FDA/CDC

Cannabis: Doctors tell FDA to get out of the weeds


 

FROM AN FDA PUBLIC HEARING

The Food and Drug Administration held its first-ever public hearing about products containing cannabis or cannabis-derived compounds – and it got an earful.

Hearing from over 100 individuals, the all-staff FDA panel was asked repeatedly to take the lead in bringing order to a confused morass of state and local cannabis regulations. The regulatory landscape currently contains many voids that slow research and put consumers at risk, many witnesses testified.

The federal Farm Bill of 2018 legalized the cultivation of hemp – cannabis with very low 9-tetrahydrocannabinol (THC) content – with regulatory restrictions.

However, the Farm Bill did not legalize low-THC cannabis products, said FDA Acting Commissioner Norman Sharpless, MD. The agency has concluded that both THC and cannabidiol (CBD) are drugs – not dietary supplements – and any exception to these provisions “would be new terrain for the FDA,” he said.

Dr. Norman Sharpless

And although restrictions on CBD sales have generally not been enforced, “under current law, CBD and THC cannot lawfully be added to a food or marketed as a dietary supplement,” said Dr. Sharpless.

Though the FDA could choose to carve out regulatory exceptions, it has not yet done so.

Stakeholders who gave testimony included not just physicians, scientists, consumers, and advocates, but also growers, manufacturers, distributors, and retailers – as well as the legal firms that represent these interests.

Broadly, physicians and scientists encouraged the FDA to move forward with classifying CBD and most CBD-containing products as drugs, rather than dietary supplements. In general, the opposite approach was promoted by agriculture and manufacturing representatives who testified.

However, all were united in asking the FDA for clarity – and alacrity.

Again and again, speakers asked the FDA to move posthaste in tidying up the current clutter of regulations. Ryan Vandrey, PhD, of Johns Hopkins University, Baltimore, explained that today, “Hemp-derived CBD is unscheduled, Epidiolex is Schedule V, and synthetic CBD is Schedule I in the DEA’s current framework.”

Kevin Chapman, MD, of Children’s Hospital Colorado, representing the American Epilepsy Society, called for regulation of CBD as a drug, and an accelerated clinical trial path. He noted that many families of children with epilepsy other than Lennox-Gastaut or Dravet syndrome (the only approved Epidiolex indications) are dosing other CBD products, “making it up as they go along."

Kari Oakes/MDedge News

Dr. Jacqueline French

Jacqueline French MD, chief scientific officer of the Epilepsy Foundation, agreed that many families of children with epilepsy are doing their best to find consistent and unadulterated CBD products. She said her worry is that “abrupt withdrawal of CBD from the market could lead to seizure worsening, injury, or even death for patients who now rely on non-pharmaceutical CBD for seizure control.”

Dr. French and Dr. Chapman each made the point that without insurance reimbursement, Epidiolex costs families over $30,000 annually, while CBD is a small fraction of that – as little as $1,000, said Dr. Chapman.

The lack of standards for CBD preparations means the content of oils, tinctures, and e-cigarette products can vary widely. Michelle Peace, PhD, a forensic scientist at Virginia Commonwealth University, Richmond, receives funding from the U.S. Department of Justice to study licit and illicit drug use with e-cigarettes. She and her colleagues have found dextromethorphan and the potent synthetic cannabinoid 5F-ADB in vaping supplies advertised as containing only CBD.

In a recent investigation prompted by multiple consumer reports of hallucinations after vaping CBD-labeled products, “17 of 18 samples contained a synthetic cannabinoid. Clinics will not find these kinds of drugs when they just do drug testing,” Dr. Peace said.

Another sampling of CBD products available from retail outlets showed that claims often bore little relation to cannabinoid content, said Bill Gurley, PhD, co-director of the Center for Dietary Supplement Research at the University of Arkansas, Little Rock. While several products that claimed to have CBD actually contained none at all, some had many more CBD than the labeled amount – 228 times more, in one instance. One tested product was actually 45% THC, with little CBD content.

The potential for CBD to interact with many other drugs is cause for concern, noted several presenters. Barry Gidal, PharmD, director of pharmacy practice at the University of Wisconsin, Madison, said that “CBD is a complicated molecule. It has a complicated biotransformation pathway” through at least 9 enzymes within the hepatic cytochrome P450 system.

“It wasn’t until the Epidiolex development program that we began to understand the clinical ramifications of this…. The effect of CBD on other drugs may go beyond the anti-seizure drugs that have been studied so far,” said Dr. Gidal. He pointed to recent published case reports of potential CBD-drug interactions reporting elevated international normalized ratios for a patient on warfarin using CBD, and another report of elevated tacrolimus levels in a patient using CBD.

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