Pubdate: Sat, 29 Apr 2006
Source: Economist, The (UK)
Section: Science and Technology
Copyright: 2006 The Economist Newspaper Limited
Bookmark: (Cannabis - Medicinal)


Medical Marijuana

Marijuana Is Medically Useful, Whether Politicians Like It Or Not

IF CANNABIS were unknown, and bioprospectors were suddenly to find it 
in some remote mountain crevice, its discovery would no doubt be 
hailed as a medical breakthrough. Scientists would praise its 
potential for treating everything from pain to cancer, and marvel at 
its rich pharmacopoeia--many of whose chemicals mimic vital molecules 
in the human body. In reality, cannabis has been with humanity for 
thousands of years and is considered by many governments (notably 
America's) to be a dangerous drug without utility. Any suggestion 
that the plant might be medically useful is politically 
controversial, whatever the science says. It is in this context that, 
on April 20th, America's Food and Drug Administration (FDA) issued a 
statement saying that smoked marijuana has no accepted medical use in 
treatment in the United States.

The statement is curious in a number of ways. For one thing, it 
overlooks a report made in 1999 by the Institute of Medicine (IOM), 
part of the National Academy of Sciences, which came to a different 
conclusion. John Benson, a professor of medicine at the University of 
Nebraska who co-chaired the committee that drew up the report, found 
some sound scientific information that supports the medical use of 
marijuana for certain patients for short periods--even for smoked marijuana.

This is important, because one of the objections to marijuana is 
that, when burned, its smoke contains many of the harmful things 
found in tobacco smoke, such as carcinogenic tar, cyanide and carbon 
monoxide. Yet the IOM report supports what some patients suffering 
from multiple sclerosis, AIDS and cancer--and their doctors--have 
known for a long time. This is that the drug gives them medicinal 
benefits over and above the medications they are already receiving, 
and despite the fact that the smoke has risks. That is probably why 
several studies show that many doctors recommend smoking cannabis to 
their patients, even though they are unable to prescribe it. Patients 
then turn to the black market for their supply.

Another reason the FDA statement is odd is that it seems to lack 
common sense. Cannabis has been used as a medicinal plant for 
millennia. In fact, the American government actually supplied 
cannabis as a medicine for some time, before the scheme was shut down 
in the early 1990s. Today, cannabis is used all over the world, 
despite its illegality, to relieve pain and anxiety, to aid sleep, 
and to prevent seizures and muscle spasms. For example, two of its 
long-advocated benefits are that it suppresses vomiting and enhances 
appetite--qualities that AIDS patients and those on anti-cancer 
chemotherapy find useful. So useful, in fact, that the FDA has 
licensed a drug called Marinol, a synthetic version of one of the 
active ingredients of marijuana--delta-9-tetrahydrocannabinol (THC). 
Unfortunately, many users of Marinol complain that it gets them high 
(which isn't what they actually want) and is not nearly as effective, 
nor cheap, as the real weed itself.

This may be because Marinol is ingested into the stomach, meaning 
that it is metabolised before being absorbed. Or it may be because 
the medicinal benefits of cannabis come from the synergistic effect 
of the multiplicity of chemicals it contains. Just what have you been smoking?

THC is the best known active ingredient of cannabis, but by no means 
the only one. At the last count, marijuana was known to contain 
nearly 70 different cannabinoids, as THC and its cousins are 
collectively known. These chemicals activate receptor molecules in 
the human body, particularly the cannabinoid receptors on the 
surfaces of some nerve cells in the brain, and stimulate changes in 
biochemical activity. But the details often remain vague--in 
particular, the details of which molecules are having which clinical effects.

More clinical research would help. In particular, the breeding of 
different varieties of cannabis, with different mixtures of 
cannabinoids, would enable researchers to find out whether one 
variety works better for, say, multiple sclerosis-related spasticity 
while another works for AIDS-related nerve pain. However, in the 
United States, this kind of work has been inhibited by marijuana's 
illegality and the unwillingness of the Drug Enforcement 
Administration (DEA) to license researchers to grow it for research.

