UK company GW Pharmaceuticals has raised $15 million in a US institutional placing and says it will use the proceeds to develop its cannabis-derived drug Sativex for the American market.

Sativex (tetrahydrocannabinol plus cannabidiol), an oral spray product designed to relieve pain and other symptoms in patients with multiple sclerosis, is already available in Canada, its first market, and is sold there by Bayer Healthcare. GW has just filed an Investigational New Drug application seeking approval in the USA to start Phase III trials of Sativex to treat pain in patients with advanced cancer that has not been adequately relieved by opioid medications.

Cancer pain could be a much bigger market opportunity for Sativex than MS, according to market research data published in November by Decision Resources, which suggests that the world market for all chronic pain medications was $15 billion in 2004 and due to rise to $24 billion by 2014.

Other research has estimated that around 10% of the chronic pain market is accounted for by cancer patients, and GW notes that each year more than 250,000 terminal cancer patients in the USA take opioids for pain relief.

“A previous Phase III clinical study showed that Sativex achieved a statistically significant improvement in pain relief in terminally ill cancer patients," said Dr Russell Portenoy, chairman of the department of pain medicine and palliative care at Beth Israel Medical Center in New York City.

"Although opioids are highly effective analgesics, studies suggest that as many as one-third of patients with pain due to advanced cancer do not obtain adequate relief and new treatments are needed.”

The new shares represent around 5.4% of GW’s issued capital, said the company in a statement. Moreover, the placing is a welcome endorsement of Sativex’ potential, coming just two weeks after an inquest ruled that the product was linked to the death of a patient who took part in a Sativex clinical trials programme in 2003. The case, while unfortunate, is not expected to have any impact on the regulatory progress of Sativex, according to GW.

Meanwhile, the UK form was also lifted in early December by the signing of a £46 million ($80.5m) licensing deal with Spain’s Almirall Prodesfarma for European rights to Sativex.