Upon entering the extension phase (BUP3201S), subjects will receive BTDS 5, regardless of their dose level at discontinuation or completion of the BUP3201 core study. Subjects are allowed to titrate after 48 hours to BTDS 10 or 20 that provided stable pain control with minimal tolerability problems. Additional medical therapies are permitted if necessary, and there is no restriction on concomitant analgesic medications. The subjects have weekly visits for 4 consecutive weeks, and every 4 weeks thereafter, until the end of the scheduled extension phase.
