Marijuana Medical

Image source: Getty Images.

After years of research involving large, scientifically controlled studies, marijuana-derived medicine may be finally coming of age. If so, GW Pharmaceuticals (NASDAQ:GWPH) and Insys Therapeutics (NASDAQ:INSY) -- two publicly traded drugmakers that are researching marijuana medicine -- could benefit handsomely. 

So far, however, it's only GW Pharmaceuticals' shares that are on the upswing. A troubled past that includes investigations into Insys Therapeutics' marketing of the opioid pain-killer Subsys has caused its shares to crash more than 50% in the past year. Meanwhile, GW Pharmaceuticals shares have more than doubled on reports that its marijuana drug, Epidiolex, successfully reduces seizures in rare forms of epilepsy.

Let's take a closer look at why these two stocks have been heading in different directions.

Man With Money Falling Getty Images Happy Retiree Raining Money

Image source: Getty Images.

GW Pharmaceuticals delivers wins

In 2015, GW Pharmaceuticals reported that its THC-based medicine Sativex failed to beat a placebo in phase 3 studies evaluating its use in cancer pain patients. While that failure cast doubt on the future of marijuana as medicine, a wave of success this year has ignited optimism that marijuana could reshape how doctors treat rare forms of epilepsy. 

Epidiolex, a purified version of a non-psychoactive chemical cannabinoid found in marijuana known as cannabidiol, or CBD, has been proven to effectively reduce monthly seizure rates in patients diagnosed with both Dravet syndrome and Lennox-Gastaut syndrome. 

GW Pharmaceuticals reported in March that patients participating in a Dravet syndrome trial saw a 39% decline in their monthly seizure rate and since then, the company has reported significant declines in seizure rates for patients diagnosed with Lennox-Gastaut syndrome participating in two separate trials.

In the first Lennox-Gastaut trial, drop seizures in Epidiolex patients declined 44%, and in the second trial, drop seizures declined by 42%.

The results are potentially transformative given that both Dravet syndrome and Lennox-Gastaut syndrome are particularly hard to treat. For example, patients participating in the second Lennox-Gastaut trial had previously tried and failed an average of seven anti-epileptic medicines.   

Although the addressable patient population diagnosed with these rare forms of epilepsy is small, the wins suggest that CBD may play a significant role in the future in treating epilepsy. As a result, GW Pharmaceuticals' share price has more than doubled this year.

Man Thuumbs Down Gettyimages

Image source: Getty Images.

Struggling to get back on track

In July, Insys Therapeutics' won a FDA green light to begin marketing Syndros, a liquid formulation of the long-standing marijuana medicine marinol. Marinol is used to treat anorexia in AIDS patients and chemotherapy-induced nausea and vomiting in cancer patients. Syndros' oral dosing provides dosing and bioavailability advantages that could allow it to win a significant share of the $200 million marinol market.

Despite Syndros' potential to boost sales, Insys Therapeutics shares have fallen sharply this year because of ongoing investigations into the company's marketing of Subsys, a commonly used fentanyl spray. Subsys is approved for use in breakthrough cancer pain, however, a series of revelations show that the company's sales team engaged in practices to boost Subsys' use in other pain indications. 

Last November, CEO Michael Babich was shown the door following a CNBC expose on the investigations into reported kickbacks to doctors and since then, EVP and Chief Operating Officer Dan Brennan has left the company and former district sales manager Jeffery Perlman has been arrested. Last month, Insys CEO and founder John Kapoor announced he'll be stepping down as soon as a successor is found, too.

The fallout comes at a particularly tough time for the company. Rising concern over opioid abuse has led to a significant drop in demand for fentanyl drugs, including Subsys.

In the second quarter, Subsys sales tumbled 13.5% year over year to $67.1 million, reversing a long-standing trend of double-digit sales growth in previous periods. Subsys' sales decline puts additional pressure on the company to hit the ground running with Syndros and to advance other drugs in development, including a buprenorphine spray and CBD products for epilepsy -- something that may be jeopardized by the company's revolving leadership.

A big year ahead

GW Pharmaceuticals plans to file for FDA approval of Epidiolex in Dravet syndrome and Lennox-Gastaut syndrome early next year and that timeline suggests that the company could launch Epidiolex in late 2017 or early 2018. The company is also studying Epidiolex in other forms of epilepsy, and trial results from those studies could also be announced in the coming year. 

Meanwhile, falling opioid prescription volume or a stumble out of the gate for Syndros could keep Insys Therapeutics back on its heels. Additional news regarding investigations into Insys' past marketing practices and trial results could cause Insys Therapeutics' shares to swing wildly in the coming year.

In both of these cases, the coming year may be pivotal. A market cap of $2.7 billion sets the bar pretty high for GW Pharmaceuticals' Epidiolex. The bar is set pretty low for Insys Therapeutics, but it needs to get leadership in place that can resolve the Subsys overhang and capitalize on its various research programs.

Todd Campbell owns shares of Insys Therapeutics. Todd owns E.B. Capital Markets, LLC. E.B. Capital's clients may have positions in the companies mentioned. Like this article? Follow him on Twitter where he goes by the handle @ebcapital to see more articles like this. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.