Top U.S. Food and Drug Administration officials acknowledged the complexities they face in regulating products containing cannabidiol, or CBD, admitting regulators are far from answering a multitude of questions as they deal with their new terrain.

Acting FDA Commissioner Ned Sharpless got right to the point at the start of a 10-hour May 31 public hearing, admitting the agency does not know whether there is a safe amount of CBD that can be consumed in a day or the length of time it should be used, if there are risks of using it during pregnancy, whether it should be given to children in any form and how it may possibly interact with prescription medicines or other products.

He said the FDA has formed an internal working group to address the gaps in the agency's knowledge about CBD and to figure out a pathway for regulating the products, which are increasingly being illegally marketed in the U.S. in a number of forms.

Sharpless acknowledged that Congress triggered confusion over the legality of CBD in the U.S. when it removed hemp — cannabis or derivatives of it that contain less than 0.3% of delta-9-tetrahydrocannabinol, or THC, by dry weight — from the Controlled Substances Act's definition of marijuana as part of the December 2018 Agriculture Improvement Act, or the Farm Bill.

While marijuana remains a Schedule I drug under the 1970 law — drugs with no currently accepted medical use and a high potential for abuse — hemp is no longer considered a controlled substance under the 2018 Farm Bill.

But the new law did not change the FDA's authorities to regulate cannabis or products derived from it, and CBD remains a drug in the agency's eyes.

"What that means is that under current law, CBD and THC cannot lawfully be added to a food or marketed as a dietary supplement," Sharpless said.

While shops and websites are increasingly illegally marketing CBD products in the U.S. in a variety of forms — soft drinks, teas, lotions, makeup, pet treats and more — the FDA has only issued warning letters to a handful of companies.

Hot topic

The popularity of and concern about making CBD consumer products legal in the U.S. was evident by the jam-packed meeting at the FDA's headquarters in Silver Spring, Md., on May 31.

More than 400 people had asked to speak at the public hearing, but the FDA said it was able to only accommodate about 120 presenters.

Lisa Gill from the nonprofit Consumer Reports noted that a survey conducted in January of 4,355 U.S. adults by her organization found that 26% of responders said they had tried a CBD product at least once in the past two years.

Of those, 37% said they used CBD to reduce stress or anxiety or to help them relax, while 24% said they used the products to relieve joint pain. About 11% said they used CBD for fun or recreation and 10% said they used the products to improve their sleep.

Many of the responders said they replaced their prescription or over-the-counter drugs with CBD, including 36% who said they now use it in place of a prescribed opioid.

The poll, however, also found that many Americans mistakenly believed that the CBD products they were using had gone through testing and FDA regulatory processes to ensure efficacy and safety.

Cowen & Co. analysts estimated the U.S. CBD market could be worth $16 billion by 2025, while the Brightfield Group, a marketing research company, put it at $22 billion by 2022.

Clinical testing

Many of the speakers at the FDA meeting argued the agency could use its dietary supplement framework for CBD and did not need to create a new pathway, while others insisted the products should be required to submit clinical data demonstrating efficacy and safety. Other presenters fell somewhere in between.

"Ladies and gentlemen, the genie is out of the bottle and it is probably impossible to force it back inside," said Colorado lawyer Dave Rodman, whose law firm represents a number of cannabis growers, investors and dispensaries.

Andy Snyder, who authors an online newsletter, Manward Press, criticized the FDA for its "slow to non-existent" response to CBD, which he said was "just a few years away from being perceived by most Americans as vitamin C or any other common drug or vitamin."

"We're five years into a multibillion-dollar industry and we're just talking about it with you guys and you weren't even aware of some of the issues for researchers testing this stuff," said Justin Blehar, co-founder of Genco Pura Oil Co., which sells CBD products.

Some who testified said the U.S. CBD market had already turned into "the Wild West," lacking standards and uniformity and operating under a patchwork of unclear state rules.

Peter Pitts, president of the Center for Medicine in the Public Interest and a former associate commissioner at the FDA, warned that the agency needs to put a hold on the "aggressive and misleading marketing campaigns" by CBD makers and distributors, insisting the U.S. could find itself in another epidemic like the opioid crisis.

Given the rapid expansion of the CBD market, Amy Abernethy, principal deputy commissioner at the FDA, who was among the panel of regulators at the May 31 hearing, acknowledged timely clarification of a path forward was critical.

"But it's our responsibility to ensure that the regulatory path is scientifically sound and in the interest of public health," Abernethy tweeted during the public meeting.

Clear differentiation needed

The FDA has already approved one drug containing CBD — GW Pharmaceuticals PLC's Epidiolex, an oral solution indicated to treat seizures associated with Lennox-Gastaut syndrome and Dravet syndrome in patients as young as 2 years old.

"The FDA approval process is the only way to answer important questions about a drug, about the disease it seeks to treat and safety considerations that are unique to patients who will take the drug," said Alice Mead, a vice president at Greenwich Biosciences, a subsidiary of GW Pharmaceuticals PLC.

Mead noted that no one knew CBD was potentially toxic to the liver until GW conducted preclinical and clinical studies on the compound.

CBD also has been found to have drug-drug interactions with other medications, like warfarin, a common blood-thinner, Mead said.

"There is still so much we do not know about CBD," she added.

Steve Schultz, vice president of investor relations at GW, told S&P Global Market Intelligence it was critical the FDA provide a clear differentiation between products like Epidiolex, which has gone through the U.S. drug approval process, and the retail CBD products.

"The scientific evidence for Epidiolex can't be extrapolated to any other CBD product, and I think some of that is going on out there. Patients and companies are confusing the two," Schultz said.

Washington lawyer Will Garvin, shareholder and co-head of the cannabis group at Buchanan, Ingersoll and Rooney PC, argued that while anecdotal information does not rise to the level of well-run clinical trials, it nonetheless remains useful about whether there are adverse events or therapeutic benefits.

"If the use of these products lessens the impact of opioid dependency, then that would be something that would have a prevailing good for the public health that FDA should investigate," Garvin told S&P Global Market Intelligence.

But he emphasized that "first and foremost, the FDA is a public health institution of government and so they should focus primarily on science."