SAN FRANCISCO — A quarter-century after the U.S. Food and Drug Administration approved the first prescription drugs based on the main psychoactive ingredient in marijuana, additional medicines derived from or inspired by the cannabis plant itself could soon be making their way to pharmacy shelves, according to drug companies, small biotech firms and university scientists.
A British company, GW Pharma, is in advanced clinical trials for the world's first pharmaceutical developed from raw marijuana instead of synthetic equivalents— a mouth spray it hopes to market in the U.S. as a treatment for cancer pain. And it hopes to see FDA approval by the end of 2013.
Sativex contains marijuana's two best known components — delta 9-THC and cannabidiol — and already has been approved in Canada, New Zealand and eight European countries for a different usage, relieving muscle spasms associated with multiple sclerosis.
FDA approval would represent an important milestone in the nation's often uneasy relationship with marijuana, which 16 states and the District of Columbia already allow residents to use legally with doctors' recommendations. The U.S. Drug Enforcement Administration categorizes pot as a dangerous drug with no medical value, but the availability of a chemically similar prescription drug could increase pressure on the federal government to revisit its position and encourage other drug companies to follow in GW Pharma's footsteps.
"There is a real disconnect between what the public seems to be demanding and what the states have pushed for and what the market is providing," said Aron Lichtman, a Virginia Commonwealth University pharmacology professor and president of the International Cannabinoid Research Society. "It seems to me a company with a great deal of vision would say, 'If there is this demand and need, we could develop a drug that will help people and we will make a lot of money.'"
Possessing marijuana still is illegal in the United Kingdom, but about a decade ago GW Pharma's founder, Dr. Geoffrey Guy, received permission to grow it to develop a prescription drug. Guy proposed the idea at a scientific conference that heard anecdotal evidence that pot provides relief to multiple sclerosis patients, and the British government welcomed it as a potential way "to draw a clear line between recreational and medicinal use," company spokesman Mark Rogerson said.
In addition to exploring new applications for Sativex, the company is developing drugs with different cannabis formulations.
"We were the first ones to charge forward and a lot of people were watching to see what happened to us," Rogerson said. "I think we are clearly past that stage."
In 1985, the FDA approved two drug capsules containing synthetic THC, Marinol and Cesamet, to ease side-effects of chemotherapy in cancer patients. The agency eventually allowed Marinol to be prescribed to stimulate the appetites of AIDS patients. The drug's patent expired last year, and other U.S. companies have been developing formulations that could be administered through dissolving pills, creams and skin patches and perhaps be used for other ailments.
Doctors and multiple sclerosis patients are cautiously optimistic about Sativex. The National Multiple Sclerosis Society has not endorsed marijuana use by patients, but the organization is sponsoring a study by a University of California, Davis neurologist to determine how smoking marijuana compares to Marinol in addressing painful muscle spasms.