Oct 04, 2002
By Ben Hirschler, European Pharmaceuticals Correspondent
Somewhere in the south of England, cannabis plants worth a small fortune on the street are growing in high-tech glasshouses.
But this crop, cultivated at a secret location behind a tight security cordon, will never be rolled up and smoked.
Instead, it will be processed into a pharmaceutical-grade extract as part of an initiative that could see cannabis return to medical respectability.
Two British research groups are conducting the world's biggest clinical trials to determine whether the Indian hemp plant really does confer the medical benefits many users claim. They will know the answer in a few months.
Dr. John Zajicek of Derrifield Hospital in Plymouth, southwest England, is leading a government-backed study which has just recruited the last of more than 660 multiple sclerosis (MS) patients, and believes cannabis will pass scientific scrutiny.
"I'm fairly confident we are going to find an effect in reducing spasticity...and it is also going to have an effect on bladder control," he told Reuters.
Results of the 30-centre, placebo-controlled study on the effectiveness of cannabis capsules will be released next May or June.
Meanwhile, GW Pharmaceuticals, a small biotech company holding the sole British licence to develop cannabis-based medicines, will publish its first authoritative clinical trial results for a sublingual spray next month.
GW has already reported good results in treating pain in phase II studies and is optimistic this will be replicated in the pivotal phase III tests.
"One can be confident that the phase III trials are going to yield results reflective of the phase IIs," said Geoffrey Guy, GW's executive chairman. The group is growing 40,000 cannabis plants a year hidden in the English countryside.
If Zajicek and Guy are right, cannabis may be about to return to medicine cabinet after a century in the wilderness.
The British government has already indicated it is ready to alter the medical schedule of drugs that doctors are allowed to prescribe if the trials are successful and Guy expects to have cannabis medicines legally on sale by early 2004.
While shunned by modern doctors, cannabis has a long history of medicinal use, dating back to ancient Chinese times.
The British herbalist Nicholas Culpeper described its analgesic effects in 1653 and Queen Victoria, whose physician described it as "one of the most valuable medicines we possess," is said to have taken cannabis tincture for her menstrual pains.
It fell out of favour in modern medicine because of a lack of any standardised preparations and the development of more potent synthetic compounds.
Nonetheless, many MS patients are convinced that cannabis helps their condition and an estimated 10% of British patients are estimated to use it illegally.
Those expecting a marijuana high, however, are likely to be disappointed. The new medicinal cannabis products are designed to minimise psychoactive effects.
Britain's Multiple Sclerosis Society has welcomed the research but is cautious until it sees more data.
"There is a tremendous amount of anecdotal evidence that cannabis in various forms can be helpful in alleviating some of the most unpleasant symptoms of MS," said spokesman David Harrison.
"But we also know that there have been people with MS who have had very bad experiences. So the main concern is whether the substance is safe in the long term, because people with MS have a condition that is going to last the rest of their life."
Other applications for cannabis derivatives also beckon beyond pain relief and controlling symptoms of MS. One of the more intriguing prospects is using cannabis to control appetite.
It has long been known that when people smoke marijuana they get the "munchies," or a strong urge to eat. Researchers are now looking to harness this effect to stimulate appetite in AIDS and cancer patients.
The French drug maker Sanofi-Synthelabo, meanwhile, has taken the opposite approach by developing a drug that turns off the biological "switch" in the brain which triggers this hunger.
The result is an experimental drug called Rimonabant that appears to help people quit smoking without gaining weight. It is also being developed for obesity.
Scientists are still trying to establish how cannabis works by latching on to special receptors, or biochemical "docking sites," in the body. Their answers could help in the search for novel therapies for a range of ailments.
"Our brains and nervous system are stuffed full of cannabis receptors
and we are only now starting to work out what roles they play," said Zajicek.
© 2002 Reuters Ltd