Source: Flickr user Matthew Kenwrick.

GW Pharmaceuticals (NASDAQ:GWPH) is conducting some of the most advanced research on the use of marijuana cannabinoids to treat disease, and the company recently updated investors on its progress. Here are the most important things that GW Pharmaceutical executives had to say about their marijuana program.

No. 1: Progress on epilepsy continues
According to CEO Justin Gover:

Part A of the Dravet syndrome trial has completed with 34 patients randomized and only two withdrawals during the study. We are now in the process of collecting the data for review by the independent safety monitoring board. Following their advice the pivotal efficacy and safety part B of the study is due to start in March. The other pivotal studies one in Dravet and two in Lennox-Gastaut syndrome are due to start shortly thereafter, subject to the same recommendation from the safety monitoring board.

Medical marijuana advocates are excited about the potential use of the marijuana cannabinoid CBD to treat epilepsy patients, and GW Pharmaceuticals' epilepsy research is currently studying the use of a CBD drug named Epidiolex in both Dravet syndrome and Lennox-Gastaut syndrome. Patients suffering from these two relatively rare indications have few treatment options other than anticonvulsants, and the prognosis for patients is typically poor. 

GW Pharmaceuticals has already completed enrollment in the first part of its phase 2/3 trial (part A), and plans to use its findings to design the second part of the trial. Given that the company expects to have a slate of epilepsy trials under way soon, patients and advocates should have more clarity into CBD's potential in epilepsy by this time next year.

No. 2: Overcoming failure in cancer
"As we reported in January, the first of three phase 3 cancer pain trials did not meet the primary endpoint of demonstrating a statistically significant difference from placebo," said Director of Research and Development, Stephen Wright.

Medical marijuana advocates have been vocal supporters of marijuana's pain-easing potential in cancer patients; however, those advocates were likely disappointed to learn that GW Pharmaceuticals' study of its THC cannabinoid drug Sativex failed to outperform a sugar pill in a large, late-stage trial.

Sativex's inability to beat out placebo in reducing pain counters findings from previous trials, so there's still a chance that Sativex is an effective pain treatment.

The company plans to report results from a second Sativex cancer pain trial next quarter, but that study is identical in design to this first failed trial. That may suggest that it's the company's third and final cancer pain trial -- which was designed differently -- that could offer the best chance for success. Regardless, we should know whether or not Sativex has a shot at making it past FDA watchdogs as a cancer pain drug by the end of this year.

Source: GW Pharmaceuticals.

No. 3. Controlling schizophrenia
"A pure CBD product in the treatment of schizophrenia, for which a phase 2 study is under way with results expected also in the second half of 2015," said Wright.

One of the most contentious debates among researchers is marijuana's role in schizophrenia. For years it was commonly held that marijuana served as a trigger for the disease; however, evidence is mounting that could suggest that CBD could help ease the disease's symptoms.

Because schizophrenia is a disease that affects about 1% of the population, and because controlling schizophrenia is difficult, the opportunity for GW Pharmaceuticals in this indication could prove to be big. According to pharmacy benefit manager Express Scripts, schizophrenia is the eighth most costly indication in terms of drug spending.

It's still too early to tell whether or not a medical marijuana product such as the one being studied by GW Pharmaceuticals will ever capture a share of that spending, but the fact that the company expects to offer up mid-stage trial results later this year suggests that we'll soon have more insight.

Looking forward
Thanks to legislative action, medical marijuana advocates are heading into 2015 with significant momentum. Twenty-three states have passed legislation that supports the use of marijuana for medical purposes, but even more states could follow through with legislation if medical marijuana drugmakers, like GW Pharmaceuticals, can prove marijuana's benefits through controlled clinical trials. That suggests that medical marijuana industry watchers might be well served to keep a close eye on this company's progress.