Sativex
Open Door - August 2010 pages 10-11
- With the recent granting of a licence to Sativex as a treatment for MS related spasticity, Chris Jones, MS Trust trustee and former chief executive, reflects on the long process to get cannabis based medicine accepted.
At last, a licensed, legal cannabis based medicine...
Queen Victoria's personal physician, Sir Russell Reynolds, prescribed cannabis for menstrual cramps. In The Lancet in 1890, he claimed that cannabis, "When pure and administered carefully, is one of the most valuable medicines we possess."1
If it was good enough for Queen Victoria...
The fact that Queen Victoria found cannabis beneficial must be the only argument that the MS Trust has NOT used during the long struggle to allow people with multiple sclerosis legal access to a cannabis based medicine.
Back in 2001, when a body as august as the Science and Technology Select Committee of the House of Lords recommended legalisation of cannabis for medicinal purposes2, we thought it might not be too far away. The committee had accused the Medicines Control Agency (MCA), which licenses medicines, of dragging its feet and said that their stance could delay the introduction of cannabis based medicines by up to three years. They just might have had a point; it's taken nine.
Whose MS is it anyway?
For me, the argument has always been simple. Decisions by the MCA are often based on a 'one size fits all' model. As we know, one size NEVER fits all with MS - it is a hugely variable condition with variable responses to treatments. People with MS should have had - long since - the right to decide for themselves whether they benefitted from cannabis medicine. The fact that there was so much anecdotal evidence - and not an insignificant amount of scientific evidence too - should have counted. Instead of which, time and again, appeal after appeal, we were confronted with clinical measures so blunt as to be virtually useless, and yet more demands for more evidence.
At the appeal to the MCA in July 2007, as a person with MS trying to present a case, I went quickly from nervousness to anger. Two things caused the anger. Firstly, the fact that the appeal panel seemed to have little knowledge of MS, and certainly no understanding of what it means to live with MS. Secondly, the fact that credence was given to the test administered by doctors to assess improvement in spasticity, whereas the socalled PROM (patient reported outcome measure) used in the trial was judged unreliable. The doctors' spasticity assessment was the Ashworth Scale - a measure generally discredited by medics and physios alike as being insensitive because it has only five points on its scale (where no spasticity is 0 and complete inability to move a limb is 4). How many people with MS only experience severe spasticity when they go to bed?
I am of course delighted that at last common sense has prevailed. But I am still angry at the amount of time and resource that has been expended to get to the position we should have been in nine years ago.
Research funded by the MS Trust
Over the past 10 years, the MS Trust has contributed significantly to the body of knowledge on cannabis. The majority of research trials have focused on relieving symptoms of MS and we have funded work on cannabis use in advanced bladder dysfunction3 and also, as part of the CAMS trial on MS spasticity, looking at any unwanted psychological side effects of cannabis medicine.4 No significant psychological side effects were found.
The future of cannabis medicine?
However, the best might yet be still to come. It was noted during the CAMS study that those who were taking active cannabis, as opposed to the dummy placebo, seemed to be experiencing a slowing of progression in their MS disease course. For this reason, since 2006 the MS Trust has contributed £150,000 to the subsequent CUPID trial in which almost 500 people with progressive MS are taking part. Maybe cannabis can do more than alleviate pain and spasticity?
- Russell Reynolds J.
On the therapeutical uses and toxic effects of cannabis indica.
Lancet 1890;135 (3473):637-638. - House of Lords - Science and Technology Committee.
Therapeutic uses of cannabis: Science and Technology - Second Report. HL 50.
London: March 2001. - Brady CM, et al.
An open-label pilot study of cannabis-based extracts for bladder dysfunction in advanced multiple sclerosis.
Multiple Sclerosis 2004;10(4):425-433.
abstract - Zajicek JP, et al.
Cannabinoids in multiple sclerosis (CAMS) study: safety and efficacy data for 12 months follow up.
Journal of Neurology Neurosurgery and Psychiatry 2005;76(12):1664-1669.
abstract
What is Sativex?
In June 2010 the UK Medicines and Healthcare products Regulatory Agency (MHRA) licensed Sativex for use as an add-on treatment for MS related spasticity, making it the first cannabis based medicine to be licensed in the UK.
Sativex is a mouth (oromucosal) spray containing chemical extracts derived from the cannabis plant: delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD). Cannabis plants are thought to contain more than 60 such chemical extracts (cannabinoids) - but these two have been studied for their effects in MS.
How does Sativex work?
The way cannabinoids work is not fully understood as yet but discovery of the endocannabinoid system has provided some insight. This is the system of receptors found in the human body through which cannabinoids are able to exert their effects. It is thought to work in a similar way to the opioid system - the system that controls pain.
How is Sativex taken?
Sativex is taken as a mouth spray. The severity of spasticity symptoms varies from one person to another so the number and timing of sprays will also vary. At the start of treatment the prescribing doctor will advise on frequency and timing of sprays and may suggest a gradual increase until the most effective dose is found
Who can be prescribed Sativex?
The existing oral medications that are used for the treatment of MS spasticity - including oral baclofen and gabapentin - continue to be used as first line treatments for MS spasticity. It is only where these treatments offer inadequate relief or have unbearable side effects that Sativex may be considered. Sativex is licensed as an add-on therapy - meaning that it will be prescribed in combination with other anti-spasticity medications.
Sativex must be started and supervised by a specialist with experience of treating people with MS spasticity, such as a neurologist, rehabilitation consultant or pain specialist. GPs should only prescribe Sativex when instructed to do so by the specialist.
How effective is Sativex?
As with many medicines used in MS, Sativex does not work for everyone. In clinical trials, around half of people taking Sativex showed improvements in their symptoms within four-weeks of taking the medicine. Those people who did not show improvements were deemed non-responders and stopped treatment.
A phase III trial found that about three quarters of those responding to Sativex reported an improvement of greater than 30% in their spasticity score at least once during the first four weeks of treatment.
Collin C, et al.
A double-blind randomized placebo-controlled parallel-group study of Sativex in subjects with symptoms of spasticity due to multiple sclerosis.
Neurology Research 2010; 32 (5): 451-459.
abstract
Join the Open Door mailing list to receive your own copy through the post (UK addresses only) or by email.
Disclaimer
Open Door articles are reproduced as published. They are not updated to take account of subsequent developments. Use appropriate caution in acting on the information in any article.