Real-World Data Back Stiripentol’s Effect on Seizures in Dravet Syndrome

A retrospective study spanning 10 U.S. epilepsy centers found that adding stiripentol (Diacomit; Biocodox) to existing regimens reduced seizure frequency, status epilepticus episodes, and emergency health care use in patients with Dravet syndrome (DS). The findings, stemming from the STIRUS study, were presented at the 2026 Child Neurology Society (CNS) Annual Meeting, held October 14-17 in Montreal, Quebec, Canada.¹

The analysis was led by investigators including Elaine C. Wirrell, MD, professor of neurology and chair of the division of child and adolescent neurology at Mayo Clinic. For context, stiripentol is approved in the US for seizures associated with DS in patients 6 months of age and older who are taking clobazam, but real-world data on its use outside clinical trials has been limited.

STIRUS retrospectively analyzed 98 patients who started stiripentol after August 2018 and continued treatment for at least 3 months, drawing on records from 10 U.S. epilepsy centers. Investigators compared seizure frequency, status epilepticus episodes, rescue medication use, emergency department visits and hospitalizations, and quality of life across 3 periods: the 3 months before stiripentol initiation, the first 3 months on treatment, and the final 3 months of follow-up.

The median age at Dravet syndrome diagnosis was 15 months, and patients started stiripentol at a median age of 6.9 years. At baseline, patients were taking a median of 3 concurrent medications, most commonly clobazam (n = 81), cannabidiol (n = 45), valproate (n = 42), fenfluramine (n = 24), and levetiracetam (n = 23). Of note, 90% of patients had bilateral convulsive seizures, and 34% had experienced status epilepticus.

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Overall, stiripentol significantly reduced the frequency of bilateral convulsive seizures (odds ratio, 2.16; P <.006), and 44% of patients reported a marked reduction after 3 months of treatment. The prevalence of status epilepticus declined from 33 patients at baseline to 16 during the first 3 months on stiripentol and 14 during the final 3 months (odds ratios >2.8; P <.003 for both comparisons), and the median duration of status epilepticus episodes fell from 30 minutes to 15 minutes.¹

Rescue medication use declined significantly after stiripentol initiation (odds ratio, 3.5; P <.0001), as did emergency department visits and hospitalizations (odds ratio, 4.0; P <.0001). More than half of patients, 52%, showed improved quality of life over the follow-up period.

In terms of safety, somnolence and decreased appetite were each reported in 50% of patients, consistent with stiripentol's known tolerability profile; investigators reported no unexpected safety concerns. The authors concluded that stiripentol significantly reduced seizure burden, status epilepticus episodes, and health care utilization, with earlier use, particularly in infants, potentially lessening disease-related morbidity further.¹

Stiripentol, marketed as Diacomit by Biocodex, first received FDA approval in 2018 for patients with DS ages 2 years and older taking clobazam; the agency expanded that approval in 2022 to include patients as young as 6 months.² The drug's use in Dravet syndrome, then known as severe myoclonic epilepsy in infancy, was established by a placebo-controlled trial published in 2000 that found it reduced seizure frequency when added to valproate and clobazam.³

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REFERENCES
1. Fayazi M, Gwin K, Wirrell E, et al. Real-world use and effectiveness of stiripentol in U.S. patients with Dravet syndrome: results from the STIRUS study. Abstract 87. Presented at: 2026 Child Neurology Society Annual Meeting; October 14-17, 2026; Montreal, Quebec, Canada.
2. Antiseizure Drug DIACOMIT Now Approved for Children as Young as 6 Months. News release. Biocodex, Inc. Published September 21, 2022. Accessed October 16, 2026. https://www.biospace.com/antiseizure-drug-diacomit-now-approved-for-children-as-young-as-6-months
3. STICLO study group. Stiripentol in severe myoclonic epilepsy in infancy: a randomised placebo-controlled syndrome-dedicated trial. Lancet. 2000;356(9242):1638-1642. doi:10.1016/S0140-6736(00)03157-3