should occur at approximately 
the same time of day [±15 minutes])  
• Respiratory rate and oral temperature 
• Collection of urine samples: 
- 
Urine albumin and creatinine (first void) 
• Supine BP (average of 3 measurements) at the time corresponding to AM dose 
(≤ 15 minutes) on Day 1 
• Supine-to-standing (orthostatic) pulse and BP  
- 
at the time corresponding to AM dose (≤ 30 minutes) on Day 1 and at 1 and 4 hours 
(± 5 minutes) after that time  
- 
at the time corresponding to PM dose (≤ 15 minutes) on Day 1 and at 1 and 4 hours 
(± 5 minutes) after that time (Note: Supine-only pulse and BP may be taken at the 4-hour 
post PM dose timepoint if, in the Investigator’s clinical opinion, earlier orthostatic pulse 
and BPs indicate it is safe to eliminate the standing [orthostatic] pulse and BP 
measurement.) 
• ABPM starts at the time corresponding to AM dose (≤ 15 minutes)  
• AE evaluation 
• Concomitant medication recording 
 
3.8.2.3 
Day 1  
• Respiratory rate and oral temperature AM predose (≤ 30 minutes) 
• Oral temperature at 1 and 4 hours (± 30 minutes) AM postdose 
• 12-lead ECG predose (≤ 30 minutes) and at 4 hours (± 15 minutes) postdose  
• Supine-to-standing (orthostatic) pulse and BP  
- 
AM predose (≤ 30 minutes) and at 1, 4 and 8 hours (± 5 minutes) postdose  

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- 
PM predose (≤ 15 minutes) and at 1 and 4 hours (± 5 minutes) postdose  
(Note: Supine-only pulse and BP may be taken at the 4-hour post PM dose timepoint if, 
in the Investigator’s clinical opinion, earlier postdose orthostatic pulse and BPs for the 
given dosing and for previous measurements at the 4-hour postdose timepoint indicate it 
is safe to eliminate the standing (orthostatic) pulse and BP measurement.) 
•  Collection of blood samples for: 
- 
PK  
◦ 
AM predose (≤ 15 minutes) and at 1, 3, and 6 hours (± 5 minutes) postdose 
◦ 
PM predose (≤ 5 minutes) and at 1 and 3 hours (± 5 minutes) postdose 
- 
Serum creatinine AM predose (≤ 15 minutes) 
- 
Hemoglobin A1c AM predose (≤ 15 minutes) 
- 
Fasting plasma glucose AM predose (≤ 15 minutes) 
- 
Fasting plasma insulin AM predose (≤ 15 minutes) 
- 
Platelet function assessments AM predose (≤ 15 minutes) 
- 
 
• Randomization  
• Study drug administration AM and PM, 12 hours (± 30 minutes) apart 
• ABPM continues  
• AE evaluation 
• Concomitant medication recording 
3.8.2.4 
Day 2  
• Respiratory rate and oral temperature 
• ABPM ends AM predose (≤ 15 minutes) 
• Supine-to-standing (orthostatic) pulse and BP  
- 
AM predose (≤ 15 minutes) and at 1 and 4 hours (± 5 minutes) postdose  
- 
PM predose (≤ 15 minutes) and at 1 and 4 hours (± 5 minutes) postdose 
(Note: Supine-only pulse and BP may be taken at the 4-hour post PM dose timepoint if, 
in the Investigator’s clinical opinion, earlier postdose orthostatic pulse and BPs for the 
given dosing and for previous dosings at the 4-hour postdose timepoint indicate it is safe 
to eliminate the standing (orthostatic) pulse and BP measurement.) 
 

