To describe diagnosis and treatment patterns in US patients with DS and LGS.

DS and LGS are childhood-onset epileptic encephalopathies associated with significant disability. Despite increased disease awareness among child neurologists, diagnoses may be delayed for various reasons. Limited evidence exists on current diagnosis and treatment patterns.

The Adelphi DS & LGS Disease Specific Program collected data from June 2022–March 2023, using physician-completed patient record forms, based on patient charts. Summary statistics were used to describe patient characteristics. Medians (IQR) are reported throughout.

Data for 62 patients with DS and 104 with LGS were collected. Age (years) was 7.5 (3.8–13.0) for DS and 14.0 (9.0–18.0) for LGS patients and 51.6% (DS) and 60.6% (LGS) were male. Age (years) at first seizure: 1.2 (0.6–2.2) for DS and 2.5 (1.2–5.4) for LGS. Most patients were diagnosed with another seizure disorder before confirmatory diagnosis of DS (83.9%) and LGS (79.8%) at age 3.0 (1.3–4.7) and 6.0 (2.8–10.0), respectively.

Levetiracetam and valproate were the most common antiseizure medications across the first 3 lines of treatment; first-line: (DS, 35.5% and 17.7%, respectively; LGS, 19.2% and 28.8%); second-line: (DS, 35.1% and 31.6%; LGS, 36.7% and 36.7%); third-line: (DS, 29.3% and 31.7%; LGS, 36.7% and 31.6%). Polypharmacy occurred in >60% of patients after first-line treatment.

Effectiveness at seizure control (DS, 90.3%; LGS, 96.2%) was cited most frequently for adding a medication at any line and lack of effectiveness (DS, 88.9%; LGS, 66.7%) was the most common reason for discontinuing a medication.

Levetiracetam and valproate were the most frequently used early-line medications. Misdiagnosis/delayed diagnosis of DS and LGS was common. Antiseizure treatment modification may be due to inadequate seizure control, potentially resulting in polypharmacy. Early diagnosis and effective early line treatments may help reduce the burden of polypharmacy and improve outcomes.