Drugs derived from marijuana are less effective than standard drugs when it comes to curbing loss of appetite and weight in cancer sufferers, according to the latest research by the Mayo Clinic and the North Central Cancer Treatment Group (NCCTG) published in this month's Journal of Clinical Oncology.
The study, which claims to be the first of its kind, looked at the respective effects of megestrol acetate, a standard drug for treating loss of appetite and weight in cancer patients, and dronabinol (sold under the brand name Marinol), a drug derived from marijuana.
Researchers found that the standard drug was more effective than Marinol, and that there was no notable benefit when both drugs were given together.
"Anecdotal reports and previous small studies suggested that marijuana and its derivatives stimulate appetite," said Aminah Jatoi, M.D., a Mayo Clinic oncologist and researcher on the study.
"Our study found that dronabinol, in the doses prescribed in this trial, doesn't hold up to standard treatment with megestrol acetate. These findings should dampen enthusiasm for using marijuana derivatives for this purpose."
The study showed that 75% of the patients taking megestrol acetate reported appetite improvement, compared with only 49% of patients taking dronabinol. At the same time, 11% of the patients on megestrol acetate gained more weight, compared with only 3% on dronabinol.
Over 50% of cancer sufferers are affected by problems related to loss of appetite and weight, but little is known of the causes. "Nobody knows all of the factors that come into play as cancer patients lose weight," said Jatoi. "This study was an attempt to help cancer patients by finding some answers about what works and what doesn't work for those struggling with eating.
She continued: "To our knowledge, this is the first study to compare a standard drug to a drug derived from marijuana in an effort to help cancer patients with this problem."
A total of 469 cancer patients were evaluated by the study, after being randomly placed into one of three groups. The first group received 800mg of megestrol acetate liquid each day plus a capsule placebo, while the second took 2.5mg of dronabinol capsules twice a day along with a liquid placebo. The third group was given a combination of both medications in the same dosages noted.
Jatoi noted that megestrol acetate is not the complete answer to stimulating appetite and boosting weight in cancer patients and more research needs to be done to find better drugs.
"But at this time, we can say that megestrol acetate is more effective than dronabinol in the doses we tested," she said.