Long-Term Data for Cannabidiol in Dravet Syndrome

Anup Patel, MD: Another important study presented in abstract form was the long-term safety and efficacy data for patients on cannabidiol for Dravet syndrome. These are patients who have Dravet syndrome; participated in the pivotal, randomized, double-blind, placebo-controlled trials; and were able to go into the open extension. These patients were followed for a very long period, and now we have those data. Their mean dose was about 22 mg/kg per day, so it was similar to what the label has for the patients who are being given this medication in a commercial format. Once again, the adverse effect profile was very similar to what we saw during the pivotal trials, and nothing new emerged from those studies.

In addition, the efficacy was maintained. The median seizure reductions from baseline were similar to what we saw in the pivotal trials. They were in the 45% range and higher for convulsive seizures. That was the primary end point for this study. What we’re able to show is long-term use of cannabidiol in this format is still efficacious for patients with Dravet syndrome, and no new adverse effects emerged after patients were treated over that period. Specifically, these data went up to 156 weeks. These were very long-term data supporting the use of this medication without any new adverse events developing.

Additional important points, as far as safety and efficacy, are that this is a good study to look at long-term exposure to this medication in patients who are commonly treated with other antiseizure medicines that are commonly given to patients with Dravet syndrome. The 3 most common concurrent antiseizure medications in this study were clobazam, valproate, and stiripentol. That is something you’re going to see. The adverse effect profile was not more significant because these patients were on these concomitant medications, and efficacy and safety were still maintained throughout the duration of treatment with this medication.