The primary objective of this study is to evaluate the efficacy and safety of BTDS compared to placebo in subjects with moderate to severe low back pain.

The primary objective of this study is to evaluate the efficacy and safety of buprenorphine transdermal system (BTDS) compared to placebo in subjects with moderate to severe low back pain who have a sub-optimal response to their non-opioid analgesic treatment and require opioid analgesics for pain control.

Inclusion Criteria:

• Males or females age 20 years or older.
• Clinical diagnosis of low back pain for 4 weeks or longer with non-malignant pain etiology.

Exclusion Criteria:

• Subjects who have a current chronic disease(s) or who have a past history and high possibilities to relapse, in addition to low back pain, requiring frequent analgesic therapy (e.g. headache, fibromyalgia, gout, rheumatoid arthritis, osteoarthritis and diabetic neuropathy).