Abstracts

Rationale: Few studies have prospectively determined seizure free outcomes in people with medically resistant focal epilepsy followed for extended durations. The Human Epilepsy Project 2 (HEP2) is a multicenter observational study that prospectively tracked seizure outcome for up to 36 months. Subjects were comparable to patients typically enrolled in randomized controlled trials of novel therapies. We now report the seizure free outcomes in our patients._x000D_
Methods: The HEP2 study assessed the seizure outcomes over 18 to 36 months in medically resistant subjects with focal epilepsy recruited from 10 U.S. epilepsy centers starting 7/31/2018. Subjects met the following qualifications: between the ages of 16 and 65 years at time of enrollment, experienced failure of adequate trials of 4 anti-seizure medicines (ASMs), having at least 2 focal seizures per month (at least 1 observable) for the 3 months prior to study enrollment, and receiving at least 1 ASM at baseline. During the study, each subject’s care provider directed changes in treatment. Baseline seizure frequency was calculated retrospectively using the pre-HEP seizure calendar. Each subject provided prospective seizure data through My Seizure Diary and/or monthly check-ins with a study coordinator. Seizure free periods in terms of 3-month epochs were recorded and compared to the total number of seizure activity epochs._x000D_
Results: Of the 146 subjects enrolled, 120 subjects (72 females and 48 males) provided ≥3 months of evaluable prospective seizure data, 110 provided ≥6 months, and 86 provided ≥12 months. Mean monthly retrospective baseline seizure frequency was 35.6 (median = 11; range, 2-1200). Demographics of subjects with and without seizure free epochs is provided in Table 2. Overall, 668 3-month epochs, 306 6-month epochs, and 125 12-month epochs were available for analysis. Of these, during 5.24% of all 3-month epochs, 3.59% of 6-month epochs, and 2.4% of 12-month epochs subjects reported complete seizure freedom (Table 1). 13%, 6.3%, and 3.5% of subjects with available data had at least one 3, 6, or 12 month seizure free epoch, respectively._x000D_
Conclusions: Subjects with medically refractory epilepsy have a small but meaningful opportunity to achieve seizure freedom employing existing therapies. These results should be kept in mind when analyzing long-term results of novel therapies.

Funding: The HEP2 study was funded by UCB, Neurelis, and SK Life Sciences.