A British medical journal says there is little evidence supporting the use of a medical marijuana spray to treat muscle pain and spasticity in multiple sclerosis (MS) patients.
“Our findings were that the medicine has a small beneficial effect,” said David Phizackerley, deputy editor of the journal Drug and Therapeutics Bulletin (DTB).
The article looked at nearly two dozen clinical trials supporting the use of Sativex, an oral spray that contains cannabinoids, and found that many had design flaws that made their results unreliable.
“The trials compared the drug against placebo rather than against another drug, some of the trials were short, some included small numbers of patients; some trials didn’t show a benefit from using the drug and some trials used a dose greater than the recommended dose,” Phizackerley wrote.
The spray’s manufacturer, British-based GW Pharmaceuticals, said the article gave “a misleading view of the drug” and contained a number of errors.
“We are surprised and disappointed to note that the DTB article on Sativex contains numerous errors,” said Dr. Stephen Wright, GW Pharmaceuticals’ research and development director. “The writers appear to have misunderstood important elements of the design of Sativex clinical trials and provide a flawed assessment of Sativex data.”
“Furthermore, the article contradicts the opinion of 22 separate national authorities in Europe and around the world that have granted approval for Sativex and recognize the important benefits it provides to MS patients with spasticity.”
Sativex contains a formulation of cannabinoids, marijuana’s most active ingredients. It is sold throughout Europe, Canada and Mexico to treat MS and cancer pain, but is currently not approved for sale in the United States. GW Pharmaceuticals hopes to see FDA approval by the end of 2013.
A recent study out of Germany that looked at over 300 patients found that Sativex reduced MS spasticity by 20% or more in 4 out of 10 patients who were previously unresponsive to conventional therapies. After three months, there was a 30% improvement in symptoms.
In a press release, GW Pharmaceuticals also noted that the journal article “appears not to appreciate the positioning of Sativex in MS therapy… as an alternative treatment when standard therapies fail to provide adequate symptom relief.”
The company also cited Dr. David Shakespeare, lead author of a Cochrane review of anti-spasticity treatments and a consultant in neurological rehabilitation medicine at the Royal Preston Hospital in England.
“I have over six years prescribing experience of Sativex, and in my opinion it provides a valuable addition to multiple sclerosis patients whose spasticity does not respond to other drugs and who would otherwise have no other effective treatment option,” said Shakespeare.
Spasticity is a common symptom of MS causing involuntary spasms, immobility, disturbed sleep and pain. Combinations of drugs can be prescribed to manage spasticity, but they often don’t work that well and have a range of unpleasant side effects
Multiple sclerosis is a chronic disease which attacks the body’s central nervous system and destroys the myelin sheath that protects the nerve cells. An estimated 400,000 Americans have the disease and more than 2 million worldwide.