Efficacy and Safety of Buprenorphine Transdermal Patch in Non-cancer Pain of Moderate Intensity

This is a phase IV, open-label and single-arm study of patients with non-malignant pain due to osteoarthritis, rheumatoid arthritis, low back pain and joint/muscle pain, who were not responding to non-opioid analgesics. The primary objective was to assess the efficacy of buprenorphine transdermal patch for pain control among these patients.

Buprenorphine transdermal (BTDs) is a semi-synthetic opioid analgesic. Earlier studies have shown BTDs to be non-inferior to an oral codeine-paracetamol combination and prolonged-release tramadol, in terms of pain control as well as sleep quality. BTDs is registered for use in Malaysia but the scientific data on efficacy and tolerability among Malaysians was not available. Thus, this study was conducted to evaluate the efficacy and tolerability of BTDs among Malaysian patients.

Patients eligible for entry into the study were adults aged ≥ 40 years who met the inclusion criteria and qualified from baseline screening and liver function test (LFT) assessment. The study excluded patients who met the exclusion criteria and failed prior the LFT assessment. Patients received an initial dose of 5 mg BTDs after qualifying on the baseline screening and LFT test. The dose could be up-titrated to a maximum of BTDs 20mg (2 X 10 mg) to achieve stable pain control.

There were six visits during the three-month study period. At visit 1, patients received 5mg of Sovenor® as initial treatment dose. Visit 2 occurred 7 days after the first visit; visit 2 and visit 3 were dose titration visits. Visit 4 and visit 5, were for assessment purposes. Primary treatment efficacy was measured during each visit with additional assessments of patients' sleep quality and quality of life, while physicians' and patients' treatment satisfaction assessed during the final visit. Safety was measured by monitoring the occurrence of adverse events (AEs).

Eligibility Criteria:
Inclusion Criteria:

1. Males and females aged 40 years and above at the time of recruitment.
2. Clinical diagnosis of osteoarthritis, rheumatoid arthritis, lower back pain or joint/muscle pain.
3. Having non-malignant pain of moderate intensity requiring an opioid for adequate analgesia. This was determined using BS-11 scores, where the cut-off point is ≥4.
4. Patients had to be opioid treatment naïve as defined by no opioid treatment (including tramadol, morphine etc.) in the preceding 1 month.
5. Patients who have uncontrolled pain and had not responded to non-opioid analgesics for 1 month or more.
6. Patients who provided informed consent.

Exclusion Criteria:

1. Pregnant and lactating females.
2. Patients with chronic condition(s), in addition to (osteoarthritis) OA, that required frequent analgesic treatment (e.g. frequent headaches, frequent migraine, and gout).
3. Patients who were awaiting a scheduled operation or other surgical procedure during study period.
4. Prior history of being on opioids in the preceding one month prior to the study for the management of chronic non-malignant pain.
5. Patients with history of allergic reactions against paracetamol/acetaminophen, Non Steroidal Anti-Inflammatory drugs (NSAIDs) and/or opioids.
6. Patients with allergies or other contraindications to transdermal systems or patch adhesives.
7. Patients with dermatological disorders who may have problems applying patch or rotating patch placement area.
8. Patients with cancer (except for basal cell carcinoma) or history of cancer who have been diagnosed within five years prior to the visit (except for treated basal cell carcinoma).
9. Patients with conditions such as brain tumour, brain injury or raised intracranial pressure.
10. Patients with history of psychiatric disorder, uncontrollable epilepsy, untreated depression or other psychiatric disorders of a type that would make participation in the study an unacceptable risk to the patient.
11. Patients with any conditions causing poor cognitive function as assessed by the participating physician.
12. Patients with history of alcohol and drug abuse or patients who had demonstrated behaviour that suggests a dependency or drug abuse.
13. Patients who were at the time taking hypnotics or other central nervous system depressants that may pose a risk of additional central nervous system (CNS) depression with study medication.
14. Patients who were at the time being administered monoamine oxidase inhibitors (MAOIs) or have taken MAOIs within 2 weeks before screening.
15. Patients who were at the time taking adjuvant analgesics such as anti-depressants (e.g. amitriptyline, amoxapine, clomipramine, selective serotonin re-uptake inhibitors (SSRIs)) and anticonvulsants (e.g. gabapentin, pregabalin).
16. Patients who had received steroid treatment (intra-articular, intramuscular, oral, intravenous, epidural or other corticosteroid injections) within 6 weeks prior to clinical study or planned steroid treatment during the clinical study period.
17. Patients who had to use heating facility over area of patch (examples: heating lamp, electric blanket, sauna, warm compresses, heated saline baths, etc.).
18. Patients who could not or did not wish to remove hair growing at body surface where the patch can be placed.
19. Any other contraindication mentioned in the Summary of Product Characteristics for Sovenor® transdermal patch.
20. Patients who were at the time on disability claims or in the process of applying for disability claims.
21. Patients at child-bearing age who were planning to conceive a child during the study period and were not practicing adequate contraception.
22. Patients with known severe hepatic impairment as determined by liver function test within the past one year. If liver function testing was not performed within 1 year prior to study initiation, patient had to undergo liver function testing prior to recruitment.
23. Patients who were at the time in or had participated in other clinical trials within the last 30 days prior to study recruitment.
24. Patients who were unable to comply to study visits.
25. Patients who, in the investigator's opinion, were not suited to participate in the study involving the study medicine for any other reason not stated in the inclusion/exclusion criteria.