GWPCARE5 Trial Update: Lennox Gastaut Syndrome

Ian Miller, MD: Regarding the GWPCARE5 study you asked about, the abstract and the data report, the subsequent analysis of individuals that were affected by Lennox-Gastaut Syndrome—which is a severe form of epilepsy—and looks at the longer-term efficacy of the medication as well as tolerability after participating in a randomized double-blind placebo-controlled trial. And the notable findings in the study are that it was efficacious and well tolerated.

One of the issues with efficacy that we always struggle with in epilepsy is the problem of transient efficacy. Sometimes when we find a seizure medication, it stops working, and that’s a problem because the seizures come back and the individual is no better off for having taken it.

What I was heartened to see in this study is that the efficacy for the cannabidiol was sustained. If anything, it actually was a little better than the initial analysis early on. Obviously this didn’t have a placebo-controlled component in the open-label continuation. And with this analysis, however, the efficacy definitely did not drop below the results reported in the first randomized, double-blind placebo-controlled trial with the primary outcome of 12 weeks. And as they looked at it further, it seems like if anything, it only got better. This was in combination with the fact that the adverse-effect profile was not notably worse. This included in the study, the ability to use a dosage of up to 30 mg/kg per day by the investigator.

Some study subjects were exposed to that; others were not. But even when the dosage was permitted to be at that level, the number of patients who completed the study was still quite high for an anticonvulsant drug trial. And the adverse-effect profile was very reasonable relative to other medications that are offered.

The significance of this data is that they were collected over a longer period of time than the initial phase 3 study, which led to FDA approval. So it’s bringing new information about the long-term efficacy and tolerability of the medication. And I was really happy to see that the efficacy was maintained, and it seemed like it was very robust. Almost seemed like it got better over time. And the tolerability was similarly good.

The adverse effects that we saw on the randomized placebo-controlled clinical trial were very similar to what we saw in the longer-term follow-up analysis, and it’s really nice not to have surprises come up as the medication is being used at higher doses.