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• Collection of blood samples for PK: 
- 
6 hours (± 5 minutes) post Day 1 PM dose 
- 
AM predose (≤ 5 minutes)  
- 
PM predose (≤ 5 minutes)  
• Study drug administration AM and PM, 12 hours (± 30 minutes) apart 
• AE evaluation 
• Concomitant medication recording 
 
3.8.2.5 
Day 3-6  
• Respiratory rate and oral temperature 
• Supine pulse and BP AM predose (≤ 15 minutes)  
• Study drug administration AM and PM, 12 hours (± 30 minutes) apart 
• AE evaluation 
• Concomitant medication recording 
 
3.8.2.6 
Day 7  
• Respiratory rate and oral temperature 
• Supine-to-standing (orthostatic) pulse and BP  
- 
AM predose (≤ 15 minutes) and at 1 and 4 (± 5 minutes) postdose  
• ABPM starts AM predose (≤ 15 minutes)  
• Collection of blood samples for PK: 
- 
AM predose (≤ 5 minutes) and at 1, 3, and 6 hours (± 5 minutes) postdose 
- 
PM predose (≤ 5 minutes)  
• Study drug administration AM and PM, 12 hours (± 30 minutes) apart 
• AE evaluation 
• Concomitant medication recording 
 

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3.8.2.7 
Day 8  
• Respiratory rate and oral temperature 
• ABPM ends AM predose (≤ 15 minutes) 
•  Supine-to-standing (orthostatic) pulse and BP  
- 
AM predose (≤ 15 minutes) and at 1 and 4 hours (± 5 minutes) postdose  
- 
PM predose (≤ 15 minutes)  
• Collection of blood samples for: 
- 
PK  
◦ 
AM predose (≤ 5 minutes) and at 1, 3, and 6 hours (± 5 minutes) postdose 
◦ 
PM predose (≤ 5 minutes)   
- 
Hemoglobin A1c AM predose (≤ 15 minutes) 
- 
Fasting plasma glucose AM predose (≤ 15 minutes) 
- 
Fasting plasma insulin AM predose (≤ 15 minutes) 
- 
Platelet function assessments AM predose (≤ 15 minutes) 
• Study drug administration AM and PM, 12 hours (± 30 minutes) apart 
• AE evaluation 
• Concomitant medication recording 
 
3.8.2.8 
Days 9 to 12  
• Respiratory rate and oral temperature 
• Supine pulse and BP AM predose (≤ 15 minutes)  
• Study drug administration AM and PM, 12 hours (± 30 minutes) apart 
• AE evaluation 
• Concomitant medication recording 
 

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3.8.2.9 
Day 13  
• Weight 
• If planned, EndoPAT assessment completed > 30 minutes before AM dose and before all oral 
and any antihypertensive concomitant medications; for each patient, assessments should be at 
time (±15 minutes) of EndoPAT on Day -1 
• Respiratory rate and oral temperature  
• Supine-to-standing (orthostatic) pulse and BP 
- 
AM predose (≤ 15 minutes) and at 1 and 4 hours (± 5 minutes) postdose  
- 
PM predose (≤ 15 minutes)  
• Study drug administration AM and PM, 12 hours (± 30 minutes) apart 
• AE evaluation 
• Concomitant medication recording 
 
3.8.2.10 
Day 14 
• Respiratory rate and oral temperature 
• Supine pulse and BP AM predose (≤ 15 minutes)  
• ABPM starts AM predose (≤ 15 minutes)  
• Collection of blood samples for: 
- 
PK  
◦ 
AM predose (≤ 5 minutes) and at 1, 3, and 6 hours (± 5 minutes) postdose 
◦ 
PM predose (≤ 5 minutes)  
- 
Hemoglobin A1c AM predose (≤ 15 minutes) 
- 
Platelet function assessments AM predose (≤ 15 minutes) 
• Study drug administration AM and PM, 12 hours (± 30 minutes) apart 
• AE evaluation 
• Concomitant medication recording 
 
3.8.2.11 
Discharge (Day 15) 
• Weight  

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• Respiratory rate and oral temperature  
• ABPM ends 12 hours (± 15 minutes) postdose 
• 12-lead ECG 
• Supine BP (average of 3 measurements) and pulse at 12 hours (± 15 minutes) postdose 
• Supine-to-standing (orthostatic) pulse and BP at 12 hours (± 15 minutes) postdose 
• Physical examination 
• Collection of blood at 12 hours (± 15 minutes) postdose: 
- 
PK 
- 
Clinical chemistry, hematology (CBC), coagulation 
- 
Hemoglobin A1c 
- 
Fasting plasma glucose  
- 
Fasting plasma insulin 
- 
  
