Transdermal buprenorphine in clinical practice - a post-marketing surveillance study in 13179 patients

Objective: The objective of this post-marketing surveillance study was to collect effectiveness and safety data on the labelled use of buprenorphine transdermal patches (Transtec*) under routine clinical conditions. Research design and methods: For this open, observational study, patients with moderate to severe cancer or non-cancer pain requiring treatment with an opioid analgesic were recruited at hospitals, outpatient clinics and general practitioners' practices in Germany. Buprenorphine transdermal patches (35 mu g/h, 52.5 mu g/h or 70 mu g/h) were prescribed at physicians' discretion in accordance with the product's Summary of Product Characteristics (SmPC). Patients assessed their pain relief as 'very good', 'good', 'satisfactory', 'poor' or 'no effect'. Investigators were instructed to report all adverse events throughout the observation period. On completion, effectiveness and tolerability were evaluated for the overall study population, cancer and non-cancer patients, and patients < 70 years and >= 70 years. Other analyses assessed pain relief with respect to previous opioid treatment and increased patch strength, and in patients who remained on their original dose. The total observation time was 9 months, and the average individual documented treatment time was 60.8 days. Results: A total of 13 179 patients were evaluated; 3690 (28%) with cancer pain and 9489 (72%) with non-cancer pain. The most frequent diagnoses in non-cancer patients were musculoskeletal disorders (77%) and neuropathy (23%). In the great majority of cases (78%), treatment was started with the 35 mu g/h patch. The initial dose needed to be increased subsequently only in about 18% of subjects. Buprenorphine transdermal patches provided effective, sustained and dose-dependent analgesia in patients with cancer and non-cancer pain, irrespective of the patients' age or pain syndromes. Whereas good or very good pain relief was documented only for 6% of the patients with the initial assessment, this percentage increased to 71% at the first follow-up and 80% at the final assessment. Fewer than 5% of subjects discontinued treatment owing to unsatisfactory pain relief. Altogether, adverse events were documented for 2874 patients (22%), whereas a relationship with transdermal buprenorphine (adverse drug reactions) was assumed for only 10% (2220 adverse drug reactions in 1330 patients). The tolerability profile was as expected for an opioid and did not vary to a relevant extent with either the patient's age or the cause of pain (cancer or non-cancer). No evidence emerged of any previously unknown side effects. Conclusions: Buprenorphine transdermal patches are well tolerated and effective in the treatment of chronic cancer and non-cancer pain, irrespective of the patients' age. There was no clinically relevant development of tolerance.