A Safety and Efficacy Study of a Range of Linaclotide Doses Administered Orally to Children Ages 7-17 Years, With Irritable Bowel Syndrome With Constipation

Change From Baseline in 4-week Overall Spontaneous Bowel Movement (SBM) Frequency Rate (SBMs/Week) During the Treatment Period

Time frame · Baseline (14 days prior to randomization and up to randomization) to week 4

SBM was defined as a BM that occurred in the absence of laxative, suppository, or enema use on the calendar day of the BM or the calendar day before the BM. SBM rate was defined as SBMs/week during the 4-week Treatment period. Participants recorded the occurrence of BMs and use of rescue medication, morning and evening, daily in an eDiary since pretreatment period. The SBM frequency rate (SBMs/week) during the analysis period for each participant were calculated as \[(total number of SBMs in the analysis period/number of days in the analysis period)\*7\]. Baseline value was based on values collected 14 days before randomization up to randomization. Change from Baseline was calculated as the SBM frequency rate during the 4-week treatment period - SBM frequency rate at baseline. A positive change from Baseline indicates improvement.

Change From Baseline in 4-week Abdominal Pain Daytime Symptoms Based on Evening Assessment of Abdominal Pain Symptoms

Time frame · Baseline (14 days prior to randomization) to week 4

The abdominal pain score was measured using 5-point scale. Participants answered the questions, How much did your tummy hurt as: 0=none, 1=a tiny bit, 2=a little, 3=some, and 4=a lot. The 4-week daytime abdominal pain was calculated as the average of nonmissing scores in evening eDiary during the Treatment Period with higher value indicating greater symptom severity. Baseline value was the average of non-missing values collected 14 days before randomization. Change from Baseline was calculated as the daytime abdominal pain score during the 4-week treatment period (i.e. average of non-missing daytime scores during 4-week treatment period) - daytime abdominal pain score at baseline. A negative change from Baseline indicates improvement.

Change From Baseline in 4-week Stool Consistency

Time frame · Baseline (14 days prior to randomization and up to randomization) to week 4

Participants used 7-point pediatric Bristol Stool Form (p-BSFS) scale to rate stool consistency for each BM in morning and evening eDiary where 1=small hard lumps or balls like pebbles,2=fat sausage shape but lumpy and hard,3=a sausage but with cracks on it,4=sausage or snake, smooth and soft,5=chicken nuggets, soft smooth blobs,6=oatmeal, fluffy mushy pieces,7=milkshake, watery. Scores in 4-week treatment period were calculated as mean of participants non-missing, SBM associated p-BSFS scores during 4-week treatment period. Baseline value was based on values collected 14 days before randomization up to randomization.

Change From Baseline in 4-week Severity of Straining

Time frame · Baseline (14 days prior to randomization and up to randomization) to week 4

Severity of straining was scored on 5-point scale for question-When you pooped, how hard did you push? The score ranges from 0= not hard at all,1= I pushed a tiny bit hard,2= I pushed a little hard,3= I pushed hard,4= I pushed very hard with higher scores indicating more severe straining. Participants recorded degree of straining for each BM in morning and evening eDiary. Scores during 4-week treatment period were calculated as mean of participant's non-missing, SBM associated straining scores during 4-week treatment period.

Change From Baseline in 4-week Abdominal Bloating Daytime Symptoms Based on Evening Assessment

Time frame · Baseline (14 days prior to randomization) to week 4

Participants recorded their assessment of abdominal bloating in the evening eDiary. Participants answered the question: How big and full did your tummy feel? on a scale, where: 0=none, 1=a tiny bit, 2=a little, 3=medium or 4=very, with a higher score indicating more severe bloating. Baseline value was the average of values collected 14 days before randomization. The 4-week daytime abdominal bloating symptoms were calculated as the average of non-missing scores reported in the evening eDiary during the treatment period. Change from Baseline was calculated as the 4-week daytime abdominal bloating score during the treatment period - daytime abdominal bloating score at baseline. A negative change from Baseline indicates improvement.

Change From Baseline in 4-week Overall Complete Spontaneous Bowel Movement (CSBM) Frequency Rate (CSBMs Per Week)

Time frame · Baseline (14 days prior to randomization and up to randomization) to week 4

SBM was defined as a BM that occurred in the absence of laxative, suppository, or enema use on the calendar day of the BM or the calendar day before the BM. A CSBM was an SBM that was associated with a sense of complete evacuation. Participants recorded their assessment of the sensation of incomplete evacuation for each BM in the morning and evening eDiary. The 4-week overall CSBM frequency rate was calculated as \[total number of CSBMs in the analysis period/number of days in the analysis period\]\*7). Baseline value was based on values collected 14 days before randomization and up to randomization. Change from Baseline was calculated as the CSBM frequency rate during the 4-week treatment period - CSBM frequency rate at baseline. A positive change from Baseline indicates improvement.