• Collection of urine samples, first void 
- 
Urinalysis 
- 
Urine albumin and creatinine 
• AE evaluation 
• Concomitant medication recording 
• Discharge from the clinic 

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3.8.3 
Follow-up Period (Day 16 to Day 42 ±3) 
3.8.3.1 
Follow-up Visit (Day 21 ±2) 
• Weight  
• Respiratory rate and oral temperature  
• Supine BP and pulse   
• Collection of blood and urine samples for: 
- 
PK  
- 
Serum pregnancy test for all females  
- 
Drug screen 
- 
 
 
• Alcohol breathalyzer  
• AE evaluation 
• Concomitant medication recording 
 
3.8.3.2 
End of Trial Visit (Day 42 ± 3) 
• Weight  
• Respiratory rate and oral temperature  
• Supine BP and pulse 
• Physical exam 
• Collection of blood and urine samples for: 
- 
PK  
- 
Urine pregnancy test for all females  
- 
Clinical chemistry, hematology (CBC), coagulation 
- 
Urinalysis 
- 
Urine albumin and creatinine 
- 
Hemoglobin A1c 
- 
  
• AE evaluation 
• Concomitant medication recording 

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3.9 
STATISTICAL METH ODS 
Details regarding the statistical methods will be provided in the Statistical Analysis Plan (SAP), 
to be finalized before unblinding of the study. 
3.9.1 
Determination of Sample Size 
Twenty-six patients (at least 11 males and 11 females) will be randomized in a 5:5:3 ratio to 1 of 
2 IW-1973 treatment regimens or placebo. The sample size for this study was determined outside 
of statistical considerations.  
3.9.2 
Analysis Populations  
3.9.2.1 
 Safety Population 
The Safety Population will consist of all patients who receive at least 1 dose of study drug. 
3.9.2.2 
PK Population 
The PK Population will consist of all patients who receive at least 1 dose of study drug and have 
at least 1 postdose PK parameter assessment. 
3.9.2.3 
PD Population 
The PD population will consist of all patients who receive at least 1 dose of study drug and have 
at least 1 postdose PD parameter assessment. 
3.9.3 
Stati stical Methods 
3.9.3.1 
General Considerations 
Continuous variables will be summarized using the mean, standard deviation, minimum, median, 
interquartile range, and maximum. Categorical variables will be summarized using the frequency 
and percentage of patients in each category. Data summaries will be presented by treatment 
group. 
Inferential statistics, if calculated, will only be used for descriptive purposes. 

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3.9.3.2 
Patient Disposition, Demographics, and Baseline Characteristics 
The number and percentage of patients who were randomized, included in each of the 3 analysis 
populations (Safety, PK, and PD), completed the study or discontinued early, as well as the 
reasons for discontinuation will be presented by treatment group. 
Patient demographics (age, sex, race, ethnicity, weight, height, BMI), and other baseline 
characteristics will be summarized for the Safety Population by treatment group. 
3.9.3.3 
Pharmacodynamic Analyses 
3.9.3.3.1 
Hemodynamics 
Descriptive statistics will be presented for the following hemodynamic PD parameters by 
treatment group for each postdose assessment: 
• Change from baseline in supine and standing pulse, systolic BP, and diastolic BP 
measurements  
• Proportion of patients with postdose supine BP less than 130/80 mm Hg 
• Orthostatic change in pulse, systolic BP, and diastolic BP. An orthostatic measurement is 
obtained by subtracting the supine measurement from the standing measurement 
• Change from baseline in 24-hour, 4-hour, 30-minute, daytime, and nighttime averages of 
systolic BP, diastolic BP, mean arterial pressure and pulse measurements from ambulatory 
BP monitoring 
 
3.9.3.3.2 
Endothelial Function 
Endothelial function will be assessed using the RHI parameter. Descriptive statistics will be 
presented by treatment group for the change from baseline in RHI on Day 14. 
3.9.3.3.3 
Other PD Parameters 
Descriptive statistics will be presented for the following PD parameters by treatment group for 
each postdose assessment: 
• Proportion of patients with decreased platelet reactivity 
• Change from baseline in platelet function assessments 

