A serious adverse event was defined as any adverse event (AE) that resulted in any of the following outcomes: death, life-threatening AE, hospitalization or prolongation of existing hospitalization, a persistent or significant disability/incapacity, or a congenital anomaly/birth defect. Important medical events that may not result in death, be life threatening, or require hospitalization were considered an SAE when, based upon appropriate medical judgment, they jeopardized the patient or required medical or surgical intervention to prevent one of the outcomes listed above.

Adverse drug reactions (ADRs) were defined as adverse events that were considered by the investigator to be definitely, probably, or possibly related to study drug. Serious ADRs were defined as serious AEs considered by the investigator to be definitely, probably, or possibly related to study drug.

Safety population

Participants monitored their bowel movements and completed a daily bowel habits diary the week prior to study visits (i.e. during Weeks 11, 23, 35, and 51).

The intent-to-treat population includes all randomized participants. Five participants were excluded due to double enrollment at different sites.

Participants who were taking stable routine/regular laxatives at Screening were to continue taking the same regimen throughout the study.

The percentage of participants meeting each of the criteria below are reported:

1. Participants not on stable laxatives, defined as participants who did not use laxatives from 28 days prior to the Screening Period to the final dose of study drug or who received only rescue laxative. Rescue is defined as any laxative taken for the first time during the Treatment Period.

1a. Out of participants who were not on stable laxatives, participants who received rescue laxatives.

2. Participants on stable laxatives, defined as participants who may have had at least one/any stable laxative use reported from 28 days prior to Screening Period to the final dose of study drug.

2a. Out of participants who were on stable laxatives, participants who received rescue laxatives.

3. Participants who did not meet criteria 1 or 2.

Intent-to-treat population

The Patient Assessment of Constipation Symptom Questionnaire (PAC-SYM) asked participants to rate the severity of 12 constipation symptoms in the last 2 weeks on a scale from 0 (absent) to 4 (very severe). The overall score was calculated as the mean of all 12 items and ranges from 0 (best) to 4 (worst). A negative change from baseline value indicates improvement.

The intent-to-treat population includes all randomized participants. Five participants were excluded due to double enrollment at different sites.

The Patient Assessment of Constipation Symptom Questionnaire (PAC-SYM) asked participants to rate the severity of 12 constipation symptoms in the last 2 weeks on a scale from 0 (absent) to 4 (very severe). The abdominal-symptom domain score was calculated as the mean of the following 4 items: abdominal discomfort, abdominal pain, abdominal bloating and stomach cramps.

A negative change from baseline value indicates improvement in symptoms.

Intent-to-treat population

The Patient Assessment of Constipation Symptom Questionnaire (PAC-SYM) asked participants to rate the severity of 12 constipation symptoms in the last 2 weeks on a scale from 0 (absent) to 4 (very severe). The abdominal-symptom domain score was calculated as the mean of the following 3 items: painful bowel movements, rectal burning during or after a bowel movement, and rectal bleeding or tearing during or after a bowel movement. A negative change from baseline value indicates improvement in symptoms.

Intent-to-treat population

The Patient Assessment of Constipation Symptom Questionnaire (PAC-SYM) asked participants to rate the severity of 12 constipation symptoms in the last 2 weeks on a scale from 0 (absent) to 4 (very severe). The stool-symptom domain score was calculated as the mean of the following 5 items: incomplete bowel movements, bowel movements that were too hard, bowel movements that were too small, straining or squeezing to try to pass bowel movements, and false-alarm bowel movements.

A negative change from baseline value indicates improvement in symptoms.

Intent-to-treat population

The Patient Assessment of Constipation Quality of Life Questionnaire (PAC-QOL) consists of 28 questions designed to measure the impact constipation has had on participants' daily life during the past 2 weeks.

Each question was evaluated by the participant on a five-point scale ranging from 0 (not at all or none of the time) to 4 (extremely or all of the time), where higher scores represent poorer quality of life. The overall score was calculated as the mean of all 28 item scores. A negative change from baseline value indicates improvement.

Intent-to-treat

The Patient Assessment of Constipation Quality of Life Questionnaire (PAC-QOL) consists of 28 questions designed to measure the impact constipation has had on participants' daily life during the past 2 weeks.

Each question was evaluated by the participant on a five-point scale ranging from 0 (not at all or none of the time) to 4 (extremely or all of the time), where higher scores represent poorer quality of life. The physical discomfort domain consists of 4 questions related to bloating, feeling heavy, how much of the time participants felt any physical discomfort and how much time they felt the need to open their bowel but were not able to. The physical discomfort score was calculated as the mean of the 4 individual scores. A negative change from baseline value indicates improvement.

Intent-to-treat population

The Patient Assessment of Constipation Quality of Life Questionnaire (PAC-QOL) consists of 28 questions designed to measure the impact constipation has had on participants' daily life during the past 2 weeks.

Each question was evaluated by the participant on a five-point scale ranging from 0 (not at all or none of the time) to 4 (extremely or all of the time), where higher scores represent poorer quality of life. The psychosocial discomfort domain consists of 8 questions related to participants' embarrassment regarding their constipation and effects of constipation on eating habits and appetite.

The psychosocial discomfort score was calculated as the mean of the 8 individual scores. A negative change from baseline value indicates improvement.

Intent-to-treat population

The Patient Assessment of Constipation Quality of Life Questionnaire (PAC-QOL) consists of 28 questions designed to measure the impact constipation has had on participants' daily life during the past 2 weeks.

Each question was evaluated by the participant on a five-point scale ranging from 0 (not at all or none of the time) to 4 (extremely or all of the time), where higher scores represent poorer quality of life. The worries and concerns domain consists of 11 questions related to participants' feelings and concerns about their constipation. The worries and concerns domain score was calculated as the mean of the 11 individual scores. A negative change from baseline value indicates improvement.

Intent-to-treat population

The Patient Assessment of Constipation Quality of Life Questionnaire (PAC-QOL) consists of 28 questions designed to measure the impact constipation has had on participants' daily life during the past 2 weeks.

Each question was evaluated by the participant on a five-point scale ranging from 0 (not at all or none of the time) to 4 (extremely or all of the time), where higher scores represent poorer quality of life. The satisfaction domain consists of 5 questions related to participants' feelings of satisfaction with their bowel function. The satisfaction domain score was calculated as the mean of the 5 individual scores. A negative change from baseline value indicates improvement.

Intent-to-treat population

Participants were asked to rate their degree of satisfaction of constipation and abdominal symptoms from the start of study drug dosing to Week 52 (or early termination).

Satisfaction was rated based on the following seven grades:

• Grade 1 = markedly worsened
• Grade 2 = moderately worsened
• Grade 3 = slightly worsened
• Grade 4 = unchanged
• Grade 5 = slightly improved
• Grade 6 = moderately improved
• Grade 7 = markedly improved

Intent-to-treat population