Marijuana advocates aren't the only ones cheering wins in 2016, investors in the medical marijuana company GW Pharmaceuticals (GWPH) are also shouting for joy. Successful trials of its epilepsy drug Epidiolex, a purified formulation of the marijuana cannabinoid CBD, has led to the company's stock posting eye-popping returns in 2016. Will investors be similarly rewarded next year?

In this clip from The Motley Fool's Industry Focus: Healthcare podcast, analyst Kristine Harjes is joined by contributor Todd Campbell to discuss how this marijuana stock is overcoming the odds to deliver out-sized returns for its shareholders.

A full transcript follows the video.

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This podcast was recorded on Nov. 18, 2016.

Kristine Harjes: The second company we wanted to talk about today is a company in that is up 70% year to date, which, while not as good as 200%, I would still take that and be very thankful for it. 

Todd Campbell: Are we going to use the M-word, Kristine? (laughs) 

Harjes: Are we? Do you want to go for it?

Campbell: Marijuana! (laughs) 

Harjes: Yes, this is a marijuana stock. (laughs) It almost makes me cringe to say that, because we have said so many times on here that there are no good marijuana stocks to invest in, or hardly any. But this stock is kind of an exception to the rule. It's a legitimate company, which you can't say about 99% of marijuana stocks. Its name is GW Pharmaceuticals.

Campbell: Right. Shares have increased by more than 80% this year. A little bit like the stock we were just talking about, last year, 2015, was a tough year for the company. They were conducting studies, basically evaluating the use of cannabinoids, or the chemical compounds found in marijuana, to treat various conditions. Last year, they had huge studies in cancer pain fall flat, which made a lot of people -- including, admittedly, myself -- very doubtful that they would be able to deliver positive trial results in 2016 in some of these other indications they were evaluating. And I was wrong on that.

Harjes: This is actually such a parallel with the story of Exelixis, where they had this one drug, Sativex, that had hardly any sales, and they tried it in cancer pain and it failed, and people started to doubt them. And then you had this huge "but," where all of the sudden, they try something else and it really works.

Campbell: Yeah, "but ..." And that "but" is a drug called Epidiolex. How should we pronounce that?

Harjes: That sounds great to me. I'm thankful for our listeners' forgiveness for our pronunciations.

Campbell: That drug is a formulation of the cannabinoid CBD. Sativex is THC, which is the psychoactive ingredient in marijuana, and CBD is the non-psychoactive ingredient. What they evaluated Epidiolex in was Dravet syndrome and Lennox-Gastaut syndrome, which are two rare forms of epilepsy that are exceptionally hard to treat. Patients participating in these trials failed on an average of seven anti-epileptics before turning toward this drug. And yet, despite it being tough to treat, patients participating in this trial who were given this drug saw 40%, roughly, reduction in monthly seizures, which is a tremendous potential improvement over what patients are enduring today in these indications.

Harjes: Absolutely. This drug had a couple of different spikes throughout the year. One of them came just recently after the election. Healthcare as a whole, especially biotech, got a big boost from Trump winning the United States presidency. Do you think that was warranted with GW?

Campbell: No. GW Pharmaceuticals isn't selling their drug through medical dispensaries. These are FDA-quality pathways that they're approaching the market through. These medicines would be prescribed by doctors, filled at regular pharmacies. They would be FDA-approved for use in these indications. Whereas, with medical marijuana, treatments are not as vetted and proven scientifically to deliver these kinds of benefits. That doesn't mean that GW Pharmaceuticals, if Epidiolex is approved, wouldn't face competition from patients who may decide to go in and buy Charlotte's Web, which is a very high-CBD strain, through a dispensary. But it's not really a direct line of sight, in my view, between the votes we saw on the 8th approving medical and recreational marijuana in a number of states and GW Pharmaceuticals' ultimate success or failure.