Since 2001, for example, Lyle Craker, a researcher at the University 
of Massachusetts, has been trying to obtain a licence from the DEA to 
grow cannabis for use in clinical research. After years of 
prevarication, and pressure on the DEA to make a decision, Dr 
Craker's application was turned down in 2004. Today, the saga 
continues and a DEA judge (who presides over a quasi-judicial process 
within the agency) is hearing an appeal, which could come to a close 
this summer. Dr Craker says that his situation is like that described 
in Joseph Heller's novel, "Catch 22". "We can say that this has no 
medical benefit because no tests have been done, and then we refuse 
to let you do any tests. The US has gotten into a bind, it has made 
cannabis out to be such a villain that people blindly say 'no'."

Anjuli Verma, the advocacy director of the American Civil Liberties 
Union (ACLU), a group helping Dr Craker fight his appeal, says that 
even if the DEA judge rules in their favour, the agency's chief 
administrator can still decide whether to allow the application. And, 
as she points out, the DEA is a political organisation charged with 
enforcing the drug laws. So, she says, the ACLU is in this for the 
long haul, and is already prepared for another appeal--one that would 
be heard in a federal court in the normal judicial system.

Ms Verma's view of the FDA's statement is that other arms of 
government are putting pressure on the agency to make a public 
pronouncement that conforms with drug ideology as promulgated by the 
White House, the DEA and a number of vocal anti-cannabis congressmen. 
In particular, the federal government has been rattled in recent 
years by the fact that eleven states have passed laws allowing the 
medical use of marijuana. In this context it is notable that the 
FDA's statement emphasises that it is smoked marijuana which has not 
gone through the process necessary to make it a prescription drug. 
(Nor would it be likely to, with all of the harmful things in the 
smoke.) The statement's emphasis on smoked marijuana is important 
because it leaves the door open for the agency to approve other 
methods of delivery. High hopes

Donald Abrams, a professor of clinical medicine at the University of 
California, San Francisco, has been working on one such option. He is 
allowed by the National Institute on Drug Abuse (the only legal 
supplier of cannabis in the United States) to do research on a German 
nebuliser that heats cannabis to the point of vaporisation, where it 
releases its cannabinoids without any of the smoke of a spliff, and 
with fewer carcinogens.

That is encouraging. But it does not address the wider question of 
which cannabinoids are doing what. For that, researchers need to be 
able to do their own plant-breeding programmes.

In America, this is impossible. But it is happening in other 
countries. In 1997, for example, the British government asked 
Geoffrey Guy, the executive chairman and founder of GW 
Pharmaceuticals, to come up with a programme to develop cannabis into 
a pharmaceutical product.

In the intervening years, GW has assembled a "library" of more than 
300 varieties of cannabis, and obtained plant-breeder's rights on 
between 30 and 40 of these. It has found the genes that control 
cannabinoid production and can specify within strict limits the seven 
or eight cannabinoids it is most interested in. And it knows how to 
crossbreed its strains to get the mixtures it wants.

Nor is this knowledge merely academic. Last year, GW gained approval 
in Canada for the use of its first drug, Sativex, which is an extract 
of cannabis sprayed under the tongue that is designed for the relief 
of neuropathic pain in multiple sclerosis. Sativex is also available 
to a more limited degree in Spain and Britain, and is in clinical 
trials for other uses, such as relieving the pain of rheumatoid arthritis.

At the start of this year, the company made the first step towards 
gaining regulatory approval for Sativex in America when the FDA 
accepted it as a legitimate candidate for clinical trials. But there 
is still a long way to go.

And that delay raises an important point. Once available, a 
well-formulated and scientifically tested drug should knock a herbal 
medicine into a cocked hat. No one would argue for chewing willow 
bark when aspirin is available. But, in the meantime, there is unmet 
medical need that, as the IOM report pointed out, could easily and 
cheaply be met--if the American government cared more about suffering 
and less about posturing.
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MAP posted-by: Beth Wehrman