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• Change from baseline in insulin resistance (HOMA-IR) 
3.9.3.4 
Safety Analyses 
3.9.3.4.1 
Adverse Events 
Adverse events will be coded using the latest version of Medical Dictionary for Regulatory 
Activities (MedDRA) available at the start of the study. Treatment-emergent adverse events 
(TEAEs) are those AEs that started or worsened in severity after the administration of study 
drug. All TEAEs as well as those that occurred during the first 7 days of treatment will be 
summarized by system organ class (SOC) and preferred term (PT) for each treatment group. In 
addition, listings of severe TEAEs, drug-related TEAEs, SAEs, AEs leading to study 
discontinuation, and AEs leading to death (if any) will be provided. 
3.9.3.4.2 
Vital signs, ECGs, and Clinical Laboratory Tests 
Vital signs, 12-lead ECGs, and clinical laboratory evaluations (including clinical chemistry, 
hematology, coagulation, urinalysis, and UACR) at each assessment timepoint and the change 
from study baseline at each postdose timepoint will be summarized by treatment group. 
3.9.3.4.3 
Estimated glomerular filtration rate (eGFR) 
The eGFR will be calculated according to the CKD-EPI creatinine equation (9); each assessment 
timepoint and the change from study baseline at each postdose timepoint will be summarized by 
treatment group. 

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3.9.3.5 
Pharmacokinetic Analyses 
Plasma concentration values of IW-1973 will be summarized for each assessment timepoint by 
treatment group. Mean plasma concentrations will be plotted over time for each active treatment 
group. 
If systemic levels of IW-1973 are detectable, the following PK parameters will be calculated, 
when appropriate: 
• AUClast:  Area under the plasma concentration time curve from time zero to Tlast, the time at 
which the last measurable plasma concentration (Clast) is observed 
• AUCtau:  Area under the plasma concentration time curve during a dosing interval (tau) 
• AUCinf:  Area under the plasma concentration time curve extrapolated to infinity 
• Cmax:  Maximum observed plasma concentration, occurring at Tmax 
• Ctrough:  Trough plasma concentration observed at the end of a dosing interval (collected 
before the next administration) 
• CL/F:  Apparent total body clearance after oral administration  
• t1/2:  Apparent terminal phase half-life 
• Tmax:  Time of maximum observed plasma concentration 
• Vz/F:  Apparent volume of distribution during the terminal phase after oral administration 
 
3.9.3.6 
Interim Analysis 
There are no interim analyses planned for this study. 
3.9.3.7 
Computer Methods 
Statistical analyses will be performed using Statistical Analysis System (SAS®), version 9.3 (or 
newer). 
3.10 
CHANGES IN THE CONDUCT OF THE STUDY OR PLANNED 
ANALYSES 
Any amendment to this protocol will be provided to the Investigator in writing by Ironwood or 
its designee. Prior to implementation, any protocol amendment regarding reportable deviations 
(as defined by the IRB) must be approved by the IRB and the signature page must be signed by 

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the Investigator and received by Ironwood or its designee, with the following exception: If the 
protocol is amended to eliminate or reduce the risk to patients, the amendment may be 
implemented before IRB review and approval. However, the IRB must be informed in writing of 
such an amendment, and approval must be obtained within reasonable time limits. 
Deviating from the protocol is permitted only if absolutely necessary for the safety of the 
patients and must immediately be reported to Ironwood or its designee. 

