Transdermal Buprenorphine for the Treatment of Cancer Pain: Results from a Multicenter, Observational, Post-Marketing Study in Spain (RELIEF Study)

Abstract

SUMMARY This study evaluated health outcomes in patients with cancer pain during treatment with transdermal buprenorphine, including quality of life, effectiveness, tolerability, and functional consequences for patients and their carers. In this 3-month, noncomparative, multicenter, observational study performed in a normal clinical practice setting in Spain, patients received transdermal buprenorphine 37, 52.5 or 70 µg/h, with patches changed every 96 h. The effect of transdermal buprenorphine on quality of life (primary study focus) was assessed using the Visual Analog Scale (VAS) component of the EuroQol 5 Dimensions™ (EQ-5D). In addition, pain (assessed using the Brief Pain Inventory - Short Form [BPI-SF] and VAS-pain), the impact of pain on patients and carers (assessed using the Beck Depression Inventory, sleep quality analysis, VAS-patient limitation, VAS-carer limitation and the Palliative Care Scale), patient's use of health resources, patient satisfaction, and tolerability, were evaluated. Of 116 patients entering the study, 42 completed the 3-month study period. Five patients withdrew due to adverse events. The two main reasons for study discontinuation were nontreatment-related death (27.1%) and lost to follow-up (18.8%). The mean age was 62.9 years and the mean baseline duration of pain was 7.78 weeks. In the month prior to starting transdermal buprenorphine, 80% of patients had received at least one nonopioid analgesic medication; 21% had received an opioid analgesic (most commonly tramadol). The most common dose of transdermal buprenorphine used was 35 µg/h. The mean improvement from baseline in the EQ-5D VAS score among 65 patients with data was 15.20 ± 24.96 (p < 0.0001). EQ-5D descriptive parameters also improved during the study (not statistically significant). Mean improvements in BPI scores for worst pain (3.76) and average pain (3.03) were significant (p < 0.0001). The other measures of pain relief also supported transdermal buprenorphine as an effective analgesic. Sleep quality improved during the study. VAS scores (100 mm scale) for patient limitation and caregiver burden due to pain improved, with a significant mean change in VAS-carer limitation score (30.34; p < 0.0001). Adverse events were reported by ten (8.6%) patients, most commonly affecting the gastrointestinal system (vomiting [4.3% of patients], nausea [2.6%] and constipation [0.9%]). The majority of patients reported satisfaction with their analgesic treatment. In this observational study in normal clinical practice, transdermal buprenorphine provided effective pain relief and was generally well tolerated by patients with cancer pain. It also improved quality of life for patients and reduced caregiver burden. Considering the high number of study discontinuations (mainly due to nontreatment-related death and lost to follow-up), the results of this study need to be evaluated with caution.