Evaluation of the Tolerability of Switching Subjects on Chronic ATC Opioid Therapy to Buprenorphine HCl Buccal Film

Inclusion Criteria: 1. Written informed consent obtained prior to any study-related procedure being performed 2. Male or non-lactating female subjects 18 to 60 years of age at time of consent 3. Female subjects who are non-pregnant on the basis of screening serum pregnancy test and who are practicing abstinence or using a medically acceptable form of contraception (eg, intrauterine device, hormonal birth control, or double barrier method) or have been post-menopausal, biologically sterile, or surgically sterile (ie, hysterectomy, bilateral oophorectomy, or tubal ligation) for more than 1 year 4. Male subjects who are practicing abstinence, surgically sterile or are using a medically acceptable form of contraception 5. Subjects with a ≥6 months history of chronic pain (including peripheral neuropathic pain) requiring ATC opioid therapy with ≥80 mg but ≤220 mg MSE per day for at least 28 days 6. Receiving one of the following opioids ATC for ≥28 days: (i) Morphine Sulfate; (ii) Oxycodone hydrochloride 7. Displays signs and symptoms of withdrawal (ie, COWS score ≥5) within 5 minutes following naloxone challenge 8. Able to understand the study procedures, complete the assessment scales, and communicate meaningfully with study personnel 9. Stable health, as determined by the Principal Investigator, on the basis of medical history, physical examination, and screening laboratory results Exclusion Criteria: 1. Inability to meet study participation requirements, including two 2-night stays with pharmacokinetic sampling 2. A history or current evidence of clinically significant pulmonary (eg, asthma, chronic obstructive pulmonary disease, cor pulmonale or severe bronchial asthma ), gastrointestinal, hepatic, renal, hematologic, immunologic, endocrine, neurologic, oncologic or psychiatric disorder or any other condition, including evidence of abnormalities on physical examination, abnormal vital signs, electrocardiogram (ECG), or clinical laboratory values which in the opinion of the Investigator, would jeopardize the safety of the subject or impact the validity of the study results 3. Supine systolic blood pressure \>180 mm Hg or \<90 mm Hg or diastolic blood pressure \> 105 mm Hg or \<50 mm Hg at screening (may be repeated once) 4. COWS score greater than 4 prior to the screening naloxone challenge 5. Aspartate aminotransferase or alanine aminotransferase \>3 times the upper limits of normal or serum creatinine \>1.9 mg/dL at Screening, or any laboratory abnormalit…