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NIH Record

For Medicinal Purposes
Expert Group Examines Science Of Smoking Marijuana

By Carla Garnett

On the Front Page...
NIH convened a group of experts Feb. 19-20 to hear scientific presentations and review research data on use of marijuana as a therapeutic agent. Following the 11/2-day workshop, the 8-member group agreed that further study of the most promising clinical applications of smoked marijuana is warranted, said Dr. William Beaver, professor of pharmacology at Georgetown University School of Medicine and chair of the ad hoc group.

NIH assembled the workshop in response to recent passage of referenda in California and Arizona that make it legal for physicians in those states to prescribe marijuana cigarettes for their patients. Attempting to distance itself from policy battles over marijuana smoking, NIH asked the group of pharmacologists, physicians and investigators to undertake the difficult task of sorting through what meager clinical research exists about benefits and risks of smoking the illegal drug for such disorders as glaucoma, the nausea and vomiting associated with cancer chemotherapy, and AIDS wasting.

"NIH is seeking advice on four major questions," said Dr. Alan Leshner, NIDA director, in opening remarks on behalf of NIH. NIDA is one of 10 NIH components that cosponsored the workshop, and is the only source from which doctors can legally obtain marijuana for clinical research. The panel sought specifically to answer the following: What research has been done on the medical uses of marijuana? What are the unanswered questions involving use of the drug? What are the diseases and disorders for which marijuana might have potential as a treatment and that merit further study? What special issues have to be considered in conducting clinical trials on the therapeutic uses of marijuana?

"We are interested only in the science of this issue," Leshner stressed, "not in the politics or policymaking of smoking marijuana."

About 5 minutes into Leshner's introduction, a group of a dozen or so people carrying placards rose shouting from their seats in Natcher auditorium. "Stop the war on patients!" they yelled repeatedly. "Stop harassing doctors!" The outbursts were referring to what some see as unfair treatment of people -- some doctors, some patients -- who have been prescribing or smoking marijuana despite the current illegality of the drug. Gen. Barry McCaffrey, White House drug control policy director, and others in the government's battle against drug abuse have criticized all illegal marijuana use.

The planned disruption was a protest against the workshop, which some advocates of marijuana viewed as a stalling tactic by federal policymakers. Patients are suffering and dying, protesters contended, while NIH, HHS and other government entities delay potential therapy in the form of marijuana. The demonstrators also denounced NIH's decision to exclude from the ad hoc group physicians who prescribe the drug illegally and patients who smoke marijuana to ease disease symptoms. The interruption of the meeting lasted only moments, but set a contentious tone for the rest of the session. Disrupters who refused to pipe down were escorted out by NIH police, but were allowed to return if they caused no further disturbance to the workshop.

A lively public comment session was held on day two, at which patients who smoke marijuana for various conditions and others spoke.

Only experts in the field who said they had no particular bias toward or against smoking marijuana for medical purposes were selected for the ad hoc group. Eight other scientists gave presentations on the existing medical and scientific literature on several aspects of the issue -- the pharmacology of marijuana, its effects on appetite stimulation, nausea and vomiting associated with cancer chemotherapy, glaucoma, movement disorders, pain relief, and cachexia (wasting of body mass due to disease) in people with AIDS, and clinical trial considerations for marijuana studies.

"The individuals chosen for the presentations and the expert group were nominated by the NIH planning group," explained Dr. Frank Vocci of NIDA. "The names were ranked in terms of an individual's research experience with marijuana and whether they had offered a public opinion on marijuana effectiveness. If so, they could be a speaker but not a panelist. Those in the expert group were both medical specialists and clinical trialists. Most of these individuals had some direct clinical trials experience."

Dr. Reese Jones, professor at the Langley Porter Institute, University of California, San Francisco, began the science portion with an hour-long lecture on the clinical pharmacology of marijuana. He pointed out a number of issues that complicate the clinical study of smoked marijuana, including the difficulty of designing a blind trial, and the near impossibility of quantifying and standardizing the dosage of a drug that a study participant smokes (and thereby self doses).

"It's the nature of smoking that people dose themselves," he said. "That's one of the advantages of it. But it does present a problem in designing the studies. [In order to get reliable data] a patient must smoke the same way each time, which is virtually impossible."

Of major concern to many group members was the potential risk to the lungs and other organs that the act of smoking itself presents, an issue that must be balanced against any benefit marijuana may offer.

A member of the group of experts, Dr. Paul Palmberg, professor of ophthalmology at the Bascom-Palmer Eye Institute, University of Miami School of Medicine, reported his success with a glaucoma patient who smoked marijuana as part of a compassionate use agreement with the Food and Drug Administration in the 1970's. He said the patient's symptoms were relieved -- with no apparent ill effects to date, nor intoxication. He also said the beneficial effects lasted only a couple of hours. The patient, a woman, had to smoke about 10 cigarettes per day to maintain the level of relief she was experiencing.

In addition, Palmberg mentioned another patient also treated with marijuana cigarettes under an IND whose glaucoma was not relieved by the drug. The large number of major medical advances made in the last decade in treating glaucoma, he said, could diminish the rationale of smoking marijuana to relieve symptoms of the disorder.

Marijuana cigarettes were made available for patients with certain conditions in 1978, under a Single Patient Investigational New Drug (IND) of the FDA. A total of 14 patients ultimately received marijuana under this IND. Compassionate use ended in 1992, due in part to the unpredictability of administering the drug, and the development of newer, more potent and longer lasting alternatives, Jones reported. [One such alternative is Marinol, a synthetic derivative of the major active constituent of marijuana, which was developed with support from NCI. In 1985, FDA approved Marinol for treating the nausea and vomiting of patients undergoing chemotherapy and, in 1992, for use in wasting in patients with AIDS. However some patients, especially those with nausea, say they have difficulty swallowing a capsule.]

These reasons most likely contributed to the decline in research proposals to use marijuana in clinical trials. NIH welcomes clinical investigators to submit proposals for studying the therapeutic effects of marijuana, Leshner said. As with all NIH-funded research, he added, the studies must be carefully peer-reviewed and approved.

"You can argue policy and you can argue politics all you want," workshop chair Beaver concluded, "but if you haven't got the data, then you haven't got an issue."

The group will provide a written summary of its conclusions to NIH director Dr. Harold Varmus in 4 to 5 weeks. This will assist Varmus in considering what actions NIH could take to fund research on the therapeutic potential of marijuana for patients with certain diseases.

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