Safety, Tolerability, Effectiveness, and Pharmacokinetic Data in Opioid-experienced Children

Inclusion Criteria: 1. Were males or females 7 - ≤17 years of age. Females of childbearing potential had to be practicing abstinence or using a medically acceptable form of contraception (eg, intrauterine device, hormonal birth control, or double barrier method). For the purpose of this study, all menstruating females were considered to be of childbearing potential unless they were biologically sterile or surgically sterile for more than 1 year. 2. Had chronic pain (malignant and/or nonmalignant) or postsurgical pain expected to require ATC opioid analgesia for up to 12 weeks with at least 10 mg per day oxymorphone ER (approximately equal to 30 mg per day oral MSE). 3. Had a body weight at least 18 kg. 4. Were able to swallow oxymorphone ER tablets. 5. Had laboratory results from within 21 days prior to Baseline available including clinical chemistry and hematology laboratory analytes. Intraoperative (prior to surgical incision) labs were acceptable provided the results had been reviewed by the investigator for study eligibility prior to dosing. 6. Subjects with postsurgical pain were prescribed a parenteral analgesic regimen utilizing a short-acting opioid analgesic AND were anticipated to be switched to an oral opioid for an extended period of time (according to institutions standard of care). 7. Were able to provide pain assessment evaluations using age-appropriate instruments provided in the protocol. 8. Had been informed of the nature of the study and informed consent and assent (as appropriate) have been obtained from the legally responsible parent(s)/legal guardian(s) and subject, respectively, in accordance with IRB requirements. To participate in the PK Period, subjects had: 9. Been hospital inpatients, expected to be hospitalized for up to 72 hours following the initial administration of oxymorphone ER. 10. An indwelling access catheter in place for blood sampling. Exclusion Criteria: 1. Had known allergies or sensitivities to oxymorphone or other opioid analgesics. 2. Had a known sensitivity to any component of the oxymorphone ER. 3. Had a life expectancy \<3 months. 4. Was pregnant and/or lactating. 5. Had cyanotic heart disease. 6. Had respiratory, hepatic, renal, neurological, psychological disease, or any other clinically significant condition that would, in the Investigator's opinion, preclude participation in the study. 7. Had abdominal trauma that would interfere with absorption of oxymorphone ER. 8. Had increased intracranial pressure. 9. Had a respiratory condition requiring intubation. 10. Had a history of uncontrolled seizures that were not managed with anticonvulsants. 11. Had prior history of substance abuse or alcohol abuse. 12. Had taken a monoamine oxidase inhibitor (MAOI) within 14 days prior to the start of oxymorphone ER. 13. Had taken oxycodone or oxymorphone within 48 hours prior to Baseline. 14. The investigator anticipated that the subject and/or parent(s)/legal guardian(s) was unable to comply with the protocol. 15. The subject (and/or parent\[s\]/legal guardian\[s\]) was (were) unable to communicate effectively with study personnel.