Pubdate: Tue, 21 Jun 2005
Source: Canadian Medical Association Journal (Canada)
Copyright: 2005 Canadian Medical Association
Contact:  http://www.cmaj.ca/
Details: http://www.mapinc.org/media/754
Author: Barbara Sibbald
Photo: To meet demand for Sativex, GW Pharmaceuticals has increased 
production at its fortified greenhouses in the UK to 60 tonnes per year. 
Photo by ABPI http://www.mapinc.org/images/greenhouse.gif
Cited: GW Pharmaceuticals http://www.gwpharm.com/
Bookmark: http://www.mapinc.org/mmjcn.htm (Cannabis - Medicinal - Canada)
Bookmark: http://www.mapinc.org/find?232 (Chronic Pain)
Bookmark: http://www.mapinc.org/topics/Sativex (Sativex)
Bookmark: http://www.mapinc.org/find?323 (GW Pharmaceuticals)

Drug Regulation

CONDITIONAL OKAY FOR CANNABIS PRESCRIPTION DRUG

Health Canada has conditionally approved the first cannabis-derived
prescription pain killer. Cannabis sativa extract (Sativex), an
under-the-tongue spray, was approved in April for use as an adjunctive
treatment for the symptom relief of neuropathic pain in patients with
multiple sclerosis (MS). The drug should be available by June 21.

Figure. To meet demand for Sativex, GW Pharmaceuticals has increased
production at its fortified greenhouses in the UK to 60 tonnes per
year. Photo by: ABPI

The approval is conditional on the manufacturer, UK-based GW
Phamaceuticals, conducting more clinical trials to confirm efficacy.
Health Canada gave conditional approval because the drug fills an
"unmet need," said spokesperson Jirina Vlk.

About 160 patients with MS already obtain cannabis through the
Marihuana Medical Access Program. The department won't know whether
Sativex will reduce enrolment in that program for about a year, said
Vlk. "People may try [Sativex], then switch back [to smoking
marijuana]."

Underlying the approval is an unpublished, phase III randomized
controlled trial involving 66 patients with MS-related neuropathic
pain; half took the drug and half placebo. The group receiving Sativex
reported pain relief, less sleep disturbance and felt their condition
had improved. Side effects included dizziness, nausea and fatigue.

"The data are okay, but not overwhelming," says Dr. Paul O'Connor,
director of the St. Michael's Hospital MS Clinic -- Canada's largest,
with 5000 patients. Results from previous trials, even one with 667
patients (Lancet 2003;362:1517-26), have not produced consistent
results, adds O'Connor.

In December, the UK refused to approve Sativex for the control of
spasticity in patients with MS. The UK Medicines and Healthcare
Products Regulatory Agency raised concerns about whether the results
of a recent trial are statistically relevant. GW, which is developing
a "portfolio of cannabis medicines" to treat people with diabetes,
spinal cord injury, cancer pain and more, is appealing the decision.

O'Connors says he is "pleased patients have another option" that
offers a more controlled dose than smoked cannabis.

Many patients also want to control the "high" they get from smoking.
Health Canada's statement of approval says that 70.5% of patients
"experienced an adverse event classified as an 'intoxication type
reaction,'" including "feeling drunk."

These adverse effects can be controlled by reducing the size or
frequency of doses, says Dr. Tom Segerson of Bayer Canada, the
division of GW in charge of distributing the drug here. 
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MAP posted-by: Richard Lake