There's been debate over the use of marijuana in epilepsy patients since the use of a special marijuana strain crafted by the Stanley Brothers won widespread media attention in 2013 for helping control seizures in Charlotte, a Colorado child with Dravet syndrome, a rare form of epilepsy.
Until now, the Food and Drug Administration (FDA), the regulator in charge of reviewing scientific data and approving or rejecting drugs based on their merits, had stayed mum on the use of marijuana in epilepsy patients. That changed this week when it gave a thumbs-up to GW Pharmaceuticals' (GWPH) Epidiolex, a purified oral formulation of cannabidiol (CBD).
Big marijuana news
Because the FDA is a science-based organization that approves drugs based on their proven ability to be safe and effective in well-controlled trials, its OK is a big validation of the fact that CBD can help epilepsy patients.
The FDA didn't approve the use of CBD purchased in medical-marijuana dispensaries, but its nod does allows doctors to prescribe and patients to take Epidiolex nationwide, without fear of reprisal, even in states where marijuana is still illegal.
One of 60 cannabinoids found within the marijuana plant, CBD is the same chemical the Stanley Brothers focused on when crafting Charlotte's Web from hemp. It's also the main cannabinoid found in other marijuana strains that have been designed for medical use, including Katelyn Faith, Harlequin, and Remedy.
Unlike tetrahydrocannabinol (THC), CBD isn't psychoactive, so it doesn't cause euphoric highs. Instead, CBD appears to control seizures by interacting with multiple neurotransmitters and neuromodulators.
It's not fully understood why CBD treats epilepsy so effectively, but GW Pharmaceuticals' research suggests CBD's benefits are the result of "a cumulative anti-convulsant effect, modulating a number of endogenous systems including, but not limited to neuronal inhibition (synaptic and extrasynaptic GABA channels), modulation of intracellular calcium (TRPV, VDAC, GPR55), and possible anti-inflammatory effects (adenosine)."
Regardless of its mechanism of action, Epidiolex's ability to reduce seizures in epileptics is remarkable. In clinical trials involving hundreds of patients with Dravet syndrome and Lennox-Gastaut syndrome, two types of child-onset epilepsy, patients saw about a 40% decline in seizures.
Delivering on promise
GW Pharmaceuticals has been researching marijuana as medicine since the 1990s, but up to now its attempts to prove the efficacy of marijuana-derived medications have been mixed.
The company won European approval of a THC-based drug, Sativex, for controlling muscle spasms in patients with multiple sclerosis. However, large, placebo-controlled trials in cancer pain failed to prove Sativex effective in 2015.
Because Sativex isn't approved for use in the United States yet, Epidiolex will be the company's first marijuana medicine that's available in America. It remains to be seen how widespread the use of Epidiolex will be, but an argument can be made that it will be a top-seller.
Epidiolex is initially only approved for Dravet syndrome and Lennox-Gastaut syndrome; however, doctors can prescribe FDA-approved medications off-label, so Epdiolex could win more widespread use in epilepsy. If so, that could translate into a bonanza for GW Pharmaceuticals and its investors.
There are 2.2 million Americans suffering from epilepsy, including 470,000 children, and seizures are inadequately controlled in about one-third of patients, despite widespread use of existing antiepileptics.
What to watch now
The Drug Enforcement Agency (DEA) still lists marijuana as a Schedule I drug. But following this approval, Epidiolex could secure more favorable scheduling, and if it does, that could reduce barriers to access. The DEA has 90 days to issue an interim final rule regarding Epidiolex's scheduling; while there's no telling what the agency will do, GW Pharmaceuticals would consider a Schedule IV ruling a big win. A Schedule II decision would be a loss, because Schedule II drugs can't be as easily refilled.
Overall, Epidiolex's approval is a big advance for the medical marijuana movement. It's likely to win support among doctors and patients in this tough-to-treat patient population, and it helps pave the way for more companies to conduct their own clinical trials in other indications. Just how big of a commercial hit Epidiolex may be won't be known for a while, though. Investors may want to approach this marijuana stock with cautious optimism.