Source: Flickr user Brett Levin.

Since last summer, enthusiasm surrounding marijuana's potential as a treatment for epilepsy has led to investors more than doubling their money in Insys Therapeutics (NASDAQ:INSY).

Insys Therapeutics is one of the only publicly-traded companies pursuing the development of prescription drugs based on the chemical cannabinoids found in marijuana, but the reasons for owning shares in the company stretch far beyond its marijuana program.

Building a foundation
While competitors such as GW Pharmaceuticals are fully focused on developing marijuana medicines, Insys Therapeutics is also working on a slate of non-marijuana therapies.

Insys already markets Subsys, an oral spray formulation of the opioid fentanyl. The drug's ease in dosing and rapid onset have made it the top-selling fentanyl product on the market for managing chemotherapy pain. Last year, Subsys' sales grew 124% to $219.5 million; that momentum carried over into 2015, with Insys reporting first-quarter sales of the drug rising 74% year over year, to $70.5 million. 

Subsys' success has allowed Insys to remain free of debt and to build up cash on its balance sheet. Last quarter, the company reported adjusted net income of $23.5 million, or $0.63 per share. That enabled Insys to increase its cash on the books since December by $18.3 million, to $124.4 million. Since Insys also has no debt, the company has plenty of financial flexibility to usher along drugs in its pipeline that could fuel future growth.

Source: Insys Therapeutics,

Leveraging success
Subsys' unique sublingual spray formulation differentiates the drug from competing fentanyl products, and Insys believes it can leverage that spray technology for other medications.

Earlier this year, the company reported plans to initiate three separate phase 3 trials that will evaluate spray formulations of two other medications.

Those trials include a sublingual spray formulation of buprenorphine for use in pain relief for patients undergoing bunionectomy procedures, as well as a combination of buprenorphine and naloxone for treating addiction. A third trial testing a spray formulation of ondansetron, an anti-nausea drug, is also scheduled to begin this year.

And there's marijuana, too
Insys is also close to filing for approval of oral dronabinol, a liquid variation of the marijuana drug Marinol, which is used to treat chemotherapy-induced nausea and weight loss in HIV patients.

Oral dronabinol is a synthetic version of the THC found in marijuana, and Marinol has been approved for use in the U.S. since the mid-1980s. If the FDA eventually grants it the go-ahead, Insys believes oral dronabinol represents a $200 million annual market opportunity.

Insys is also developing its cannabidiol oral solution to help patients with rare forms of epilepsy. The company hopes this year to begin phase 3 trials studying this drug in patients with Dravet syndrome and Lennox-Gastaut syndrome. Since both of these syndromes are tough to treat, the FDA has granted orphan drug designation for these indications that provides Insys with tax credits and waives fees when filing for FDA approval.

Looking ahead
Insys is also evaluating marijuana as a potential treatment for pediatric schizophrenia and brain cancer. Whether all of these marijuana studies succeed remains a big and important question. However, given that Insys is already making money and could roll out additional spray formulated medicines to drive sales higher, Insys could be a good stock to buy regardless of how the marijuana studies pan out.