Abstracts

Rationale: Dravet syndrome is a rare, drug-resistant epilepsy that first manifests in otherwise healthy infants and is often linked to SCN1A gene mutations that result in multiple seizure types, motor deficits, and cognitive and behavioral problems. The FDA approved stiripentol in 2018 for the treatment of seizures associated with Dravet syndrome in individuals ≥ 2 years taking clobazam. Prior to this approval, stiripentol was used under compassionate use until April 2019. While stiripentol has been marketed in Europe since 2007, information regarding demographics post compassionate use has been limited in the US. To understand the prescribing behavior for stiripentol in the US, a retrospective analysis was performed over 2 years.

Methods: The data for this retrospective analysis was collected between April 29, 2019 and April 30, 2021 from the single specialty pharmacy dispensing stiripentol. All data in the analysis were without patient or prescriber identifiers; these included age, gender, weight, diagnosis code, status (naïve/transition from Compassionate Use), dosage, specific dosing instructions, and insurance coverage. Demographic and dosing data collected were based upon the last prescription filled. Concomitant drugs were captured during the specialty pharmacy’s discussions with patients. The start and end dates were either the date the specialty pharmacy captured the data or patient-reported dates.

Results: There were 548 patients aged from 0 – 42 years old. Fifty-three percent were female. Of the 548 patients, 48% of patients transitioned from Compassionate Use and 52% were new to stiripentol. The majority of individuals were covered by commercial payors (n = 276, 52%) and government payors (n = 235, 44%) insurance.

Dosing data was analyzed in 535 patients. Some patients were excluded from the analysis because of incomplete dosing data or missing weight information to calculate the daily dose. The overall average dose was 32 mg/kg/day, which is further broken down by age group in Table 1.

Concomitant medication usage information was collected in 527 patients. Clobazam was used by 84.6% of patients. Other concomitant drugs reported that are not indicated for use with stiripentol included valproic acid (56%), cannabidiol (39.8%), and topiramate (19.5%).

Conclusions: This analysis of prescription data during the first 2 years of transition from compassionate use availability following FDA approval provides several new insights. The number of patients new to stiripentol was similar to the transitioning Compassionate Use patients. Over half of the patients used commercial payor insurance coverage. Most prescription doses were lower than the approved dosing for stiripentol of 50 mg/kg/day in 2 or 3 divided doses. With dosage amounts progressively decreasing with age, US prescribing behavior outlook may be similar to those seen in Europe.

Funding: Please list any funding that was received in support of this abstract.: Biocodex, Inc.