Following up on an eventful 2016, this year brings plenty of value-creating events for marijuana stocks. Here's what to look for with Insys Therapeutics (INSY), GW Pharmaceuticals (GWPH) and Corbus Pharmaceuticals Holdings (CRBP -5.17%).

Schedule this

Last July, Insys Therapeutics gained approval from the Food and Drug Administration for Syndros, its pharmaceutical version of tetrahydrocannabinol (THC) -- a component of marijuana -- that treats anorexia associated with weight loss in AIDS patients and cancer-induced nausea and vomiting. But the company can't sell the drug yet, because it still needs to wait for the Drug Enforcement Agency to schedule it.

Marijuana grown in a greenhouse

Image source: Getty Images.

The different levels of scheduling -- from Schedule 1 to Schedule 5 -- are based on the likelihood that the drug will be abused; they determine how regulated pharmacies and doctors are in distributing the drug. Schedule 2, for instance, doesn't allow doctors to prescribe refills, so the doctor has to call in a new prescription each time the patient runs out.

Because Syndros is used on an as-needed basis, it may not be a major issue if Syndros is given a Schedule 2 designation, because one prescription may last multiple months. It's more important that the DEA issue the schedule -- any schedule -- so Insys Therapeutics can start selling Syndros.

An approval by year's end?

GW Pharmaceuticals plans to apply to the FDA for approval of its marijuana-derived cannabidiol (CBD), Epidiolex, to treat two childhood epilepsies, Lennox-Gastaut syndrome and Dravet syndrome, "at the end of the first half of 2017." Depending on how close to the end of that first half the application is submitted, and on whether the FDA gives Epidiolex a priority review -- which results in a review period of six months from the time the FDA accepts the application -- the drug could be approved this year.

Even if Epidiolex isn't approved until 2018, this year will still bring other opportunities for GW Pharmaceuticals to rise in value. Investors will get data from one more clinical trial in patients with Dravet syndrome later this year. While management has said the FDA doesn't need data from that trial for approval in the U.S., it could be helpful for approvals overseas. Assuming the clinical trial is positive, the additional data could further convince doctors that Epidiolex helps Dravet syndrome patients, as well as helping GW Pharmaceuticals gain reimbursement with insurers.

This quarter, investors will get to see data from two phase 2 trials testing other marijuana-derived drugs: a study of Sativex in children with spasticity due to cerebral palsy, and another testing a THC-CBD combination for the treatment of recurrent glioblastoma multiforme. Later in the year, GW Pharmaceuticals will release data for a third drug, cannabidivarin (CBDV), which is being tested in adults with partial-onset epilepsy.

More data coming soon

Corbus Pharmaceuticals expects to release data from a phase 2 study testing Resunab in patients with cystic fibrosis this quarter. The drug already proved successful in treating systemic sclerosis, a chronic autoimmune disease that affects about 90,000 people in the U.S. and Europe. Adding cystic fibrosis would almost double the potential number of patients Resunab could treat.

Resunab is an endocannabinoid mimetic which activates the cannabinoid receptor type 2 (CB2) that, in turn, reduces the inflammation that leads to fibrosis. The reduction of symptoms in patients with systemic sclerosis is a good sign that Resunab is working the way Corbus Pharmaceuticals thinks it is, but it doesn't necessarily mean that the drug will help cystic fibrosis patients, since the two diseases could have different thresholds for how much CB2 activation helps.

Corbus is also testing Resunab in patients with dermatomyositis and lupus, so even if cystic fibrosis fails, the company has additional opportunities beyond systemic sclerosis.