A British drug company said on 16 November it hoped to have a cannabis-based medicine ready to be prescribed by doctors within three or four years. GW Pharmaceuticals said it was making progress in clinical studies with cannabis-based medicines.

Volunteers had been taking cannabis under clinical conditions in order to determine the best dose and toleration of treatment. The pilot Phase I study involved just six healthy individuals and was intended to pave the way for larger patient trials. They had taken cannabis either from an inhaler or via liquid under the tongue.

Dr Geoffrey Guy, the company's chairman, said: "All the subjects came through very well, and we were very pleased with the study. Now we have a much better idea of what our starting point should be." Heart rate, temperature and respiration were monitored and blood samples taken for analysis. In addition each volunteer went through a battery of cognitive and psychometric tests. Dr Guy said: "We have been able to define and follow through the psychoactive effects. None of the effects is disturbing, or would be classed in a clinical trial as serious." He said patients did not need to "get high" to gain a therapeutic benefit.

If approved by the regulatory authorities, the second phase trials would commence next year. They will involve up to two or three hundred patients with multiple sclerosis, spinal cord injury, and phantom limb pain, said Dr Guy. By the end of the final Phase III trials a total of around 2,000 patients will have taken part. The main studies should be completed in 2002.

"Subject to the necessary regulatory approvals, we hope to have a cannabis-based medicine available for prescription by doctors within three to four years," Guy said. GW Pharmaceuticals is licensed by the British Home Office (Interior Ministry) to grow, possess and supply cannabis for medical research. Dr Guy personally potted GW Pharmaceuticals' 20,000th cannabis plant on August 24 this year. The plants are housed in a highly secure and environmentally controlled glasshouse at a secret location.

(Sources: Reuters of 16 November 1999)