A Study to Evaluate the Effects of Cannabis Based Medicine in Patients With Pain of Neurological Origin

To investigate the ability of a cannabis based medicine extract to relieve chronic refractory pain of neurological origin.

Patients with Multiple Sclerosis or other defect of neurological function with a qualifying symptom of chronic refractory pain, entered a seven day baseline period, followed by a 21 day randomised, double blind, parallel group comparison of GW-1000-02 with placebo, self-titrated to symptom resolution or maximum tolerated dose. The ability of the cannabis based medicine extract to relieve chronic refractory pain was assessed by the change from baseline in pain score using Box Scale-11 (BS-11) scores recorded in the patients' daily diary.

Eligibility Criteria:
Inclusion Criteria:

* Patient, or legal representative, willing and able to give informed consent for participation in the study.
* Male or Female, aged 18 years or above.
* Diagnosed with chronic refractory pain due to Multiple Sclerosis or other defects of neurological function.
* Diagnosed with pain, not wholly alleviated with current analgesic therapy at Visit 1 and an average score of over 4 on a Box Scale-11 scale on the four consecutive days leading up to Visit 2, where: zero = "no pain" and 10 = "worst possible pain".
* Stable dose of pain relieving medication for at least two weeks prior to study entry.
* Willing to ensure that they or their partner use effective contraception during the study and for three months thereafter (applicable to female patients of child bearing potential and male patients whose partners were of child bearing potential).
* No cannabinoid use (cannabis, Marinol or Nabilone) for at least seven days before Visit 1 and be willing to abstain from any use of cannabis during the study.
* Able (in the investigator's opinion) and willing to comply with all study requirements.
* Willing for his or her name to be notified to the Home Office for participation in this study.
* Willing to allow his or her general practitioner and consultant, if appropriate, to be notified of 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.
* Known 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 epilepsy.
* Female patients who were pregnant, lactating or planning pregnancy during the course of the study.
* Significant renal or hepatic impairment.
* Scheduled elective surgery or other procedures requiring general anaesthesia during the study.
* Terminally ill or inappropriate for placebo medication.
* Any other significant disease or disorder which, in the opinion of the investigator, may have put the patient at risk because of participation in the study, or may have influenced the result of the study, or the patient's ability to participate in the study.
* Regular levodopa (Sinemet®, Sinemet Plus®, Levodopa, L-dopa, Madopar®, Benserazide) therapy within seven days of study entry.
* Known or suspected hypersensitivity to cannabinoids or any of the excipients of the study medications.
* Known or suspected of having adverse reaction to cannabinoids.
* Travel outside the UK planned during the study.
* Donation of blood during the study.
* Patients who had participated in another research study in the 12 weeks leading up to study entry.
* Patients who had been previously randomised into this study.
* Male patients who were receiving Sildenafil (Viagra®) at the time of study entry and were unwilling to stop medication for the duration of the study.