FDA Approves Cannabidiol for Tuberous Sclerosis Complex

Elizabeth Thiele, MD, PhD

The FDA has approved a new indication for cannabidiol (CBD; Epidiolex; GW Pharmaceuticals) for the treatment of seizures associated with tuberous sclerosis complex (TSC), a rare disease that is the leading cause of genetic epilepsy.¹

The oral solution is approved for use in patients age 1 and older with TSC. Notably, the FDA also expanded the approved age range to patient age 1 and older for the treatment’s other indications, including treatment of Dravet syndrome and Lennox-Gastaut syndrome.

“Based on previous positive trial results in TSC patients, Epidiolex may become an important treatment option for patients. It is a new tool in the toolbox for physicians and could meet a significant unmet need," said Elizabeth Thiele, MD, PhD, director of the Herscot Center for Tuberous Sclerosis Complex at Massachusetts General Hospital, professor of neurology at Harvard Medical School, and clinical investigator.¹ “Nearly two-thirds of individuals with TSC develop treatment-resistant epilepsy and there is a need for new options that may benefit these patients who often try and fail existing treatments.”

Epidiolex was first approved in June 2018 for the treatment of seizures associated with Lennox-Gastaut syndrome and Dravet syndrome, 2 rare, treatment refractory types of epilepsy in patients aged 2 and older. The updated indication now makes the treatment available to these patients who are age 1 and older.

READ MORE: Treating Tuberous Sclerosis: A Time to Shine for a Rare Disease

The highly purified oral CBD solution is only the second FDA-approved treatment for TSC, which is associated with growth of benign tumors in the brain and other organs resulting in seizures, developmental delay, and behavioral problems. The efficacy of CBD in this population was demonstrated in the phase 3 GWPCARE6 trial, a randomized, double-blind, placebo-controlled study of 224 patients who had previously tried and discontinued a median of 4 antiepileptic drugs and were currently taking a mean of 3. The most common concomitant drugs were valproate (45%), vigabatrin (33%), levetiracetam (29%), and clobazam (27%).²

The study, which evaluated both 25 mg/kg and 50 mg/kg doses of CBD versus placebo, met its primary end point, with patients treated with either dose of CBD experiencing a 48% reduction in seizure frequency compared with 24% in the placebo group (P <.01). Those who took CBD were more likely to experience at least a 50% reduction in seizures, observed in 36% of the 25 mg group (P = .0692) and 40% of the 50 mg group (P = .0245) compared with 22% for placebo. Caregivers reported an overall improvement in 69% of those taking 25 mg of CBD, 62% of those taking 50 mg CBD, and 40% of those who received placebo.

The most common adverse events observed in those who received CBD in the study (≥10% and greater than placebo) included diarrhea, transaminase elevations, decreased appetite, somnolence, pyrexia, and vomiting.

“We assessed 2 different daily doses and found the lower dose of 25 mg/kg of weight provides the same benefit with fewer side effects compared to a dose of 50 mg/kg and will likely be the recommended dose,” Thiele said in a statement at the time.²

Indeed, the FDA’s recommended maintenance dose in patients with TSC is 25 mg/kg/day.

REFERENCES

1. FDA approves Epidiolex (cannabidiol) oral solution to treat seizures associated with tuberous sclerosis complex. News release. GW Pharmaceuticals. August 3, 2020. Accessed August 3, 2020. https://www.globenewswire.com/news-release/2020/08/03/2071601/0/en/FDA-Approves-EPIDIOLEX-cannabidiol-Oral-Solution-to-Treat-Seizures-Associated-with-Tuberous-Sclerosis-Complex.html

2. Thiele E, Wong M. Cannabidiol (CBD) treatment in patients with seizures associated with tuberous sclerosis complex: a randomized, double-blind, placebo-controlled phase 3 trial (GWPCARE6). Presented at: AES 2019. December 7—10, 2020; Baltimore, Maryland. Abstract 1.293.