The multi centre double blind, randomised, parallel group study in 58 patients assessed the efficacy, safety and tolerability of Sativex®, a whole plant medicinal cannabis extract, compared with placebo for the treatment of pain caused by Rheumatoid Arthritis. Study medication was administered by means of a spray into the mouth as an evening dose only and measures were assessed the following day.
In the Phase II trial, statistically significant improvements were seen in a range of outcome measures including morning pain at rest (p<0.05), quality of sleep (p<0.05), disease activity score (p<0.01) and Short Form McGill Pain Questionnaire – pain at present (p<0.05). Analysis of morning pain on movement approached statistical significance in favour of Sativex.
Overall the number of adverse events experienced was similar between the treatment groups. The safety profile was consistent to that shown in previous Sativex studies with adverse events being generally mild or moderate in intensity.
Dr Philip Robson, Director of GW’s Cannabinoid Research Institute, said, “These results are particularly exciting because this is the first ever controlled clinical trial of a cannabis-based medicine in the treatment of arthritis. To date, GW’s research has concentrated on multiple sclerosis and neuropathic pain and it is therefore very encouraging to see these positive effects of Sativex on pain and other symptoms of rheumatoid arthritis. Future research in rheumatoid arthritis will examine the optimal cannabinoid ratios in this indication prior to selecting the product candidate to enter into a pivotal Phase III trials programme.
Dr Robson added, “This exploratory trial provides further strong support to our belief that cannabis-based medicines may offer therapeutic potential across a range of medical conditions.”
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GW Pharmaceuticals plc
Dr Geoffrey Guy, Chairman
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Notes to Editors
Sativex is a whole plant medicinal cannabis extract containing tetrahydrocannabinol (THC) and cannabidiol (CBD) as its principal cannabinoid components. The medicine is administered by means of a spray into the mouth.
Sativex has already shown positive results in a number of Phase II and Phase III clinical trials in the areas of Multiple Sclerosis symptoms and Neuropathic (nerve-damage) pain.
Sativex is currently the subject of regulatory applications in both the UK and Canada.
Rheumatoid Arthritis (RA)
Approximately 400,000 adults in the UK have RA, which equates to around 0.8% of the adult population. (Source: Arthritis Research Campaign ("Arthritis: The Big Picture")).
RA is a systemic disease and is the most common form of inflammatory arthritis. It is characterised by inflammation of the membranes that line a joint, which in turn causes pain, stiffness, warmth, redness and swelling to the area. Symptoms are often most severe first thing in the morning. The small joints of the fingers and hands are usually first affected but the condition usually spreads to involve the wrists, elbows, shoulders and other joints. The inflamed joint lining can also invade and damage bone and cartilage when inflammatory cells release enzymes that are able to digest bone and cartilage. The involved joint can lose its shape and alignment, resulting in pain and loss of movement. The disease is typically chronic and can flare-up at intervals.
Outcome statistics demonstrate that RA is a potentially devastating disease. Functional deterioration often occurs rapidly, with up to 50% patients moderately disabled in 2 years and severely disabled by ten. Half the patients in employment at diagnosis will have stopped working within 10 years. The disease contributes to premature death in up to 20% patients.
Short Form McGill Pain Questionnaire
This questionnaire is an abbreviated version of a well validated and widely used measure of pain. It consists of three parts: a pain rating index which aims to capture the sensory and emotional components of pain; a measure of present pain; and an evaluation of the overall intensity of the pain experience. The present pain component is measured by means of a 10cm visual analogue scale with the anchors 'no pain' and 'worst possible pain'. Melzack R. The short-form McGill Pain Questionnaire. Pain 1987; 30(2):191-7.