A multicentre, multinational, randomizedm Double-Blind, Placebo Controlled, crossover trial to evaluate efficacy and safety of Fentanyl TAIFUN ® treatment after titrated dose administration for breakthrough pain in cancer patients on maintenance opioid therapy

INTERVENTION: Intervention1: Fentanyl Taifun: 100 mcg and 200 mcg Control Intervention1: Placebo: 100 mcg and 200 mcg CONDITION: Breakthrough Pain in late stage cancer patients PRIMARY OUTCOME: Efficacy parameters ( numerical Pain Scale )‐‐‐‐‐‐Timepoint: T = 15minutes , T = 60minutes SECONDARY OUTCOME: Safety parameters ( Vital Signs, Pulse oxymeter, Spirometry, ECG, PEFR, PIFR, Laboratory Parameters )‐‐‐‐‐‐Timepoint: 4 Hours in titration period immediately after drug administration. The patient will be monitored for safety parameters for 28 days INCLUSION CRITERIA: "Inclusion Criteria : 1. Age 18 years or over. 2. A medically documented diagnosis of cancer. 3. Use of a fixed around‐the‐clock dose of an opioid or a fixed combination of opioids as maintenance therapy for pain relief with a dose equivalent of at least 60 mg of oral morphine/day, or at least 25 µg of transdermal fentanyl/hour, or at least 30 mg of oxycodone daily or at least 8 mg of oral hydromorphone daily. 4. Current opioid treatment for at least 7 days prior to the randomization. 5. Current use of opioid medication for BTP. 6. At least one BTP episode per Day with peak intensity of at least 4 on the numerical pain scale (NPS) at pain onset. No more than 4 BTP episodes per day. BTP is defined as a transitory increase in pain to greater than moderate intensity which occurs on a baseline pain of moderate intensity or less. 7. The flow rat