Efficacy/Safety Study of ACTIQ® for Opioid-Tolerant Children and Adolescents With Breakthrough Pain (BTP)

The primary objective of the study is to evaluate the efficacy of ACTIQ treatment for the management of breakthrough pain (BTP) compared to placebo treatment in children with pain who are receiving around-the-clock (ATC) opioid therapy and who require additional therapy for BTP episodes. This will be determined by the analysis of the pain intensity (PI), measured by the Faces Pain Scale-Revised (FPS-R) administered 15 minutes after the start of each unit of study drug with an optimal ACTIQ dosage. The secondary objectives are: * to evaluate the characteristics of BTP in children with pain, including their response to treatment * to evaluate the efficacy of ACTIQ treatment compared to placebo treatment for these children with regard to time to adequate analgesia by utilizing a stop watch to measure the time for each unit of study drug in the double blind phase * to evaluate the efficacy of ACTIQ treatment compared to placebo treatment for these children by assessing the occurrence of inadequate analgesia as assessed by the use of rescue medication * to evaluate the efficacy of ACTIQ treatment compared to placebo treatment for these children by assessing the numbers of patients who withdraw from the study because of inadequate analgesia * to evaluate the efficacy of ACTIQ treatment compared to placebo treatment for these children by assessing the duration of analgesic effect by using the FPS-R administered at approximately 30, 45, and 60 minutes after the start of each unit of study drug after an optimal dosage is obtained * to determine the distribution of optimal doses of ACTIQ treatment for these children by age group (3 to under 6 years, 6 to under 11 years, and 11 to under 16 years) * to establish a safe and effective titration scheme for ACTIQ in these children during the open label phase * to evaluate the safety of ACTIQ treatment for these children through the assessment of adverse events, clinical laboratory assessments (serum chemistry and hematology), vital sign measurements (including blood pressure, heart rate, and respiration rate), hemoglobin-oxygen saturation level (SpO2, measured via pulse oximetry), electrocardiograms (ECGs), physical examinations, and level of sedation (measured by the University of Michigan Sedation Scale \[UMSS\]) * to characterize the pharmacokinetics profile of ACTIQ (fentanyl citrate) in these children * to investigate the exposure and efficacy relationship between plasma concentration of fentanyl and clinical measures of analgesia