BioWorld International Correspondent

LONDON - GW Pharmaceuticals plc said the first cannabis-based prescription medicine will be on the UK market next year, as it announced positive results from each of four Phase III trials in 350 patients suffering from multiple sclerosis and neuropathic pain.

Each of the four trials reported positive data, including statistically significant reductions in pain, spasticity and sleep disturbance. As a result, GW said it intends to submit its first regulatory application early next year. The results also appear to put an end to the long-running debate over whether or not smoking cannabis relieves the symptoms of MS.

Geoffrey Guy, executive chairman, said the data had exceeded expectations. "These preliminary Phase III results represent a major milestone in the pharmaceutical development of cannabis-based medicines."

The trials are part of the largest clinical program ever undertaken into the medicinal effects of cannabis. The four randomized, double-blind Phase III trials compared GW's cannabis extract, which contains tetrahydrocannabinol (THC) and cannabidiol (CBD), with placebo. The drug is administered as a sublingual spray.

In a study comparing the THC-CBD product to placebo in the treatment of neuropathic pain in 66 patients with MS, the product provided statistically significant pain relief and reduction in sleep disturbance.

In a parallel study in the treatment of chronic refractory pain in 70 patients with MS and other neurological conditions, THC-CBD provided statistically significant pain relief (as evidenced by reduced use of analgesics) and reduction in sleep disturbance. In the third study with 160 patients, there was a highly statistically significant improvement in spasticity, and positive trends also were observed in a number of other MS symptoms.

In the fourth study in 48 patients with brachial plexus injury, which causes intractable neuropathic pain, both THC-CBD and THC alone provided highly statistically significant relief of pain.

Patients receiving both the active compound and placebo continued to take their usual medication during the trial. GW, based in Salisbury, said the benefits seen in all four studies are more notable in that they represent improvements over and above that which patients obtain with their standard prescription medicines.

"The performance of GW's medicine has exceeded our own expectations and holds out the prospect of providing a significant advance in the treatment of these most challenging medical conditions," Guy said.

The trials also demonstrated that self-adjustment of the dose enabled most patients to achieve an improvement in their symptoms without incurring unwanted effects that interfered with day-to-day living.

GW, which raised £23.5 million (US$37.3 million) when it listed on London's Alternative Investment Market last year, has a further five Phase III trials in progress, in indications including cancer pain and spinal cord injury.

In the past, the UK government has been resistant to research into the medical benefits of cannabis in treating nerve damage, but more recently has allowed GW a license to carry out its work. The government also has said that if a cannabis-based medicine is approved by the UK Medicines Control Agency, it would amend legislation to allow it to be made available by prescription.