DRUG TRIAL CASTS DOUBT OVER CANNABIS-BASED PAINKILLER FOR MS SUFFERERS

A cannabis-based painkiller has performed little better than a dummy
drug in trials, raising doubts about its effectiveness in treating
multiple sclerosis.

Sativex, which contains THC, the active ingredient in cannabis, is
being used as a painkiller by around 1,400 MS sufferers in Britain.

The mouth spray's makers, Wiltshire-based GW Pharmaceuticals, also
hope to market it to ease the muscle spasms associated with MS and
the pain of cancer.

However, its worth has been thrown into doubt by a test involving
more than 300 MS patients.

While half of those taking Sativex found their pain was reduced by at
least 30 per cent, those using a dummy spray fared almost as well.

GW said the result could be explained by an "unexpectedly strong
placebo response" - in which symptoms are eased by the simple belief
that a treatment will work.

The news sent the company's shares plummeting by as much as 31 per
cent. GW, however, remains adamant there was a place for Sativex on
the pharmacist's shelf.

Managing director Justin Gover said there was a 'desperate need' for
new pain treatments and the drug had a "real role" to play.

The treatment, which is sprayed under the tongue four or five times a
day, first went on the market in Canada in 2005.

Britain's drug regulators have yet to deem it safe and effective.
However, doctors can prescribe it on a 'named patient' basis, which
means they take personal responsibility for giving the drug.

A typical daily treatment of five sprays costs around UKP4.

GW grows 40,000 cannabis plants a year at a secret location in the
English countryside.