Article In Brief
The FDA-approved cannabidiol-based drug was a welcome development for severe pediatric epilepsy syndromes, experts said. But there are still many unanswered questions about the “artisanal” cannabidiol projects that patients and families request.
CHARLOTTE, NC—Just how confident are pediatric neurologists about prescribing the use of cannabidiol (CBD) for young patients with severe epilepsy syndromes? Answers from a session at the annual meeting of the Child Neurology Society earlier this year suggest the answer is not clear-cut.
Pediatric neurologists on the panel and in the audience said they are still largely confronted with a “Wild West” environment when it comes to deciphering how to proceed with requests for CBD from their patients and families—especially in light of the tangle of federal and state regulations that govern the use and legality of marijuana-related products.
But there was consensus on this point: Emerging data on one such product, the cannabidiol product known as Epidiolex in epilepsy and the explosion of “artisanal” CBD products—from CBD oils to truffles to balm that are grown and sold without FDA regulation—has led to rampant interest from neurology patients and the general public.
“Everyone has encountered patients asking about CBD, thinking it can help with anything and everything that ails them,” said Kathryn McVicar, MD, assistant professor of clinical pediatrics in neurology at Yale University and the moderator of the session.
“We really need to understand what these preparations entail,” she said. Legal cannabis, she said, is huge business—constituting $12.2 billion in consumer spending around the world in 2018 and projected to be $31.3 billion in 2022.
The Legal Issues
Bennett L. Lavenstein, MD, FAAN, chair of the legislative affairs committee of the Child Neurology Society, recounted the ongoing perplexity involving cannabis in US marijuana has been classified as a Schedule I substance, along with heroin and other drugs, but 33 states allow medical marijuana use for qualifying patients.
“According to federal law, any level of state legislation is still illegal under federal law he noted and therein lies the conundrum,” he said.
The 2018 Farm Bill removed hemp and all its derivatives with less than 0.3 percent tetrahydrocannabinol (THC) concentration—the psychoactive compound in cannabis—from the Controlled Substances Act, effectively legalizing hemp cultivation, sale, transport and possession of hemp-derived products as a high regulated crop. But any cannabis product marketed with a claim of therapeutic benefit must be approved by the US Food and Drug Administration (FDA) for its intended use before being sold in interstate commerce.
A comprehensive review by the National Academies of Science and the National Academy of Science Engineering and Medicine found that marijuana had various degrees of effectiveness for several conditions but was specifically effective for chronic pain in cancer, chemotherapy-induced nausea, and alleviation of some symptoms of multiple sclerosis. But it reported limited or no effectiveness in other conditions.
In August 2019, the US Surgeon General issued an advisory on known and potential harms for the developing brain. Published literature reports potential risks of fetal growth restriction, low birth weight, pre-term birth, neonatal intensive care admission and stillbirth.
Clinical research—and therefore FDA approval of— cannabis-related products has been slow largely because research requires registering with the Drug Enforcement Agency and getting cannabis from the National Institute on Drug Abuse (NIDA), which comes from just one grower, the University of Mississippi. But the FDA doesn't object to the clinical investigation of cannabis for medical use, Dr. Lavenstein said. Other potential growers have applications pending.
Patients can potentially get access to cannabis or cannabis-related products through expanded access in serious or life-threatening cases. Another possible option outside of conventional avenues is Right to Try, a federal act designed to help with access to certain investigational drugs, for those with life-threatening illnesses who have tried all other medical options and are not able to enter a clinical trial. These decisions don't involve the FDA.
Frustration has been building over the lack of oversight of CBD. In July, a group from the American Epilepsy Society presented written comments to the FDA, authored by the Council on Clinical Activities, Dr. Lavenstein noted. Those comments were published in Epilepsy Currents in October, suggesting that CBD and cannabis-derived compounds be viewed as drugs as defined by the FDA. This would place CBD and cannabis-derived compounds under the full regulatory control of the FDA and would lead to an appropriate path forward, with all the associated scientific data, safeguards, warnings, marketing and labeling, he said.
What the FDA Approval Means
The FDA-approved cannabidiol-based drug, which became available for use in October of 2018, was a welcome development, said Amy R. Brooks-Kayal, MD, FAAN, chief of pediatric neurology at the University of Colorado, who works in a state where poorly regulated artisanal CBD products were widely used.
