Efficacy and tolerability of a new opioid analgesic formulation, buprenorphine transdermal therapeutic system (TDS), in the treatment of patients with chronic pain.: A randomised, double-blind, placebo-controlled study

This randomised, double-blind, placebo-controlled study evaluated the efficacy and tolerability of buprenorphine TDS, a new transdermal formulation of the opioid analgesic buprenorphine. Patients (151) with severe to very severe chronic pain of malignant or nonmalignant origin who maintained at least satisfactory pain relief with sublingual buprenorphine 0.8-1.2 mg/day during an open-label 5-day run-in phase, were randomly allocated to buprenorphine TDS in one of three dose strengths: 35 mug/h, 52.5 mug/h or 70 mug/h, or placebo, receiving two patches consecutively, each applied for 72 hours. Rescue analgesic medication comprised sublingual buprenorphine tablets (0.2 mg). Responders were patients reporting at least satisfactory pain relief and taking no more than 0.2 mg/day rescue analgesic. The proportion of responders in each treatment group increased dose-dependently (34%, 37% and 50% for the 35 mug/h, 52.5 mug/h and 70 mug/h groups, respectively). However, because of a high response rate in the placebo group (31%), these response rates failed to reach statistical significance (p = 0.374). Twenty percent less patients in the placebo group reported good to complete pain relief while the proportion reporting moderate to very severe pain increased by 14%. In contrast, relative numbers of patients in the active treatment groups reporting good to complete pain relief increased by 5-13%, while the proportion reporting moderate to very severe pain fell by 3-14%. The duration of sleep uninterrupted by pain was shorter in the placebo than in the active treatment groups. The incidence of adverse events was 23%. Most local adverse events were mild to moderate erythema or pruritus.