FDA Approves Epidiolex to Treat Seizures From Tuberous Sclerosis

The US Food and Drug Administration (FDA) has expanded the list of conditions Epidiolex, a CBD-based medication, can treat.

The cannabis-derived oral spray can now be prescribed for seizures associated with tuberous sclerosis complex (TCS), a rare genetic condition that causes benign tumors to develop in different parts of the body.

From two to three

Back in 2018, Epidiolex became the first cannabinoid drug approved for use by the FDA. After reviewing three randomized, double-blind, placebo-controlled clinical trials involving 516 patients, the strawberry-flavored CBD solution was deemed to be a safe and effective treatment for children aged two years or older with Lennox-Gastaut and Dravet syndrome, two severe forms of epilepsy.

Now the FDA has added a third indication, TCS-related seizures, to Epidiolex’s list of treatable conditions and expanded the patient age range to allow one-year-olds and older living with Lennox-Gastaut and Dravet syndrome to access the medication.

GW Pharmaceuticals, the manufacturer of Epidiolex, made the announcement on Monday, August 3.

“FDA approval of this new indication is exciting news for those with refractory seizures due to tuberous sclerosis complex,” Justin Gover, GW’s chief executive officer, said in a statement. “Since Epidiolex is already available to patients by physician’s prescription, patients with TSC can immediately access the medication.”

About 50,000 people live with TSC in the US, along with some one million people worldwide. Around 85 percent of those living with the condition experience epilepsy, most of which struggle to achieve seizure control.

The FDA judged Epidiolex to be safe and effective treatment for TCS seizures following a randomized, double-blind, placebo-controlled trial, in which 148 patients (from a total of 224) received the CBD solution. Although common side effects of the drug included diarrhea, a decreased appetite, sleepiness, and vomiting, the FDA still found that the Epidiolex patients experienced a significantly greater reduction in seizure frequency than patients who received a placebo.

“The FDA continues to believe the drug approval process represents the best way to make new medicines, including any drugs derived from cannabis, available to patients in need of appropriate medical therapy such as the treatment of seizures associated with these rare conditions,” Douglas Throckmorton, the deputy center director for regulatory programs in the FDA’s Center for Drug Evaluation and Research, said in a statement.

The FDA approval includes a recommended maintenance dose of 25 milligrams per kilogram per day of Epidiolex for TSC patients.

Further approved

The US’s Drug Enforcement Administration (DEA) removed Epidiolex from the FDA’s list of controlled substances this April. And just this June, The UK Home Office reclassified the medication under the lowest level of control for drugs in the country.

But despite its increasing acceptance, some scientists are still concerned about Epidiolex’s effectiveness. In late 2019, a paper published in the British Journal of Clinical Pharmacology argued that the beneficial effects seen in clinical trials of Epidiolex could actually be attributed to a drug-drug interaction between CBD and clobazam, another common anti-epileptic medication. 

“I went back to [two of the three cited] papers… and I thought, ‘let’s have a look.’ How many of those patients were actually using clobazam?” Geert Jan Groeneveld, the study’s lead author, told Analytical Cannabis last November.

“And I was awestruck,” he said. “I was flabbergasted when I saw that 50 percent in one study and 60 percent in the other study were actually using this other drug, clobazam.”

“I'm not saying that I know for a fact that cannabidiol (CBD) does not have any anti-epileptic effects. What I am saying is, I can explain the effects that you've observed through elevated blood levels of clobazam.”

Since being approved by the FDA in 2018, more than 15,000 US patients have taken Epidiolex. GW Pharmaceuticals earned $86.1 million in revenue from the drug in 2019’s first quarter alone.