The objectives of this study are to examine the safety, tolerability, and efficacy of repeated topical administration of AB001 topical patches for the treatment of chronic low back pain.

This is a randomized, double-blind, placebo-controlled, parallel-group study of the safety and efficacy of AB001 topical patches in patients with chronic low back pain. Subjects meeting inclusion criteria are randomized in a 1:1 ratio to receive AB001 patches or placebo patches. Two AB001 or placebo patches will be given topically once daily for 14 days. The primary end point is the change of low back pain intensity rated on a visual analog scale (VAS) scale on Day 15, the secondary end points include the subject global assessment (SGA) of low back pain, the subject global perceived effect (GPE) of study medication, the Roland-Morris Disability Questionnaire (RMDQ), and the pain assessment from subject diary (Days 1 - 3 only). Subjects' safety will be monitored throughout the study, including the adverse event (AE) incidence and severity, laboratory test results (hematology and clinical chemistry), vital signs, and physical examination.

Inclusion Criteria:

1. Are generally healthy males or non-pregnant females, 18 to 75 years of age.
2. Have a body mass index (BMI) ≤35.
3. Have chronic low back pain for at least 3 months.
4. Have low back pain that is located inferior to the twelfth thoracic vertebra (T-12).
5. Back pain classified, using the Quebec Task Force system, as either Class 1 or Class 2.
6. Currently require use of analgesics for lower back pain (required at least 3 days per week for at least the last 4 weeks).
7. Have a score of 30 mm or greater on the visual analog scale (VAS) and a score of 2, 3, or 4 on the Subject Global Assessment (SGA) of Back Pain Scale at Screening.
8. Are willing to discontinue current analgesics for the 3 to 15 day washout period.
9. Have an increase of at least 10 mm or more from the score at Screening and an absolute score of 50 mm or more on the VAS (ie, VAS ≥ 50 mm) and a score of 3 or 4 on the SGA of Back Pain Scale at Baseline.
10. If female, are: 1).Of non-childbearing potential or have a confirmed clinical history of sterility or, 2).Of childbearing potential, must be willing to use effective contraception at trial entry and until completion.
11. Are willing to provide written informed consent.

Exclusion Criteria:

1. Have chronic lower back pain (CLBP) due to any of the following pathologies: infection, neoplasia, metabolic or structural disturbance of spine, lumbar radiculopathy, osteoporosis, hip dysplasia, inflammatory arthritis, ankylosing spondylitis, Paget's disease, cauda equine syndrome, gout, pseuodgout, fibromyalgia, post-surgical pain.
2. Have low back pain caused by major trauma.
3. Have excess hair, tattoo(s), or other dermatologic conditions in the patch application area that might interfere with efficacy evaluation.
4. Have had surgery for low back pain within the previous 6 months.
5. Have had clinical depression within 2 years or are currently undergoing treatment for depression;
6. Have a hypersensitivity to non-steroidal anti-inflammatory drugs (NSAIDs, including aspirin) or hypersensitivity to acetaminophen.
7. Have used opioids within 72 hours prior to the Baseline / Day 1 visit or during the course of the study.
8. Have used oral or injected corticosteroids chronically or intermittently within the past 60 days (oral), or 90 days (injected).
9. Are a current drug or alcohol abuser.
10. Are pregnant, plan to become pregnant during the study, or are breastfeeding.
11. Have a pending workman's compensation claim, litigation, or any other monetary settlement relating to the subject's lower back pain.
12. Have any chronic or acute medical condition that may pose a risk to the safety of the subject, or may interfere with the assessment of safety or efficacy in this trial.
13. Have a history of sensitivity to any component of the investigational product.
14. Have a known history of liver or kidney disorders (hepatic or renal insufficiency).
15. Have a known history of gastric ulcer, gastrointestinal bleeding, or significant cardiovascular events.
16. Have a history of cancer, other than treated basal cell carcinoma, within the past 5 years.
17. Use of any medication, including prescription, OTC, vitamins, herbal and/or mineral supplements, dietary supplements, enzyme altering agents within at least14 days prior to the first treatment or during the trial, which may influence the trial results.
18. Use of anti-coagulant medication within the past 30 days, including but not limited to heparins, warfarin/Coumadin, rivaroxaban/Xarelto, dabigatran/Pradaxa, apixaban/Eliquis, etc.
19. Participation in another clinical trial or received an investigational product within 30 days prior to screening.