The clinical efficacy and safety of transdermal buprenorphine was confirmed in three double-blind, placebo-controlled, randomised studies in chronic, moderate to severe pain. These studies which formed the basis of its registration in core countries within Europe, covered pain management in both cancer and non-cancer patients.
239 of these patients continued treatment for up to six years in an open-label extension study, which demonstrated long-term effectiveness, safety and a good tolerability profile.
There was no clinical evidence of a ceiling effect for analgesia, and only a low incidence of tolerance development regarding pain control was observed. In the cancer population, approximately 20% of patients stayed on transdermal buprenorphine until their end of life.

A large-scale post-marketing study conducted in Germany, in more than 13,000 patients (cancer and non-cancer population) confirmed the trial data indicating favourable safety and tolerability profiles in elderly patients, treated with transdermal buprenorphine.
Approximately 50% of patients studied did not require any analgesic co-medication or rescue analgesics in addition to their transdermal buprenorphine.

Following the introduction of transdermal buprenorphine in Spain, the Spanish Pain Society embarked on five clinical trials in order to evaluate its effectiveness and safety in 1) chronic nociceptive non-cancer related pain, 2) cancer related pain, 3) neuropathic pain,
4) rotation from morphine, and 5) in combination with tramadol.
The results (currently being prepared for publication) confirmed the beneficial efficacy and safety profile of transdermal buprenorphine in these indications and in combination.

The well-described efficacy of buprenorphine in neuropathic pain conditions in line with published preclinical and clinical findings is currently under-going further investigation with transdermal administration.
The accumulating new evidence on buprenorphine is gaining scientific acceptance, as is reflected in recent guidelines.
Buprenorphine's data profile, reflecting a superior safety profile (with respect to respiratory depression, immunological effects, and use in renal insufficiency) compared to standard WHO step III opioids, together with good efficacy in pain of different origins, makes it a highly suitable candidate for treatment of moderate to severe cancer pain.