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4. 
ETHICAL CONSIDERATIONS 
4.1 
 INSTITUTIONAL REVIEW BOARD 
Prior to the study onset, the protocol, any protocol amendments, ICFs, advertisements to be used 
for patient recruitment, and any other written information regarding this study to be provided to a 
patient or patient’s legal guardian must be approved by the IRB. 
All IRB approvals must be dated and signed by the IRB Chairman or his or her designee and 
must identify the IRB by name and address, the clinical protocol by title and/or protocol number, 
and the date upon which approval or favorable opinion was granted for the clinical research. 
Copies of IRB approvals should be forwarded to Ironwood. All correspondence with the IRB 
should be maintained in the Investigator File. 
No drug will be released to the site(s) to dose a patient until written IRB approval has been 
received by Ironwood. 
The Investigator is responsible for obtaining continuing review of the clinical research at least 
annually or more often if specified by the IRB. The Investigator must supply Ironwood with 
written documentation of the approval of the continued clinical research. 
The IRB must be constituted in accordance with Federal and International Conference on 
Harmonization (ICH) Good Clinical Practice (GCP) guidelines and any relevant and applicable 
local regulations. 
Major changes in this research activity, except those to remove an apparent immediate hazard to 
the patient, must be reviewed and approved by Ironwood and by the IRB that approved the study. 
Amendments to the protocol must be submitted in writing to the Investigator’s IRB for approval 
prior to patients being enrolled into the amended protocol. 
4.2 
PATIENT INFORMATION AND INFORMED CONSENT 
Informed consent procedures will comply with the Code of Federal Regulations (CFR) 21, 
Parts 50 and 312. 

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The written ICF must be approved by the IRB for the purposes of obtaining and documenting 
consent. 
Before entry into the study, each patient will be provided with a written explanation of the study. 
It is the responsibility of the Investigator or appropriately trained health professional to give each 
patient full and adequate information regarding the objectives and procedures of the study and 
the possible risks involved. Patients will then be given the opportunity to ask questions and the 
Investigator will be available to answer questions as needed. Patients will be informed of their 
right to withdraw from the study at any time without prejudice. After this explanation and before 
entering the study, the patient will voluntarily sign an ICF. The patient should receive a copy of 
the signed and dated ICF. The Investigator must retain each patient’s original signed ICF. 
If new information becomes available that may be relevant to the patient’s consent and 
willingness to participate in the study, the ICF will be revised. The revised ICF must be 
submitted to the IRB for review and approval prior to its use. 

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5. 
INVESTIGATORS AND STUDY ADMINISTRATIVE 
STRUCTURE 
This study will be performed at up to 3 study centers in the US. The Investigator at each study 
center will be responsible for ensuring that the study is conducted according to the signed 
Clinical Trial Agreement, the protocol, IRB requirements, and ICH GCP guidelines. 
The Investigator will be responsible for the oversight of the site’s conduct of the study, which 
will consist of completing all protocol assessments, maintaining the study file and the patient 
records, drug accountability, corresponding with the IRB, and completing the eCRF. 
5.1 
GENERATION OF STUDY RECORDS 
Ironwood or its designated representative will conduct a study center visit to verify the 
qualifications of each Investigator, inspect study center facilities, and inform the Investigator of 
responsibilities and procedures for ensuring adequate and correct study documentation. 
The Investigator is required to prepare and maintain adequate and accurate case histories 
designed to record all observations and other data pertinent to the study for each study patient. 
All information recorded in the eCRFs for this study must be consistent with the patient’s source 
documentation. 
During the course of the study, the Clinical Site Monitor will make study center visits to review 
protocol compliance, compare eCRFs and individual patient’s medical records, assess drug 
accountability (in a blinded manner), and ensure that the study is being conducted according to 
pertinent regulatory requirements. All eCRFs will be verified with source documentation. The 
review of medical records will be performed in a manner that ensures patient confidentiality is 
maintained. 
The Clinical Site Monitor will discuss instances of missing or uninterpretable data with the 
Investigator for resolution. Any changes to the study data will be made to the eCRF and 
documented via an electronic audit trail associated with the affected eCRF. 

