18 and older, any sex, with Irritable Bowel Syndrome With Constipation. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Change From Baseline in Weekly Abdominal Pain Score Over the 12-Week Treatment Period: DR1 or IR vs. PlaceboPrimary· Baseline, up to Week 12
Abdominal pain assessment was based on an 11-point numerical rating scale (0=No symptom; 10=Worst possible) assessing the symptom "at its worst in past 24 hours." A participant's weekly abdominal pain score is the average of the nonmissing abdominal pain scores reported by the participant during each week.
Group
Value
95% CI
Placebo
-1.370
± 0.241
Linaclotide IR 290 μg
-1.938
± 0.241
Linaclotide DR1 30 μg
-1.667
± 0.234
Linaclotide DR1 100 μg
-1.656
± 0.240
Linaclotide DR1 300 μg
-2.140
± 0.236
Change From Baseline in Weekly Abdominal Pain Score Over the 12-Week Treatment Period: DR2 or IR vs. PlaceboPrimary· Baseline, up to Week 12
Abdominal pain assessment was based on an 11-point numerical rating scale (0=No symptom; 10=Worst possible) assessing the symptom "at its worst in past 24 hours." A participant's weekly abdominal pain score is the average of the nonmissing abdominal pain scores reported by the participant during each week.
Group
Value
95% CI
Placebo
-1.370
± 0.241
Linaclotide IR 290 μg
-1.938
± 0.241
Linaclotide DR2 30 μg
-1.825
± 0.238
Linaclotide DR2 100 μg
-1.669
± 0.235
Linaclotide DR2 300 μg
-1.628
± 0.239
Change From Baseline in Weekly CSBM Frequency Rate Over the 12-Week Treatment Period: DR1 or IR vs. PlaceboPrimary· Baseline, up to Week 12
A participant's weekly CSBM frequency rate is the CSBM rate (CSBMs/week) calculated over that week.
Group
Value
95% CI
Placebo
1.115
± 0.285
Linaclotide IR 290 μg
2.107
± 0.286
Linaclotide DR1 30 μg
1.163
± 0.278
Linaclotide DR1 100 μg
1.414
± 0.283
Linaclotide DR1 300 μg
1.776
± 0.279
Change From Baseline in Weekly CSBM Frequency Rate Over the 12-Week Treatment Period: DR2 or IR vs. PlaceboPrimary· Baseline, up to Week 12
A participant's weekly CSBM frequency rate is the CSBM rate (CSBMs/week) calculated over that week.
Group
Value
95% CI
Placebo
1.115
± 0.285
Linaclotide IR 290 μg
2.107
± 0.286
Linaclotide DR2 30 μg
1.275
± 0.282
Linaclotide DR2 100 μg
1.019
± 0.278
Linaclotide DR2 300 μg
0.869
± 0.282
Number of 6/12 Week Abdominal Pain and Constipation (APC) +1 Responders Over the 12-Week Treatment Period: DR1 or IR vs. PlaceboPrimary· up to Week 12
A 6/12 Week APC +1 Responder is a participant who meets the Weekly APC +1 Responder criteria for at least 6 out of the 12 weeks of the Treatment Period.
* Weekly APC +1 Responder: A participant who meets the criteria to be a Weekly Abdominal Pain Responder and a Weekly CSBM +1 Responder.
* Weekly Abdominal Pain Responder: A participant who has a decrease from baseline of ≥30% in the mean daily worst abdominal pain scores for that week.
* Weekly CSBM +1 Responder: A participant who has an increase from baseline of ≥1 in the CSBM weekly rate for that week.
A participant with \<4 days of comple
Responder
Group
Value
95% CI
Placebo
14
Linaclotide IR 290 μg
21
Linaclotide DR1 30 μg
18
Linaclotide DR1 100 μg
17
Linaclotide DR1 300 μg
26
Non-Responder
Group
Value
95% CI
Placebo
52
Linaclotide IR 290 μg
45
Linaclotide DR1 30 μg
49
Linaclotide DR1 100 μg
50
Linaclotide DR1 300 μg
41
Number of 6/12 Week Abdominal Pain and Constipation (APC) +1 Responders Over the 12-Week Treatment Period: DR2 or IR vs. PlaceboPrimary· up to Week 12
A 6/12 Week APC +1 Responder is a participant who meets the Weekly APC +1 Responder criteria for at least 6 out of the 12 weeks of the Treatment Period.
