Safety Study of CB-5945 for the Treatment of Opioid-Induced Constipation

This is a multicenter, double-blind, placebo-controlled, parallel-group study in
participants with OIC taking opioid therapy for chronic non-cancer pain. Approximately 1,400
participants (approximately 700 participants per treatment group) with OIC will be
randomized at approximately 225 study centers to receive either 0.25 milligrams (mg) CB-5945
twice daily (BID) or a matching placebo BID for the 52-week double-blind treatment period,
followed by a 4-week follow-up period. All randomized participants will be evaluated for
safety, tolerability, and quality of life from the first dose of study drug through Week 56.

Inclusion Criteria:

- Is taking a stable daily dose of opioids of ≥30-mg morphine-equivalent total daily
dose (METDD) for chronic non-cancer pain

- Has constipation that is caused by the chronic use of opioids

- Is willing to use only the study-provided laxative(s) and to discontinue use of all
other laxatives, enemas, stool softeners, and other medications to treat constipation
(for example, lubiprostone) during the study period (from Screening until the last
study assessment).

- Is able and willing to refrain from facilitating defecation via manual maneuvers (for
example, digital evacuation or support of the pelvic floor) during the study period
(from Screening to the last study assessment)

Exclusion Criteria:

- Has gastrointestinal (GI) or pelvic disorders known to affect bowel transit (for
example, obstruction) or contribute to bowel dysfunction

- Has evidence of intestinal obstruction

- Has a history of rectal bleeding not due to hemorrhoids or fissures

- Has an active malignancy of any type (participants with a history of successfully
treated malignancy >5 years before the scheduled administration of study medication
and participants with treated basal or squamous cell cancer may be enrolled)

- Is taking antispasmodics (for example, dicyclomine), antidiarrheals (for example,
loperamide), prokinetics (for example, metoclopramide), or locally acting chloride
channel activators (for example, lubiprostone)

- Is taking non-opioid medications known to cause constipation (for example, iron
sulfate therapy or tricyclic antidepressants)