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5.2 
DATA QUALITY ASSURANCE 
Ironwood performs quality control and assurance checks on all of its clinical studies. Section 5.4 
provides details regarding study monitoring procedures. 
The study may be subject to audit by Ironwood, its representatives, or regulatory authorities. In 
the event of an audit, the Investigator must agree to allow Ironwood, representatives of 
Ironwood, or the FDA or other regulatory agencies access to all study records. 
5.3 
ELEC TRONIC CASE REPORT FORMS AND DATA MANAGEMENT 
All data relating to the study will be recorded in the patient’s source documentation and eCRF to 
be provided by Ironwood or designee via the electronic data capture (EDC) system. Source 
documentation supporting the eCRF data should indicate the patient’s participation in the study 
and should document the dates and details of study procedures, AEs, all observations, and patient 
status. The Investigator is responsible for verifying that all data entries on the eCRFs are accurate 
and correct and ensuring that all data are entered in a timely manner, as soon as possible after the 
information is collected. An explanation should be provided for any missing data. The 
Investigator must provide through the EDC system his or her formal approval of all the 
information in the eCRFs and changes to the eCRFs to endorse the final submitted data for each 
patient. 
Ironwood will retain the final eCRF data and corresponding audit trails. A copy of the final 
archival eCRF in the form of a compact disc or other electronic media will be placed in the 
Investigator’s study file. 
A record of screen failures and pretreatment failures will be maintained for patients who do not 
qualify for enrollment, including the reason for the failure. 
5.4 
STUDY MONITORING 
Ironwood performs quality control and assurance checks on all of its clinical studies. Before any 
patients are enrolled in the study, a representative of Ironwood or its authorized designee will 
meet with the Investigator and his/her staff to review relevant and important study-related 
information including, but not limited to, the protocol, the Investigator’s Brochure, the eCRFs 

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and instructions for their completion using the EDC system, the procedure for obtaining 
informed consent, and the procedure for reporting AEs and SAEs. 
An Ironwood representative, the Clinical Site Monitor, will monitor the progress and conduct of 
the study by periodically conducting monitoring visits and by frequent communications 
(telephone, e-mail, letter, and fax) with the study centers. The site monitor will ensure that the 
study is conducted according to the protocol and regulatory requirements. During monitoring 
visits, the information recorded on the eCRFs will be verified against source documents. Upon 
request of the monitor, auditor, IRB, or regulatory authority, the Investigator should make all 
requested study-related records available for direct access. 
All aspects of the study will be carefully monitored by Ironwood or its designee for compliance 
with applicable government regulations with respect to GCP and current standard operating 
procedures. 

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6. 
STUDY SPONSORSHIP 
6.1 
INVESTIGATOR AND STUDY TER MINATION 
Ironwood may terminate Investigator participation at any institution for any reason. If 
participation is ended at the site by either Ironwood or the Investigator, the Investigator must 
• Return all study medications and any study materials to Ironwood 
• In cases where the Investigator opts to self-terminate, provide a written statement describing 
why the study was terminated prematurely 
 
Ironwood may terminate the study in its entirety or at a specific center at any time for any 
reason, including but not limited to the following: 
• Failure to enroll patients 
• Protocol violations 
• Inaccurate or incomplete data 
• Unsafe or unethical practice 
• Questionable safety of the study medication 
• Administrative decision 
 
6.2 
REPORTING AND PUBLICATION 
All data generated in this study will be the property of Ironwood. An integrated clinical and 
statistical report will be prepared at the completion of the study. 
Publication of the results by the Investigator will be subject to mutual agreement between the 
Investigator and Ironwood. 

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Clinical Trial Protocol: C1973-202-P-03 
 
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7. 
INVESTIGATOR OBLIGATIONS 
7.1 
DOCUMENTATION 
The Investigator must provide the Sponsor with the following documents BEFORE the 
enrollment of any subjects, in accordance with ICH E6 (Note: Ironwood must be notified if there 
are any changes to these documents): 
1. Completed and signed Form FDA 1572 (Statement of Investigator) including all sub-
investigators involved in the study 
2. Financial disclosure form(s) for the Investigator and all sub-investigators listed on Form 
FDA 1572 
3. Current, signed curricula vitae of the Investigator and all sub-investigators 
4. Copy of current medical license of the Investigator and all sub-investigators (as applicable) 
5. Copy of the IRB approval letter for the protocol and ICF 
6. Copy of the IRB-approved ICF to be used 
7. Copy of the IRB approval of recruitment advertising (if applicable) 
8. A list of IRB members and their qualifications, and a description of the committee’s working 
procedures 
9. Protocol Approval Page signed by the Investigator 
10. Fully executed Clinical Trial Agreement 
11. Written document containing the name, location, certification number, and date of 
certification of the local laboratory to be used for laboratory assays and those of other 
facilities conducting tests 
12. List of normal laboratory values and units of measurements for all laboratory tests required 
by the protocol. This list is required for each local laboratory to be used during the study. 
 
