Buprenorphine (CAM2038) in Subjects With a Recent History of Moderate to Severe Chronic Low Back Pain

Inclusion Criteria

• Written informed consent provided prior to the conduct of any study-related procedures.
• Male or non-pregnant, non-lactating female subject, greater than or equal to 18 years old.
• Body mass index (BMI) between 18 and 38 kg/m2, inclusive.
• Treated with daily opioids for moderate to severe CLBP for a minimum of 3 months prior to Screening.
• On a stable dose of ≥40 mg/day of oral morphine or MED during the 14 days prior to Screening.
• Systolic blood pressure ≥100 mmHg and diastolic blood pressure ≥60 mmHg.
• Female subject of childbearing potential who is willing to use a reliable method of contraception during the entire study (Screening Visit to final Follow-up). To be considered not of childbearing potential, female subjects must be surgically sterile (hysterectomy or bilateral oophorectomy, or bilateral tubal ligation with surgery at least 6 weeks before Screening).
• Male subject who is willing to use reliable contraception
• Willing and able to comply with all study procedures and requirements.

Exclusion Criteria

• Positive for hepatitis B surface antigen, hepatitis C viral RNA, or antibodies to human immunodeficiency virus (HIV).
• Clinically significant symptoms, medical conditions, or other circumstances which, in the opinion of the investigator, would preclude compliance with the protocol, adequate cooperation in the study, or obtaining informed consent, or may prevent the subject from safely participating in the study, including the following:
• Severe respiratory insufficiency, respiratory depression, airway obstruction, gastrointestinal motility disorders, biliary tract disease, severe hepatic insufficiency, or planned surgery.
• Bipolar disorder
• Current diagnosis of Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition-defined moderate to severe substance use disorder (including alcohol), other than caffeine or nicotine.
• Female subject planning to become pregnant during the study.
• Surgical procedure(s) for CLBP within 6 months prior to Screening.
• Concomitant disease(s) that could prolong the QTcF interval, such as autonomic neuropathy (caused by diabetes or Parkinson's disease), HIV, cirrhosis, Long QT Syndrome, or family history of Long QT Syndrome.
• QTcF >450 ms for males and >470 ms for females, or clinically significant electrocardiogram (ECG) abnormality at Screening, at the investigator's discretion.
• Currently taking medications that have the potential to prolong the QTcF interval or may require such medications during the course of the study (Appendix 1) and has clinically significant abnormalities on screening ECG readings, as determined by the investigator.
• A nerve or plexus block, including epidural steroid injections or facet blocks, within 1 month prior to Screening or botulinum toxin injection in the lower back region within 3 months of Screening.
• History of chemotherapy or confirmed malignancy (except basal cell carcinoma) within the past 2 years.
• Any other acute or chronic pain condition that could interfere with the subject's ability to report their CLBP accurately and consistently and/or interfere with the study staff's ability to assess the subjects CLBP.
• An active or pending workman's compensation, insurance claim, or litigation related to back pain (i.e., primary claim is back pain).
• Clinically significant history, in the opinion of the investigator, of suicidal ideation or current evidence that the subject is actively suicidal.
• Clinically significant history of major depressive disorder that is poorly controlled with medication, per investigator judgment.
• Hypersensitivity or allergy to BPN, other opioids, or excipients of CAM2038.
• Hypersensitivity or allergy to acetaminophen.
• Use of strong inhibitors or inducers of cytochrome P450 3A4 (CYP3A4), such as some azole antifungals (e.g., ketoconazole), macrolide antibiotics (e.g., clarithromycin), or protease inhibitors (e.g., ritonavir, in