Cannabis fails to slow progress of MS in UK study

* No evidence of benefit in long-term clinical trial

* Study tested capsules of active cannabis ingredient THC

LONDON, May 29 (Reuters) - Cannabis capsules failed to slow the progression of multiple sclerosis in a large British study, dealing a blow to hopes that the drug could provide long-term benefits for patients with the debilitating nerve disease.

Despite promising signs in earlier, shorter studies, researchers found patients who took capsules containing tetrahydrocannabinol (THC), a key active ingredient in cannabis, fared no better than those given a placebo.

The finding is a disappointment for researchers who thought cannabis might provide a viable therapy in the disease's secondary progressive stage, when patients have few treatment options.

Multiple sclerosis (MS) patients were assessed in the trial known as CUPID (cannabinoid use in progressive inflammatory brain disease) on both a disability scale administered by neurologists and another based on their own reporting.

"Overall the study found no evidence to support an effect of THC on MS progression in either of the main outcomes," researchers led by John Zajicek of the Peninsula College of Medicine and Dentistry, Plymouth University, said.

Results from the study, which was funded by Britain's Medical Research Council, will be presented at the Association of British Neurologists' annual meeting in Brighton later on Tuesday.

Cannabis contains more than 60 different cannabinoids, of which THC is thought to be the most active, and many MS patients have long said the drug helps them cope with the effects of the disease.

Drug companies, too, have been interested in cannabis as a medicine. Britain's GW Pharmaceuticals (LSE: GWP.L - news) , working with Bayer and Almirall (Berlin: E2Z.BE - news) , recently started selling an under-the-tongue cannabis spray called Sativex to relieve spasticity.

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Cannabis fails to slow progress of MS in UK study