This study was terminated early for administrative reasons.

The purpose of this phase is to evaluate the long-term safety and tolerability of BTDS. Qualified subjects are started on BTDS 5 and the dose may be titrated, if necessary, to a maximum of BTDS 20 to achieve stable pain control.

Buprenorphine is a synthetic opioid analgesic with over 25 years of international clinical experience indicating it to be safe and effective in a variety of therapeutic situations for the relief of moderate to severe pain.

Inclusion Criteria:

• Subjects who completed all visits of the double-blind phase on study drug and subjects who discontinued study drug due to lack of therapeutic effect in the double-blind phase but completed all visits of the double-blind phase off study drug are eligible to enroll in the extension phase.

Exclusion Criteria:

• Subjects who prematurely discontinue study drug in the double-blind phase due to adverse event, subject's choice, administrative reason or lost to follow-up are NOT eligible to enter the extension phase
• Subjects with electrocardiograms (ECGs) that show any QT data corrected for heart rate using Fridericia formula (QTcF) interval ≥ 500 millisecond (msec) will be discontinued from the extension phase.
• Subjects requiring long-acting opioid analgesics (once- or twice-daily dosing with an every (q) 24 hour (h) or q12h drug) or transdermal fentanyl during the extension phase should be discontinued from the study.

Refer to core study for additional inclusion/exclusion information.