Discontinuation vs Continuation of Long-term Opioid Therapy in Suboptimal and Optimal Responders With Chronic Pain

Inclusion Criteria: 1. Be male or non-pregnant, non-lactating female aged 18 to 75 years, inclusive. 2. Have a clinical diagnosis of non-radicular CLBP (pain that occurs in an area with boundaries between the lowest rib and the crease of the buttocks) of Class 1 or proximal radicular (above the knee) pain of Class 2 based on the Quebec Task Force Classification for Spinal Disorders (subjects with previous surgery or chronic pain syndrome, i.e., classes 9.2 or 10, will be allowed if their pain does not radiate or radiates only proximally) for a minimum of 12 months and 1. For the Suboptimal Responder group, pain must have been present for at least several hours a day and have an Average PI score of 6-9 on an 11-point NRS within the past 24 hours of screening. 2. For the Optimal Responder group, subjects must have an Average PI score of 1-4 on an 11-point NRS within the past 24 hours of screening. 3. Have been taking ER/LA opioids or immediate release opioids (at least 4 times at day) for at least 12 months. 4. Have been taking one of the 3 index ER opioid drugs around-the-clock at a twice-a-day frequency for at least 3 consecutive months at a total daily dose within the range shown below. Daily Dose Range 1. Morphine sulfate extended-release: 120-540mg 2. Oxycodone extended-release: 80-360mg 3. Oxymorphone extended-release: 40-180mg 5. Be considered, in the opinion of the Investigator, to be in generally good health other than CLBP at screening based upon the results of a medical history, physical examination, 12-lead ECG, and laboratory profile. 6. Speak, read, write, and understand English (to reduce heterogeneity of data), understand the consent form, and be able to effectively communicate with the study staff. 7. Have access to the Internet (to access the patient support program). 8. Voluntarily provide written informed consent. 9. Be willing and able to complete study procedures. Exclusion Criteria: 1. Have any clinically significant condition that would, in the opinion of the Investigator, preclude study participation or interfere with the assessment of pain and other symptoms of CLBP or increase the risk of opioid-related AEs. 2. Have a primary diagnosis of fibromyalgia, complex regional pain syndrome, neurogenic claudication due to spinal stenosis, spinal cord compression, acute nerve root compression, severe or progressive lower extremity weakness or numbness, bowel or bladder dysfunction as a result of cauda equina compression, diabetic amyotrophy…