Canada first to OK cannabis spray for MS

But other patient groups ask "What about us?"

By Owen Dyer

Increasingly, the doctor's potential role in cannabis prescription was abandoned to patient groups, who provide the drug to a far larger number of patients than the government's official program, while police diplomatically look the other way.

But all that may be set to change with the news that marijuana is about to hit mainstream Canadian medicine. Canada has just become the first country in the world to approve a liquid cannabis extract as a medical drug, for the treatment of neuropathic pain in multiple sclerosis (MS).

SPRAY AWAY THE PAIN
The British-made drug Sativex is not a synthetic tetrahydrocannabinol (THC) substitute like Marinol (dronabinol), which is sold in the US. It's a whole plant extract taken from real Cannabis sativa plants and contains all of the psychoactive ingredients found in its black market cousin. The only major difference between Sativex and a joint is that Sativex is not smoked. Instead it will be sold as a buccal spray, allowing dosage to be tightly monitored.

Sativex will be marketed in Canada by the drug giant Bayer, and will very likely be available from pharmacies before the end of May. That does not mean it will hit the pharmacy shelves. Classed as a narcotic, all supplies of Sativex will be held under lock and key in Toronto, and shipped individually to pharmacies in response to each prescription. Repeating prescriptions are not on offer, and since a typical patient will go through about one spray pump a month, some may find accessing Sativex more of a hassle than getting their hands on the raw material through more traditional channels.

Dr Thom Segerson from Bayer said that 30-60% of Canada's estimated 50,000 MS sufferers could benefit from the drug. "Chronic neuropathic pain in MS can be severe and debilitating, and it's a condition for which there's a dearth of effective treatments."

WEED OUT THE SMOKERS
Dr William McIlroy, National Medical Advisor to the MS Society of Canada, agrees that Sativex will be a very useful treatment. "It's clearly important that those who do benefit from cannabinoids are not exposed to unnecessary health risks such as smoking," he says. Naturally, those who are already using marijuana will have to be persuaded to join the fold of Sativex users. In a strictly commercial sense, Bayer could end up competing with drug dealers in a country that has some of the lowest black market prices in the developed world. Bayer hasn't yet named a price for Sativex, but few observers expect it to be cheap. Dr Segerson argues that MS patients will be attracted by the precise titration and improved safety of a carefully designed pharmaceutical product.

Titration is indeed key to Sativex's prospects, because there is no doubt that this product can get you stoned. GW Pharmaceuticals, the British company that grows the plants in a secure undisclosed location, tried a thousand ways to keep the analgesic effect of cannabis while losing the psychoactive effect, but ultimately gave up, concluding that the two were inseparable.

The phase III study of Sativex, in which 424 patients took the drug, found that "intoxication-type adverse reactions" occurred in 70.5% of Sativex patients. But "most of these reactions occurred during the titration period," according to Dr McIlroy.

This has also been the experience of the British leading researcher, Dr William Notcutt, who consistently found that patients didn't want to get high. Rather, they tended to gradually adjust to a dose that gave pain control without intoxication. Of course Sativex will come with warnings about driving and operating dangerous machinery, but in that, says Dr Segerson, it's no different from the vast majority of drugs currently used to control MS symptoms.

GROWING DEMAND
How big is the target market? The number of Canadians currently licensed to receive or grow cannabis for their medical conditions is just 850. But that may be the tip of the iceberg. Philippe Lucas runs the Vancouver Island Compassion Society, which provides cannabis to about 600 people suffering from a range of diseases. He says that the six well-established compassion societies in Canada serve about 8,000 users.

But only 5-10% of his society's members are MS sufferers, says Mr Lucas. Others take the drug for appetite stimulation, sleep disorders, pain or nausea in conditions ranging from cancer to AIDS to, in his case, hepatitis C infection.

Ultimately, he believes, "The Sativex business plan must depend on extensive off-label use." Dr Segerson says: "The approval leaves room for physician discretion in prescribing for other conditions." This would seem to clash with the position of the Therapeutic Products Directorate, whose conditional approval says: "Sativex contains two principal active components: THC and CBD, that are scheduled under the Controlled Drugs and Substances Act and as such cannot be used or prescribed except for their recognized indication." That indication is for MS in adults.

GW pharmaceuticals has a lot more research on other potential uses of Sativex. Ultimately, it seems inevitable that they will be presenting it to Health Canada. But the Holy Grail for pharmaceutical marijuana is the US market. According to Mr Lucas the greatest hotbed of medicinal cannabis use is California. "Their compassion societies serve 100,000 people compared to 8,000 here in Canada, and while Canada has six societies, San Francisco alone has 37."

CANADA LEADS THE WAY
US activists have seized on the Canadian approval as a stick to beat their own government. "The Canadian government has just certified that virtually everything our own government has been telling us about marijuana is wrong," wrote Rob Kampia, director of the Marijuana Policy Project in Washington.

Of course, officially, Washington is dead set against using cannabis as a medicine. Former deputy drug tsar Andrea Barthwell, until recently the Bush administration's spokesperson on medical marijuana, insisted on calling it "medical excuse marijuana."

She once said: "The people who are advancing marijuana as a medicine are perpetuating a cruel hoax that exploits our compassion for the sick." Strangely enough, the new spokesperson for Sativex approval in the US is — you guessed it — former deputy drug tsar Andrea Barthwell. I guess the times are changing.