GW Pharma's cannabis-based drug comes up short in ulcerative colitis

GW Pharmaceuticals' ($GWPH) in-development treatment for ulcerative colitis missed its primary endpoint in a midstage trial, a setback for the U.K. drugmaker and its pipeline of cannabinoid treatments.

The drug, GWP42003, is an oral capsule that contains both cannabidiol and tetrahydrocannabinol (THC), active ingredients derived from cannabis. In a Phase II pilot trial involving 60 patients with uncontrolled ulcerative colitis, 41% of those in the treatment arm achieved disease remission compared to 30% taking placebo, a difference that was not statistically significant.

Furthermore, of the 29 patients randomized into the GWP42003 arm of the study, an eyebrow-raising 12 dropped out due to side effects GW described as "minor THC-related adverse events such as dizziness."

But, on the bright side, the 17 patients who remained--a group GW is calling the protocol-compliant population--charted marked benefits on the study's secondary goals, beating out the placebo group in patient- and physician-reported assessments of disease severity.

GW R&D Director Stephen Wright

"The results support the further investigation of GWP42003 and have provided useful pointers as to how this further investigation should best be done," GW R&D Director Stephen Wright said in a statement. "In addition, the relatively poor tolerability of the dosage form used in this study suggests that further reductions to the THC content may be helpful."

The Phase II miss dings the potential of GWP42003, but it likely won't harm the thesis at the heart of GW's R&D efforts: that cannabis-based drugs can treat a wide array of diseases.

The biotech's most promising prospect is Epidiolex, a purified cannabidiol treatment for a rare form of epilepsy. The drug is designed to suppress seizures in patients with Dravet syndrome, a rare, treatment-resistant type of childhood epilepsy. GW, which is touting positive physician-reported results for the drug, plans to kick off a Phase III trial this month. Beyond Dravet syndrome, GW is developing Epidiolex for the rare Lennox-Gastaut syndrome, another severe, drug-resistant form of childhood epilepsy.

GW has crafted a pipeline based around its proprietary cannabinoid development platform, anchored by the Bayer-partnered Sativex, which is approved in Europe to treat muscle spasms in multiple sclerosis patients. In the U.S., GW is working with Otsuka Pharmaceuticals to get the spray-delivered treatment FDA-approved to treat cancer pain.

- read the results