Perampanel useful in hard-to-manage myoclonic seizures

The AMPA receptor antagonist perampanel appears effective in reducing the frequency of myoclonic seizures in patients with predominantly idiopathic generalised epilepsy (IGE), an Australian-led study has shown.

The international PERMIT study, published earlier this year, has already demonstrated that perampanel is effective and generally well tolerated in people with focal and/or generalised epilepsy.

Now in a post-hoc analysis of the PERMIT study, comprising 156 patients with myoclonic seizures, investigators found the number of seizures per month decreased significantly between baseline and the last visit (mean decrease 64.9%; p<0.001).

“Similarly, the number of days with myoclonic seizures per month decreased significantly between baseline and the last visit, the mean decrease being 64.8% (p<0.001),” the study said.

“At 12 months, the responder rate was 89.5% (77/86) and the rate of seizure freedom since the previous visit was 68.8% (64/93); the proportions of patients with unchanged and worsening seizure frequency were 5.8% (5/86) and 3.5% (3/86), respectively.”

Similar rates were observed at a subsequent follow-up visit.

Writing in the journal Seizure, the investigators said current treatment options for patients with myoclonic seizures were limited.

“The findings of this study are encouraging given that myoclonic seizures are challenging to treat and few ASM treatment options are currently available.”

The study found AEs were common (46.8%) with dizziness/vertigo, irritability and somnolence reported most frequently. There were no new or unexpected safety signals.

AEs led to discontinuation in 14.0% of patients over 12 months.

The investigators noted the trade-off between the large size and the limitations of PERMIT — more than 5,000 patients but from uncontrolled, retrospective analyses of real-world studies.

The study was led by Associate Professor Wendyl D’Souza, from St Vincent’s Hospital Melbourne and the University of Melbourne. He and some other co-authors have received research support or honoraria from Eisai Ltd who funded the study.

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