If marijuana advocates hope to win over voters in tough-to-convince states like Florida next year, they'll need more than anecdotal evidence of marijuana's medical benefits.

Instead, they'll need hard science that proves marijuana's efficacy in large, controlled studies. Fortunately, they may have just gotten some of what they need from the researchers at GW Pharmaceuticals plc (GWPH), a biotechnology company that is evaluating marijuana's potential to treat rare forms of epilepsy.

Re-inventing marijuana use
There's a seismic shift in marijuana use that is taking the drug from the land of lava lamps and tie dyes to the world of beakers and white lab coats, and GW Pharmaceuticals is at the forefront of that movement.

The company already markets a marijuana drug that is derived from the cannabinoid THC in Europe, where it's sold under the brand name Sativex as a therapy for multiple sclerosis spasticity, and it's researching marijuana's potential as a treatment for a host of important indications including cancer pain, diabetes, and schizophrenia.

But it's GW Pharmaceuticals work on using the non-psychoactive part of the plant known as CBD to treat epilepsy that could be closest to winning approval in the United States.

The company is working in tandem with researchers at various epilepsy centers in America to evaluate whether or not its CBD-based drug Epidiolex can bring new hope to patients suffering from severe forms of the disease.

So far, it appears that it can.

Research will be presented at the American Academy of Neurology's annual conference later this month showing that 137 patients with tough-to-treat forms of epilepsy, such as Dravet syndrome and Lennox-Gestaut syndrome, saw the number of epileptic seizures fall by more than half after taking Epidiolex for three months.

That's an impressive finding given that patients with these variations of epilepsy typically have few treatment options that deliver significant improvements.

Instead, epileptics are often treated with a slate of anticonvulsants that fail to adequately control the disease in up to one-third of all patients. The study results are even more impressive considering that all 137 patients participating had failed on these other prior medications.

Ongoing work to be done
The epilepsy results will be presented by lead researcher Orrin Devinsky, the director of the New York University Langone Comprehensive Epilepsy Center on April 22 in Washington, D.C. While that research is likely to create a groundswell of optimism among doctors and patients, considerably more work needs to be done before GW Pharmaceuticals can file for an FDA approval of Epidiolex.

That work includes generating positive results in phase 3 research trials -- the final phase of trials that are required prior to filing for FDA approval. GW Pharmaceuticals kicked off two of these phase 3 trials evaluating Epidiolex in Dravet syndrome patients earlier this year, and it plans to launch phase 3 trials for Lennox-Gestaut syndrome patients later this year.

Results from the placebo-controlled Dravet syndrome trials could be available by year end, and the Lennox-Gestaut results would likely come in early 2016. If these trials pan out, then GW Pharmaceuticals could conceivably file for FDA approval next year.

The FDA has already committed to quickly evaluating such an application for approval. Last year, the agency awarded orphan drug and fast track designation to Epidiolex for use in Dravet syndrome patients. That designation means that the FDA will provide GW Pharmaceuticals with ongoing insight into the preparation of its filings and a six month review period for its decision -- four months shorter than usual.

Carts and horses
Although the results being presented at the conference are incredibly intriguing, a bit of caution may be warranted. The results were not part of a placebo controlled study, and that could mean that phase 3 results from the company later this year may not show similar levels of improvement.

It also shouldn't be ignored that despite previous signs of success in treating cancer pain, GW Pharmaceuticals reported a high profile phase 3 failure in that indication earlier this year. GW Pharmaceuticals has other studies ongoing evaluating the use of its marijuana drug in cancer pain that could contradict that failure, but the stumble is a reminder that we're still a ways away from being able to say that Epidiolex definitively proves that marijuana can be used to successfully treat epilepsy.