Safety and Pharmacokinetics Study of Naldemedine in Paediatric Participants Receiving Opioids

Inclusion Criteria:

Disease Characteristics

• Participants with cancer or non-cancer pain who are receiving (or who are about toreceive) acute or chronic treatment with opioids.

• Participants with either newly diagnosed constipation, a history of constipationtreated with laxatives, or are expected to develop constipation after opioidtreatment.

• Able to remain in the clinic for blood sampling for at least 12 hours following thefirst study intervention dose and are able to return for blood sampling at the 24-hour time point.

Weight

• Body mass index within approximately the 3rd to 97th percentile for their ageaccording to the World Health Organization Child Growth Standards.

Exclusion Criteria:

Medical Conditions

• History of a gastrointestinal (GI) neoplasm or an ongoing GI-related issue or anyrecent (within last 1 year) or planned GI tract surgery.

• Signs or symptoms of GI obstruction or participants with recurrent obstruction whomay be at increased risk of GI perforation.

• Inability to eat/swallow or have need of a nasogastric tube.

• No bowel movements reported for 7 consecutive days at the time of obtaining informedconsent or on the initial day of study intervention administration (Study Day 1).

• History of more than 1 week of Common Terminology Criteria for Adverse Events (CTCAE) Grade 3 neutropenia or thrombocytopenia with clinical sequelae.

• Participants who need mechanical ventilation.

• Severe CTCAE Grade 3 or above hepatic or renal impairment including end-stage renaldisease requiring hemodialysis, as determined by the investigator.

• Progressive neurological disorders or potential disruption to the blood-brainbarrier (for example, primary brain malignancies, central nervous system metastases,active multiple sclerosis, etc.) considering the risk of opioid withdrawal orreduced analgesia.

Prior/Ongoing Medications

• Currently receiving the first cycle of chemotherapy.

• Previously received naldemedine.

Other Exclusions

• Positive pregnancy test for females of childbearing potential.

Note: Other protocol-defined Inclusion/Exclusion criteria may apply.