A Study of Cannabis Based Medicine Extracts and Placebo in Patients With Pain Due to Spinal Cord Injury

A study to investigate the effects of sublingual cannabis based medicine extracts on neuropathic pain associated with spinal cord injury.

This was a multi-centre, double-blind, randomised, placebo-controlled, parallel-group study to evaluate the efficacy and tolerability of GW-1000-02 in central neuropathic pain associated with spinal cord injury. Patients were screened to determine eligibility and completed a seven to 21 day baseline period. Patients then returned to the centre for assessment, randomisation and initial dosing. Visits occurred at the end of treatment week one and at the end of the study (treatment week three) or upon withdrawal. Throughout the study, patients were permitted to take paracetamol as escape analgesic to relieve breakthrough pain. Patients in this study could elect to be screened for an open label extension study of GW-1000-02.

Eligibility Criteria:
Inclusion Criteria:

* Gave informed consent for participation in the study.
* Male or Female, aged 18 years or above.
* Diagnosis of non-acute spinal cord injury, with central neuropathic pain not wholly relieved by current therapy.
* Central neuropathic pain with a mean severity Numerical Rating Scale score at least four during last seven days of the baseline period.
* Relatively stable neurology during the preceding six months.
* Stable medication regimen during the preceding four weeks.
* Agreement, if female and of child bearing potential or if male with a partner of child bearing potential, to ensure that effective contraception was used during the study and for three months thereafter.
* Had not used cannabinoids for at least the preceding seven days and willing to abstain from any use of cannabinoids during the study.
* Clinically acceptable laboratory results at Visit 2.
* Ability (in the investigator's opinion) and willingness to comply with all study requirements.
* Agreement for the UK Home Office, their general practitioner, and their consultant if appropriate, to be notified of their participation in the study.

Exclusion Criteria:

* History of schizophrenia, other psychotic illness, severe personality disorder or other significant psychiatric disorder other than depression associated with their underlying condition.
* History of alcohol or substance abuse.
* Severe cardiovascular disorder, such as ischaemic heart disease, arrhythmias (other than well controlled atrial fibrillation), poorly controlled hypertension or severe heart failure.
* History of autonomic dysreflexia.
* History of epilepsy.
* If female, were pregnant or lactating, or were planning a pregnancy to occur during the course of the study.
* Significant renal or hepatic impairment.
* Elective surgery or other procedures requiring general anaesthesia scheduled to occur during the study.
* Terminal illness or were considered inappropriate for placebo medication.
* Any other significant disease or disorder which, in the opinion of the investigator, may have either put the subject at risk because of participation in the study, or may influenced the result of the study, or the subject's ability to participate in the study.
* Regular levodopa therapy within the seven days leading to study entry.
* If male, were receiving and were unwilling to stop sildenafil for the duration of the study.
* Known or suspected hypersensitivity to cannabinoids or any of the excipients of the study medications.
* Known or suspected adverse reaction to cannabinoids.
* Intention to travel internationally during the study.
* Intention to donate blood during the study.
* Participation in another research study in the 12 weeks leading to study entry.
* Previous randomisation into this study.