GWPCARE5 Trial Update: Dravet Syndrome

Ian Miller, MD: For the abstract presented by Dr Jonathan Halford, et al, regarding the long-term efficacy and tolerability in patients with Dravet syndrome over the 3-year interim analysis, it shows that the efficacy of cannabidiol in Dravet syndrome is maintained, and that’s really nice to see over a 3-year outcome because that’s a very long-term outcome study in Dravet syndrome, which is a very hard-to-treat form of epilepsy.

It gives us that additional data. It also shows that the adverse-effect profile of the medication over that period of time was relatively comparable with the adverse-effect profile we saw in 12-week primary outcome study, which led to FDA approval. As a result, we didn’t get surprised by any rare or idiosyncratic reactions to the medication, which is really nice to see over a 3-year period.

The significance of the study is that they followed the patients out for a longer period of time, and they also permitted a higher dose of cannabidiol at the highest-used dosing interval. They went up to a dosage of 30 mg/kg per day, which was not permitted in the study that led to FDA approval, and they followed them longer. The combination of those 2 factors really gives us more peace of mind and relief about the adverse-effect profile for cannabidiol.

The incidence of dropout due to adverse effects was only about 9%, which is remarkably low for a seizure medication. Seizure medications are often part of life for a person who has epilepsy. They really want to do everything they can to avoid them, and they really don’t like to stay on them if there are adverse effects. The fact that 91% of individuals were willing to stay on them, when you take adverse effects into account, is pretty remarkable.