During the study, the Investigator must maintain the following essential/administrative 
documents related to the study: 
1. Copy of the signed Protocol Signature Page 
2. Copy of financial disclosure form(s) for the Investigator and all sub-investigators (as 
applicable) if updated 
3. Curricula vitae of any new Investigator(s) and/or sub-investigators involved in the study 
4. Copy of current medical license of the Investigator and all sub-investigators (as applicable) if 
updated 

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Clinical Trial Protocol: C1973-202-P-03 
 
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5. Copy of the signed Form FDA 1572 
6. IRB Approval Notification for the following: 
a. Protocol 
b. Informed consent document 
c. Recruitment advertising (if applicable) 
d. Amendment(s) (if applicable) 
e. Annual review of the protocol and the informed consent document 
f. SAEs 
g. Study closure 
7. SAE Reports 
8. Drug Inventory Forms (drug receipts, drug dispensing, and inventory forms) 
9. Name and address of local or central laboratory, list of normal laboratory values and units of 
measurement, as well as laboratory certification or hospital accreditation 
10. Updates of medical/laboratory/technical procedures/tests: 
a. Normal value(s)/ranges(s) 
b. Certification 
c. Accreditation 
d. Established quality control and/or external quality assessment 
e. Other validation (where required) 
11. Record of retained body fluids/tissue samples (if any) 
12. Correspondence with Sponsor 
13. Written assurance of continuing approval (at least annually) as well as a copy of the annual 
progress report submitted to the IRB must also be provided to the Sponsor. Any changes in 
this study or unanticipated problems involving risks to the patients must be reported 
promptly to the IRB. An Investigator must not make any changes in a study without IRB and 
Sponsor approval, except when necessary to eliminate apparent immediate hazards to the 
subjects. All protocol amendments must be submitted to the IRB and approved. 
14. Responsibility Log 
15. Other logs (eg, screening, enrollment) 
16. Signed ICFs 
17. Patient source documentation 
18. eCRFs 
19. Audit certificate(s), if applicable 
 

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Clinical Trial Protocol: C1973-202-P-03 
 
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7.2 
PERFORMANCE 
The Investigator must demonstrate reasonable efforts to obtain qualified patients for the study. 
The Sponsor may terminate the study with any Investigator for any reason, including, but not 
limited to, Investigator nonperformance or Investigator noncompliance. 
7.3 
ACCOUNTABILITY 
Ironwood requires accountability of all study drug received and administered by the Study 
Center. Required records of drug disposition are to include logs or dispensing-records capturing, 
but not limited to, the date study drug was received, date(s) individual dosing units were 
prepared and labeled, date administered, quantity administered, and the subject to whom study 
drug was administered. At the end of the study, a complete reconciliation of the study drug 
supplies will be performed. All unused and reconciled drug supplies will be destroyed according 
to standard institutional policy or per written instruction from Ironwood should an alternate 
disposition be requested. No study drug is to be destroyed without prior written permission of 
Ironwood. A copy of the Certificate of Destruction or equivalent shall be provided to Ironwood 
once available. 
7.4 
RETEN TION AND REVIEW OF RECORDS 
Records and documents pertaining to the conduct of this study, including eCRFs, source 
documents, ICFs, laboratory test results, and medication inventory records, must be retained by 
the Investigator in accordance with locally applicable regulatory requirements; and, in any event, 
for a minimum period of 5 years.  
No study records shall be destroyed without notifying Sponsor and giving Sponsor the 
opportunity to take such study records or authorizing in writing the destruction of records after 
the required retention period. 
If the Investigator retires, relocates, or otherwise withdraws from the responsibility of keeping 
the study records, custody must be transferred to another person (Ironwood, IRB, or other 
Investigator) who will accept the responsibility. Ironwood must be notified of and agree to the 
change. 