* Weekly APC +1 Responder: A participant who meets the criteria to be a Weekly Abdominal Pain Responder and a Weekly CSBM +1 Responder.
* Weekly Abdominal Pain Responder: A participant who has a decrease from baseline of ≥30% in the mean daily worst abdominal pain scores for that week.
* Weekly CSBM +1 Responder: A participant who has an increase from baseline of ≥1 in the CSBM weekly rate for that week.
A participant with \<4 days of comple
Responder
Group
Value
95% CI
Placebo
14
Linaclotide IR 290 μg
21
Linaclotide DR2 30 μg
16
Linaclotide DR2 100 μg
16
Linaclotide DR2 300 μg
14
Non-Responder
Group
Value
95% CI
Placebo
52
Linaclotide IR 290 μg
45
Linaclotide DR2 30 μg
51
Linaclotide DR2 100 μg
50
Linaclotide DR2 300 μg
52
Adverse events — posted to ClinicalTrials.gov
Time frame: From the first dose of study drug through Week 12/End-of-Treatment Period Visit (Day 85+3).
Reporting threshold: 5%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
The objectives of this study are to evaluate the safety, efficacy, and dose response of two delayed release formulations of linaclotide (DR; DR formulation 1 is DR1; DR formulation 2 is DR2) administered orally to patients with irritable bowel syndrome with constipation (IBS-C). Additional objectives include understanding how the two DR formulations compare with each other and with the FDA-approved 290 μg LINZESS® (the immediate release \[IR\] formulation of linaclotide).
Publications & conference data
3 peer-reviewed publications reference this trial (live from Europe PMC):
NCT05760313 — A Study to Assess Adverse Events and Change in Disease Activity in Pediatric Participants (Age 6 Months to <2 Years) Wit
· Phase 2
· completed
NCT05652205 — A Study to Assess Adverse Events and Change in Symptoms With Linaclotide Versus Placebo in Pediatric Subjects, Ages 2 to
· Phase 3
· completed
NCT05107219 — GCC Agonist Signal in the Small Intestine
· Phase 1
· completed
NCT05137145 — Effect and Safety of Polyethylene Glycol Combined With Linaclotide on Colon Cleansing for Patients With Chronic Constipa
· NA
· unknown
NCT04804267 — Evaluation of Clinical Equivalence Between Two Linaclotide Products in the Treatment of Chronic Idiopathic Constipation
· Phase 3
· unknown
Other recruiting trials for Irritable Bowel Syndrome With Constipation
Currently open trials in the same condition.
NCT06219707 — Electro-acupuncture for Irritable Bowel Syndrome With Constipation
· NA
· recruiting
Other Ironwood Pharmaceuticals, Inc. trials
Trials by the same sponsor.
NCT05740007 — A Phase 2 Study of IW-3300 for the Treatment of Bladder Pain in Subjects With Interstitial Cystitis/Bladder Pain Syndrom
· Phase 2
· terminated
NCT05362695 — A Study of Multiple-ascending Doses of IW-3300 in Healthy Subjects
· Phase 1
· completed
NCT05188261 — A Study of Single Ascending Doses of IW-3300 in Healthy Volunteers
· Phase 1
· completed
NCT03931785 — A Study of MD-7246 to Treat Abdominal Pain in Patients With Diarrhea-predominant Irritable Bowel Syndrome
· Phase 2
· completed
NCT03856970 — Study to Evaluate the Effect of IW-3718 on the Pharmacokinetics of Oral Contraceptive, Levothyroxine, Glyburide, and Dig
· Phase 1
· completed
Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Ironwood Pharmaceuticals, Inc.
Last refreshed: 24 April 2020
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT02559206.