“The FDA approval really got rid of issues that we saw with variation in strains and in potency,” she said. “Variations in purity were a major issue for us—and complete lack of information, often, on the specific concentrations, how to dose, interactions, efficacy and safety.... This was a real advance for those of us that had been managing those things.”
The cannabidiol product, Epidiolex, is highly purified and meets FDA standards of consistent concentrations and lack of contaminants, with a regulated manufacturing process. Being available by prescription, and eligible for prescription coverage, has been helpful to families who have been covering the big expense of artisanal products.
CBD has produced significantly greater seizure-reduction rates in Dravet syndrome and Lennox-Gastaut patients compared to placebo, but adverse event rates—most commonly gastrointestinal effects and fatigue—are seen in a lot of patients, Dr. Brooks-Kayal said. These effects usually didn't require patients to leave the trials, she pointed out.
Greenwich Biosciences, which developed Epidiolex, recently announced in a release that researchers saw a reduction in seizure-frequency compared to baseline compared to placebo in tuberous sclerosis patients, but publication of the data is pending.
Doses of first 5 mg per kg per day, then increased to 10 mg per kg per day, tend to give maximal efficacy, with higher doses possible if done “judiciously,” Dr. Brooks-Kayal said.
She cautioned, however, that CBD can have significant drug interactions with some CYP enzyme inhibitors and it also increases sedation with clobazam dosing.
“You may well need to adjust clobazam dosing if you're adding Epidiolex to a patient who is already receiving clobazam,” she said. But there are also data suggesting a synergistic effect with clobazam, “so it may be that that's really a great combination to use if carefully monitored.”
Neurologists are learning more and more about Epidiolex but important questions are still unanswered, she said, including medications it will work with best.
“What we really don't know—and continues to keep many of us up at night—are what are the long-term development and cognitive effects of cannabidiol, and specifically Epidiolex over time? And that is something that will require continued study.”
In the world of artisanal CBD products, confusion still reigns, said Anup D. Patel, MD, FAAN, chief of pediatric neurology at Nationwide Children's Hospital. “There is no monitoring of these ‘street-based’ [artisanal] products and little data on their efficacy and long-term risks,” Dr. Patel said. Even though these artisanal products are often thought of as “natural,” that's a misleading label, he said, much as St. John's Wort came to be found to cause serious interactions with prescription drugs.
CBD products are not legally allowed to make medical claims—and FDA testing of them has found that half contained no cannabinoids and others had less CBD content, or higher THC content, or both, than what was on the label, Dr. Patel said. Still, the general public has been trusting of the products.
A study in Colorado looking prospectively at families who were considering oral cannabis extracts to treat seizures, following them for 12 weeks, saw an observed response rate of 24 percent, with 14 percent stopping use of the products because of an increase in seizures. The median age of the 21 patients was 10 years old. Concentrations were labeled in just nine of the cases and eight used products without concentration information available. The other four used a combination of products that had labeled and unlabeled concentrations.
“What that says is that parents were willing to give their children a product without actually knowing what was in it—nor was there advertising of what was in it,” Dr. Patel said.
An oral CBD formulation called PTL101—manufactured with a proprietary gelatin matrix made with a natural and digestible polymer soluble at body temperature—includes CBD derived from a highly purified extract that is more than 93 percent CBD and less than 0.2 percent THC. At an initial dose of 50 mg up to a maximum of 25 mg/kg per day or 450 mg, whichever was lower, patients had an average 73 percent reduction in monthly seizure frequency. But five of the initial 16 patients withdrew, two because of worsening seizures and one, due to mild adverse events. The most common effects were nervousness and sleep disturbances, each reported by four patients, as well as sleepiness and increased epileptic seizures.
Another study, STAR 1—in which 188 patients were randomized to a CBD transdermal gel or placebo, with 174 completing the trial—found no statistically significant reduction in monthly seizure frequency, with a high rate of placebo response.
Dr. Patel said it's important to remember that the products are grossly understudied, so claims made about them are mostly not backed by data.
“They will tell you—you will hear this from your families—there's no side effects to these products, and there's side effects to the FDA-approved product Epidiolex,” he said. “The absence of side effects is only because those were not tested in these products, so therefore you can't say they're without side effects.”
Drs. McVicar, Lavenstein, and Brooks-Kayal had no disclosures. Dr. Patel has received consulting fees from Greenwich Biosciences, UCB Pharma, LivaNova, and Supernus.