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7.5 
PATIENT CONFIDENTIALITY 
All data collected in the context of this study will be stored and evaluated in such a way as to 
guarantee patient confidentiality in accordance with the legal stipulations applying to 
confidentiality of data. All patient records will be identified only by initials and patient 
identification (PID) number. Patient names are not to be transmitted to Ironwood or its 
authorized designee. The Investigator will keep a Master Patient List on which the PID number 
and the full name, address, and telephone number of each patient is listed. 

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8. 
REFERENCE LIST 
1. Vanhoutte PM, Vanhoutte PM, Shimokawa H, Feletou M, Tang EH, Shimokawa H, et al. 
Endothelial Dysfunction and Vascular Disease - A Thirthieth Anniversary Update. Acta 
Physiologica 2015;n/a. 
2. Corson MA, James NL, Latta SE, Nerem RM, Berk BC, Harrison DG. Phosphorylation of 
endothelial nitric oxide synthase in response to fluid shear stress. Circulation research 
1996;79(5):984-91. 
3. Stasch JP, Pacher P, Evgenov OV. Soluble guanylate cyclase as an emerging therapeutic 
target in cardiopulmonary disease. Circulation 2011;123:2263-73. 
4. Nossaman BD, Kadowitz PJ. Stimulators of soluble guanylyl cyclase: future clinical 
indications. The Ochsner journal 2013;13:147-56. 
5. Centers for Disease Control and Prevention. National Diabetes Statistics Report: Estimates of 
Diabetes and Its Burden in the United States, 2014. Atlanta, GA: US Department of Health 
and Human Services; 2014.  
6. Iglay K, Hannachi H, Joseph HP, Xu J, Li X, Engel SS, et al. Prevalence and co-prevalence 
of comorbidities among patients with type 2 diabetes mellitus. Current medical research and 
opinion 2016;32(7):1243-52. 
7. Arauz-Pacheco C, Parrott MA, Raskin P. Hypertension management in adults with diabetes. 
Diabetes care 2004;27 Suppl 1:S65-S67. 
8. Rahman S, Rahman T, Ismail AA, Rashid AR. Diabetes-associated macrovasculopathy: 
pathophysiology and pathogenesis. Diabetes, obesity & metabolism 2007;9(6):767-80. 
9. Levey AS, Stevens LA, Schmid CH, Zhang YL, Castro AF, Feldman HI, et al. A new 
equation to estimate glomerular filtration rate. Annals of internal medicine 2009;150(9):604-
12. 
10. Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF, Turner RC. Homeostasis 
model assessment: insulin resistance and beta-cell function from fasting plasma glucose and 
insulin concentrations in man. Diabetologia 1985;28(7):412-9. 
11. Wallace TM, Levy JC, Matthews DR. Use and abuse of HOMA modeling. Diabetes care 
2004;27(6):1487-95. 
 
 
 

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Clinical Trial Protocol: C1973-202-P-03 
 
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9. 
SPONSOR SIGNATURE 
Study Title: 
A Phase 2 Study to Compare the Safety, Tolerability, 
Pharmacokinetics, and Pharmacodynamics of 2 Dose Regimens of 
IW-1973 in Patients with Stable Type 2 Diabetes and Hypertension 
Study Number: 
C1973-202 
Final Date: 
16 March 2017 
 
This clinical study protocol was subject to critical review and has been approved by the sponsor.  
 
Signed: 
 
 
Date:  
 
 
 
 
Ironwood Pharmaceuticals, Inc. 
 
 
Print Name: 
 
 
 
 

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Clinical Trial Protocol: C1973-202-P-03 
 
16 March 2017 
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10. 
INVESTIGATOR’S SIGNATURE 
Study Title: 
A Phase 2 Study to Compare the Safety, Tolerability, 
Pharmacokinetics, and Pharmacodynamics of 2 Dose Regimens of 
IW-1973 in Patients with Stable Type 2 Diabetes and Hypertension 
Study Number: 
C1973-202 
Final Date: 
16 March 2017 
 
I have read the protocol described above. I agree to comply with all applicable regulations and to 
conduct the study as described in the protocol.  
 
Signed: 
 
 
Date:  
 
 
 
 
Print Name: