Abstracts

Rationale: Understanding the real world use, dosing and titration of rufinamide, an antiepileptic drug (AED) indicated for the adjunctive treatment of seizures associated with Lennox-Gastaut syndrome in children aged 4 years and older and adults, is important. According to the U.S. Prescribing Information (USPI), the target dose of rufinamide for children is 45 mg/kg/day or 3,200 mg/day, whichever is less, and for adults, a maximum dose of 3,200 mg/day. Using a retrospective analysis of pharmacy claims, we conducted a study to evaluate rufinamide use, dosing, and concomitant AED utilization in patients treated for seizure disorder. Methods: Continuously enrolled patients with medical and pharmacy benefits in the Optum™ database, who had at least two prescription claims for rufinamide, were identified from January 2009 to September 2013. Of the total number of patients with rufinamide prescription claims (n=1,589), 361 patients met the inclusion criteria for the study. Data was extracted 6 months prior to and 12 months following the index prescription. Rufinamide dosing, duration of therapy, and concomitant AED use in children (age 1-17) and adults (>18), was examined. Results: Rufinamide was typically prescribed within 151-180 days from the first epilepsy claim. At index, 66% of patients were prescribed rufinamide in combination with another AED while 34% were prescribed rufinamide alone. The average starting dose of rufinamide in children was 698 mg/day in combination and 699 mg/day when prescribed alone. The average maximum dose in children was 1,092 mg/day and 1,113 mg/day, respectively. For adults, the initial dose was 1,231 mg/day in combination and 1,257 mg/day alone, and the maximum dose was 1,949 mg/day and 1,989 mg/day, respectively. The primary change following index prescription dose increase, typically at 69-95 days, and the mean number of changes in the followup ranged from 1.6 to 1.9. Regarding discontinuation, 16.1% of patients discontinued rufinamide at the first change, at an average of 159 days. For duration of therapy, 37% of patients remained on drug during the 12 month followup. Some variation in the choice of AED prescribed in combination with rufinamide (Table 1) was observed, and most patients were prescribed 2-4 AEDs. Conclusions: The analysis provides an important snapshot of the real world prescribing of rufinamide. The results indicate that rufinamide was prescribed soon after the first claim of epilepsy but at a dose that was less than what is recommended in the USPI. Similarly, dose titration did not appear to follow the recommended schedule, both in size of increase and time to change. Regarding discontinuation of rufinamide, the proportion of patients who stopped therapy at the first change was small, suggesting that patients tolerated the titration. However, the low initial dose and slow titration may affect patients attaining optimal treatment. The limitations using claims to understand dosing and titration of medications are well documented, so the current analyses will require further exploration.